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Thursday, September 26
 

8:00am HST

CE 4 - Night Light Pollution Delays Flowering in Soybean and Cannabis
Thursday September 26, 2024 8:00am - 8:15am HST
As urban centers encroach on agricultural land, it is increasingly important to study the effects of light pollution on sensitive short day flowering crops such as Glycine max (soybean) and Cannabis sativa. Common responses to light pollution include delayed flower initiation and development, and Cannabis growers additionally speculate a myriad of other detriments as a result of light pollution. We conducted a series of studies with three soybean and ten Cannabis cultivars to elucidate responses to light pollution. Plant were grown under full-night light pollution ranging from 0 to 150 nanomols m-2 s-1 of cool white light or 0 to 40 nmols m-2 s-1 of red light at 660 nm. We found that continuous light pollution as low as 10 nmol m-2 s-1 from cool white LEDs delayed inflorescence initiation and development of the most sensitive Cannabis cultivars, while red light pollution as low as 5 nmol m-2 s-1 caused similar effects. In cultivars that did not experience a delay in inflorescence initiation, other plant characteristics including height and inflorescence development rate were negatively impacted. In soybean, flower delay in response to light pollution varied by cultivar but was reduced or absent in more modern lines, indicating that breeding may have selected against light sensitivity. Future growers must consider tolerance to light pollution during cultivar selection in order to avoid the detrimental impacts to short day crops.
Speakers
avatar for Madigan Eckels

Madigan Eckels

Utah State University
NA
Co-authors
BB

Bruce Bugbee

Utah State University
NA
MW

Mitch Westmoreland

Utah State University
NA
PK

Paul Kusuma

Utah State University
NA
Thursday September 26, 2024 8:00am - 8:15am HST
Coral 1

8:00am HST

EcoPhys 2 - Exploring the Effects of Irrigation Water Salinity on Physiology and Growth of Papaya (Carica papaya) in a Calcareous S
Thursday September 26, 2024 8:00am - 8:15am HST
In many tropical fruit production areas, including southern Florida, a rise in ocean levels resulting from climate change is anticipated to lead to greater inland intrusion of saltwater, thereby increasing salinity of the soil and/or irrigation water. Thus, knowing the salinity level of the soil or irrigation water that negatively impacts tropical fruit crops, including papaya, is important to alleviate salinity-induced damage to these crops. A study was conducted to evaluate physiological and growth responses of two papaya (Carica papaya L.) cultivars grown commercially in Florida (‘Red Lady’ and ‘Exp15’) to different irrigation salinity levels. Papaya seedlings were transplanted into 11.4-liter pots with Krome very gravelly loam soil; a calcareous soil collected from the papaya production area in south Florida. Each plant was manually irrigated three times per week with 1 liter of deionized water containing different concentrations artificial sea salt (Instant Ocean®) to obtain 4 salinity levels based on electrical conductivity (EC) of the irrigation water i.e., 0 (control), 3, 6, and 9 dS/m. Plants performance under different salinity levels was evaluated by determining net CO2 assimilation (A), stomatal conductance (gs), transpiration (E), the leaf chlorophyll index (LCI), and the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) on a weekly basis throughout the study. Normalized difference vegetation Index (NDVI) values derived from multispectral images were also collected weekly. After seven weeks, plants were harvested and leaf relative water content (RWC), leaf water potential, leaf area, and leaf, stem, and root dry weights were determined for all plants. Five weeks after treatments were initiated, for both cultivars, plants in the 6 and 9 dS/m treatments had lower A, E, gs, LCI, and Fv/Fm than plants in the other treatments. At the end of the experiment, plants in the 3, 6, and 9 dS/m treatments had significantly lower A, E, gs, LCI, Fv/Fm, leaf water potential, leaf area, and leaf, stem, and root dry weights than plants in the other treatments. Also at the end of the experiment, ‘Exp15’ plants in the 9 dS/m treatment had lower NDVI values than plants in the other treatments, whereas there was no difference in NDVI among treatments for ‘Red Lady’. There was no significant effect of salinity treatment on RWC. The findings suggest that 'Red Lady' and ‘Exp15’ papaya plants are unable to withstand salinity levels of 3 dS/m or higher in the calcareous agricultural soil of southern Florida.
Speakers
avatar for Ana Vargas

Ana Vargas

Biological Scientists III, University of Florida
Co-authors
AS

Ali Sarkhosh

University of Florida
NA
BS

Bruce Schaffer

University of Florida
DH

Dong Hyeon Kim

University of Florida
NA
MS

Muhammad Shahid

University of Florida
NA
YG

Young Gu Her

University of Florida
NA
YL

Yuncong Li

University of Florida
NA
Thursday September 26, 2024 8:00am - 8:15am HST
Lehua Suite

8:00am HST

FLOR 2 - Sustainability Beliefs and Practices in the United States Floriculture Industry
Thursday September 26, 2024 8:00am - 8:15am HST
Today’s environmental and social concerns – including climate change and economic inequality – push sustainability to the forefront of many business strategies, from tech companies to grocery retailers to flower farmers. To better understand the scope and limitations of sustainable practices among flower growers, wholesalers, retail florists, and floral suppliers, the research team administered an industry-wide survey. Sections of the survey delve into aspects of floriculture businesses throughout the United States, including scale of operations, current sustainability measures, motivations driving sustainability activities, and barriers preventing sustainable practices. The results indicate strong personal motivations for sustainability measures within floriculture, yet respondents perceived a lack of financial or regulatory incentives to implement such practices. A subset of results for growers are compared to a 2008 survey to assess changes in sustainability practices within domestic flower production over time. Regional variances in perceived access to resources and implementation of sustainability practices will also be discussed. Our study aims to identify key areas where progress has been made or can be made in the industry, including educational efforts and incentives to address the perception of risk when implementing sustainability practices. A subset of results for growers are compared to a 2008 survey to assess changes in sustainability practices over time within domestic flower production. Our study aims to identify key areas where progress has been made or can be made in the industry, including educational efforts to address the perception of risk when implementing sustainability practices and communicating benefits to consumers.
Speakers
avatar for Amanda Solliday

Amanda Solliday

PhD student, North Carolina State University
Hi, I'm a PhD student at NC State University conducting sustainability and climate research in cut flowers.
Co-authors
MK

Melinda Knuth

North Carolina State University
Thursday September 26, 2024 8:00am - 8:15am HST
South Pacific 3

8:00am HST

O/LT 2 - The Climate Ready Landscape Plants Project. Testing Plants For Drought Tolerance Across The Western U.S.
Thursday September 26, 2024 8:00am - 8:15am HST
The Climate Ready Landscape Plants project evaluates the performance of plants exposed to three different deficit irrigation treatments in six climate zones. The experimental fields are completely replicated at all of the sites with plants spaced in a 2m x 2m layout, 8 replicates per treatment, up to 15 taxa tested per site, and irrigation based on reference evapotranspiration (ETo) with treatments of 20%, 50%, and 80% of ETo. Irrigation applications consist of a fixed volume of water depending on soil plant available water as determined by the US Geological Survey maps accessed via SoilWeb. The interval between irrigations was determined by accumulating daily ETo modified by the treatment factor. Irrigation occurred when the trigger value was attained. Plants were installed in the fall and irrigated with sufficient water for establishment during the first irrigation season and treatments were imposed during the second irrigation season. Monthly during treatment, 6 qualitative assessments of each plant were conducted and measurements in three directions were recorded to calculate a Plant Growth Index until the end of the treatment period that typically concluded in October. A substantial effort was made to ensure site-to-site consistency of the qualitative assessments by developing a ratings rubric and conducting frequent site visits with project management to “calibrate” site staff conducting the evaluations. Open House Field Days were conducted during the treatment season to which horticultural professionals and Master Gardeners were invited to evaluate the plants. This provided additional data and introduced the plants to potential users. This project started in 2004 as a graduate student research project, was expanded periodically at UC Davis, and then duplicated in 2017 at the UC South Coast Research and Extension Center in Irvine, CA as the University of California Landscape Plants Irrigation Trials™ (UCLPIT) project. With an award from the USDA Specialty Crops Multistate Program in 2019, the project was expanded to the University of Washington, Oregon State University, Utah State University, and the University of Arizona which facilitates the comparison of plant performance in response to deficit irrigation treatments across the western region of the U.S. The data collected leads to recommendations for irrigating those plants that are used by homeowners and landscape irrigation managers and assists landscape designers and architects designing landscapes that are water conserving and complying with California's landscape water conservation regulation, the Model Water Efficient Landscape Ordinance (MWELO).
Speakers
LO

Lorence Oki

University Of California, Davis
Dr. Oki is a UC Cooperative Extension Specialist Emeritus. In 2004, Dr. Oki initiated the trial research program that has developed into the current UC Landscape Plant Irrigation Trials™ (UCLPIT). He currently leads the California Department of Food Agriculture / USDA Specialty... Read More →
Co-authors
DH

Darren haver

University of California
NA
KR

Karrie Reid

University of California
NA
LN

Lloyd Nackley

oregon state university
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
RC

Ryan Contreras

Oregon State University
SK

Soohyung Kim

University of Washington
US

Ursula Schuch

University of Arizona
YS

Youping Sun

Utah State University
Thursday September 26, 2024 8:00am - 8:15am HST
South Pacific 1

8:00am HST

OPB 1 - The Boons of Breeding at a Botanic Garden
Thursday September 26, 2024 8:00am - 8:15am HST
While many institutions have staff that dabble in plant breeding, the Chicago Botanic Garden is one of the only gardens to administer a breeding program dedicated to introducing ornamental perennials. A botanic garden possesses a wealth of resources not available to hobbyist breeders and other companies, providing key advantages that aid in cultivar development. Among these resources are staff members that support plant breeding with different fields of expertise, such as horticulture, production, propagation, and landscape design. Other resources include well-maintained breeding beds and greenhouses for crossing plants and growing progenies as well as a plant exploration program that conducts both national and global plant collection trips. Various lab facilities are available through the science department, including equipment and staff that can help with seed cleaning and banking, pollen banking, flow cytometry, and more. Because the Chicago Botanic Garden and its plant introduction program Chicagoland Grows® are non-profits, there is more freedom to work on lesser known genera. This contrasts with traditional industry breeding, which often focuses on well-established genera when introducing new cultivars. Using Baptisia (false wild indigo) as an example, we’ll explore some past breeding conducted at the Chicago Botanic Garden by Dr. Jim Ault and how this breeding will continue moving forward. This will illustrate how ornamental cultivar development is possible without modern genotyping methods and high input costs.
Speakers
JL

Justin Lombardoni

Chicago Botanic Garden
Thursday September 26, 2024 8:00am - 8:15am HST
South Pacific 4

8:00am HST

PH 3 - Assessing Apple Cultivar Responses to Low Oxygen Limit Determination Using Chlorophyll Fluorescence and Respiratory Quotient
Thursday September 26, 2024 8:00am - 8:15am HST
Dynamic controlled atmosphere (DCA) is a prominent technology used worldwide for long-term apple storage. In Washington, the adoption of DCA technologies to manage low oxygen levels is limited, partly because the benefits are not clearly demonstrated for some major cultivars, such as ‘Honeycrisp’ and new varieties like ‘WA 38’. The response of ‘Honeycrisp’, ‘Gala’, and ‘WA 38’ apples to lower oxygen levels was monitored monthly until 8 months of storage (1oC or 3oC) through chlorophyll fluorescence (CF) and respiratory quotient (RQ) by a stepwise decrease in O2 levels at each time point during 2023/2024 season. Ethanol and acetaldehyde concentrations were obtained from fruit juice before and after the lower oxygen limit (LOL) determinations. ‘Honeycrisp’ and ‘Gala’ apple cultivars showed differences in LOLs determined through CF or RQ. CF LOL for ‘Honeycrisp’ was approximately 0.3-0.2 kPa O2 compared to 0.1 kPa O2 for ‘Gala’ while RQ response occurred at 0.1 kPa O2 level in both cultivars. ‘WA 38’ apples displayed inconsistent CF responses at 0.3 and 0.4 kPa oxygen levels. Ethanol concentration increased after low oxygen stress irrespective of the cultivar. During the first month of storage and after the low oxygen stress, ‘Honeycrisp’ apples accumulated (in average) 120 ppm of ethanol, ‘Gala’ 2.92 ppm, and ‘WA 38’ 4.24 ppm. Towards the end of storage, the ethanol concentration showed an increase for ‘Gala’ (25 ppm), which was not observed for the other two cultivars. Small amounts of acetaldehyde were accumulated only in ‘Honeycrisp’ apples. This study highlights the different responses of apple cultivars to low oxygen stress during the lower oxygen limit (LOL) determination, with ‘Honeycrisp’ being the most sensitive one among the cultivars tested. Further seasons are needed to confirm these results and include the seasonal-dependent responses in each cultivar.
Speakers
HP

Hnin Phyu Lwin

Washington State University
Co-authors
CT

Carolina Torres

Washington State University
DR

David Rudell

USDA-ARS
NA
SA

Sadat Amankona

Washington State University-TFREC
I am a second-year Ph.D student at Washington State University-TFREC
Thursday September 26, 2024 8:00am - 8:15am HST
Nautilus

8:00am HST

TCHG 2 - Seed Your Future Horticultural Salary Survey
Thursday September 26, 2024 8:00am - 8:15am HST
What do careers in the horticultural industry pay? To answer this question, Seed Your Future (SYF) in cooperation with the American Floral Endowment (AFE) and North Carolina State University jointly launched an industry-wide salary survey program in Fall 2022. The survey collected salary and benefits information on a broad range of positions from CEO to seasonal workers as well as hiring trends for eight horticultural sectors: floriculture/greenhouse, florist, nursery, landscape, public gardens, fruit/vegetables and other edibles, garden center/markets, and horticultural services. More information on the sectors can be found at: https://research.seedyourfuture.org/. Average production salaries ranging from a low of $30,160 for fruit/vegetable production seasonal workers to $98,590 for public garden production manager. Pay for most positions was above $40,000. Pay for administration positions was higher and ranged from $46,740 for public garden merchandizers and $50,800 for landscape inventory managers to over $100,000 for fruit/vegetable production maintenance managers at $120,580, horticultural services research/development managers at $129,750 and horticultural services sales managers at $132,633. Needless to say, executive positions were the highest paid. While the average salaries for several positions were relatively low, the large range of salaries for those positions indicates that some positions had high pay, likely where employees had greater longevity. Salaries for many of the administrative-type positions were higher and potential horticulture students need to be aware that these positions are open to them as well. Indeed, these positions could be attractive to students as they would allow them to combine a love of plants and horticulture with various other interests such as business management, marketing, IT, graphic design, etc. Overall, the most common benefits for employees were paid time off, professional development and medical. Other common benefits provided include dental, vision, life insurance, and retirement. A host of other benefits reported by individual companies included Employee Stock Ownership Plan, profit sharing, bonuses, short-term/long-term disability, vehicle, phone, purchase discounts, flexible working environment, meals, and wellness days. The outlook is bright. Future hiring plans were mostly split between increasing hiring (51%) and hiring at the same rate (43%). Few businesses in either sector planned to decreasing hiring. For those looking for positions at either large or small business, horticulture has it covered. Of the businesses surveyed, 54% had 21 or more employees and 46% had 20 or fewer employees.
Speakers
JD

John Dole

North Carolina State University
Co-authors
JA

Jazmin Albarran

Seed Your Future
NA
Thursday September 26, 2024 8:00am - 8:15am HST
Kahili

8:00am HST

VCM 4 - Watermelon Rootstock Variety Trial to Understand the Impacts of Grafting on Watermelon Yield and Fruit Quality
Thursday September 26, 2024 8:00am - 8:15am HST
In California, watermelon grafting has been gaining tremendous popularity over other graft-eligible vegetable commodities especially among large-acreage growers. To maintain viability and continued popularity of grafted watermelons in California, we conducted a watermelon rootstock variety trial in 2023 to evaluate the impact of different types of locally popular rootstocks on watermelon yield and quality. Seven watermelon rootstocks, grouped into three distinct types: Interspecific hybrid squash (Cucurbita maxima x Cucurbita moschata), Citron (Citrullus amarus), and Bottled gourd (Lagenaria siceraria), were grafted with a 45-ct field scion, ‘Warrior’ by a commercial greenhouse located in Mills River, NC. All grafted and non-grafted seedlings were then mechanically transplanted into a commercial field near Modesto, CA on 19 April 2023. The trial was arranged as a randomized complete block design with four replications for each treatment. Each plot was 24 m long and contained 13 triploid plants, either grafted or not, alongside four grafted or non-grafted pollenizers. Four harvests were conducted from 25 July to 17 Oct with the help of farm crew. Total yields at each harvest and fruit quality from the first harvest were recorded and compared among rootstock-scion combinations. For quality assessment, fruit length and width were measured with a yardstick. Sugar content (ºBrix) was measured by scooping the central flesh of each halved fruit using a portable reflectometer. Flesh firmness was evaluated using a fruit penetrometer, with measurements taken at spots located one-third and two-thirds of the distance from the blossom end after halving the melon. Rind thickness at the blossom and stem ends were measured using a digital caliper. The overall impact of grafting resulted in an average increase of total yield by 51.5% compared to the non-grafted control (54.7 vs. 36.1 tons per acre) with the most significant difference occurred at the second harvest (27.0 vs. 14.8 tons per acre). Differences of fruit quality between grafted and non-grafted watermelons were primarily observed for fruit firmness. The significant increase of firmness (4.9 vs. 3.4 kg.cm-2) for grafted fruit was also confirmed based on the results of taste sensory evaluation. Slight increases of fruit width and stem end rind thickness after grafting were also found. No changes of ºBrix after grafting were detected. Overall, grafting has proven to be a reliable method for enhancing watermelon yield and maintaining fruit quality in California. Continuous needs assessment will be performed to monitor any pressing issues of watermelon grafting in California.
Speakers
FB

Fayrouz Buojaylah

University ofr California, Cooperative Extension Stanislaus County
Co-authors
ZW

Zheng Wang

Univ. of California Cooperative Extension
Thursday September 26, 2024 8:00am - 8:15am HST
Coral 2

8:00am HST

VSF 3 - Using Biochar As a Soil Amendment in Blueberry Production
Thursday September 26, 2024 8:00am - 8:15am HST
Biochar was tested as a possible soil amendment for blueberry production and compared with pine bark, which is commonly used as a soil amendment in blueberry production in the southeastern United States. Three treatments were established in sandy soil: biochar, pine bark (commercial standard), and control (non-amended soil) in which the variety ‘Farthing’ was planted. Soil characteristics were measured two months and 11 months after the incorporation of the amendments. Plant growth, and physiological traits were measured a year after planting. Biochar increased soil pH compared to pine bark and non-amended soil (control). Organic matter (OM) was higher in pine bark amended soil than in biochar. Biochar increased the Ca/Mg ratio 2 months after its incorporation and maintained P availability compared to the control and pine bark treatments. Eleven months after the incorporation of the amendments, the aluminum content was higher in the soil amended with biochar than in the control, whereas the Fe content was higher in the soil amended with pine bark than in the control. Manganese levels were lower in the pine bark-amended soil than in any other treatment. Plant growth and physiological responses were not affected by the incorporation of biochar as a soil amendment. However, plants established on the pine-bark amended soil had lower Soil Plant Analysis Development (SPAD), stomatal conductance, and maximum fluorescence than blueberry plants established on biochar or non-amended soil.
Speakers
ZR

Zilfina Rubio

University of Georgia
Co-authors
NE

Natalia Espinoza

University of Georgia
NA
Thursday September 26, 2024 8:00am - 8:15am HST
South Pacific 2

8:15am HST

CE 4 - Planting Density on the Growth and Production of Select Fruiting Crops in Aquaponic Systems
Thursday September 26, 2024 8:15am - 8:30am HST
Traditionally, aquaponic systems are used to produce leafy greens and herbs, while fruits and fruiting vegetables have been considered more difficult to grow due to additional nutrient requirements. When nutrients are not a limiting factor, the possibility of producing more fruit per square foot by increasing planting density is tempting as global populations increase and agricultural land area decreases. This study examined the effects of two different densities on banana peppers (Capsicum annuum L. var ‘Goddess F1’) and pole beans (Phaseolus vulgaris L. ‘Seychelles OG’) in a 20 sq ft grow bed. High densities consisted of 14 and 22 pepper and bean plants respectively, while low densities were 7 and 11 pepper and bean plants. Higher densities of peppers and beans produced more fruits than lower densities, while plant dry biomass of higher densities appeared to be lower than higher densities. Results suggest that higher planting densities of peppers and beans may increase harvestable fruit.
Speakers
TH

Teal Hendrickson

Oklahoma State University
Co-authors
BD

Bruce Dunn

Oklahoma State University
MS

Mitchell Sommer

Symbiotic Aquaponic
NA
Thursday September 26, 2024 8:15am - 8:30am HST
Coral 1

8:15am HST

EcoPhys 2 - Physiological, Biochemical, and Morphological Responses of Achachairu (Garcinia humilis) to Soil Salinity, Flooding, and
Thursday September 26, 2024 8:15am - 8:30am HST
Achachairu (Garcinia humilis (Vahl) C.D. Adams) is a slow-growing tropical fruit tree indigenous to the Amazonian forests in Bolivia. Each tree can produce over 15,000 fruit (400 kg/tree) harvested from cultivated and wild trees. It has significant horticultural potential because the fruit is considered delicious by many people who have tasted it. Thus, its commercial cultivation has extended to Brazil, Mexico, and Australia. The responses and tolerance of this species to abiotic stresses and the use of chemical priming to mitigate stress have never been reported. The study investigated the physiological, biochemical, and morphological responses to flooding and salinity, and the priming with 24-epibrassinolide (EB) to increase flooding and salinity tolerance of G. humilis. Three-year-old achachairu seedlings were used in several sequential experiments, including applying flooding, salinity, and EB priming in different combinations and durations. Physiological variables including leaf gas exchange [net CO2 assimilation (A), stomatal conductance of H2O (gs), and intercellular CO2 concentration (Ci)], leaf chlorophyll index (LCI), and the ratio of variable to maximum chlorophyll fluorescence (Fv/Fm) were measured. Leaf and root nutrient concentrations, antioxidant responses, reactive oxygen species (ROS), and lipid peroxidation (MDA) were also measured. Results showed that G. humilis is very tolerant of prolonged flooding of up to 30 d, medium levels of salinity of up to 6 dSm-1, and the combined effect of flooding and salinity. Tolerance to these stresses was exhibited by physiological, biochemical, and morphological responses, consistent with tolerance traits, such as maintaining basal levels of photosynthesis, ion homeostasis, and nutrient balances, robust antioxidant responses to counter ROS increases, and limited lipid peroxidation, all of which may help limit physiological damage. Application of 1.0 mg L-1 EB as a foliar and root-drench before flooding or salinity treatments increased the levels of tolerance of G. humilis to salinity and flooding, most likely by reinforcing antioxidant responses which helped decrease ROS and lipid peroxidation.
Speakers
avatar for Federico Sanchez

Federico Sanchez

University of Florida
Co-authors
AS

Ali Sarkhosh

University of Florida
NA
BS

Bruce Schaffer

University of Florida
HB

Haimanote Bayabil

University of Florida
NA
JH

Jonathan H Crane

University of Florida
MA

Muhammad Adnan Shahid

University of Florida
NA
Thursday September 26, 2024 8:15am - 8:30am HST
Lehua Suite

8:15am HST

FLOR 2 - Hydroponic, Soilless, and Field Produced Cut Flower Bouquets in the Northeast US.
Thursday September 26, 2024 8:15am - 8:30am HST
Cut flower production in the Northeastern United States is restricted by a short growing season. This impacts profitability for many growers and reduces the number of flower options available to them. While there is a reduced selection available, it can still be difficult to select which flowers are profitable and high yielding during a short season. For these reasons, field and controlled environment production of a variety of flowers that could be used in bouquets sold at markets or available for events was investigated. An early- and late-season arrangement was designed utilizing six different plants which could be harvested, assembled, and sold as a bouquet. Two synchronized trials occurred in 2024 with one in the field and the other in the greenhouse. The field plants were germinated indoors and transplanted in a full sun location in USDA Hardiness Zone 5a. The greenhouse plants were grown in three systems which included drip irrigated plants in containers with 4:1 coconut coir: parboiled rice husks, drip irrigated containers filled with rockwool GrowCubes, or hydroponic nutrient film technique. Greenhouse and field plants in both trials were assessed for germination rate and timing; time to flower; flower number, stem length, and subjective quality; and vase life utilizing 3 different floral preservatives. Plants grown in the greenhouse were also compared for adaptability to each growing system. Seeds for the early season bouquet were germinated in April and transplanted into their respective systems in May. Seeds for the late season bouquet were germinated in June and transplanted in July. This information can be used by cut flower growers in the Northeast to potentially extend their season and develop a market for designed “grow-a-bouquet” planting strategies.
Speakers
avatar for Jacob Schwab

Jacob Schwab

University of Maine
Co-authors
SB

Stephanie Burnett

University of Maine
NA
Thursday September 26, 2024 8:15am - 8:30am HST
South Pacific 3

8:15am HST

O/LT 2 - Performance of landscape shrubs under three irrigation levels in Arizona
Thursday September 26, 2024 8:15am - 8:30am HST
Fifteen taxa of shrubs growing in a field in Tucson, Arizona were irrigated with three levels of irrigation based on local reference evapotranspiration (ETo) to assess growth and plant quality. Plants established during 2021 under 80% of ETo and in 2022 were irrigated at 20%, 50% or 80% of ETo. Irrigation was applied 2, 9, and 15 times between April 1 and October 31, 2022 for the low, medium, and high irrigation, respectively. Best performing plants were Asclepias linaria ‘Monarch Magnet’, Dodonaea viscosa ‘Emerald Ice’, Eremophila glabra ssp. carnosa ‘Winter Blaze’, Ericameria laricifolia ‘Aguirre’, Hamelia patens ‘Sierra Red’, Leucophyllum frutescens ‘San Antonio Rose’, Leucophyllum langmaniae ‘Rio Bravo’, Tecoma ‘Red Hot’ and Rosmarinus officinalis 'Arp'. Irrigation did not affect plant growth of these nine taxa from April to October. Monthly visual quality assessment of some taxa was temporarily affected by irrigation, however, all performed acceptable or better at the low irrigation with the exception of Asclepias linaria ‘Monarch Magnet’ which had less than acceptable ratings in July and August for the low and high irrigation treatments. This taxa also had 62% mortality of plants under the high irrigation treatment between July and October. Hamelia patens ‘Sierra Red’ plants had frozen to the ground in winter 2022 and started to regrow in May. Five of the taxa (Dodonaea viscosa ‘Emerald Ice’, Eremophila glabra ssp. carnosa Winter Blaze, Ericameria laricifolia Aguirre, Hamelia patens Sierra Red, and Leucophyllum frutescens ‘San Antonio Rose’) maintained a high overall rating at the lowest irrigation treatment. Two field days were held in August and October 2022 where participants from the green industry and related sectors were invited to rate overall appearance, flowering and foliage of one representative plant from each taxa and irrigation treatment. Ratings from field day participants were similar to those from researchers during that month. Most participants’ favorite plants included the five taxa with consistently high overall ratings, only Dodonaea ‘Emerald Ice’ was among the top four favorites at both field days. All nine taxa tested are low water use shrubs that can grow in the landscape with 20% of ETo in the low desert in Arizona. However, some may benefit from additional irrigation during the hottest time of the year for optimum performance.
Speakers
US

Ursula Schuch

University of Arizona
Dr. Schuch is a Professor and Extension Specialist in Environmental Horticulture in the School of Plant Sciences. Dr. Schuch’s research focuses on plant selection and management strategies to conserve water, maintain plant health, and aesthetic function. She is the principal investigator... Read More →
Co-authors
DH

Darren Haver

University of California
NA
JS

Jared Sisneroz

University of California
JG

Jeffrey Gilbert

University of Arizona
NA
KR

Karrie Reid

University of California, Coop Ext
NA
LN

Lloyd Nackley

oregon state university
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
LO

Loren Oki

University of California
NL

Natalie Levy

University of California
NA
RC

Ryan Contreras

Oregon State University
SK

Soohyung Kim

University of Washington
YS

Youping Sun

Utah State University
Thursday September 26, 2024 8:15am - 8:30am HST
South Pacific 1

8:15am HST

OPB 1 - Mutagenesis of Hardy Hibiscus Using Ethyl Methanesulfonate
Thursday September 26, 2024 8:15am - 8:30am HST
Hardy hibiscus (Hibiscus moscheutos) are native herbaceous perennial plants. Due to their ornamental nature, variations in flowers, foliage, color, and variety are important. Mutagenesis is a method to increase variation in hibiscus plants, and ethyl methanesulfonate (EMS) is a common chemical mutagen that causes nucleotide substitutions. It converts guanine-cytosine pairs to adenine-thymine pairs. This study aimed to determine the EMS LD50 value for hardy hibiscus. The cultivar ‘Luna Red’ (Ball Horticulture) seed was used for treatment. An EMS LD50 determination study was performed using a factorial randomized complete block design. Three replications of 15 seeds were used for each treatment. EMS treatments consisted of 0, 0.25, 0.5, 0.75, and 1% EMS solution, each treated for 4, 8, and 12 hours to determine the ideal treatment concentration and time. The germination rate, survival rate, and height of seedlings were measured. The interaction effect for germination was insignificant when measuring concentration and time, so the LD50 values were identified for each time separately. The LD50 values for seedling survival were 0.64% EMS for 4 hours, 0.45% EMS for 8 hours, and 0.38% EMS for 12 hours. Notable phenotypic differences between the treated and control plants were observed. There was 92% greater two-month survival in the control plants compared to those treated with 0.75% EMS solution. The control plants were 90% taller at three months after treatment than the plants treated with 0.75% EMS solution.
Speakers
GG

Greta Gallina

University of Georgia
Co-authors
JR

John Ruter

University of Georgia
Allan Armitage Endowed Professor of Horticulture and Director, Trial Gardens at UGA
Thursday September 26, 2024 8:15am - 8:30am HST
South Pacific 4

8:15am HST

PH 3 - Understanding how physiological maturity and storage regime affect skin greasiness on WA 38 apples
Thursday September 26, 2024 8:15am - 8:30am HST
‘WA 38’ (Cosmic Crisp®) is the newest cultivar released by the Washington State University apple breeding program, and today in its sixth year of commercial production in WA. This cultivar has a high pack-out, i.e. highly colored fruit and few external and internal defects. Nevertheless, skin greasiness has been one of the main defects at harvest and postharvest, making waxing during packaging challenging, and affecting the cosmetic appearance. Since the starch degradation index is the only maturity index used to commercially harvest WA 38, the correlation between maturation and the onset of greasiness was studied during two seasons. Different maturity indices pre-and postharvest (firmness, soluble solid content, internal ethylene concentration (IEC), starch index (1-6), IAD values) along with skin greasiness were evaluated from 3-4 weeks before harvest (WBH) until 6 months in air (1oC) or controlled atmosphere (2.5 kPa O2, 1.5 kPa CO2) storage in fruit from four commercial orchards (#1 to #4; 2nd-4th-leaf). In 2022 and 2023 the rate of change of all maturity indices were block-dependent. In both years, IEC was detected in up to 80% of the fruit sampled four WBH in orchard #1 (average 0.3 ppm). At this same time point, only 16% of the fruit had started the starch degradation process (SI=1.5/6.0). The climacteric peak occurred 3-5 months into cold storage, and it was block-dependent. Greasiness on fruit skin was detected 2 WBH in two of the four orchards in 2022; in 2023 this occurred at commercial harvest. Overall, there was a higher incidence (and severity) of greasiness in fruit from air storage compared to CA, and in both cases, it increased during the shelf-life period (7 d at 20oC). The results indicate that fruit greasiness appears to be more related to fruit maturity and perhaps seasonal weather than tree age, nevertheless, additional seasons are needed to confirm these results.
Speakers
CT

Carolina Torres

Washington State University
Co-authors
DR

David Rudell

USDA-ARS
NA
OG

Oswaldo Gonzalez

Washington State University
NA
RM

Rene Mogollon

Washington State University
Thursday September 26, 2024 8:15am - 8:30am HST
Nautilus

8:15am HST

TCHG 2 - Horticultural and Plant Science Undergraduate Enrollment Summary Based on Food and Agricultural Education Information System (FAEIS) Data
Thursday September 26, 2024 8:15am - 8:30am HST
There’s a colloquial belief that horticulture-based enrollment in associates, bachelors, master’s, and doctoral degrees across the United States is waning. However, based on data compiled by the Food and Agricultural Education Information System (FAEIS), enrollment in horticultural bachelor majors went from the lowest enrollment in twenty years in 2018 to reach the highest point in last ten years in 2021 (3786 students). Bachelor’s degree enrollment in the West has steadily increased over the last ten years, while remaining level in the South. Enrollment in the Midwest has been generally declining for the last 20 years, while enrollment in the Northeast has been declining since 2015. However, both of the latter regions showed an increase in 2021. The West has the highest proportion of students enrolled in horticulture as a percentage (0.15%) of the total number of public high school graduates. Enrollment in horticultural master’s programs reached a peak in 2018 and has been variable since. Doctoral horticultural enrollment peaked in 2018 and 2019, declining in 2020 and 2021. Associates degree enrollment remained generally level from 2002 to 2019; however, it declined to a ten-year low point in 2020 and recovered by about 1/3 in 2021 to 432 students. Horticulture associates degree students have been predominantly male for the last ten years. However, when turfgrass enrollment is excluded, horticulture disciplines were 42% female and 58% male in 2021. At the beginning of the reporting period, in 2002, horticultural science bachelor programs were predominantly male (62%); by 2021 female enrollment increased to 48%. Over the last twenty years, the gender ratio in horticultural master’s degrees has remained quite consistent with the percent of female students ranging from 44 to 50% and of male students generally a little higher at 46% to 54%. In 2002 about a third of the doctoral graduate students were female, with the percentage increasing over time such that it reached close to parity by 2021 with 52% male and 47% female. Enrollment across all the fields and degrees, except for doctoral, is predominantly White, non-Hispanic. The percentage of bachelor Hispanic students has increased over time, representing the largest ethnic group after White, non-Hispanic. Asian student numbers also increased but not to the same level as Hispanic students. The percentage of non-US citizens in doctoral degrees has been quite high for many years across all the plant-related areas and was often the largest category. Implications are discussed.
Speakers
JD

John Dole

North Carolina State University
Co-authors
MK

Melinda Knuth

North Carolina State University
Thursday September 26, 2024 8:15am - 8:30am HST
Kahili

8:15am HST

VCM 4 - Effect of Biofungicides Containing Trichoderma and Grafting on Watermelon Productivity and Plant Health
Thursday September 26, 2024 8:15am - 8:30am HST
The goal of the project is to evaluate the potential of reducing chemical fumigation in California's watermelon production using grafting and Trichoderma-based biofungicide. Two field experiments in 2022 and 2023 were implemented within commercial watermelon fields in Stockton and Modesto, CA. Each trial included three rootstocks (Cobalt, Flexifort, and RS841) grafted onto a 45-ct scion (Summer Breeze). Two Trichoderma-containing products were applied to the grafted and nongrafted seedlings through tray soaking at one day before transplanting or field chemigation at 30 and 62 days after transplanting (DAT). The application rates for soaking and chemigation were 45 g.75 L-1 of water and 2.2 kg.ha-1, respectively. All seedlings were mechanically transplanted during mid-May of both years into a split-split plot design with the Trichoderma product as the main factor and application method as the sub-plot. All treatments were replicated four times. Each treatment row was 18.6 m long and contained ten grafted or nongrafted triploids and three grafted or nongrafted pollenizers. Vine health was visually assessed three times for symptoms associated with soil-borne fungal pathogens. Canopy coverage was measured starting at 22 DAT in 2022 and 40 DAT in 2023 and thereafter at an approximate interval of two weeks for a total of six measurements. Harvest was conducted three times in 2022 and twice in 2023 to analyze yield and quality differences among treatments. Runner and root samples were taken amid the harvest and shipped to the UC Davis Fungal Pathology Lab for further identification. Results indicated that the Trichoderma-containing bio-fungicides were not as effective as grafting on preventing vine decline and maintaining canopy coverage in both trials. The synergistic effects of grafting and Trichoderma inoculation provided some but limited benefits to plant health compared to the single factor of grafting. The overall influence of biofungicides on yield was also less notable than that of grafting regardless of application method. For fruit quality, grafting dominated the impacts over biofungicides on fruit firmness and rind thickness in both trials. Charcoal rot (Macrophomina phaseolina) with other putative co-infestations of Fusarium pathogens were diagnosed from nongrafted inoculation-free plots in 2022 while no significant soil-borne diseases were identified from 2023. Overall, grafting with multi-pathogen resistant rootstocks prove to be a reliable method for enhancing watermelon yield while maintaining crop health. More work is still needed to further explore the optimal application protocols tailored to grower’s farming system to maximize the effects of biofungicide.
Speakers
FB

Fayrouz Buojaylah

University ofr California, Cooperative Extension Stanislaus County
Co-authors
ZW

Zheng Wang

Univ. of California Cooperative Extension
Thursday September 26, 2024 8:15am - 8:30am HST
Coral 2

8:15am HST

VSF 3 - Effects of Aged Pine Bark Amendments on Container-Grown Southern Highbush Blueberry Growth and Substrate Properties
Thursday September 26, 2024 8:15am - 8:30am HST
Blueberry cultivation is rapidly expanding due to a dramatic increase in the consumption of the fruit. Soilless substrates have been viewed as a method to increase the production and geographic availability of this fruit. The identification of optimal and alternative substrates for the growth and development of the plants is needed to further guide a new and growing industry. The purpose of this study was to investigate the suitability of aped pine bark substrates amended with coconut coir or wood fiber substrates produced from Pinus taeda for container production of southern highbush blueberry (Vaccinium sp.). Plant linears of ‘Star’ blueberry were grown in 7.3-L pots filled with substrates consisting of coconut coir, aged pine bark, and hammermilled wood fiber. These were each amended at three rates (0%, 20%, 40%, 60%, 80%, and 100%). The plants were harvested at 0 days, 70 days, 140 days, and 365 days to assess their growth and development, measuring plant dry weight at each interval. Additionally, the substrate's physical properties, including particle size and air space, were measured during these four periods to determine the degradation and its influence on substrate quality over time. The findings of this study suggest that coconut coir usage can be reduced by using wood fiber or aged pine bark due to the positive effect on early vegetative blueberry growth.
Speakers
BS

Brandan Shur

PhD Student, Virginia Tech
Co-authors
BJ

Brian Jackson

North Carolina State University
NA
Thursday September 26, 2024 8:15am - 8:30am HST
South Pacific 2

8:30am HST

CE 4 - Planting Density and the Growth of Kale and Cilantro in Year-round Aquaponics
Thursday September 26, 2024 8:30am - 8:45am HST
Use of aquaponic systems has the potential to provide sustainable food production in a variety of environments year-round. Unfortunately, little is known about the limitations of aquaponics regarding planting density in a grow bed and year-round growing outside of tropical climates. This study evaluated two different planting densities of kale (Brassica oleracea var. acephala L. ‘Winterbor’) and cilantro (Coriandrum sativum L. ‘Cruiser’) in a 20 sq ft grow bed in a hoophouse grown during winter and early spring in Stillwater, OK, using bluegill (Lepomis macrochirus L.) as the fish species. High planting densities comprised of 54 kale plants and 68 cilantro plants. Low densities contained 36 kale plants and 48 cilantro plants. High planting density reduced fresh weight and chlorophyll content in kale, and chlorophyll content in cilantro. Additionally, total nitrogen content decreased at higher densities of kale while sulfur content increased. Cold weather mitigation was utilized in the form of a secondary plastic covering, extra light sources, and in-line heaters. Results suggest that higher planting density may be feasible for some leafy green and herb species while being detrimental to others and that year-round growing may be possible with the addition of inline water heaters.
Speakers
TH

Teal Hendrickson

Oklahoma State University
Co-authors
BD

Bruce Dunn

Oklahoma State University
MS

Mitchell Sommer

Symbiotic Aquaponic
NA
Thursday September 26, 2024 8:30am - 8:45am HST
Coral 1

8:30am HST

EcoPhys 2 - Plant Physiological and Root Anatomical Responses of Two Novel Olive Cultivars (‘Oliana’ and ‘Lecciana’) Under Salinity
Thursday September 26, 2024 8:30am - 8:45am HST
Soil salinity poses a significant challenge in agriculture, disrupting the normal functioning of plants by reducing water and nutrient uptake. Olive trees (Olea europaea), common in Mediterranean regions, exhibit moderate to high tolerance to salinity, varying by cultivar. Interest in cultivating olive trees is growing in Florida’s coastal areas, characterized by poorly drained soil and low-quality groundwater, leading to salt accumulation in the root zone. The high salinity levels in these areas present a significant challenge for crop cultivation. Therefore, introducing new salt-tolerant cultivars is necessary to mitigate salinity stress. This study aimed to evaluate the plant physiological and root anatomical responses of two novel olive cultivars - ‘Oliana’ and ‘Lecciana’ - to salinity stress, assessing their salt tolerance. Eight-month-old plants were grown in pots using a sand medium under greenhouse conditions and treated with varying salt concentrations (0 mM, 50 mM, and 100 mM). The experiment followed a completely randomized design with three replications, each consisting of nine plants. Plants were irrigated at weekly intervals with half-strength Hoagland solution to meet their nutrient requirements. Height and trunk diameter were measured at four different time points (0, 15, 30, and 45 days). At the end of the trial, plants were destructively sampled for biomass, nutrient content, and root anatomical measurements at the latter three time points. Significant differences were observed in height, trunk diameter, and nutrient contents between the control and NaCl treatments. These findings serve as a baseline for the commercial development of salt-tolerant olive cultivars.
Speakers
KH

Khalid Hussain

University of Florida
NA
Co-authors
JF

John-Paul Fox

University of Florida
LR

Lorenzo Rossi

University of Florida
Thursday September 26, 2024 8:30am - 8:45am HST
Lehua Suite

8:30am HST

FLOR 2 - Influence of UV-A Night Interruption Lighting on the Growth of Potted Basil Plants
Thursday September 26, 2024 8:30am - 8:45am HST
Basil (Ocimum basilicum) is one of the most popular culinary herbs sold in containers, but plants can quickly become tall, leggy, and unmarketable. Chemical plant growth regulators (PGRs) are not labelled for use on herbs, so there is a need for a nonchemical alternative. Ultraviolet radiation (UV) has been shown to be an effective alternative to PGRs on ornamentals, but there are no guidelines for effective use of UVA in potted basil production. Therefore, the objectives of this study were to determine the stage of development plants should be exposed to UVA radiation and the effective duration. Fifteen seeds of either sweet basil cultivars ‘Nufar’ or ‘Genovese’ were sown into 15-cm containers. The containers were placed in a glass-glazed greenhouse at 23 °C and under a 16-h photoperiod (LD) provided by LED supplemental lighting or under a 9-h photoperiod and 6-h night interruption lighting providing 385 nm of UVA radiation at an intensity of 20 µmol∙m–2∙s–1. Seeds were germinated for one week under either LD or UVA and then grown for 3 weeks under 10 treatments. The treatments included: LD entire time, LD 1 week-UV 2 weeks, LD 1.5 Weeks-UV 1.5 Weeks, LD 2 weeks-UV 1 week, LD 1 week-UV 1week-LD 1week, UV entire time, UV 1 week-LD 2 weeks, UV 1.5 weeks-LD 1.5 weeks, UV 2 weeks-LD 1 week, and UV 1 week-LD 1week- UV 1 week. Both cultivars responded differently to UVA radiation. Generally, plants grown under UVA from germination to harvest were the most compact. For example, ‘Genovese’ under UV entire time were 3.6 cm shorter than plants under LD entire. However, the chlorophyll content and dry mass of ‘Genovese’ were reduced by 33 and 53%, respectively, when exposed to UV entire compared to plants under LD entire. Additionally, if the treatment a plant ended under was LD, the chlorophyll content was generally higher than those ending under UV. Therefore, the most compact and green potted basil ‘Nufar’ and ‘Genovese’ were those grown under UV 2 weeks-LD 1 week.
Speakers
SB

Seth Benjamin

Michigan State University
Co-authors
RL

Roberto Lopez

Michigan State University
NA
Thursday September 26, 2024 8:30am - 8:45am HST
South Pacific 3

8:30am HST

O/LT 2 - Performance of Landscape Plants in California’s Central Valley Under Three Levels of Deficit Irrigation
Thursday September 26, 2024 8:30am - 8:45am HST
To develop landscape irrigation recommendations, 22 taxa of landscape plants were evaluated under three levels of deficit irrigation in a field trial. The taxa consisted of common horticultural perennials and shrubs including multiple cultivars of Hibiscus syriacus, Nandina domestica, Rosa spp., and Salvia spp. Based on anticipated plant size and cultural requirements, taxa were planted in one of three adjoining fields, with each field laid out in a grid pattern with either 2 or 3 meter spacing between rows and between individual plants in each row. All fields were covered with a 2-3” layer of chipped bark mulch. For each taxon, 24 individuals were planted with eight replicates per irrigation treatment in a randomized complete block layout with both taxa and irrigation treatment being randomly assigned. Plants were installed in March as bareroot inputs, with containerized plants installed from April to early June of 2021. Daily reference evapotranspiration (ETo) values from a local weather station were obtained from the California Irrigation Management Information System. The amount of plant available water (PAW) for the trial site was obtained from the US Geological Survey via the Soilweb application. In 2021, plants were irrigated regularly to fully establish their root systems. From April to October 2022, plants were irrigated with one of three deficit irrigation treatments equal to 80%, 50%, or 20% of ETo. The treatments functioned similarly to a crop coefficient to modify daily ETo values. The modified ETo values were used to estimate when 50% of PAW was depleted for each treatment. Irrigations occurred whenever this threshold was reached, with the volume of water applied being equal to 50% of PAW. The volume applied at each irrigation was constant across treatments with the frequency between irrigations varying by treatment. As a result, the 80% treatment was irrigated most frequently with the 20% treatment was irrigated thrice during the deficit period. Monthly during the deficit period, each plant was rated on six categories of aesthetic quality and length, width, and height measurements were collected to develop a plant growth index. Aesthetic performance between the treatments was compared using an ANOVA in conjunction with Tukey’s HSD post-hoc test in R. A majority of the taxa evaluated maintained acceptable aesthetic quality ratings on the lowest irrigation treatment. Two taxa evaluated, Lagerstroemia ‘SMNLCIBF’ Center Stage® Red and Rosa ‘ChewPatout’ Oso Easy® Urban Legend achieved high levels of aesthetic performance on the 20% treatment.
Speakers
JS

Jared Sisneroz

UC Davis
Mr. Sisneroz is the project manager of the UC Landscape Plant Irrigation Trials (UCLPIT) and the ‘Climate Ready Landscape Plants’ programs. He specializes in landscape plant water-use efficiency research and water resource management.
Co-authors
DH

Darren Haver

UC Agriculture and Natural Resources
NA
KR

Karrie Reid

UC Agriculture and Natural Resources
NA
LN

Lloyd Nackley

oregon state university
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
LO

Lorence Oki

University Of California, Davis
RC

Ryan Contreras

Oregon State University
SK

Soohyung Kim

University of Washington
US

Ursula Schuch

University of Arizona
YS

Youping Sun

Utah State University
Thursday September 26, 2024 8:30am - 8:45am HST
South Pacific 1

8:30am HST

OPB 1 - Genetic Sterilization of Four Invasive Ornamental Plant Species to Reduce Their Invasive Potential: Progress and Prospects
Thursday September 26, 2024 8:30am - 8:45am HST
Invasive ornamental plants have been considered as a major contributor to the spread of invasive plant species in the United States and many other countries in the world. To mitigate the economic and ecological impacts of invasive ornamental plants, we have focused on genetic sterilization of four invasive ornamental plants that are commonly produced and widely used in Florida to develop sterile, triploid cultivars as alternatives to the invasive types. Toward this goal, we have made progress in (1) artificial induction of tetraploids in nandina, privet, and porterweed, 2) developing and releasing new sterile, non-invasive triploid lantana cultivars, 3) understanding the reproductive biology of lantana, 4) developing and applying new genomic and molecular tools, and 5) testing alternative breeding approaches. By applying the mitotic inhibitor agent colchicine to germinating seeds or seedlings, we have induced tetraploids in nandina, privet, and porterweed. Tetraploid nandina showed significantly reduction in pollen stainability and seed set. Tetraploid privet lines exhibited thicker leaves with darker green color. Induced tetraploid nandina, porterweed, and privet lines have come into flowering, and interploidy crosses are made to produce new triploids. Using existing tetraploids in lantana, we have generated hundreds of new triploids, evaluated their male and female sterility, and released five sterile, non-invasive triploid cultivars, three of which have become popular replacements of the invasive types. Ploidy and molecular marker analyses have revealed the production of unreduced female gametes and apomictic seeds in lantana and natural sexual polyploidization in lantana and several other lantana species. Genome and transcriptome analyses have uncovered candidate genes that are linked or directly involved in the production of unreduced female gametes in Lantana. A number of diploid and tetraploid lantana genotypes with male or female sterility have been identified, which are being used to generate new triploids through open pollination. Additional tools are needed to rescue triploid embryos and screen breeding populations for high female sterility. These new plant materials, genetic and genomic resources, and molecular tools are expected to facilitate the genetic sterilization of lantana, nandina, porterweed, and privet. The findings may guide similar genetic sterilization efforts in other invasive ornamental plants.
Speakers
ZD

Zhanao Deng

University of Florida
Co-authors
AS

Alexander Schaller

University of Florida
NA
BP

Brooks Parrish

University of Florida
MF

Mohammed Fetouh

Tanta University
NA
SW

sandra wilson

University of Florida
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
Thursday September 26, 2024 8:30am - 8:45am HST
South Pacific 4

8:30am HST

PH 3 - Chlorophyll to Carotenoid Ratio Measured Nondestructively Correlates with Peel Pigment Content and Canopy Attachment Position of ‘Granny Smith’ Apples
Thursday September 26, 2024 8:30am - 8:45am HST
‘Granny Smith’ is an important apple variety for Washington State, where it has consistently been ranked as the third most-produced conventional cultivar since 2017. This apple variety is highly susceptible to sunscald, a sun-stress-related postharvest disorder that typically appears after three months of cold storage and makes apples unmarketable. Previous research has shown that a decrease in chlorophyll (chl) and an increase in carotenoids (car) in fruit peel have been associated with increased sunlight exposure and the development of sunscald. In order to assess the use of the chl/car ratio measured non-destructively with a Vis/NIR hyperspectral imager as a predictive index for sun exposure and sunscald development postharvest, ‘Granny Smith’ apples were picked from the periphery and inner canopy sections of the tree in 2021 and 2023 seasons. Fruit position in the canopy was documented during sampling and later correlated with hyperspectral images, chlorophyll, and carotenoid content in the peel. Subsequently, the collected peel sample was immediately frozen with liquid nitrogen and stored at -80°C. The chl/car ratio obtained from the reflectance values from the hyperspectral images was well correlated (r2 = 0.82) with the destructive determination of the ratio. Based on k-means clustering analysis, samples were grouped in accordance with the chl/car ratio and associated with fruit position on the tree. Apples with the highest chl/car ratios (1.4 to 1.7) were those located on the shaded portion of the trees. Apples with sunburn had the lowest chl/car ratios (0.1 to 1.2) and were located on the periphery of the tree. The results indicate that the chlorophyll to carotenoid ratio measured non-destructively at harvest can potentially be used for pre-storage sorting of ‘Granny Smith’ apples based on relative sun exposure and sunscald susceptibility, reducing postharvest losses. However, the establishment of the index reliability can benefit from additional years of data collection.
Speakers
avatar for Manoella Mendoza

Manoella Mendoza

WA State University
Co-authors
CT

Carolina Torres

Washington State University
DR

David Rudell

USDA - ARS
NA
LK

Lee Kalcsits

Washington State University
NA
RM

Rene Mogollon

Washington State University
Thursday September 26, 2024 8:30am - 8:45am HST
Nautilus

8:30am HST

TCHG 2 - Creating a Sustainable Vegetable Production Registered Apprenticeship Program: A Review of Curriculum Development and Lessons Learned
Thursday September 26, 2024 8:30am - 8:45am HST
The average age of principal farm operators was 58.1 years in 2022. With this reality, agricultural educators, extension personnel, and agricultural businesses are looking for innovative strategies to recruit and effectively train the next generation of diverse farm operators. On-farm apprenticeships in the U.S. are an increasingly popular method of training future farmers. However, these apprenticeships tend to be informal with little or no formal curriculum. Registered apprenticeships are an emerging trend in workforce development with rapidly increasing popularity among non-traditional trade occupations such as healthcare and information technology, but are still relatively new in agriculture. Registered apprenticeship programs have been shown to help recruit and develop a diverse and highly skilled workforce, increase productivity, allow employers to participate in training, and increase job retention. At the Center for Environmental Farming Systems (CEFS), we developed North Carolina’s first two registered agricultural apprenticeship programs. This session will cover the basic components of registered apprenticeships and how they can meet the growing need for skilled farm labor in vegetable operations. We will share how we created the Sustainable Vegetable Production Apprenticeship in North Carolina, including curriculum development, administrative logistics, and the opportunities and challenges associated with registered agricultural apprenticeships. We will also share reflections on the successes and challenges of our first three years of the program. During the first two pilot cohorts we had 123 applications with more than 40 applications from military veterans with 13 veterans joining the apprenticeship program. Our pilot program demonstrates that registered agricultural apprenticeships are a viable pathway for recruiting and effectively training veteran and minority beginning farmers.
Speakers
AC

Angel Cruz

North Carolina State University
Research Scholar at NC State University
Co-authors
KW

Kathleen Wood

North Carolina State University
NA
SK

Sara Kidd

North Carolina State University
NA
Thursday September 26, 2024 8:30am - 8:45am HST
Kahili

8:30am HST

VCM 4 - Canary Melons Cultigen Yield and Quality Evaluations in North Carolina, 2023
Thursday September 26, 2024 8:30am - 8:45am HST
Canary melons, Cucumis melo var. inodorus, are grown in the United States, with most acreage produced in California and Arizona. There is very limited production acreage in the southeastern United States, including North Carolina. No statistics are gathered by USDA on canary melons as this type of melon is truly a specialty melon. The goal of this study was to determine how well adapted canary melon cultigens are with respect to yields and quality when grown in North Carolina and to gauge the possibilities of producing this crop as a commercial option in the state. Fourteen cultigens were evaluated from eight different seed companies for yield and size over 16 harvests, flesh firmness and sweetness, and shape and rind characteristics. Statistical design was a randomized complete block with four replications and mean separation across measures was conducted using a LSD test at the P
Speakers
JS

Jonathan Schultheis

North Carolina State University
Jonathan Schultheis is a Professor in the Department of Horticultural Science at North Carolina State University. He has worked exclusively with North Carolina State University for over 35 years. He research and extension work primarily involves cucurbit crops and sweetpotatoes. Key... Read More →
Co-authors
AP

Andrew Pfefferkorn

North Carolina State University
NA
BS

Baker Stickley

North Carolina State University
BP

Brandon Parker

North Carolina State University
NA
SM

Stuart Michel

NC State University
Thursday September 26, 2024 8:30am - 8:45am HST
Coral 2

8:30am HST

VSF 3 - Ground Covers Shape Canopy Microclimate And Fruit Quality Components In A Blueberry Orchard
Thursday September 26, 2024 8:30am - 8:45am HST
Fruit quality parameters are typically reported by growers and researchers as an average. However, for small fruits such as blueberries, berry-to-berry variability in texture and flavor also impacts the consumer eating experience. The objective of this project was to capture how the uniformity of fruit quality parameters varies by 1) cultivar, 2) berry maturity, and 3) exogenous phytohormone applications. From 2022-2023, analyses were conducted on individual blueberries from multiple studies carried out in commercial fields in Michigan. First, we compared the uniformity of berry mass, diameter, firmness, and total soluble solids (TSS) in six northern highbush blueberry cultivars: “Duke,’ ‘Bluecrop,’ ‘Draper,’ ‘Calypso,’ ‘Elliott,’ and ‘Aurora.’ The uniformity was highest/lowest for berry mass in 'Bluecrop'/'Calypso', firmness in 'Bluecrop’ /‘Aurora,’ and TSS in 'Bluecrop'/'Elliott'. Second, we evaluated how changes in berry maturity due to delayed harvest affected the uniformity of berry mass, diameter, firmness, TSS, pH, total acidity (TA), TSS/TA, and aroma volatile concentrations in: ‘Duke,’ ‘Draper,’ and ‘Calypso’. Delayed harvest did not alter the uniformity of berry mass or TSS, but increased the uniformity of TA and TSS/TA in all three cultivars. The implications of delayed harvest on the uniformity of consumer liking scores will also be discussed. Finally, we tested whether exogenous application of multiple phytohormones impacted the uniformity of berry mass, diameter, firmness, and TSS in ‘Bluecrop’ and ‘Elliott’. Abscisic acid improved the uniformity of berry mass in 'Elliott,' but not firmness or TSS. Meanwhile, jasmonates had a limited effect on the uniformity of fruit quality parameters in 'Bluecrop'. The relative importance of the "average" and "uniformity" of fruit quality parameters will be discussed. We conclude that “uniformity” is an important component of fruit quality in blueberry.
Speakers
JV

Josh VanderWeide

Michigan State University
Co-authors
RI

Rufus Isaacs

Michigan State University
NA
SL

Sheng-yang Li

Michigan State University
NA
SV

Steve Van Timmeren

Michigan State University
NA
Thursday September 26, 2024 8:30am - 8:45am HST
South Pacific 2

8:45am HST

CE 4 - The Physiological Responses of Citrus Tree Roots to Soil Acidification
Thursday September 26, 2024 8:45am - 9:00am HST
Citrus tree roots are vital in nutrient uptake, water absorption, and overall plant health. Soil pH alters the availability and mobility of essential nutrients in the soil, thus influencing root physiological processes; like most plants, citrus trees are particularly vulnerable to changes in soil pH levels. The root apoplast is the plant component that first encounters adverse soil chemical conditions; hence, the conditions in the root apoplast determine a plant's response. This study aims to investigate the physiological responses of citrus tree roots to soil acidification, focusing on the impact of varying soil pH on root morphology, nutrient uptake, and overall root health. A controlled three-month greenhouse study was conducted at the Citrus Research and Education Center (CREC), hypothesizing that soil acidification will alter apoplast and phloem pH, reducing CLas population and root damage. This study was conducted utilizing citrus trees subjected to different soil pH levels. Forty trees were used and divided into four groups by pH treatment. These trees were irrigated thrice a week with pH treatments: 5.5, 6.5, 7.5, and 8.5. Soil acidity and alkalinity were routinely monitored with pH probe sticks. Once soil pH stabilized, feeder root samples were taken for apoplastic and phloem pH experiments. The pH-sensitive fluorescent stains were used for microscopy and vacuum infiltration to collect apoplastic fluids. Parameters such as root length, root surface area, and root diameter were measured to assess the morphological changes in citrus tree roots under different pH treatments. The concentration of essential macro- and micronutrients from the soil, plant tissue, and leachates was also analyzed weekly to evaluate nutrient uptake efficiency. Preliminary results indicate that soil acidification significantly improves fruit yield and feeder root density. By ascribing the specific mechanisms underlying root responses, this research provides valuable insights into the adaptive capabilities of citrus trees. It informs future practices to preserve the health and productivity of citrus groves.
Speakers
avatar for Duplicate Sambani

Duplicate Sambani

PhD Student, University of Florida
Co-authors
DK

Davie Kadyampakeni

University of Florida
NA
Thursday September 26, 2024 8:45am - 9:00am HST
Coral 1

8:45am HST

EcoPhys 2 - Continuous monitoring of tree water status using microtensiometers for irrigation management in olive
Thursday September 26, 2024 8:45am - 9:00am HST
Water scarcity is challenging agricultural production, demanding more precise and efficient irrigation management. Plant-based continuous monitoring has emerged as a promising approach for detecting water stress progression and optimizing irrigation. However, its practical implementation is hindered by the complex interpretation of the sensors’ outputs and plant physiological status relationships. Plant water potential is among the most robust water status indicators and is widely used for irrigation management. Nevertheless, its measurement is time-consuming and requires skilled personnel, making it difficult to have frequent assessments. In this study, we explored the potential of using continuous water potential sensing to quantify olive water status and its response to irrigation. Specifically, we compared continuous and discrete tree-level measurements of water status using microtensiometers and the pressure chamber, respectively. The microtensiometers proved effective in capturing tree water status dynamics, enabling a prompt assessment of the impact of irrigation practices. Preliminary analyses show a good linear correlation between midday trunk and stem water potential values obtained with microtensiometers and the pressure chamber, with the former being less than 0.5 MPa lower, a difference that could be attributed to the specific measurement of each technique. Importantly, having continuous data allows the extrapolation of several water status parameters which can provide key information in addition to the single timepoint midday values. Overall, this study suggests microtensiometers can be a useful tool to optimize water application in olive orchards.
Speakers
PG

Paula Guzman-Delgado

University of California Davis
Co-authors
AP

Amrit Pokhrel

University of California Davis
NA
ES

Emily Santos

University of California, Davis
NA
KS

Kosana Suvočarev

University of California Davis
NA
Thursday September 26, 2024 8:45am - 9:00am HST
Lehua Suite

8:45am HST

FLOR 2 - Evaluating Nighttime Application of Low Intensity LED Light Qualities to Suppress Downy Mildew Caused by Plasmopara obducens on Greenhouse Grown Impatiens
Thursday September 26, 2024 8:45am - 9:00am HST
Downy mildew (DM) of impatiens (Impatiens walleriana), caused by the oomycete, Plasmopara obducens, results in chlorosis, defoliation, and significant crop losses. Current management includes fungicides and genetic resistance. We applied photoperiodic light quality treatments to ‘Accent Premium White’ impatiens from seed sowing until flowering to limit DM and enhance plant quality. Seeds were sown in a greenhouse with a day and night greenhouse air temperature set point of 23 °C and a target daily light integral of 12 mol·m–2·d–1. A truncated 9-h short-day (SD) photoperiod was achieved by opening and closing opaque black cloth over individual greenhouse benches. Supplemental light-emitting diode (LED) fixtures provided 120 µmol·m–2·s–1 at plant height. Each bench was randomly assigned to one of nine discreet photoperiod treatments: 9-h SD (control) or 9-h SD extended by continuous 7-h LED fixtures emitting blue (405 nm), blue (445 nm), green (525 nm), red (660 nm), far-red (730 nm), white fixtures provided 100-nm waveband ratio (%) of 18:38:41:3 blue:green:red:far-red radiation, a screw-in LED flowering lamps provided 100-nm waveband ratio (%) of 7.6:15:72.4:5. Additionally, 6-h intermittent (1900 to 2200 HR and 0300 to 0600 HR) LED fixtures emitting ultraviolet-A (385 nm) were assigned to one bench. The total photon flux density was adjusted to 20 µmol·m–2·s–1 at plant height under black out curtains for each treatment. Impatiens were inoculated 70 days post sowing with a P. obducens sporangial suspension (2.6 to 3 x 105 sporangia·mL–1) until runoff on the abaxial side of the leaves. Afterwards, each plant was placed in a clear plastic bag containing 300 mL of Hoagland Solution (50%) and returned to its respective treatment. After 9-10 days post inoculation, the ratio of diseased leaves to the total leaf number was determined. In the initial experimental trial, control plants exposed to a 9-h SD treatment displayed an average disease incidence of 72.7%, while other treatment groups ranged from 30.6 to 98.3%. In the subsequent trial, control plants exposed to the same 9-hr SD treatment showed an average disease incidence of 42.6%, while other treatment groups ranged from 0 to 59.5%.
Speakers
avatar for River Dean

River Dean

Graduate Research Assistant, Michigan State Univeristy
My research is focused on environmental control strategies to limit losses from greenhouse pathogens on culinary herbs and bedding plants. 
Co-authors
MH

Mary Hausbeck

Michigan State University
NA
RL

Roberto Lopez

Michigan State University
NA
Thursday September 26, 2024 8:45am - 9:00am HST
South Pacific 3

8:45am HST

O/LT 2 - Field Trials of Landscape Plants under Reduced Irrigation Frequency
Thursday September 26, 2024 8:45am - 9:00am HST
Utah has experienced significant drought conditions, with 99.3% of the land under drought stress from the previous year to the present. In response to this challenge, deficit irrigation landscapes are gaining popularity in arid regions. This study aimed to investigate the overall appearance, plant growth, and physiological response of ten ornamental plants to deficit irrigation. The selected species include Caryopteris ×clandonensis ‘Blauer Splatz’ (Sapphire SurfTM bluebeard), Cercis canadensis (eastern redbud), Cercis occidentalis (western redbud), Cotoneaster ×suesicus ‘OSUCOT2’ (Emerald BeautyTM cotoneaster), Hesperaloe parviflora ‘Straight Up Red’ (‘Straight Up Red’ texas red yucca), Miscanthus sinensis ‘NCMS2B’ (bandwidth maiden grass), Physocarpus opulifolius ‘Diabolo’ (Diabolo® ninebark), Physocarpus opulifolius ‘Little Devil’ (Little DevilTM ninebark), Rosa ×hybrida ‘Meifranjin’ (Blushing Drift® rose), and Vitex agnus-castus ×rotundifolia ‘Helen Froehlich’ (Summertime BluesTM chaste tree). Eight plants per species were randomly assigned to one of three deficit irrigation frequencies, calculated based on 80% reference evapotranspiration (ETo) (high), 50% ETo (medium), and 20% ETo (low) at the Utah Agriculture Experiment Station’s Greenville Research Farm, North Logan, UT, USA. The overall appearance was evaluated biweekly, spanning from 30 Jun to 31 Oct 2023. Plant growth and stomatal conductance were recorded monthly during the growing season. The growth of plants was not significantly affected by reduced irrigation frequency. However, the impact of deficit irrigation on aesthetic performance and stomatal conductance was notable, particularly during August and September. The results highlight variability in plant performance across species, with Caryopteris ×clandonensis and Cotoneaster ×suesicus showing consistent performance across irrigation levels. However, Cercis canadensis and Physocarpus opulifolius ‘Diabolo’ exhibited a more pronounced difference under varying irrigation levels. Funding Source USDA Agricultural Marketing Service Specialty Crop Multi-State Program, USDA NIFA Hatch project UTA01666, 2022 Extension Water Initiative Grants Program, Utah State University’s Center for Water-Efficient Landscaping, and the Utah Agricultural Experiment Station
Speakers
ZW

Zirui Wang

Utah State University
Co-authors
YS

Youping Sun

Utah State University
Thursday September 26, 2024 8:45am - 9:00am HST
South Pacific 1

8:45am HST

OPB 1 - Inheritance and Genetics of Ornamental Traits in Pomegranates
Thursday September 26, 2024 8:45am - 9:00am HST
Pomegranates, renowned for their fruit, also possess ornamental varieties with unique traits such as double flowering, diverse flower colors, and dwarfing characteristics. Despite their appeal, limited information exists on the genetics and inheritance of these ornamental traits. In this study, we investigated the inheritance and genetic controls of these traits through crosses between the dwarfing cultivar Peppy Le Pom and pomegranate cultivars showcasing ornamental traits. By analyzing multiple families and conducting a genome-wide association study (GWAS) using resequencing data from 64 cultivars, we made several key findings. Firstly, the double flower trait exhibited Mendelian inheritance with a single locus controlling its expression, as evidenced by a 1:1 ratio of double to single flower plants in the F1 generation where a double flower individual was crossed onto a single flower individual. Subsequent analysis identified a SNP within an AP2-like gene on chromosome 3 that was able to differentiate between a single and double flower phenotype. Secondly, flower color inheritance revealed the recessive nature of white flowers compared to orange and red hues. SNPs near a PGLOX gene, previously linked to anthocyanin-less pomegranates, distinguished between white and red/orange flowers, suggesting specific genetic loci involved in determining flower color. Lastly, the dwarfing trait was identified as recessive, exhibiting phenotypic diversity among selfed F1 individuals, indicating potential multiple loci control. Further investigation into the genetic mechanisms governing dwarfing is warranted. In conclusion, our study contributes to understanding the genetic underpinnings of ornamental traits in pomegranates, offering insights valuable for breeding programs aimed at developing novel varieties with desirable ornamental characteristics. Further research into the identified genetic loci promises to enhance our understanding and facilitate targeted breeding efforts in this versatile fruit species.
Speakers
AS

Alexander Schaller

University of Florida
Co-authors
JC

John Chater

University of Florida
ZD

Zhanao Deng

University of Florida
Thursday September 26, 2024 8:45am - 9:00am HST
South Pacific 4

8:45am HST

PH 3 - Early Spectral Differences on Scald Disorders in ‘Granny Smith’ Apples
Thursday September 26, 2024 8:45am - 9:00am HST
‘Granny Smith’ apples are highly susceptible to skin browning (=scald). These disorders can significantly reduce fruit’s marketability due to their unattractive appearance. Superficial scald and sunscald have different etiologies but their symptoms are similar and easily mistaken. The oxidation of α-farnesene causes superficial scald (SS); on the other hand, sunscald (SC) is a non-oxidative process that affects only the sunlit sides of the fruit. To correlate the spectral fingerprint with fruit susceptibility to these disorders, hyperspectral images (400-1000 nm, 640x865 px; Headwall Photonics, Bolton, MA) were taken at harvest from sun-exposed and unexposed sides of the fruit (n=216; ~26,000 px) and later, after six months in air storage (33 oF), correlated with scald incidence. The dataset grouped 145 asymptomatic, 117 with SS and 170 with SC fruit. After pre-processing spectral information (Savitzky-Golay dev, standard normal variate), iPLS wavelength selection showed that bands from 400 to 650 and 900 to 950 nm were the most accurate for at-harvest spectral differentiation between superficial and sunscald symptoms. A neural network classification model was trained (18,226 px) and validated on an independent dataset (7,808 px), achieving overall accuracies of 78 % and 73 %, respectively. After prediction, SC px obtained the highest classification metrics (accuracy 87 %, precision 86 %); meanwhile, the asymptomatic class showed the lowest metrics (accuracy 74 %, precision 60 %). These preliminary results showed that in the same way, sunscald could be identified close to harvest using hyperspectral fingerprints, superficial scald could also be predicted at harvest on susceptible fruit and differentiated from sunscald susceptible fruit.
Speakers
avatar for Rene Mogollon

Rene Mogollon

Washington State University
Co-authors
CT

Carolina Torres

Washington State University
DR

David Rudell

USDA-RS
NA
MM

Manoella Mendoza

WA State University
Thursday September 26, 2024 8:45am - 9:00am HST
Nautilus

8:45am HST

TCHG 2 - Impact of Greenhouse Training Online Program
Thursday September 26, 2024 8:45am - 9:00am HST
Availability of trained labor is a challenge for greenhouse and nursery growers in the U.S., and access to online education is limited in many countries. To supply this need, the Greenhouse Training Online extension program was initiated in 2015 at the University of Florida (UF). The goal of the program is to deliver bilingual professional development training on horticultural science. Four-week courses on crop management topics (basic skills, nutrients, weeds, diseases, water quality, climate management, and economics) are delivered in English and Spanish using an eLearning platform. Each course consists of eight pre-recorded lessons and associated assignments, with interactive feedback provided by instructors via email or discussion forums. Mandatory pre- and post- evaluation surveys were used to measure impacts. For 2023, a total of 563 participants enrolled in seven courses with 473 successfully completing requirements (84%). The completion rate is high for an extension program because of asynchronous delivery across time zones and work schedules, specific deadlines, a course fee to increase perceived value, interaction with instructors to customize instruction, and a certificate of completion as a graduation reward. Participants included 23% international, and 17% completed lessons in Spanish. The majority (73%) of participants were industry professionals in production and other roles, and 71% indicated that their highest level of horticulture training was either learned on the job, or in high school. The proportion of students rating their technical knowledge in the course topics as very good to expert increased from 11% to 53% following the completion of the courses. Instructors are currently from 12 institutions, and Michigan State University (MSU) and UF have collaborated since 2022 on a "Plant Health Professional" certificate program through their combined institutions. We have a keen interest in collaborating with university and industry partners to develop a comprehensive and coordinated curriculum tailored to the needs of the industry. UF is well-positioned to assist in promoting, hosting, or translating courses, to mitigate barriers to course development and enhance accessibility for learners. Overall, the Greenhouse Training Online program has proven to be a sustainable model for bridging a gap in horticultural education, and empowering greenhouse and nursery growers with the knowledge and skills needed for success in their industry.
Speakers
NR

Nelda Raquel Hernandez Martinez

University of Florida
Co-authors
MK

Maria Kinslow

University of Florida
NA
PF

Paul Fisher

University of Florida
NA
Thursday September 26, 2024 8:45am - 9:00am HST
Kahili

8:45am HST

VCM 4 - Watermelon Cultigen Yield Response to Fusarium oxysporum f. sp. niveum Incidence in North and South Carolina, USA
Thursday September 26, 2024 8:45am - 9:00am HST
Fusarium wilt of watermelon, caused by the soilborne pathogen Fusarium oxysporum f. sp. niveum (FON), is a major disease impacting the watermelon industry. FON can severely reduce yields and is easily dispersed. Cultivar resistance is a desired control strategy due to high fungicide and grafting costs. In 2021 and 2022, triploid watermelon cultivars were evaluated at two locations (Clayton, NC and Charleston, SC) for their tolerance to FON. Eight common cultivars were evaluated for disease incidence and yield at both locations in both years. In 2022, two unreleased cultigens were also evaluated at both locations. All studies used a randomized complete block design with four replications. ‘Fascination’ grafted to ‘Carolina Strongback’ rootstock was included as a control each year. Disease incidence was measured every week starting three weeks after transplanting and until the first harvest at each location. Fruit weights and counts were taken to measure yield. In 2021, ‘Fascination’ had the lowest disease incidence at 75% in NC and ‘Embasy’ had the lowest incidence at 15% in SC. ‘Joy Ride’ had 100% incidence in NC and ‘Shoreline’ had the highest incidence in SC at 68%. Yields correlated with disease incidence with ‘Fascination’ having the highest yield of the ungrafted treatments in NC with 17,878 lb/ac (pounds per acre) and ‘Embasy’ with 22,687 lb/ac in SC. ‘Shoreline’ was the lowest yielding at both locations with 6,556 lb/ac in NC and 5,376 lb/ac in SC. The grafted ‘Fascination’ treatment had the lowest disease incidence and the highest yield at both locations in 2021. In 2022, the unreleased cultigen HMC633802 had the lowest disease incidence at both locations with 50% in NC and 51% in SC. Of the eight common cultivars, Fascination had the lowest incidence in NC at 83% and El Capitan had the lowest in SC at 52%. ‘Shoreline’ had the highest incidence at both locations with 100% in NC and 94% in SC. Yields correlated with disease incidence. Unreleased cultigen HMC633800 had the highest yield of the ungrafted treatments in NC with 15,575 lb/ac and Powerhouse had the highest yield in SC with 27,243 lb/ac. The grafted ‘Fascination’ treatment had the lowest incidence and highest yield at both locations in 2022. The cultigens we evaluated provided minimal tolerance to FON in both years.
Speakers
SM

Stuart Michel

NC State University
Co-authors
AK

Anthony Keinath

Clemson University
NA
JS

Jonathan Schultheis

North Carolina State University
Jonathan Schultheis is a Professor in the Department of Horticultural Science at North Carolina State University. He has worked exclusively with North Carolina State University for over 35 years. He research and extension work primarily involves cucurbit crops and sweetpotatoes. Key... Read More →
LQ

Lina Quesada

North Carolina State University
NA
Thursday September 26, 2024 8:45am - 9:00am HST
Coral 2

8:45am HST

VSF 3 - Enhancing Blueberry Production with Photo-Selective Devices
Thursday September 26, 2024 8:45am - 9:00am HST
Blueberries rank among the top ten agricultural commodities in Georgia, contributing 2.45% to the state's GDP, with 27,000 acres across the state and a farm gate value of $449.4 million. Blueberry plants are exposed to elevated temperatures and intense solar radiation during the growing season. This research aimed to reduce adverse environmental effects by modifying the spectral distribution of sunlight. Our team examined the application of photoselective devices Opti-Gro and ChromaGro in blueberry production in Georgia. The research experiment was conducted at two locations (Alma and Rebecca, GA) using a randomized complete block design with four treatments: T1 (Opti-Gro), T2 (ChromaGro), T3 (a commercial grow tube), and T4 (control-unprotected plant), each replicated five times. Photoselective devices positively impacted plant height, yield, total soluble solids, anthocyanins, and titratable acidity. Plants under T1 and T2 also resulted in higher net photosynthesis and stomatal conductance. In summary, the use of photoselective devices presents a promising approach to improve blueberry production in Georgia.
Speakers
AG

Amit Godara

The University of Georgia
Co-authors
AD

Angelos Deltsidis

The University of Georgia
ZR

Zilfina Rubio Ames

The University of Georgia
Thursday September 26, 2024 8:45am - 9:00am HST
South Pacific 2

9:00am HST

CE 4 - Towards Sustainable Controlled Environment Agriculture Systems: Developing An Intelligent Decision-Making Tool For Impro
Thursday September 26, 2024 9:00am - 9:15am HST
Controlled Environment Agriculture (CEA) systems significantly enhance crop yields per unit area in comparison to traditional open-field farming methods. Moreover, they contribute to reduced water consumption and offer extended and more predictable growing seasons. While CEA systems show promise in meeting urban vegetable demand, the question remains what the required inputs are (water, fertilizer, energy, labor) for different systems (vertical farm, greenhouses) in different climate locations. In this work, an easy-to-use transient energy model that simulates the internal microclimate of CEA systems is developed. The microclimate will include changes in temperature, humidity, water, nutrient, and carbon dioxide while also computing the energy costs associated with conditioning the space and electricity. This model will also accurately map the leaf temperature and hence compute the transpiration water loss accounting for the spectra of different artificial light sources. The energy model will be linked to a functional crop growth model that can simulate the yield of the plant over multiple growth cycles and quantify water and nutrient uptake. The potential of the developed model is demonstrated by performing simulations of year-around greenhouse operation within the U.S. Two climates categorized into hot, and cold based on annual temperature are selected for the simulation of tomato production. Results indicate that supplemental lighting energy requirement ranged between 128-160 kWh/m2-year across the selected climate zones to achieve target yield in a given duration. Overall energy consumption ranges from 200 - 400 kWh/m2-year. Overall, the supplemental lighting requirement makes upto 75 percent of the total required DLI and provides comparable improvements in biomass compared to yield in greenhouses without supplemental lighting. Finally, the model indicates that upto 90 percent of total supplemental lighting requirements require light intensities in the combination of 250 and 500 µmoles m-2 s-1 to satisfy the additional DLI requirement. However, a higher lighting intensity of 1000 µmoles m-2 s-1 is required sporadically at night during winter between October – March in the northern latitudes. Overall, this model integrates energy, temperature, nutrition, and crop yield considerations for various crops and acts as a useful predictive tool for assessing operational costs based on target yield and duration of growth for greenhouses operating in any given climate.
Speakers
ER

Eshwar Ravishankar

Assistant Professor, Cal Poly Pomona
Co-authors
LS

Lahari Sandepudi

Cal Poly Pomona
NA
RH

Ricardo Hernandez

North Carolina State University
NA
Thursday September 26, 2024 9:00am - 9:15am HST
Coral 1

9:00am HST

EcoPhys 2 - The Carbon Cost of Phosphorus Deficiency in Southern Highbush Blueberry
Thursday September 26, 2024 9:00am - 9:15am HST
Phosphorus (P) deficiency in plants causes detrimental effects on their growth and development, as P is a key macronutrient used in various physiological, biochemical and cell signaling processes. Research has shown that P-deficient plants exhibit several symptoms such as changes in leaf coloration, root morphology, and plant growth. However, many of those studies ignore gas exchange parameters. In this research, we studied the connection between P-deficiency and carbon (C) gain and loss in southern highbush blueberry (SHB, Vaccinium corymbosum interspecific hybrids) young plants to estimate the C cost of P-deficiency. The experiment was conducted using a hydroponic system where three-month old plants of ‘Farthing’ and ‘Keecrisp’ varieties grew in individual 2-L reservoirs filled with continuously-aerated complete nutrient solution containing 15 mg/L P during a 35-day acclimation period. After the acclimation period, plants were separated into two groups and continued to grow for 56 more days (treatment period). One group ( P) was grown in the complete nutrient solution, while the second group (-P) was grown in a P-free nutrient solution (0 mg/L P). We designed and tested a whole-plant gas exchange system that utilizes two infrared gas analyzers (CIRAS-3 and CIRAS-4) to simultaneously measure root system respiration and whole-plant C assimilation. Additionally, we measured root C exudation, fresh and dry mass accumulation, and P concentration and content. We induced P-deficiency as -P plants of both varieties had mature and young leaf P concentration below 0.12% (reference deficiency level). P plants had higher P concentration after treatment period. -P ‘Farthing’ plants had 89% less daily C assimilation than P plants, while no differences were observed in ‘Keecrisp’. Daily root respiration and C exudation, considered as ways of C loss, were, 3.5 and 2.9 times higher in -P than in P plants of ‘Farthing’. Similarly, -P ‘Keecrisp’ plants had 3.8 and 2.5 times more daily root respiration and C exudation compared to those under P. Ultimately, P deficiency caused a 136% reduction in daily C gain of ‘Farthing’ plants, while there were no differences between treatments in ‘Keecrisp’ plants. Our findings suggest that responses to P deficiency in SHB are genotype-specific, and that C budget and distribution in the plant play an important role in the responses to P-deficiency.
Speakers
MR

Marlon Retana-Cordero

University of Florida
Co-authors
GN

Gerardo Nunez

University of Florida
Thursday September 26, 2024 9:00am - 9:15am HST
Lehua Suite

9:00am HST

FLOR 2 - Supplemental Day-Extension Lighting Influences Rooted Cutting Growth and Quality of Finished Annual Bedding Plants
Thursday September 26, 2024 9:00am - 9:15am HST
Floriculture makes up the largest sector of ornamental horticulture production, valued at $6.7 billion and dominated by the production of annual bedding-plants. Production is timed to meet spring market dates, starting during a time of year when ambient outdoor temperatures and daily light integrals are below optimal for high-quality plant production. As a result, heating and supplemental lighting can represent a significant operational and energy cost for producers. Yet, producers and investors of the industry have acknowledged an inability to evaluate their resource use due to a lack of industry-wide benchmarks and key performance indicators (KPIs). Past research has compiled energy and water data from controlled environment agriculture (CEA) and, for floriculture, investigated the potential of energy-efficient production strategies and used life cycle assessments (LCAs) to evaluate the environmental impact of the products produced. However, CEA focuses on food production and both the compiled CEA data and the LCAs are largely based off modeled data. Therefore, this research will validate models utilized in LCAs and carbon footprint studies with experimental data, giving producers additional benchmarks and KPIs to evaluate their operational resource-use efficiency. The objectives of this study were to (1) evaluate the use of supplemental day-extension lighting (SDEL) from two different fixtures [(light-emitting diodes (LEDs) and high-pressure sodium (HPS)] during unrooted cutting (URC) propagation of five annual bedding plants and (2) to quantify the greenhouse energy and water consumption. Unrooted cuttings were received from a commercial propagator and stuck in a 105- (calibrachoa, coleus, impatiens, and petunia) or 72- (geranium) propagation tray filled with a pre-moistened soilless propagation substrate and placed under oner of three SDEL treatments on root-zone heating set to 23℃. Each treatment consisted of a propagation tent for callusing and an adjacent rooting environment. Until adventitious root formation, cuttings were misted with clear water, and then were removed from the propagation tent where they were irrigated daily with 150 mg·L–1 nitrogen provided by 15-5-15 water-soluble fertilizer (JR Peters, Inc.; Allentown, PA). After 21 days, data were collected on rooted cuttings. As expected, the energy-use of HPS-lamps exceed that of the LEDs. However, cutting stem-length and stem and leaf dry mass were decreased under SDEL, resulting in liners that were more compact, uniform, and of higher quality than those propagated under ambient conditions. An opposite trend was observed for root dry mass. This indicates that SDEL is a critical tool when utilized for bedding-plant propagation.
Speakers
LS

Lauren Seltsam

The Ohio Sate University,
Co-authors
GO

Garrett Owen

The Ohio State University
Thursday September 26, 2024 9:00am - 9:15am HST
South Pacific 3

9:00am HST

O/LT 2 - Understanding Hernando County Residents' Perspectives on Fertilizer Use and Regulations
Thursday September 26, 2024 9:00am - 9:15am HST
In response to recent revisions to the fertilizer ordinance in Hernando County, our research endeavors to delve into the attitudes and behaviors of residents towards fertilizer usage. With over 100 counties and municipalities in Florida implementing urban landscape fertilizer ordinances, Hernando County serves as a significant case study in understanding the dynamics of public perception and compliance. Our project employs a multi-faceted approach to gather comprehensive insights into resident perspectives. Tailored surveys have been developed to assess various aspects, including residents' knowledge of lawn care, familiarity with the county's fertilizer ordinances, current landscape conditions, and practices regarding fertilizer application. These surveys are being disseminated through diverse channels, encompassing social media platforms, the Hernando Extension networks, and Hernando County Utilities Department customers. Additionally, forthcoming focus group interviews will provide qualitative insights, offering a deeper understanding of community sentiments and the underlying factors shaping attitudes and behaviors. Through the integration of quantitative and qualitative data analysis, our aim is to gain a holistic understanding of the landscape of fertilizer usage in Hernando County. This entails not only identifying prevalent practices but also discerning the concerns and barriers faced by residents in adhering to the fertilizer ordinances. Such insights are pivotal in informing the development of targeted educational materials aimed at addressing community concerns, dispelling misconceptions, and providing practical guidance on responsible fertilizer usage. Our initial online survey revealed that 31% considered themselves very familiar with the Hernando County Fertilizer Ordinance, but 31% were not familiar with the details at all (n=383). Of these respondents, 73% care for their lawn and landscape themselves, with 11% using a professional service. Most residents responded that their lawn was fertilized at least once per year, with 18% saying that their lawn was never fertilized (n=844). Ultimately, the findings of our research hold significance beyond Hernando County, offering valuable lessons and strategies for promoting sustainable landscape management practices in similar contexts across Florida and potentially beyond. By fostering greater awareness, understanding, and knowledge of proper fertilizing practices, our project contributes to the broader goal of safeguarding water quality and environmental integrity for present and future generations.
Speakers Co-authors
WL

William Lester

Dr., University of Florida/IFAS Extension
YZ

Yilin Zhuang

University of Florida
YJ

Younghyeon Jeon

1University of Florida Institute of Food and Agricultural Science (UF/IFAS) Mid-Florida Research and Education Center
NA
Thursday September 26, 2024 9:00am - 9:15am HST
South Pacific 1

9:00am HST

OPB 1 - Induction and Characterization of Mutations Related to Dwarf Habit in Hardy Hibiscus (Muenchhusia section)
Thursday September 26, 2024 9:00am - 9:15am HST
Hybrids originating from different species within the Muenchhusia section of Hibiscus are well-received in commercial markets for their vibrant and abundant blossoms. However, many commercially available varieties prove overly robust for smaller garden spaces, often yielding a limited number of blooming flowers. The cultivation of stable, heritable mutants displaying a dwarf stature and improved branching architecture holds significant promise for enhancing the commercial production of resilient Hibiscus. The objective of this project was to induce point mutations in genes linked to the biosynthesis or signaling of plant growth-related hormones, using ethyl methanesulfonate (EMS). Successful induction of multiple mutations associated with dwarf, compact phenotypes was achieved. Hybridizations were carried out between M2 plants exhibiting a dwarf phenotype and hybrids generated through traditional breeding that lacked the dwarf mutation in their genetic background. This aimed to produce a diverse array of dwarf plant selections. The inheritance patterns of the dwarf genes were elucidated by analyzing the segregation ratios of the dwarf phenotype in the F1 and F2 generations of these hybrids. In comparison to non-dwarf progeny, dwarf progeny exhibited significantly shorter internode lengths and a greater number of primary branches.
Speakers
CA

Conner Austin

University of Florida
Thursday September 26, 2024 9:00am - 9:15am HST
South Pacific 4

9:00am HST

PH 3 - Apple Ripening After DCA Storage: Assessing The Risk Of Flavor Loss
Thursday September 26, 2024 9:00am - 9:15am HST
Dynamic controlled atmosphere (DCA) storage suppresses the ripening of apple fruit during storage to a greater extent than standard CA storage. DCA is a relatively new technology, and it has the potential to markedly alter the volatile profile of apple fruit. It has been found that DCA storage can suppress the most important aroma volatiles of stored apple fruit. What we don't know is the length of time and the conditions needed to recover that loss in aroma, especially when DCA is applied in combination with the ethylene action inhibitor 1-methylcyclopropene (1-MCP). A critical concern about 1-MCP is that apple flavor is compromised in treated fruit because aroma volatiles are so closely linked with ethylene response. Apple fruit from high-value cultivars were stored under a DCA regimen (approximately 0.4% O2), with and without 1-MCP treatment, for 3, 6, and 9 months. Following removal of fruit from DCA, the volatile profile and fruit quality traits were measured for up to 5 weeks while being held at room temperature. The recovery of aroma formation following storage for 6 months was essentially immediate for ‘Red Delicious’ fruit if 1-MCP was not used. The recovery was a little slower for one of the replicate studies if DCA was used. If the fruit were treated with 1-MCP, there was a 2-week delay in the recovery of aroma formation. ‘Evercrisp’ aroma formation was much lower than ‘Red Delicious’ and the responses to DCA and 1-MCP differed from that of Red Delicious. Aroma formation remained very low for 3 to 4 weeks at room temperature following CA and DCA storage and never recovered following 1-MCP treatment for the 5-week duration of the study. The data for aroma formation after 9 months was similar to that at the 6-month time point for ‘Red Delicious’ in terms of 1-MCP responses. However, the effect of DCA seemed to be more pronounced, suppressing aroma recovery for an additional week at room temperature. For ‘Evercrisp’, the 9-month data were quite similar to those from 6 months storage.
Speakers
RB

Randolph Beaudry

Michigan State University
Dr. Randolph Beaudry, Professor, MSU Department of Horticulture (MSc, PhD, University of Georgia). His appointment is 50% MSU Extension and 50% AgBioResearch. His research program includes both regional and international projects and focuses on the physiology of plant responses to... Read More →
Co-authors
JX

Jiarui Xu

Michigan State University
NA
NS

Nobuko Sugimoto

Michigan State University
NA
OH

Ozge Horzum

Ankara University
NA
Thursday September 26, 2024 9:00am - 9:15am HST
Nautilus

9:00am HST

TCHG 2 - Invasive Species Education in Florida: Insights from a Yearlong Webinar Pilot Program
Thursday September 26, 2024 9:00am - 9:15am HST
Invasive species pose significant threats including economic losses in agriculture and horticulture, decreased biodiversity, human and animal health hazards, disruption of native ecosystems, and more. In the U.S., the losses due to invasive species were historically estimated at around $120 billion annually, but a more recent study suggests this cost is much higher at $1.2 trillion. Florida is a high-risk state for the introduction and establishment of invasive species due to the state’s diversity of agricultural commodities, mild winters, large number of international deep-water ports and airports, and highly desirable tourism operations. Research shows that the public plays an important role in early detection of invasive species, but awareness is critical to the development of strong volunteer-based networks. Licensed pesticide applicators, often the first to observe suspicious pests, play a crucial role in both early detection and ongoing management of non-native species in Florida. To address these challenges, the First Fridays with Florida First Detector webinar program was developed. This yearlong pilot program offered one-hour lunch time webinars on the first Friday of every month beginning in September 2022. Leveraging innovative online education techniques, the program aimed to connect diverse professional and public audiences across Florida. Due to the interdisciplinary nature of invasive species issues, webinars engaged multiple stakeholder groups including farmers, horticultural professionals, landscapers, land managers, master gardener volunteers, homeowners, and beyond. The content focused on increasing knowledge about invasive species, including the identification of species not yet detected and recently introduced species in Florida. The goals were to promote early detection of new species, monitor the spread of recently introduced species, and offer sustainable management recommendations for species currently impacting Florida. Each month highlighted a different pest group including invasive fruit flies, palm pests, wood boring insects, citrus pests, snails, and more. Post-reflective surveys demonstrated that 94.7% (n=675) of respondents increased their knowledge on invasive species and 99.9% intended to adopt at least one practice learned. Six-month follow up surveys, evaluating behavior implementation over time, showed that 97.5% (n=166) of respondents had adopted at least one practice (i.e. submitted samples of suspicious pests, employed integrated pest management, etc.) since attending a webinar. The findings underscore the effectiveness of interdisciplinary, collaborative approaches in addressing invasive species challenges. This presentation will discuss the methodologies and experiences in developing and implementing the one-year pilot program as well as the program’s future directions and potential applicability to other regions.
Speakers
MP

Morgan Pinkerton

Sustainable Agriculture and Food Systems Agent, UF/IFAS Extension Seminole County
Co-authors
AH

Amanda Hodges

University of Florida
NA
KM

Kaydie McCormick

UF/IFAS Extension Seminole County
Thursday September 26, 2024 9:00am - 9:15am HST
Kahili

9:00am HST

VCM 4 - Effect of Biostimulants on Field Grown Watermelon (Citrullus lanatus) under Deficit Irrigation and Fertility.
Thursday September 26, 2024 9:00am - 9:15am HST
The impacts of climate change and drought threaten water supplies crucial for watermelon production. Rising fertilizer costs and off-site effects also pose problems for the sustainability of watermelon production. Biostimulants shown promise in helping plants maintain production under deficit irrigation conditions and may offset fertility addition through ecosystem services and stimulatory effects. In this study two watermelon cultivars (Crimson Sweet and Fascination) were treated with three biostimulant products (Mighty Mycorrhizae, Spectrum DS, and Continuum) and then subjected to reduced fertility (67% of recommended rate) and irrigation (75% evapotranspiration). Raised beds covered in plastic mulch were used with rows spaced 1.83 meters apart and plants 0.61 meters apart within rows. Growth metrics and stages were recorded and compared among treatments. Watermelon fruits were harvested at maturity over a one-week period and yield was compared. The final biomass was measured after harvest. Statistical analysis is ongoing, and a second year of this field trial will be completed in August 2024, allowing for final conclusions to be drawn.
Speakers
avatar for Evan Christensen

Evan Christensen

Utah State University
Co-authors
DD

Dan Drost

Utah State University
NA
YS

Youping Sun

Utah State University
Thursday September 26, 2024 9:00am - 9:15am HST
Coral 2

9:00am HST

VSF 3 - Modeling Production Curves of Southern Highbush Blueberry for Improved Productivity and Efficient Harvestability
Thursday September 26, 2024 9:00am - 9:15am HST
Agronomic crops have their yield potential assessed once per growing season at harvest time. In contrast, horticultural crops such as blueberries (Vaccinium spp.) require prolonged harvest periods, spanning 6 to 8 weeks of recurrent mechanical- or hand-picking. Collected data throughout the harvest period offer a comprehensive source of information to estimate production curves (cumulative harvest). These capture the yield dynamics of each cultivar under specific environmental conditions and treatments. For blueberry growers in Florida, desirable production curves should exhibit: 1) accumulation at the beginning of the harvest season (earliness), and 2) reduced harvest periods (concentration). This pattern is advantageous as it could significantly enhance productivity and profitability while simultaneously cutting down labor costs linked to harvest operations. Thus, pinpointing cultivars displaying these beneficial traits is paramount. In this study, we considered the Weibull distribution to model the production curves for each genotype-in-environment combination. Phenotypic and genomic information were combined for model calibration to predict the corresponding parameters of the distribution besides yield performance in a multi-trait framework. To our knowledge, there are no methods in the current literature that address the identification of cultivars that both ripen early and/or are suited for concentrated harvesting. In this study, we employ a novel analytical approach designed to fill this gap, aiming to systematically identify cultivars aligning with these ideal production characteristics.
Speakers
JM

J. Martin Zapien-Macias

PhD Student, University of Florida
Co-authors
DJ

Diego Jarquin

University of Florida
GH

Gerardo H. Nunez

University of Florida
Thursday September 26, 2024 9:00am - 9:15am HST
South Pacific 2

9:15am HST

CE 4 - Global Sensitivity Analysis and Validation of the Modified Energy Cascade Crop Model for Controlled Environment Agricult
Thursday September 26, 2024 9:15am - 9:30am HST
The Modified Energy Cascade (MEC) crop model was originally developed to predict the edible biomass production of bioregenerative life support systems (BLSS) along with BLSS consumption and production of O2 and CO2. Three distinct MEC versions support this original goal and controlled environment agriculture (CEA) on Earth. Cavazzoni built the first MEC for predicting crop growth, transpiration, and productivity of BLSS. Boscheri et al. and Amitrano et al. each developed versions building off Cavazzoni's work. While each of these model versions builds off each other, differences in methodology and assumptions of plant physiology impact the outputs of the model, necessitating a comparison between versions. To describe the effects of input variability and model structure on the outputs of the MEC versions before further development for BLSS and CEA production facilities, four research questions were chosen to guide this evaluation. 1) How much variation in transpiration and yield predictions can be attributed to the model version? 2) How are input variations propagated through the cascading nature of the models? 3) Which model components are highly sensitive or uncertain to which environmental conditions? 4) How well does each model version predict the outcome of lettuce yield and transpiration outcomes of data sets independent from model development? To answer the first three questions, a series of global sensitivity and uncertainty analyses were performed. They revealed that 1) for daily transpiration rate and edible biomass model version alone can explain between 69% and 82% with Amitranos representing the lowest values and Boscheris the highest typically. 2) Even in sequences of identical equations, where each subsequent calculation is identical, variability is gradually reduced with final output variations between 40% - 55% that can be attributed to the prior upstream differences. 3) The Cavazzoni and Boscheri edible yield predictions are highly sensitive to photosynthetic photon flux density (PPFD) and CO2 across calculations while Amitrano’s is more responsive to photoperiod rather than PPFD. 95% of Boscheris transpiration output is driven by relative humidity while the other two utilize a combination of that and photoperiod. Lastly, these models and their performance were evaluated using environmental and yield data from an indoor vertical farming facility and growth chamber experiments. Together these analyses provide the information necessary to continue the development of the MEC for the prediction of resource flows and yield of CEA and BLSS supporting the optimization of electricity usage and circularity processes within closed-loop agriculture.
Speakers
DC

Donald Coon

University of Florida
NA
Co-authors
AM

Ana Martin Ryals

University of Florida
CA

Chiara Amitrano

University of Naple
NA
GN

Gerardo Nunez

University of Florida
MC

Melanie Correll

University of Florida
NA
RC

Rafael Carpena

University of Florida
NA
YZ

Ying Zhang

University of Florida
ZB

Ziynet Boz

University of Florida
NA
Thursday September 26, 2024 9:15am - 9:30am HST
Coral 1

9:15am HST

EcoPhys 2 - Intra- and Inter-Annual Changes in Soil Health with Native Plant Monocultures
Thursday September 26, 2024 9:15am - 9:30am HST
The interactions between plants and their soil environment influence overall soil system health. Soil provides plants with the structural support, water, nutrients, and microbial interactions they need for creating biomass and for reproduction. Conventional agriculture practices degrade soil; however, small plots of native plants within agricultural settings have been shown to provide disproportionally large benefits to both ecological and agricultural landscapes. In other words, even small plots of native plants can improve soil health. Although small plots of mixed native plant species improve soil health, they offer little in the way of income opportunities for producers through seed collection and sales. However, plots of native monocultures may offer producers an opportunity to harvest and sell seeds, taking advantage of the increasing demands of the native seed market while also increasing soil health. Therefore, this study's objective is to quantify the effects of small native plant monocultures on soil health and compare them to soil health from conventional crop plots. We investigated biological indicators of soil health such as organic matter, organic carbon, and microbial communities as well as abiotic indicators like nutrient composition. We hypothesize that, compared to crop plots, native monoculture plots will have more microbial diversity and higher amounts of soil nutrients. We tested our hypothesis by comparing soil health characteristics from plots containing five established native monocultures: Dalea candida, Agastache nepetoides, Glycyrrhiza lepidota, Liatris ligulistylis, and Tradescantia occidentalis; and one crop plot planted with a corn and soybean rotation. During the second and third season of growth, monthly soil samples were taken, and soil indicator values were compared using Tukey’s HSD post hoc tests after performing an analysis of variance (ANOVA). Results suggest that native plant species influenced soil health differently than crop rotations after three seasons of growth. Compared to crop plots, soil samples from two species of native plants, Agastache nepetoides and Tradescantia occidentalis, had higher fungi-to-bacteria ratios (p = 0.0160 and p < 0.0001, respectively), and higher amounts of saprophyte biomass (p = 0.0040 and p = 0.0484, respectively). Soils from the Agastache nepetoides plots also had higher amounts of Pre18 cyclo fatty acids (p = 0.0022) and potassium (p = 0.0159). These two species of native plants show potential for improving soil health after three years of establishment. Adding these two native monocultures to marginal production land may add soil health benefits during early establishment periods while providing a marketable crop for producers.
Speakers
BL

Bret Lang

Student, South Dakota State University
Co-authors
LP

Lora Perkins

South Dakota State University
NA
Thursday September 26, 2024 9:15am - 9:30am HST
Lehua Suite

9:15am HST

FLOR 2 - Daily Light Integral Influences Adventitious Rooting of Achillea Cuttings
Thursday September 26, 2024 9:15am - 9:30am HST
Rooting of herbaceous perennial cuttings occurs year-round in greenhouses under photosynthetic daily light integrals (DLIs) ranging from ≈1–20 mol·m–2·d–1. The effects of DLI on rooting and cutting growth have not been quantified for many vegetatively propagated herbaceous perennials. As such, our objectives were to determine the effects of DLI on adventitious rooting and cutting quality of a popular herbaceous perennial, yarrow (Achillea sp.). Unrooted cuttings of yarrow (Achillea millefolium ‘Apricot Delight’) were received from a commercial cutting supplier and callused in a glass-glazed greenhouse for 5 d under ≈3.6 mol·m–2·d–1 at 24 °C root-zone and air temperatures. Upon callusing, cuttings were transferred to a rooting environment with 21 °C air temperature and 24 °C root-zone temperature set points. Cuttings were rooted under one of four different fixed-woven shadecloth providing ≈86%, 62%, or 26% shade or no shade (0%) thereby establishing mean DLIs ranging from 1.6 to 15.2 mol∙m‒2∙d‒1. Cutting growth and biomass accumulation evaluations were made 8, 11, and 14 d after transfer. In general, yarrow stem caliper, stem length, and leaf number were unaffected by increasing DLI; however, leaf, stem, root, and total biomass accumulation increased with increasing DLI though to different magnitudes. For example, as DLI increased from 1.6 to 15.2 mol∙m‒2∙d‒1, leaf, stem, root, and total biomass accumulation increased by 84%, 85%, 458%, and 93% at 8 days after transfer to 98%, 110%, 893%, and 128% at 14 days after transfer, respectively. When taken together, DLI should be properly managed to hasten and improve rooting and growth of yarrow cuttings during adventitious root development.
Speakers
avatar for Garrett Owen

Garrett Owen

Extension Specialist and Assistant Professor of Sustainable Greenhouse & Nursery Systems, The Ohio State University
Dr. W. Garrett Owen is Assistant Professor and Extension Specialist of Sustainable Greenhouse and Nursery Production Systems with primary responsibilities in teaching (20%), research (30%), and Extension (50%) in the Department of Horticulture and Crop Science at The Ohio State University... Read More →
Co-authors
RL

Roberto Lopez

Michigan State University
NA
Thursday September 26, 2024 9:15am - 9:30am HST
South Pacific 3

9:15am HST

O/LT 2 - Using Different Ratios of Blue and Red Light to Induce Drought Tolerance Morphology in Zinnia
Thursday September 26, 2024 9:15am - 9:30am HST
Growing population, rapid urbanization and economic expansion have been raising the demand for fresh water. Additionally, climate changes, characterized by warmer temperatures, shifting precipitation patterns, and reduced snowpack are diminishing the water availability presenting new challenges for agricultural water use and conservation, particularly in the arid western states. One approach to addressing water scarcity involves inducing drought tolerance in crops. Plants exhibit physiological, morphological, and biochemical changes upon exposure to different wavelengths of light. This study focuses on determining the optimal ratio of blue to red light for inducing drought tolerance morphology in Zinnia elegans ‘Envy’. Seeds were sowed in Metro-Mix® 820 (SunGro Horticulture, Agawam, MA, USA) and kept on a misting bench. After germination, the plugs were exposed to full spectrum LED grow lights (ScynceLED, Mesa, Arizona) maintained at three ratios of blue and red light, 10:90, 25:75, and 50:50, controlled using a spectrometer (StellarNet Inc., Tampa, Florida, USA) in a covered chamber. The Photosynthetic photon flux density (PPFD) was maintained at 150 µmol.m-2.s-1 and the photoperiod was maintained at 12 hour dark and 12 hour light period. After four weeks of treatment, physiological and morphological parameters were measured in five destructively harvested plugs per treatment. The leaf number, growth index, and leaf area index showed no significant differences among treatments, however, the rate of assimilation and stomatal conductance were found highest under the 50:50 blue and red light ratio, compared to 25:75 but similar to 10:90. The total dry weight, leaf thickness, SPAD, and NDVI values were also higher at the 50:50 ratio, with total dry weight comparable to the 25:75 ratio. Subsequent irrigation treatments at 25% and 35% volumetric water content (VWC) were applied with the help of automated irrigation system using capacitance sensor, ECH2O 10HS (Meter Group, Pullman, WA, USA) to assess water requirements under different ratios of blue and red light suggesting a potential of these light treatments to reduce the Zinnia’s water needs.
Speakers
AC

Anju Chaudhary

Utah State University
Co-authors
SP

Shital Poudyal

Utah State University
NA
Thursday September 26, 2024 9:15am - 9:30am HST
South Pacific 1

9:15am HST

OPB 1 - Compatibility of Cross-hybridizing Lagerstroemia taxa
Thursday September 26, 2024 9:15am - 9:30am HST
Lagerstroemia indica L. is a favored landscape plant in mild-climate regions, cherished for its easy propagation and cultivation, prolonged blooming period, and variety of plant forms. The majority of new cultivars are the result of cross hybridization. However, compatibility issues arise with some cultivars and species. To enhance our understanding of the cross-compatibility of our elite cultivars, we selected four plants (C14-35, C14-39, D03-29, and D03-34) for reciprocal crosses and for crossing with other elite plants, chosen for their clean foliage and extended summer bloom periods. A total of 3126 crosses were made in the summer of 2023. By the season's end, 731 fruits were harvested to assess seed set, and viable seeds were counted in winter 2023. From these efforts, 20,862 seeds were harvested, with 5,470 identified as viable. Interspecific crosses with L. speciosa revealed that C14-35 and C14-39 had significantly better fruit set percentages (40% and 35.2%, respectively) compared to D03-29 and D03-34 (6.3% and 0%, respectively). Thus, C14-35 and C14-39 exhibit greater compatibility with L. speciosa. For reciprocal crosses, C14-39 and D03-34, when used as pollen donors, resulted in much lower fruit set percentages and seed sets than C14-35 and D03-29. Pollen studies of the four cultivars indicated that both C14-39 and D03-34 produced little to no pollen, while C14-35 and D03-29 were prolific pollen producers. Future cross hybridization studies will therefore avoid using C14-39 and D03-34 as pollen donors. A seed germination study is planned for spring 2024 to further assess the various cross combinations and confirm interspecific hybrids.
Speakers
YY

Yongjun Yue

University of Georgia
Co-authors
DZ

Donglin Zhang

University of Georgia
Thursday September 26, 2024 9:15am - 9:30am HST
South Pacific 4

9:15am HST

PH 3 - The Impact Of Hot Water Treatment On Organic Apple Quality With Different Storage Systems
Thursday September 26, 2024 9:15am - 9:30am HST
There has been a surge in demand for organic apples in the U.S. in the last decade. Washington State supplies more than 90% of them because of the ideal climate and soil conditions that favor production. Thermotherapy methods are widely used in Europe to reduce postharvest rots, but they have not been adopted in the U.S. because of their potential detrimental effects on fruit quality. The objective of this research was to evaluate the impact of hot water treatments at harvest on fruit quality during long-term storage. ‘Royal Gala’ and ‘Honeycrisp’ apples were immersed at 49 °C or 52 °C for 2 minutes in a controlled hot water bath immediately after harvest. After fruits were dried at 20 °C, they were placed in controlled atmosphere (CA; 2 kPa O2, 0.5 kPa CO2, 1°C-‘Royal Gala’, 3oC-‘Honeycrisp’) and air (RA; 1°C-‘Royal Gala’, 3oC-‘Honeycrisp’) storage for up to 9 months. Fruit quality (firmness and titratable acidity), defects, and physiological disorders were evaluated 1 and 7 days at 20 °C. In general, ‘Royal Gala’ apples immersed at 49 °C and stored in CA had no decay after 3 and 6 months of storage, but it was the highest (around 9%) in ‘Honeycrisp’ in both CA and RA. Peel damage was less at 49 °C for both ‘Royal Gala’ (RA-1.3%; CA-5%) and ‘Honeycrisp’ (RA-7.4%; CA-2.8%) compared to 52 °C after 3 months. Fruit firmness and titratable acidity were statistically different (p≤0.05) at 49 °C compared to 52 °C after 3 months. Although the hot water treatment in ‘Royal Gala’ apples was effective in reducing decay incidence without compromising fruit quality, the opposite was found in ‘Honeycrisp’; therefore, further research is needed to confirm these results and understand the variety-dependent effect.
Speakers
avatar for Sadat Amankona

Sadat Amankona

Washington State University-TFREC
I am a second-year Ph.D student at Washington State University (Tree Fruit Research & Extension Center). My research is about using non-chemical solutions for long-term storage of organic apples.
Co-authors
CT

Carolina Torres

Washington State University
Thursday September 26, 2024 9:15am - 9:30am HST
Nautilus

9:15am HST

TCHG 2 - Closing the Gap: Developing Greater Awareness of Horticulture Careers in Controlled Environment Agriculture in Secondary Schools
Thursday September 26, 2024 9:15am - 9:30am HST
In today's high schools, students are often unaware of the diverse and meaningful careers available in horticulture, especially within controlled environment agriculture (CEA). From machine learning to design engineering, CEA encompasses a wide range of technical fields, yet these opportunities are frequently overlooked in state-led agriculture curricula. This presentation underscores the need for improved national communication among agriculture teachers to develop effective programs that educate students about the rich array of horticulture careers. We advocate for the creation of equipment and curriculum that vividly depict these career paths. Furthermore, there's a pressing need to expand students' awareness of post-secondary education options beyond state boundaries. While careers in medicine are well-known, horticulture careers, which are equally complex and rewarding, often go unnoticed by technically-minded students. As the demand for locally-produced, sustainable food rises, the need for skilled horticulturists in every niche grows. We urge for a greater influx of horticulture students to meet this demand and drive innovation in the field. In summary, this presentation highlights the urgency of bridging the gap between students and the myriad opportunities available in horticulture, particularly within the dynamic realm of controlled environment agriculture.
Speakers
MY

Melanie Yelton

GrowBig Consulting
Melanie Yelton, Dr. Yelton leverages over 25 years of plant science leadership to guide controlled agriculture entities towards climatically resilient food systems. Via her consultancy company, GrowBig, she advises controlled environment agriculture farms, lighting partners and R... Read More →
Co-authors
EW

Eli Weissman

GrowBig Consulting
NA
Thursday September 26, 2024 9:15am - 9:30am HST
Kahili

9:15am HST

VCM 4 - Development of the winter artichoke production system in a subtropical climate
Thursday September 26, 2024 9:15am - 9:30am HST
Artichoke (Cynara cardunculus var. scolymus) belongs to the sunflower family and is cultivated for its flower buds. Being adapted to Mediterranean climates, artichoke plants require adequate winter chilling for flower bud induction and yet is susceptible to freeze damage. Because of these climatic requirements, nearly 100% of artichoke production in the United States currently comes from California. Insufficient winter chilling is among the major environmental constraints for artichoke production in subtropical and tropical climates. We started this study in 2015 with the goal of developing artichoke as a new winter crop in Florida. First, we developed a protocol for artificial flower bud induction using a plant hormone, gibberellic acid (GA3). With the optimum rate and timing, GA3 application is highly effective in inducing bud formation, irrespective of winter chilling. Second, we evaluated eight cultivars based on earliness of bud formation, yield, and bud quality. ‘Imperial Star’ and ‘Green Queen’ were selected as the most promising cultivars in Florida, with the maximum yields of 17.3 and 11.8 t ha–1, respectively. The current artichoke production guide provides recommendations on GA3 application, cultivars, planting configurations, plastic mulch, and basic pest management. In 2023, artichoke was grown on about 12 hectares in Florida using the production guide we developed. We are currently testing additional hybrid cultivars and assessing nutritional values and postharvest quality to enhance the viability of artichoke as Florida’s new winter crop.
Speakers
SA

Shinsuke Agehara

University of Florida
Co-authors
WW

Weining Wang

University of Florida
Thursday September 26, 2024 9:15am - 9:30am HST
Coral 2

9:30am HST

CE 4 - Pre-breeding Leafy Green Watercress (Nasturtium officinale; Brassicaceae) In an Indoor Vertical Farm: A Discovery Trial
Thursday September 26, 2024 9:30am - 9:45am HST
Our research is to define and develop pre-breeding resources as foundational knowledge to underpin breeding of a specialty leafy green crop watercress (Nasturtium officinale; Brassicaceae). This is being achieved by screening a unique, worldwide collection of watercress population to discover and to enhance nutritional traits for health, morphology, and sensory of the indoor controlled environment agriculture (CEA) market. Watercress is a perennial semi-aquatic leafy green vegetable in the Brassicaceae family and is an understudied specialty crop that has important human health benefits. The most abundant secondary metabolite glucosinolate (GLS) in watercress is gluconasturiin, an aromatic GLS, which hydrolyses and releases phenethyl-isothiocyanates (PEITC). PETIC, specifically from watercress, has been proven to have chemo-preventative potentials. Wild germplasm collection harbours natural variations and useful trait discovery opportunities for introgression of novel traits into the existing gene pool. There is limited interdisciplinary research on crop nutrition and breeding for the CEA settings. We found that watercress is well-suited to indoor hydroponic growing. We established the first indoor vertical farm (VF), a controlled growth chamber in a shipping container, at University of California, Davis. Light quality and quantity both serve important roles in watercress growth and development, and a fully controllable vertical farm allows testing a suite of traits of interests with altered LED light regimes. Results showed that VF grown wild watercress possessed significant genotypic differences across treatments, indicating an abundant natural diversity. Altering red to blue LED light ratio and duration may further enhance the anti-cancer GLS compounds as well as nutritional quality profile of this leafy crop.
Speakers
avatar for Yufei Qian

Yufei Qian

PhD candidate, University of California, Davis
Co-authors
DK

Daniel Klibenstein

University of California, Davis
NA
EK

Ella Katz

University of California, Davis
NA
GT

Gail Taylor

University of California, Davis
NA
Thursday September 26, 2024 9:30am - 9:45am HST
Coral 1

9:30am HST

O/LT 2 - Techniques to Improve Growth, Heat, and Drought Tolerance in Container Grown Trees
Thursday September 26, 2024 9:30am - 9:45am HST
Heat and moisture stress are increasing limitations to production of container-grown trees and growth of landscape trees, while reducing water use is an increasingly common goal. In two experiments, we investigated methods for reducing stress caused by limited water and extreme heat in container-grown tree seedlings in Aurora, Oregon. In the first experiment, we evaluated the potential for several ‘biostimulant’ or stress-tolerance inducing, soil-applied materials to improve growth of tree seedlings (Betula nigra) under limited water conditions. In the second experiment, we evaluated one of the most promising materials from that study in comparison to several other known or potential stress-reducing materials or techniques. In the first study, B. nigra seedlings were grown in pots with full water (determined by site evapotranspiration rate), one-half water, or one-half water with four different commercially available ‘biostimulant’ products that are marketed as inducing tolerance to moisture and heat stress in plants. Caliper growth, visual rating, and chlorophyll fluorescence values all showed that in the low-water groups, the plants treated with a mannitol plus calcium chelate product or a potassium phosphite product performed best and significantly better than the low-water control group. In the second experiment, over the course of two seasons we compared the effects of soil-applied potassium phosphite with other methods previously shown to reduce heat and/or drought stress. Abnormal extreme heat events, or ‘heat domes’, occurred during both growing seasons. Container-grown red maple (Acer rubrum) saplings were grown with moderate water and subjected to one of six treatments: untreated control, fresh-water misters triggered by preset ET value, kaolin foliar treatment, potassium phosphite soil application, propiconazole foliar treatment, and paclobutrazol foliar treatment. After two growing seasons, the mist treatment significantly improved growth compared to control plants while the potassium phosphite and kaolin treatments showed non-significant trends of improved growth. Based on these two studies, it is concluded that where possible, mist treatments during hot and dry conditions can improve container-grown tree seedling growth and condition, while potassium phosphite soil treatment and kaolin foliar treatments are likely to improve growth and condition in landscapes or where installation of misting apparatus is not feasible.
Speakers
DZ

Drew Zwart

Plant Pathologist & Physiologist, Bartlett Tree Research Labs
Co-authors
LN

Lloyd Nackley

oregon state university
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
Thursday September 26, 2024 9:30am - 9:45am HST
South Pacific 1

9:30am HST

PH 3 - Fungicides and Scald Inhibitor Diphenylamine Shift Microbiomes of ‘Fuji’ Apples Through Short Term Cold and Room Temperature Storage
Thursday September 26, 2024 9:30am - 9:45am HST
Recent studies have shown that the native microbiome plays an important role in biocontrol efficacy, but in comparison less is known about how the microbiome responds to conventional and natural product fungicides. This study investigated the effects of conventional fungicide fludioxonil, natural product fungicide natamycin, and scald inhibitor diphenylamine (DPA) on the microbiomes of ‘Fuji’ apples (Malus x domestica) from 1-28 days of cold storage and 7 days of room temperature after the cold storage. We hypothesized that fludioxonil would have a smaller effect on the microbiome than natamycin due to being more limited in targeting specific pathogens, and that antioxidant activity from DPA would shift the microbiome. DPA showed a strong effect on the fungal microbiome that increased with storage time, while natamycin resulted in modest fungal shifts and fludioxonil resulted in no observed shifts. While chemical treatment was not a predictor of bacterial microbiome variation, bacterial communities shifted throughout storage with many of the trends reversing when samples were removed and left at room temperature. Time in cold storage decreased the relative abundance of Pseudomonas and DPA application reduced the relative abundance of Aureobasidium, both notable biocontrol genera. These results highlight how chemical applications like DPA may have unintended effects on beneficial microbes that protect crops from pathogen infection.
Speakers
CL

Connor Lane

Cornell University
Co-authors
CW

Chris Watkins

Cornell University
NA
JK

Jenny Kao Kniffin

Cornell University
NA
YA

Yosef Al Shoffe

Cornell Univeristy
Thursday September 26, 2024 9:30am - 9:45am HST
Nautilus

9:30am HST

TCHG 2 - Educational Initiatives in Cannabis: Curriculum Development for a Growing Workforce
Thursday September 26, 2024 9:30am - 9:45am HST
The cannabis and hemp industries have grown at a remarkable rate over the last decade, requiring the creation of comprehensive curricula to ensure proper workforce development. This discussion focuses on the educational initiatives employed at Cornell University to support industry growth and mitigate business failure in hemp-related fields. Our approach to curriculum design was tailored to meet the unique requirements for both undergraduate and graduate students, as well as industry stakeholders. This includes the creation of in-person and robust online hemp programs that are data-driven and up to date with the rapidly growing field of scientific knowledge. In doing so, we aim to ensure that students and the public are equipped with the most recent insights from scientifically-sound resources to support responsible practices within the industry, while also aligning with the institution’s curriculum standards. The School of Integrative Plant Science (SIPS) at Cornell University has been at the forefront of offering hemp-specific courses including Cannabis: Biology, Society and Industry, Hemp Breeding, Hemp Production, Hemp processing, and Chemistry and Pharmacology of Cannabis since 2019, with two of them also available through the online certificate program. Additionally, many professionals in the cannabis industry participated in the Cannabis Science and Hemp Sciences concentration for one year master’s degree program, Master of Professional Studies (MPS) at Cornell University, with approximately 30 students completing the degree in 2023. We will also highlight prior years' student expectations in order to suggest effective educational experiences and the challenges of this growing discipline in the absence of a comprehensive textbook. Through sharing insights, best practices, and case studies, this presentation aims to inspire dialogue and collaboration among educators, industry professionals, and legislators to advance the development of cannabis education within higher education institutions.
Speakers
YB

Yousoon Baek

Lecturer, Cornell University
Thursday September 26, 2024 9:30am - 9:45am HST
Kahili

9:30am HST

VCM 4 - Globe Artichokes - Variety Trials for Florida Production and Marketing Evaluations
Thursday September 26, 2024 9:30am - 9:45am HST
The globe artichoke (Cynara cardunculus) is a large thistle crop of the Asteraceae family, native to the Mediterranean. Globe artichokes are a large, leafy plant, with edible component as an immature flower bud. With production dominated by California, Florida can provide a new commodity for southeastern growers while reducing our carbon footprint. Globe artichokes have not been a traditional crop in the state of Florida, even as a garden variety. This study demonstrates the need to focus on varieties for the subtropics. We evaluated the best performing artichoke variety in addition to the retail favorite by curb appeal. Within a farmer's market survey, more than 80% of shoppers voted for 'Green Queen' amongst five other varieties (Imperial Star, Green Globe Improved, etc.). It also represented the highest yielding, at 12,707 lbs/acre, followed by 'Imperial Star' at 11,484 lbs/acre. An artichoke was valued at $4 each globe, while the flower was $5 per stem during the Mother's Day market. The demand continues from chefs and newly transplanted retail shoppers.
Speakers
avatar for Evelyn

Evelyn "Prissy" Fletcher

Faculty - UF/IFAS Lecturer, University of Florida
I am a lecturer and academic advisor for the Soil, Water and Ecosystem Sciences Department. My research and extension background included alternative crop assessments for Florida growers, insecticide fate and transport in citrus and phosphorus nutrient management in artichokes. These... Read More →
Co-authors
KM

Kelly Morgan

UF/IFAS CALS
NA
SA

Shinsuke Agehara

University of Florida CALS
Thursday September 26, 2024 9:30am - 9:45am HST
Coral 2

9:45am HST

O/LT 2 - Using Marketing Initiatives to Promote the UF/IFAS Extension Florida-Friendly Landscaping Program
Thursday September 26, 2024 9:45am - 10:00am HST
The UF/IFAS Florida-Friendly LandscapingTM (FFL) Program is Florida's premier Extension program for ecologically sustainable, science-based landscape practices that conserve water, protect water quality, and promote biodiversity. Since 1993, the FFL program has promoted water resource protection through both water conservation (water savings) and reducing non-point source pollutants (fertilizer nitrogen and phosphorus; pesticides) that may otherwise be carried into the state’s water bodies via runoff and/or leaching into groundwater. Despite longstanding promotion of FFL through Florida’s 67 county Extension offices, most Florida residents remain unaware of the program and its benefits. To promote public awareness of FFL, the program has undertaken a variety of marketing initiatives involving radio, television, social media, webinars, and online educational opportunities. On the radio, FFL produced a series of one-minute-long spots providing sustainable gardening tips. Called Florida-Friendly Landscaping in a Minute, the episodes aired twice each weekday on two NPR stations covering 19 northeast Florida counties. The daily listening audience was estimated at 4,600 for each airing, with 2.4 million total listeners each year. Webpage links to additional information back-up each episode. A wider audience was reached through the subsequent production of the Flip My Florida Yard television series. Produced in partnership with Crawford Entertainment with funding from the Florida Department of Environmental Protection, each 30-minute episode chronicles the complete makeover, or flip, of a homeowner’s typical Florida landscape into a more sustainable Florida-friendly landscape. All accomplished in eight hours, each episode features local designers and contractors and the local Extension agent, as well as a Maintenance Moment tip and a Yard Science segment featuring experts from UF/IFAS and other state entities. New shows air statewide on PBS and past episodes are streamed online. The program received a regional Emmy award in 2023. Flip My Florida Yard has been viewed more than 9.9 million times in the past year. FFL also recently hired a social media manager to increase FFL’s visibility on Facebook, Pinterest, Instagram, YouTube, and Linked-In. FFL’s social media reach is now growing exponentially. FFL also offers monthly webinars for both commercial and homeowner audiences. These webinars are archived to the FFL website and have accounted for more than 38,000 live and recorded views in the past year. Finally, the program has developed numerous online trainings and certification programs to help reach audiences at their convenience. As FFL begins its 32nd year, these marketing initiatives are helping it grow and reach new audiences.
Speakers
TW

Tom Wichman

FFL Assistant Dir., University of Florida
Co-authors
AG

Angela Gregory

UF/IFAS Extension Florida-Friendly Landscaping Program
NA
CL

Claire Lewis

Director, UF/IFAS Extension Florida-Friendly Landscaping Program
Florida-Friendly Landscaping, water conservation, green stormwater infrastructure, behavior change, and almost anything at all!
JM

Jen Marvin

UF/IFAS Extension Florida-Friendly Landscaping Program
NA
JB

John Bossart

UF/IFAS Extension Florida-Friendly Landscaping Program
NA
Thursday September 26, 2024 9:45am - 10:00am HST
South Pacific 1

9:45am HST

ORGH 2 - Digging into Clover Living Mulch Effects on Soil
Thursday September 26, 2024 9:45am - 10:00am HST
Living mulch research has focused on crop health without digging in to the effects on soil health. Soil management influences soil structure, water infiltration, and compaction. The recent drought has affected the Great Plains where precipitation is already limited. This makes it important for the water to infiltrate into the soil instead of running off, taking nutrients along with it. Soil compaction limits plant root’s ability to reach ground water and nutrients deeper in the soil profile which are needed during dry spells. In this study, living mulches of three established clover varieties, ‘Domino’ white clover (WC) (Trifolium repens), ‘Aberlasting’ white x kura clover (KC) (T. repens x ambiguum), and ‘Dynamite’ red clover (RC) (Trifolium pratense), bare ground control (BG), in combination with in-row management of tilled (T), no-tilled (NT), tilled fabric (TF), and no-tilled fabric (NTF) were evaluate for water infiltration, soil compaction, soil temperature and moisture. Water infiltration was measured using a 25.4 cm PVC ring which was pounded in the ground to prevent lateral flow. Water was added every minute to measure the infiltration rate. Soil compaction was measured using a SpotOn soil penetrometer measuring the PSI needed to pass through the soil. Soil moisture and temperature were measured every hour using HOBO MX soil moisture and temperature logger. Water infiltration in NT soil management had a was 67% greater when compared to T soil management. Soil compaction readings from 0-15 cm had a range from 324 PSI in NT to 351 PSI in NTF. After one year of changing the soil management, there was a significant increase in on water infiltration rate in the NT which means the soil can handle much larger volumes of water compared to T. Soil compaction has changed very little between soil managements which can be expected since it takes many years to break compaction layers and improve the soil structure. Soil management can improve water infiltration rates which increases the water added to the soil and decreases the risk of erosion. More time is required to determine how soil management will affect compaction in this study.
Speakers
CR

Connor Ruen

South Dakota State University
NA
Co-authors
KL

Kristine Lang

South Dakota State University
TN

Thandiwe Nleya

South Dakota State University
NA
Thursday September 26, 2024 9:45am - 10:00am HST
South Pacific 4

9:45am HST

PH 3 - Pyrus communis: A Model for Studying Climacteric Ripening and Senescence
Thursday September 26, 2024 9:45am - 10:00am HST
Fruits constitute a critical part of a healthy diet. However, they often perish prior to consumption due to unpredictable ripening. Especially in climacteric fruit, blockage in the perception or synthesis of ethylene has been used to prolong shelf life. European pear (Pyrus communis) are classified as climacteric fruit. However, System 2 ethylene production requires a genetically pre-determined period of cold conditioning, which triggers ripening—in addition, applying 1-MCP, an ethylene perception inhibitor, indefinitely blocks ripening. Using a physiological and developmental transcriptomics approach, we have shown that in 1-MCP fruit stored in a controlled atmosphere, activating alternative respiration via glyoxylic acid stimulation of AOX expression can reverse the effect of 1-MCP. Interestingly, 1-MCP fruit without CA storage responds differently to glyoxylic acid. It shows classic signs of senescence. The underlying processes of ripening and senescence can be discerned by utilizing the fruit that has been treated differently post-1-MCP application. This knowledge is expected to aid in identifying strategies to prolong fruit shelf life.
Speakers
avatar for Amit Dhingra

Amit Dhingra

Head of the Department of Horticultural Sciences, Texas A&M University
Dr. Amit Dhingra is the Head of the Department of Horticultural Sciences, Professor of Genomics and Biotechnology, and Senior Scientist at the Norman Borlaug Institute for International Agriculture at Texas A&M University. After his post-doctoral training at Rutgers University, the... Read More →
Co-authors
EC

Evan C. Stowe

Washington State University
NA
SL

Seanna L. Hewitt

Washington State University
NA
Thursday September 26, 2024 9:45am - 10:00am HST
Nautilus

10:00am HST

CE 5 - Quality Analysis of Bitter Acids in Hops (Humulus lupulus L.) from a Controlled Environment Versus Field Production Syst
Thursday September 26, 2024 10:00am - 10:15am HST
Hop plants are produced for harvest of mature hop cones that are utilized in the medicinal, agricultural, cosmetic and craft beer industries. Hop plants are vigorously climbing perennials that require shorter than 15-hour days for flowering induction, and a trellis structure (3-6m annual height) for seasonal support. In the United States, the majority of hops are grown in field production systems in the Pacific Northwest where summer day lengths are long. The demand for hops has increased due to a boom in the craft beer industry which has led growers in southern states to seek alternative methods for producing hops outside of their traditional commercial growing region. Hop performance in greenhouse systems has not been evaluated in Oklahoma before, but controlled environments offer an alternative for hop producers in the south to limit pests, reduce contact with Downy Mildew (Pseudoperonospora humuli), and harvest multiple crops per year. Four cultivars of hops (‘Cascade’, ‘Comet’, ‘Newport’, ‘Tahoma’) were grown on a 3m trellis using a Dutch bucket hydroponic system with one rhizome per bucket spaced 0.5m apart without supplemental lighting in the USDA research greenhouses at Oklahoma State University. Four identical cultivars of hops were grown in a field system using a V-style trellis (5m height) at the Cimarron Valley Research Station in Perkins, OK. Mature hop cones were hand harvested at 80% moisture and dried at ambient temperature to 8-10% moisture. Hops were stored for up to six months frozen under nitrogen in vacuum sealed bags until analysis was performed. Hop bitter acids (α-acids and β-acids) were extracted using a 0.1% formic acid solvent, and hop quality was determined by HPLC. Bitter acids of greenhouse hops were determined to be highest in cultivars ‘Comet’ (α- 2.12%, β- 0.73%), ‘Cascade’ (α- 2.00%, β- 1.04%), and ‘Tahoma’ (α- 1.92%, β- 1.23%), where ‘Newport’ had a notably lower α and β-acid content (α- 0.71%, β- 0.81%). Bitter acid quality in field hops were comparable to hops produced in the greenhouse (‘Cascade’ α- 2.99%, β- 1.77%; ‘Newport’ α- 2.95%, β- 1.56%; ‘Tahoma’ α- 1.42%, β- 1.56%; ‘Comet’ α- 1.95%, β- 0.71%). With the information from this research, local greenhouse growers will be able to determine if hops are a viable option for their region.
Speakers
KS

katie stenmark

OKLAHOMA STATE UNIVERSITY
Crop Science PhD Student Department of Horticulture and Landscape Architecture Oklahoma State University
Co-authors
BD

Bruce Dunn

OKLAHOMA STATE UNIVERSITY
CF

Charles Fontanier

OKLAHOMA STATE UNIVERSITY
NA
VH

Victoria Hughes

OKLAHOMA STATE UNIVERSITY
NA
Thursday September 26, 2024 10:00am - 10:15am HST
South Pacific 3

10:00am HST

ORGH 2 - Effects of Mulch Type on Day-Neutral Strawberry Yield and Quality in an Organic Production System in the Upper Midwest
Thursday September 26, 2024 10:00am - 10:15am HST
Organic, locally produced strawberries are in high demand in the Upper Midwest. Day-neutral cultivars fit well within an annual production system, allow growers an extended harvest period, and previous research shows they can be productive in our region. However, key production challenges limit adoption of organic production of day-neutral strawberries including weed, insect, and disease pressure. To address these challenges, we established controlled experiments investigating the effects of four different mulch types: white-on-black poly (standard), black poly, reflective metallic poly, and biodegradable paper mulch on yield and quality of ‘Cabrillo’ strawberries across two years (2022 and 2023) and two locations (Madison, WI and St. Paul, MN). Our results show that strawberry yield ranged from 5,000 - 18,000 lbs per acre across treatments and years. The highest yields were achieved in 2023 in Wisconsin in the reflective metallic poly treatment, which was significantly different from the white-on-black treatment in the same year. Proportion marketable yield was equal between treatments in both years in Wisconsin and in 2022 in Minnesota, however we observed a significant decline in marketable fruit quality in Minnesota in 2023 under the paper treatment compared to black plastic.The paper mulch broke down before the end of the production season in Minnesota in both years which led to increased weed pressure and reduce fruit quality; however paper mulch retained at least 90% coverage and integrity in Wisconsin across both years. Tarnished plant bugs (TPB) are a key pest in this system and will significantly reduce fruit yield and quality if not managed. In both Minnesota and Wisconsin, TPB damage was higher in our standard white-on-black poly compared to the reflective metallic poly mulch in both years. In addition, thrips counts were significantly higher on white-on-black poly compared to reflective metallic poly in Minnesota in both years. Anthracnose fruit rot was the most common disease observed and was most common in the white-on-black poly treatment. Anthracnose was also a significant problem on row edges where weeds were actively growing and retaining moisture near the fruits. Overall, reflective metallic poly mulch significantly reduces strawberry insect pest pressure while maintaining yield and fruit quality and outperforms the current grower standard white-on-black plastic mulch. Price premiums for organic strawberries marketed direct by growers combined with the longer day-neutral production season, make day-neutral strawberries financially lucrative despite production issues and high labor requirements.
Speakers Co-authors
AA

Amaya Atucha

University of Wisconsin Madison
CG

Christelle Guedot

University of Wisconsin - Madison
EB

Eric Burkness

University of Minnesota
NA
GD

Gigi DiGiacomo

University of Minnesota
NA
JM

Jarret Miles-Kroening

University of Wisconsin
NA
Thursday September 26, 2024 10:00am - 10:15am HST
South Pacific 4

10:00am HST

PH 3 - Characterization of Postharvest Rots and the Susceptibility to Decay of 38 European Pear Genotypes during Cold Storage.
Thursday September 26, 2024 10:00am - 10:15am HST
Phytopathogenic fungi can cause rots during cold storage leading to the loss of pear fruit and significant economic costs. Currently, all commercially available pear varieties are susceptible to postharvest rots. Genetic resistance to fruit rot pathogens including Penicillium expansum and Colletotrichum spp. has been identified in wild apple germplasm. The objective of this study was to evaluate diverse genotypes of European pears (Pyrus communis L.) for disease incidence during cold storage and evaluate susceptibility to prevalent phytopathogenic fungi by directly challenging fruit using a wound inoculation method. Fruit from 38 pear genotypes were harvested at maturity, then evaluated weekly for the presence of postharvest rots during cold storage. If rot was observed, the diseased fruits were removed from cold storage and fungal isolates were collected from fruit with disease symptoms. The identity of fungal isolates was determined based on morphology and genetic sequencing of marker genes including ITS and TEF1. After 12 weeks in cold storage, the incidence of rot ranged from 8.3% to 100%. Colletotrichum was the most prevalent genus isolated from the rotting pears. Twenty pear genotypes were directly challenged with P. expansum or C. fioriniae using a wound inoculation method on fruit that was harvested at commercial maturity. Five genotypes had significantly reduced disease development when challenged with P. expansum compared to susceptible varieties Gem and Bartlett. Four of these five genotypes also had significantly reduced disease development when challenged with C. fioriniae. One additional genotype was found to have significantly reduced disease development when challenged with C. fioriniae but was highly susceptible to P. expansum. These results will be a valuable resource for pear breeders and aid efforts to develop European pear varieties that have genetic resistance to fruit rot pathogens.
Speakers Co-authors
BE

Breyn Evans

USDA ARS
NA
CB

Caitlin Barnes

USDA ARS Appalachian Fruit Research Station
NA
CG

Christopher Gottschalk

USDA ARS
During his Ph.D. studies, Dr. Gottschalk studied the molecular mechanisms that control flowering in apple as they relate to seasonal bloom times and biennial/alternate bearing in diverse apple germplasm, from wild species to cultivated varieties. Moreover, he investigated plant growth... Read More →
JB

John Bennett

USDA ARS
NA
Thursday September 26, 2024 10:00am - 10:15am HST
Nautilus

10:00am HST

PNM 2 - Methods of Fertilization in Commercial Production of Saw Palmetto (Serenoa repens Small (Bartr.) form green and glauca)
Thursday September 26, 2024 10:00am - 10:15am HST
Saw palmetto is an endemic palm of the Southeastern United States that has been widely used as an ornamental food source for birds and mammals, and the fruit is used as a medicinal supplement for prostate cancer. The production of this palm still relies on wild harvesting. We analyzed the effects of different fertilization methods on the plant growth and fruit production of two saw palmetto forms (green and silver) from 2022 to 2023. Fertilization methods consisted of 1. Control- no fertilizer application; 2. Injection by Arbor-Jet: Palm-Jet Mg 1-2-2 (N-P2O5-K2O) 2.5 ml per plant once a year (ArborJet, Woburn, MA); 3. Granular (Harrell’s, Lakeland, FL): 8-2-12 4 Mg (N-P2O5-K2O 4 Mg) with micronutrients 146 g/m2 of plant canopy; 4: Granular and drench fertilizer: 8-2-12 4 Mg with micronutrients 146 g/m2 with drench application – 20-10-20 Epsom salts Non-staining Micros (Harrell’s MAX, liquid foliar nutritional, Lakeland, FL). Treatments 3 and 4 were applied every three months for a year. Green saw palmetto only differed and performed better than silver form in the number of leaves and offshoot per plant. The granular and granular with drench fertilization provided the best plant growth rates, regarding plant height, width, visual quality, and green canopy cover, then control and injection treatments. Even though the drench had a higher supply of nutrients for the plants, the differences were not statistically significant from granular fertilization.
Speakers
VP

Vania Pereira

University of Florida
Co-authors
KW

Karen Williams

University of Florida
NA
MM

mica mcmillan

University of Florida
PR

Patricia Ramos Barros

University of Maryland
NA
TS

Thiago Souza Campos

University of Florida
NA
WV

Wagner Vendrame

University of Florida
NA
Thursday September 26, 2024 10:00am - 10:15am HST
Coral 1

10:00am HST

POM 3 - Seven-year Yield and Fruit Quality Comparison of Four Apple Cultivars Between Tall Spindle and Bi-axis Systems in Western New York
Thursday September 26, 2024 10:00am - 10:15am HST
Increasing orchard planting density has helped improve grower profits and yields but establishment costs can be high. It is believed that by using bi-axis trees the number of trees required during planting can be reduced while possibly improving yields and fruit quality. To test this possibility, an orchard of four cultivars (‘Brookfield Gala’, ‘Aztec Fuji’, ‘Honeycrisp’, and ‘Ruby Mac’) was established and trained to either Tall Spindle (TS) or Bi-axis (BA) at 1m x 4m spacing. After the third year of growth, all TS trees and half of BA trees were summer hedged, resulting in three systems to compare: 1) TS hedged; 2) BA hedged; and 3) BA non-hedged. Measurements of trunk cross sectional area (TSCA), phenology, yield, and fruit quality were recorded for seven years to calculate cumulative values. At the end of the study, TSCA was larger on TS trees compared to hedged or non-hedged BA trees across cultivars. Biennial bearing was lower with ‘Brookfield Gala’ and ‘Aztec Fuji’ compared to ‘Honeycrisp’ and ‘Ruby Mac’ and trended lower on hedged or non-hedged BA trees than TS trees. The hedged or non-hedged BA trees had higher cumulative yields compared to TS trees across cultivars. Fruit size was reduced on hedged or non-hedged BA trees compared to TS trees, but all three systems had similar fruit color, firmness, and soluble solids on average. After seven years, there was no obvious benefit of using hedged or non-hedged BA systems to improve fruit quality, but higher yield from BA trees over TS trees when planted at the same density, regardless of hedging during the summer, was achieved. We calculated that BA trees could be planted at 15% lower planting density than TS trees to achieve the same yield.
Speakers
avatar for Brian Lawrence

Brian Lawrence

Cornell University
Co-authors
TR

Terence Robinson

Cornell University
NA
Thursday September 26, 2024 10:00am - 10:15am HST
South Pacific 2

10:00am HST

TECH 2 - Development of Crop Water Stress Index for Hazelnuts in the Willamette Valley Using Distributed Low-Cost Infrared Thermometers
Thursday September 26, 2024 10:00am - 10:15am HST
Incorporating data-driven technologies into agriculture offers an effective strategy for optimizing crop production, particularly in regions reliant on irrigation. This becomes increasingly crucial in the face of escalating heatwaves and droughts associated with climate change. Recent advancements in sensor technologies have spawned various methods for assessing irrigation needs. Notably, infrared thermometry stands out as a non-destructive remote sensing method capable of monitoring transpiration, holding significant potential for integration into drone- or satellite-based remote sensing models. This study focuses on the application of infrared thermometry to develop a Crop Water Stress Index (CWSI) model for European hazelnuts (Corylus avellana), a significant crop in Oregon, the leading hazelnut-producing state in the United States. Using low-cost open-source infrared thermometers and data loggers, this research aims to provide hazelnut farmers with a practical tool for monitoring crop water status, improving irrigation efficiency, and ultimately enhancing hazelnut yields. The study, spanning from June to September 2021 in a ‘Jefferson’ hazelnut (Corylus avellana) orchard, applied three distinct irrigation treatments. The calibration of the low-cost IRT sensors achieved a high accuracy (R² = 0.99), validating their utility in detecting variations in canopy temperature consistent with irrigation treatments. The developed CWSI is well-correlated with traditional plant water status indicators including stem water potential, leaf conductance, and transpiration. These results demonstrate the potential of this model to accurately reflect physiological symptoms of water stress in hazelnuts. This research not only introduces a novel CWSI model tailored to hazelnuts but also underscores the utility of low-cost technology in enhancing agricultural monitoring and decision-making.
Speakers
avatar for Dalyn McCauley

Dalyn McCauley

Sr. Faculty Research Assistant, Oregon State University
Co-authors
LN

Lloyd Nackley

Oregon State University
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
NW

Nik Wiman

Oregon State University
NA
Thursday September 26, 2024 10:00am - 10:15am HST
Kahili

10:00am HST

WCPM 3 - A Water Soluble β-triketone Enriched Extract of Manuka Oil has Increased Efficacy Compared to Vinegar and D-Limonene in a Field and Greenhouse Evaluation
Thursday September 26, 2024 10:00am - 10:15am HST
Weed management strategies for specialty and organic crop production are challenging due to limited chemical weed control products with good efficacy that are cost effective. The need for new bioherbicide modes of action has become increasingly urgent in modern agriculture as most bioherbicides have nonspecific modes of action with no systemic activity. Introducing new modes of action is essential to diversify weed control strategies, minimize the risk of resistance development, and ensure sustainable weed management practices. By fostering innovation in bioherbicide development and promoting the use of novel modes of action, we can safeguard our agricultural systems, reduce the environmental impact of weed management, and maintain the ability to feed a growing global population while preserving the long-term health of our ecosystems. Manuka oil is derived from the leaves and branches of the Manuka tree (Leptospermum scoparium) and contains β-triketones. The β-triketone rich fraction contains leptospermone and inhibits a key enzyme, p-hydroxyphenylpyruvate dioxygenase (HPPD). This process directly inhibits carotenoid biosynthesis, upstream in the biochemical pathway, which causes damage to the photosynthetic apparatus and leads to bleaching of the leaf tissue which eventually kills the plant. The β-triketone extract at 2% and 4% had up to 97% control against different weed species in field and greenhouse evaluations. The β-triketone extract was significantly more efficacious verse other bioherbicides such as the 20% vinegar and 12.5% D-limonene. Additionally, the β-triketone extract was just as effective as the 2% glyphosate treatment in the greenhouse evaluation against Amaranthus palmeri and Digitaria sanguinalis. The β-triketone extract also reduced Cyperus esculentus growth by 70% at 9 days after treatment. Thus, there is significant evidence that commercializing a water soluble β-triketones enriched extract of Manuka oil can be an effective weed control strategy in crop production systems, especially in specialty and organic cropping systems where the need of bioherbicides is critically imperative.
Speakers
avatar for T. Casey Barickman

T. Casey Barickman

Research Plant Physiologist, USDA-ARS
I am a Research Plant Physiologist with USDA-ARS in the Natural Product Utilization Research Unit in Oxford, MS. We are housed on the beautiful campus of the University of Mississippi. My research encompasses bioherbicide discovery from natural products and elucidating their modes... Read More →
Co-authors
AR

Amber Reichley

USDA-ARS
NA
CL

Charles L. Cantrell

USDA-ARS-NPURU
NA
Thursday September 26, 2024 10:00am - 10:15am HST
Lehua Suite

10:15am HST

CE 5 - The Affect of High pH on Hydroponic Lettuce in a Controlled Environment
Thursday September 26, 2024 10:15am - 10:30am HST
In North Dakota, indoor-grown lettuce faces water pH levels higher than the ideal 5.5 to 6.5 range, with Fargo's water averaging a pH of 9.2 from 2018 to 2022. Addressing the gap in research on high pH's impact on lettuce, this study, running from 2023 to 2024, explored the effects of pH levels on the yield of lettuce grown in deep water culture (DWC) hydroponic systems. We tested three lettuce varieties (Casey, Gladius, and Tendita) under four pH conditions (6.3, 7.0, 8.3, and an unbuffered level), with each setup replicated four times. Th initial growth was in rock wool cubes under a clear dome for a month before transferring to DWC for another month. The results indicated significant differences in yield and size across pH levels and varieties. Gladius yielded the highest at pH 6.3 (86.0 g/plant), while Casey showed the lowest yield at pH 7.0 (9.6 g/plant). Gladius also achieved the largest diameter (25.1 cm) at pH 6.3, contrasting with Casey's smallest at 7.0 pH (10.2 cm). Notably, high pH (8.3) still produced reasonable yields and sizes, especially with the Gladius variety, highlighting the potential for selecting suitable varieties to mitigate adverse pH effects. This study underscores the importance of variety selection in hydroponic systems with non-ideal water pH, providing crucial insights for optimizing indoor lettuce production.
Speakers
AS

Alexander Speck

North Dakota State University
Co-authors
XF

Xiaoyu Feng

North Dakota State University
XJ

Xinhua Jia

North Dakota State University
Thursday September 26, 2024 10:15am - 10:30am HST
South Pacific 3

10:15am HST

FRBR 1 - Validation of Diagnostic Markers for Stenospermocarpic Seedlessness and Flower Sex in Diverse Muscadinia and Vitis Grape
Thursday September 26, 2024 10:15am - 10:30am HST
Muscadine grapes (Muscadinia rotundifolia) are perennial vines grown commercially in the Southeast United States for the fresh market and as wine and juice grapes. Two highly sought-after traits in fresh market muscadine cultivars are stenospermocarpic seedlessness and perfect-flowered vines. However, the genetic disparity between Vitis and Muscadinia subgenera, coupled with differing chromosome numbers (Vitis=38 chromosomes, Muscadinia=40 chromosomes), presents challenges in introgression of stenospermocarpy from V. vinifera to M. rotundifolia. Although conventional breeding has introduced stenospermocarpy into M. rotundifolia, no molecular markers for this trait have been validated in muscadines. Recently, two Kompetitive Allele Specific PCR (KASP) markers targeting candidate genes for male sterility (VviINP1) and stenospermocarpy (VviAGL11) in V. vinifera have shown promise. Sequence comparisons with published V. rotundifolia genomes suggest that these markers might be effective across diverse Vitis, Muscadinia, and wide hybrid germplasm. In this study, we validated the predictive ability of KASP markers for flower sex and stenospermocarpy across thirteen Vitis x Muscadinia hybrid seedling populations and 191 diverse genotypes. In 2023, 891 seedlings were evaluated for seedlessness, with an additional 214 seedlings assessed for flower sex. Furthermore, 191 diverse accessions underwent evaluation for both flower sex and seedlessness. Of the 891 seedlings, 66 were seedless, 490 were seeded, and 335 could not be phenotyped due to fruit absence. Among the 214 seedlings assessed for flower sex, 88 were perfect, 106 were female, and 20 could not be phenotyped due to flower absence. The stenospermocarpy marker accurately predicted 771 of 783 seedlings and diverse material, while the flower sex marker matched 366 of 383 seedlings and diverse accessions. Discrepancies between marker predictions and observed phenotypes may be due to human error or pollen sterility. Notably, most fruitless seedlings were predicted to be stenospermocarpic, indicating potential issues with partial sterility or cold hardiness in seedless hybrids. We intend to reevaluate the populations for flower sex and seedlessness in summer 2024 to address discrepancies. Overall, the KASP markers developed in V. vinifera exhibited excellent predictive ability across diverse germplasm, offering valuable insights for muscadine breeding programs.
Speakers
IV

Isabella Vaughn

University of Arkansas
Co-authors
CJ

Carmen Johns

University of Arkansas
CZ

Cheng Zou

BRC Bioinformatics Facility, Institute of Biotechnology, Cornell University
NA
LN

Lacy Nelson

University of Arkansas
NA
LC

Lance Cadle Davidson

United States Department of Agriculture-Agricultural Research Service, Grape Genetics Research Unit
NA
MW

Margaret Worthington

University of Arkansas
NA
QS

Qi Sun

BRC Bioinformatics Facility, Institute of Biotechnology, Cornell University
NA
Thursday September 26, 2024 10:15am - 10:30am HST
South Pacific 1

10:15am HST

ORGH 2 - The Nebraska Urban Soil Health Initiative: Combined Effects of Cover Crops, No-till, Compost, and Biochar on Soil Health and Vegetable Crops
Thursday September 26, 2024 10:15am - 10:30am HST
Adoption of soil health management practices like cover crops, no-till, and organic soil amendment is increasing in rural agroecosystems, but less in known about whether urban farmers and gardeners are using these practices and how implementing these practices might influence their soil. To address this knowledge gap, we started the Nebraska Urban Soil Health Initiative to 1) benchmark soil health and current management practices in urban gardens throughout Nebraska, and 2) evaluate the effects of adding new soil health management practices on urban soil health and crop performance. Using a citizen-science approach, we recruited and have retained over 300 participants who collect annual soil samples, complete surveys about their practices and knowledge, and implemented an assigned soil health management practice. Soil health management practice treatment groups ranged from low (e.g., individual practices) to high management intensities (e.g., combinations of practices) and include: 1) a cover crop mixture; 2) no-till with geotextile fabric; 3) compost soil amendment; 4) biochar soil amendment; 5) cover crop mixture no-till; 6) cover crop mixture no-till compost, or 7) cover crop mixture no-till compost biochar. Prior to implementing, most participants (>70%) had positive perceptions about cover crops, no-till, and compost soil amendment, whereas >60% had no opinion or prior knowledge about biochar soil amendment. Over 50% of participants characterized their garden weed pressure as somewhat to very high and over 60% reported very low to low pesticide use, which suggests room for improvement using cover crops and a no-till weed barrier. Baseline soil P across gardens was 186 mg/kg (above a sufficiency level of 25 mg/kg in 98% of gardens) and average soil organic matter was 6.9%, which suggests a legacy of compost amendment to meet crop nitrogen needs. Biochar soil amendment (8 tons/acre) alone reduced zucchini yield by 37%, but yield loss was avoided by pairing biochar with compost and the weed barrier. Initial changes in soil health among participant gardens following implementation of new practices in year one will be analyzed along with year two sweet corn crop response.
Speakers
CE

Collin Eaton

University of Nebraska - Lincoln
NA
Co-authors
MK

Michael Kaiser

University of Nebraska - Lincoln
NA
RS

Ronald Stephenson

University of Nebraska-Lincoln
NA
SW

Samuel Wortman

University of Nebraska - Lincoln
XC

Xinzheng Chen

University of Nebraska - Lincoln
NA
Thursday September 26, 2024 10:15am - 10:30am HST
South Pacific 4

10:15am HST

PNM 2 - Soil Amendments Alter Soil Chemical Properties and Toxic Elements Accumulation in Sweetpotato cvs. Bayou Belle and Beauregard
Thursday September 26, 2024 10:15am - 10:30am HST
Field trials were conducted to investigate the feasibility of applying commonly used soil amendments to reduce the accumulation of arsenic (As), cadmium (Cd), and lead (Pb) in sweetpotato storage roots. The cultivars Bayou Belle and Beauregard were grown on an experimental site with natural levels of As, Cd, and Pb. The following soil amendments were used: agricultural lime (AGL) (1 t·ac−1), gypsum (GYP) (1 t·ac−1), biochar (BIO) (1 t·ac−1), and silicon provided as wollastonite (WOL) (2.5 t·ac−1). Compared to the unamended plots, WOL and GYP were associated with elevated soil pH and sulfur levels while reducing Mn and Fe availability. There were no differences in storage root yield grades for both cultivars. The soil amendments were associated with reducing As and Cd extractability by 12 to 31% and 2 to 5%, respectively. A notable finding was the increase in Cd and Pb accumulation in the cultivar Beauregard amended with WOL. We hypothesize that the elevated pH was associated with reducing available binding sites and surface complexes such as with Mn and Fe, leading to the increased bioavailability of Cd and Pb. These preliminary findings support the hypothesis that AGL is a viable soil amendment under mixed toxic element conditions, reducing Pb accumulation without increasing the uptake of other toxic elements. The data also support the need for a systems-based approach for the long-term management of toxic elements in sweetpotato, where soil amendment application is integrated with the use of cultivars associated with low accumulation of specific toxic elements.
Speakers
avatar for Mae Ann Bravo

Mae Ann Bravo

Graduate Student Assistant, Louisiana State University
Co-authors
AV

Arthur Villordon

Louisiana State University
BT

Brenda Tubana

Louisiana State University
NA
CG

Cole Gregorie

Louisiana State University
NA
DL

Don La Bonte

Louisiana State Univ
NA
LA

Lisa Arce

Louisiana State University
MB

Marissa Barbosa

Lousiana State University
MA

Mary Ann Munda

Louisiana State University
Thursday September 26, 2024 10:15am - 10:30am HST
Coral 1

10:15am HST

POM 3 - After Avery: Apple Photosynthesis and Evidence of a Changing Environment. A Historical and Technical Evaluation
Thursday September 26, 2024 10:15am - 10:30am HST
In 1977 Avery published a review of apple leaf photosynthesis (Pn) rates to estimate maximum rates with current technologies and conditions. This presents a recent review of more than 90 published reports of apple photosynthesis from 1978-2022 evaluated the techniques and equipment used, the experimental parameters of CO2, temperature, light, and vapor pressure deficit. The goal of the review was to determine if techniques used reflected changes in global atmospheric [CO2], and if there was evidence of response of apple leaves to changing [CO2] with time. Avery in 1977 estimated mean apple Pn rate to be ca. 14 µgCO2m-2s-1 and a maximum rate of ca. 22 µgCO2m-2s-1. The current review suggests an estimated mean apple Pn rate to be ca. 15.6 µgCO2m-2s-1 , similar to Avery, but a maximum rate of ca. 31-35 µgCO2m-2s-1, higher than Avery. Since 1977, there has been an approximately 26% increase in global CO2. There was no correlation between experimental [CO2] or atmospheric [CO2] and reported Pn, and although reported Pn rates tended to increase with time, there was no significant correlation to time. Experimental[CO2] was reported in 58% of the reports but omitted in others. Experimental parameters of measurement temperature or vapor pressure deficit were commonly not reported.
Speakers
avatar for Curt Rom

Curt Rom

University Professor. And Associate Director, University of Arkansas and ASHS
Thursday September 26, 2024 10:15am - 10:30am HST
South Pacific 2

10:15am HST

TECH 2 - Performance Evaluation of a Robust Chip-based RF sensor for Soil Moisture Determination
Thursday September 26, 2024 10:15am - 10:30am HST
Controlling water cycles, anticipating disasters, and enhancing agriculture depends on accurate soil moisture understanding. To address climate-related challenges, precise and real-time measurements from soil moisture sensors are essential. Radio Frequency (RF) soil moisture sensors are wireless, low-cost, and simple devices that revolutionize agriculture with real-time accuracy, advance environmental science, and promote sustainable resource management. This study aims to calibrate an innovative chip-based RF sensor using the gravimetric method for moisture content detection. Sensor calibration will be performed for sandy and loamy soils, as varying soil types affect the dielectric constant and complex permittivity measured by RF sensors. The project will explore linear and polynomial regression machine learning techniques to improve the accuracy, efficiency, and reliability of the calibration curves. A pot test with sandy and loamy soils will validate the sensor for moisture content monitoring by comparing it with a commercial moisture content device. The detection range of the sensor is calibrated and validated up to 35% moisture content. This research can demonstrate the accuracy, simplicity, affordability, and robustness of the chip-based RF sensor for soil moisture detection, contributing to the improvement of precision agricultural enhancements.
Speakers
JF

Jannatul Ferdaous Progga

North Dakota State University
Co-authors
IF

Iris Feng

North Dakota State University
SD

Shuvashis Dey

North Dakota State University
NA
SM

Srabana Maiti

North Dakota State University
NA
Thursday September 26, 2024 10:15am - 10:30am HST
Kahili

10:15am HST

WCPM 3 - Weed Control in Bell Pepper after Herbicide Application in a Reduced Sunnhemp Cover Crop Population.
Thursday September 26, 2024 10:15am - 10:30am HST
Sunnhemp cover crop seed germination can be lowered due to poor seed quality, incorrect planting depth, or adverse weather effects. The objective of this research is to evaluate weed control by herbicides in a reduced sunnhemp population. Research trials were conducted at the Plant Science Research and Education Unit, Citra, Florida, and the Syngenta Vero Beach Research Center, Vero Beach, FL. The treatments were sunnhemp at 44.83 kg/ha, sunnhemp at 22.4 kg/ha ( no herbicide, bentazon at 1.12 kg/ha, sulfentrazone at 0.14 kg/ha, halosulfuron at 0.04 kg/ha, glyphosate at 5.5 kg/ha followed by glyphosate at 5.5 kg/ha, and oxyfluorfen at 0.56 kg/ha), and a nontreated weed fallow. Sunnhemp was planted in Citra on July 18, 2023 and in Vero Beach on July 27, 2023; herbicides were applied 2 weeks after planting when the sunnhemp were 15 to 25 cm tall. After 8 weeks of growth, the sunnhemp was mowed and the field was prepared for laying plastic and planting bell pepper. The oxyfluorfen caused significant injury to the sunnhemp; this treatment had similar broadleaf, grass, and nutsedge populations to the weed fallow. In Citra at 14 and 28 days after application, bentazon, sulfentrazone, or halosuluron had lower populations than sunnhemp at 22.4 kg/ha alone, but at cover crop termination all the cover crop treatments had similar nutsedge control. All cover crop alone and cover crop herbicide treatments had similar grass and broadleaf control at crop termination. In the bell pepper crop at Vero Beach, oxyfluorfen had greater nutsedge populations than all the other treatments. Crop yields were similar among the cover crop alone or with a herbicide. The application of a herbicide in a reduced cover crop population is not necessary for increased weed control in a fall cash crop. However, the reduced cover crop population in this study was artificially created so the sunnhemp population was equal spaced through the entire plot. If the sunnhemp is significantly impacted like the oxyfluorfen treatment, then more intense recovery action may be necessary.
Speakers
PD

Peter Dittmar

University of Florida
Co-authors
DD

Devin Davis

University of Florida
NA
Thursday September 26, 2024 10:15am - 10:30am HST
Lehua Suite

10:30am HST

CE 5 - Drought Stress Responses of North American Native Bog Birch and Sweetgale in a Sensor-automated System
Thursday September 26, 2024 10:30am - 10:45am HST
Climate change in the Northern United States is causing less consistent rain events that pressure horticulturists to mitigate the negative impacts of drought stress in ornamental plants. Selecting ornamental native plants that can adapt to predicted changes in climate is a way to preserve and strengthen landscape biodiversity and resilience. Bog birch (Betula pumila) and sweetgale (Myrica gale) are native, colony-forming shrubs indigenous to bogs across the Northern regions of North America with aesthetic features that merit their introduction as ornamental plants. The successful introduction of wetland plants into the nursery industry depends upon their tolerances to variation in water availability typical of managed landscapes. Our 8-week study assessed physiological responses to gradual declines in substrate volumetric water content (VWC) for both shrubs, as water stress intolerance may be a constraint in horticultural landscapes. To model a severe water deficit, we built an automated irrigation system using Arduino microcontrollers connected to soil moisture sensors and solenoid valves that allowed us to track and control VWC. Control plants were maintained at 40% throughout the 8-week period, while drought was simulated by decreasing VWC by 5% each week. Water potential, stomatal conductance, and rate of leaf photosynthesis declined in the plants experiencing drought, with symptoms of leaf dieback and yellowing. In contrast, plants held at 40% VWC maintained physiological functions and had minimal aesthetic decline. By week 8, droughted bog birch and sweetgale reduced their leaf dry masses by 20% and 28%, respectively, relative to control plants. Plants held at 5% VWC had lower stomatal conductance and photosynthetic rates compared to those held at 40%, with sweet gale showing a steeper decline compared to bog birch. During the experiment, stomatal conductance of drought-stressed bog birch and sweetgale decreased by 93% and 77% respectively, and increased for control plants. Similarly, bog birch and sweetgale experienced photosynthetic declines, with respective average decreases of 68% and 62%. At the end of the experiment bog birch maintained a higher leaf retention after severe drought. Most plants of both species retained some living leaf tissue under severe drought. Despite their natural habitats in waterlogged areas, bog birch and sweetgale have potential as drought tolerant, native ornamental shrubs for gardens and landscapes.
Speakers
JH

Jessica Hutchinson

University of Maine
Co-authors
BP

Bryan Peterson

University of Maine
SB

Stephanie Burnett

University of Maine
NA
Thursday September 26, 2024 10:30am - 10:45am HST
South Pacific 3

10:30am HST

FRBR 1 - High-Density Linkage Mapping and Identification of Quantitative Trait Loci Associated with Leaf-Scab Resistance in Pecan
Thursday September 26, 2024 10:30am - 10:45am HST
Genetic maps are essential tools for gene positional cloning and marker-assisted breeding. A pecan mapping population of 119 F 1 trees was derived from a cross of the widely planted cultivars Pawnee and Elliott. Whereas ‘Pawnee’ is susceptible, ‘Elliott’ has long- standing resistance to pecan scab caused by the fungal pathogen Venturia effusa. Molecular markers were developed using genotyping-by-sequencing, and linkage maps were constructed for each parent following the two-way pseudo-test-cross strategy used for cross-pollinated species. The ‘Pawnee’ and ‘Elliott’ maps contain 1,347 and 1,050 single nucleotide polymorphism markers spanning a genetic distance of 4,493.0 and 3,758.4 cM, respectively. While these map lengths are likely inflated due to genotyping errors, a high level of synteny between genetic and physical distances of the markers in both parental maps was achieved. Scab resistance was evaluated through controlled inoculations in the greenhouse using two scab isolates, and a significant quantitative trait locus (QTL) for scab resistance was identified on chromosome 5 in ‘Elliott’. Candidate gene searches within the 2-logarithm of the odds interval of the scab-resistant QTL identified a number of disease resistance related genes, including genes encoding wall-associated receptor kinases, cytochrome P450s, leucine-rich repeats receptor-like serine/threonine-protein kinases, a pectinesterase inhibitor, a cellulose synthase, a flavonol synthase, a 4-coumarate-CoA ligase, a caffeic acid 3-O-methyltransferase, and a MYB domain transcription factor.
Speakers
avatar for Gaurab Bhattarai

Gaurab Bhattarai

USDA Southeastern Fruit and Tree Nut Research Laboratory
NA
Co-authors
CB

Clive Bock

USDA Southeastern Fruit and Tree Nut Research Laboratory
NA
CP

Cristina Pisani

USDA Southeastern Fruit and Tree Nut Research Laboratory
NA
NB

Nolan Bentley

University of Texas at Austin
NA
PC

Patrick Conner

University of Georgia
SC

Shanshan Cao

University of Georgia-Tifton Campus
NA
Thursday September 26, 2024 10:30am - 10:45am HST
South Pacific 1

10:30am HST

ORGH 2 - HydroMulcH2O: A Novel, Certifiably Organic, Biodegradable Mulch Technology for Northern Highbush Blueberries
Thursday September 26, 2024 10:30am - 10:45am HST
Utilizing single-use polyethylene (PE) mulch in agriculture is controversial due to concerns with plastic waste generation and pollution. An alternative option to PE mulch is hydromulch (HM), which is paper-based, biodegradable, and potentially could be certified organic. HMs can be produced from water, recycled paper, and organic-approved tackifier(s). The objective of this experiment was to determine the efficacy of different HM formulations on yield, fruit quality, mulch coverage, and weed suppression in a mature planting of northern highbush blueberry (Vaccinum corymbosum ‘Valor’) grown in eastern Washington. Using a randomized complete block design with four replications, four mulch treatments were tested: (i) HM with 4% guar gum, (ii) HM with no tackifier, (iii) paper mill slurry, and (iv) woven PE mulch (hereafter “weedmat”). The papermill slurry was made by agitating recycled paper with water and sodium hydroxide until the paper was pulped and ink removed. Yield, fruit firmness, titratable acidity as percent citric acid, total soluble solids, and pH were similar across all treatments. Mulch coverage measured as percent soil exposure was greatest for the slurry, followed closely by the 4% tackifier and no tackifier treatments. Weedmat had the lowest percent soil exposure. All treatments mostly suppressed dicot weeds, however, the no tackifier and slurry treatments had the greatest dicot numbers. The 4% tackifier suppressed nearly all dicots. HMs struggled to suppress monocots, with the slurry and no tackifier treatments performing the worst at monocot suppression. The 4% tackifier treatment was better than the other HM formulations, however, it had little-to-no effect on nutsedge (Cyperus esculentus) while weedmat suppressed all monocots. Weed biomass data revealed different patterns with the 4% tackifier treatment having similar weed biomass compared to the slurry and no tackifier treatments. This was likely due to lack of competition, as when weeds penetrated the 4% treatment they did not have other plants to compete with, and thus accrued biomass much faster than weeds in the slurry and no tackifier treatments. Although weed and fruit quality was maintained, future research should focus on increasing HMs ability to suppress nutsedge and other vigorous weed species.
Speakers
BW

Ben Weiss

Washington State University
Ben is from Philadelphia and has been interested in food systems since an early age. He attended his first natural products expo before kindergarten because his parents worked in the natural foods industry. During late adolescence, he started a prolific tomato garden that blossomed... Read More →
Co-authors
AF

Alice Formiga

Oregon State University
NA
AD

Andrew Durado

Montana State University
NA
BM

Brian Maupin

Washington State University
NA
DB

Dilpreet Bajwa

Montana State University
NA
GG

Greta Gramig

North Dakota State University
NA
LD

Lisa DeVetter

Washington State University
NA
SW

Sharon Weyers

USDA, ARS
NA
SG

Suzette Galinato

Washington State University
NA
WA

Waqas Ahmad

North Dakota State University
NA
Thursday September 26, 2024 10:30am - 10:45am HST
South Pacific 4

10:30am HST

PB 3 - Leaf Culture and Regeneration in Two Cultivated Strawberries (Fragaria x ananassa)
Thursday September 26, 2024 10:30am - 10:45am HST
Strawberry (Fragaria × ananassa) holds significant commercial importance as a fruit crop. Tissue culture regeneration techniques offer a promising avenue for rapid propagation, genomic study, and biotech breeding, including genome editing and genetic transformation. However, literature reports on cultivated variety-based strawberry regeneration and transformation/genome editing is limited. This study aims to investigate the influence of various tissue culture conditions on the regeneration efficiency of two major cultivated strawberry varieties, 'Chandler' and 'Festival', by assessing the impact of different culture conditions and hormonal treatments on the regeneration of selected varieties' in vitro leaf cultures. The first three open leaves from 4-week-old in vitro cultures were collected and cultured on Murashige and Skoog (MS) medium supplemented with varying concentrations of Thidiazuron (TDZ) (0, 0.5, 1, 2, 4 mg/L) combined with 2,4-dichlorophenoxyacetic acid (2,4-D) (0.2 mg/L). The cultures were maintained in a growth chamber with varying light (dark/light) and photoperiod conditions. Regeneration parameters, including regeneration rate, regeneration number, and root development, were recorded over an 8-week period. Preliminary results indicate a significant influence of TDZ concentrations and light conditions on shoot regeneration rate and number. The combination of TDZ at 1 mg/L and 2,4-D at 0.2 mg/L under a 20-day dark pretreatment followed by a light (16/8-hour) condition resulted in the highest regeneration efficiency. Rooting was observed when the cultures were transferred to a hormone-free MS medium.
Speakers
KD

Kedong Da

North Carolina State University
Director of plant transformation lab at North Carolina State University
Co-authors
AN

Anna Nelson

NC State University
NA
CS

Calyssa Stevenson

North Carolina State University
NA
EK

Ezra Kinsch

North Carolina State University,
NA
GF

Gina Fernandez

NC State University
NA
HL

Huani Leng

North Carolina State University
NA
KM

Keren Molina Morale

NC State University
NA
SM

Sydney McLennan

North Carolina State University
NA
TY

Tianbao Yang

USDA-ARS
NA
WL

Wusheng Liu

North Carolina State University
Thursday September 26, 2024 10:30am - 10:45am HST
Nautilus

10:30am HST

PNM 2 - Iron Biofortification in Radish and Pea Microgreens Using Alternative Iron Sources and Ascorbic Acid
Thursday September 26, 2024 10:30am - 10:45am HST
Iron (Fe) is an essential and versatile micronutrient in plants and humans, and inadequate levels of dietary Fe can cause impaired development in children and poor physical and cognitive functioning in adults. Iron deficiency is the leading micronutrient deficiency worldwide, affecting around 1.6 billion people, with the most vulnerable demographic being pregnant women and infants. Contributing factors include diets that, particularly in developing regions, are predominantly comprised of cereal grains which are characterized by relatively low bioavailable Fe levels. Additionally, 30% of cultivated soils globally have low Fe availability. Defining effective ways to increase Fe content and availability in edible plants is therefore of utmost importance, and an agronomic approach to Fe biofortification could be a viable solution. Microgreens are an ideal candidate crop for tackling nutrient deficiencies. They are nutrient dense, have low antinutrient levels, can be grown in a relatively short amount of time, and can be consumed raw, making them a convenient target for agronomic Fe biofortification. Unfortunately, Fe uptake by plants is problematic, especially in alkaline and oxidizing conditions. Previous studies have suggested the potential of using ascorbic acid (AA) as an enhancer of Fe uptake. However, this approach has not been tested before in microgreens. Therefore, a study was conducted to investigate in a soilless system the effect of different Fe sources with and without organic acids (Ferric sulfate, Ferric sulfate 0.1% Ascorbic acid, Ferric citrate), applied via fertigation at different concentrations (0, 15, 30, 45 mg/L of Fe), on radish and pea microgreens’ Fe content. Treatments were arranged in a randomized factorial experimental design using three replications. We discovered that Ferric sulfate 0.1% AA was the most effective source in increasing Fe uptake, while Ferric citrate was the least efficient. Fertigating with 45 mg/L Ferric sulfate with 0.1% AA resulted in an approximately 110% increase in Fe accumulation in radish and pea microgreens, compared to the untreated control. However, using sodium hydroxide (NaOH) to adjust the nutrient solution pH, the same treatment was associated with an increased level of Na and resulted in a 3-30% reduction in fresh and dry biomass in both microgreen species. In conclusion, this study provides promising evidence that through fertigation, supplementation of AA with Fe fertilizers is effective in increasing Fe uptake in two microgreens species. However, careful consideration of Fe sources and concentrations needs to be made to not compromise yield and nutritional quality.
Speakers
RR

Rishi Ravichandran

Student, Pennsylvania State University
Co-authors
BN

Benedikt Nuesslein

Pennsylvania State University
NA
EC

Erin Connolly

Pennsylvania State University
NA
FD

Francesco Di Gioia

Pennsylvania State University
Thursday September 26, 2024 10:30am - 10:45am HST
Coral 1

10:30am HST

POM 3 - The Biological Mechanism Behind Early and Late Apple Sports
Thursday September 26, 2024 10:30am - 10:45am HST
Somatic mutations in apple commonly develop into viable bud sports for cultivation. When an apple bud sport has a desirable attribute such as improved color, size, shape, flavor, firmness, sweetness, or harvest timing, it has potential to be introduced as a new cultivar that growers utilize, and consumers enjoy. The genetic mutations and related mechanisms associated with early or delayed maturation (respectively resulting in early or late harvest date) in apple sports are not known despite their value to the industry. By acquiring knowledge about these genetic mutations and their respective molecular mechanisms, breeders can identify markers to conduct more informed crosses to select for early or late maturing apple lines. Apple lines with differing developmental rates resulting in differing ‘designed’ harvest windows would optimize the deployment of field laborers for the apple harvest and improve use of cultural practices to influence harvest time. Comparison of physiology-based markers of fruit developmental stages for apple sports with different maturation dates has been done, but, to the author’s knowledge, not on trees for which crop load has been appropriately adjusted to eliminate its effect on developmental rate. In this study, crop load was regulated on 6 different apple cultivars according to tree trunk cross-sectional area. The sports selected were the ‘Gala’ sport ‘Autumn Gala’ also known as ‘Harry Black’, the early maturing ‘Fuji’ sport ‘September Wonder Fuji’, and the early maturing ‘Cripps Pink’ (‘Pink Lady®’) sport ‘Maslin Cripps Pink’. These three sports were compared to their progenitor/standard harvest time cultivar. Apple fruits were measured on each of five trees per cultivar, and volumetric growth rate was analyzed. We found that in each comparison, fruit growth rate of the early variant was significantly greater early in fruit development, roughly coinciding with the expected conclusion of the cell division phase based on phenology. Consequently, a narrower window of genetic events responsible for the early or late harvest timing phenotype has been captured. Our work confines the search for genetic events responsible for the harvest date mutations to the early developmental stages for apple fruit. We propose that harvest date in these apple bud sports is physiologically predetermined from the very early stages of fruit development and very likely not a function of strictly ripening-related processes.
Speakers
AE

Alexander Engelsma

Michigan State University
Co-authors
BW

Berkley Walker

Michigan State University
CH

Courtney Hollender

Michigan State University
NA
MT

Mauricio Tejera-Nieves

Michigan State University
RB

Randolph Beaudry

Michigan State University
Dr. Randolph Beaudry, Professor, MSU Department of Horticulture (MSc, PhD, University of Georgia). His appointment is 50% MSU Extension and 50% AgBioResearch. His research program includes both regional and international projects and focuses on the physiology of plant responses to... Read More →
Thursday September 26, 2024 10:30am - 10:45am HST
South Pacific 2

10:30am HST

TECH 2 - Development and Demonstration of a Sensor-Based Method for Monitoring Container Substrate Fertility
Thursday September 26, 2024 10:30am - 10:45am HST
Substrate electrical conductivity (EC) measurement is a required Best Management Practice (BMP) for the application of supplemental fertilizers in Florida nursery and greenhouse industries to protect and conserve water resources. The current method of measuring substrate EC is through the Pour-through (PT) procedure, a multi-step method in which representative plants are selected for EC measurement, and a predetermined volume of water is poured on the surface of each test plant. The resulting leachate is collected and EC is determined using an EC meter. This process can be extensive for large-scale nursery production zones, requiring a significant amount of time and manual labor. With the personnel shortages that exist in production nurseries, technologies are needed to improve and optimize EC measurement and recordkeeping so the BMP is effective. This project aims to develop a new, sensor-based method for measuring EC to reduce the time invested by producers compared to the current PT method and provide real-time information on the fertility status of container-grown plants. To achieve this goal, a variety of low-cost, soil-based EC sensors were selected for measuring container substrate EC. Laboratory tests were conducted to evaluate the impact of various environmental parameters on sensor performance and select an optimal sensor for use in this application. A sensor system was designed for field deployment and wireless communication was established to monitor sensor data remotely. A field study is currently being conducted to compare EC data obtained from the sensors to EC measurements collected manually using the PT procedure and develop a protocol for sensor deployment in nurseries. At the end of the experiment, a destructive soil sampling technique will be employed to examine salt stratification within the nursery containers and help determine optimal sensor placement in the pots. This study highlights the need for technology and data-driven methods in modern agricultural practices to address challenges such as production efficiency and personnel shortages.
Speakers
ME

Michelle Ezequelle

University of Florida
Co-authors
AM

Ana Martin Ryals

University of Florida
KX

Kaiwen Xiao

University of Florida
NA
PF

Paul Fisher

University of Florida
NA
YZ

Ying Zhang

University of Florida
Thursday September 26, 2024 10:30am - 10:45am HST
Kahili

10:30am HST

WCPM 3 - Assessing the Effects of Container Sizes and Weed Densities on Weed-ornament Competition in Nursery Container Production
Thursday September 26, 2024 10:30am - 10:45am HST
Effective weed management strategies are essential for producing high-quality and successful ornamentals in nurseries and greenhouses. Weeds can affect both the productivity and quality of ornamentals, especially in containers where nutrient and moisture availability are limited, due to restricted space. The objective of this study was to determine how different types of weed species at various densities and in different container sizes affect the growth of ornamental plants. Two rounds of greenhouse experiments were conducted at the Horticulture Teaching and Research Center, Michigan State University, in summer and fall 2023. Seeds of large crabgrass {Digitaria sanguinalis (L.) Scop} and smooth pigweed (Amaranthus hybridus L.) were grown separately until they attained the 4-6 leaf stage. Liners of hydrangea {Hydrangea macrophylla (Thunb.) Ser.} and syringa (Syringa vulgaris L.) were planted in containers of three different sizes 0.67 gallons (2.54 liters), 1.5 gallons (5.67 liters), and 3 gallons (11.35 liters) containing standard bark-based substrate amended with controlled-release fertilizer. All plants received 0.5 inches (1.3 cm) of water thrice daily and were allowed to grow till they were well established. Then the weed seedlings of large crabgrass and smooth pigweed were carefully transplanted to each container-grown ornamental plant at different densities of 0,1,3,6 per pot, with the density of 0 being the control set. After weed transplantation, all pots were maintained inside the greenhouse for 8 weeks. The experimental design utilized a randomized complete block design with six replications per treatment. Initial and final growth indices of ornamentals were recorded. At 8 Weeks After Potting (WAP) fresh weights of both the weed species and the ornamentals were recorded separately. All data were analyzed in SAS by ANOVA and the Tukey’s HSD test were performed to separate out the means. Results showed that final growth indices of hydrangea were significantly higher than syringa and maximum in 3-gallon containers. Overall, large crabgrass at density of 6 was more competitive than smooth pigweed and hydrangea performed better than syringa in 3-gallon container size in competing the weed species.
Speakers
DS

Debalina Saha

Michigan State University
Co-authors
GA

Greeshmanth Alluri

Michigan State University
Thursday September 26, 2024 10:30am - 10:45am HST
Lehua Suite

10:45am HST

CE 5 - Effects of Plant Growth Promoting Rhizobacteria on Yield of Amaranth viridis Linn. Grown in a Growth Chamber and Greenhouse
Thursday September 26, 2024 10:45am - 11:00am HST
Amaranth viridis Linn. (amaranth), commonly referred to as Callaloo, is highly nutritious, drought tolerant, and require few inputs to grow. Amaranth is also known to have pharmacological properties. However, this crop is susceptible to pest damage, which hinders the crops growth, development, and marketable yield. Plant growth promoting rhizobacteria (PGPR) are naturally occurring soil microorganisms that live in the rhizosphere, aggressively colonize plant roots, and provide many benefits to plants. PGPR can promote plant growth, improve plant tolerance to biotic and abiotic stresses, increase nutrient and water uptake, and cause induced systematic resistance. This study was conducted to investigated the application of PGPR on yield and development of amaranth grown in a growth chamber and greenhouse. The study was conducted at the University of Maryland Eastern Shore Agricultural Experiment Station in a complete randomized design with four treatments (T1: Control, T2: Strand 209 (single strand), T3: Blend 5 (double strand), T4: Blend 8 (triple strand)), and six replications in the growth chamber study and nine replications in the greenhouse studies. One growth chamber study (duration for 5 weeks) and three greenhouse studies (summer 2022, fall 2022, and summer 2023) were conducted for ten weeks. Amaranth shoots grown in the greenhouse were harvested biweekly, and fresh weight and dry weight were measured. In both PGPR studies, height data and chlorophyll content were collected weekly, and fresh and dry weight of the whole plant (shoots and roots) were collected at the final harvest. Blend 5 was shown to significantly increase shoot growth when compared to the other treatments in the growth chamber study. In the 2022 summer greenhouse, Strand 209 and Blend 8 significantly increased root biomass, while Blend 5 significantly increased fresh weight of the whole plant. In the 2023 summer study, Strand 209 was significantly higher in average shoot dry weight and whole plant fresh weight when compared to the other treatments. The results of both studies showed that the application of PGPR increased amaranth growth and development. Future studies will evaluate the effects of the PGPR on systemic resistance of amaranth against the pigweed beetle.
Speakers
ZW

Zachary Williams

University of Maryland Eastern Shore
Co-authors
avatar for Corrie Cotton

Corrie Cotton

University of Maryland Eastern Shore
SZ

Simon Zebelo

University of Maryland Eastern Shore
NA
Thursday September 26, 2024 10:45am - 11:00am HST
South Pacific 3

10:45am HST

FRBR 1 - Genome Wide Association Studies Unmasks Loci Associated With Fruit Size and Sugar Content in Mango
Thursday September 26, 2024 10:45am - 11:00am HST
Mango (Mangifera indica L.) is a popular fruit produced widely along tropical climates for fresh consumption. In this study, mature fruits from a collection of 189 mango cultivars were evaluated for fruit weight and sugar content at horticultural maturity. Subsequently, a total of 10958 single nucleotide polymorphisms (SNPs) generated through genotyping by sequencing (GBS) were used to identify quantitative trait nucleotides (QTNs) associated with fruit weight and sugar content through genome wide association studies (GWAS). Fruit weight over three seasons averaged 454 g. ‘Lancetilla’ and ‘Webber’ cultivars produced the heaviest fruits averaging 1127.5 g and 1108.5 g respectively and the lowest average fruit weights (166.16 g, 184.5 g, and 189.5 g) were observed in ‘Itamaraca’, ‘13-1' and ‘Fralan’ cultivars respectively. The mango cultivars had a mean degrees Brix (°Bx) value of 14.8 with ‘Venus,’ ‘Peach Cobbler’ and ‘Julie’ displaying the highest degrees Brix (°Bx) values of 25.6, 22.4 and 20.6 respectively. Three QTNs in chromosomes 5, 8 and 10 were significantly associated with fruit weight using Fixed and random model Circulating Probability Unification (FarmCPU) association model, while two QTNs in chromosome 2 and chromosome 20 were significantly associated with sugar content using Bayesian-information, Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model. Genetic characterization of loci associated with these two traits in mango provides a solid foundation for SNP marker assisted selection (MAS) to accelerate molecular screening of segregating populations and germplasm in a mango breeding program.
Speakers
VN

Vincent Njung'e Michael

University of Florida
Co-authors
AC

Alan Chambers

University of Florida
NA
JC

Jonathan Crane

University of Florida
RD

Rebekah Davis

University of Florida
NA
XW

Xingbo Wu

Chair 2023-2024, University of Florida
NA
Thursday September 26, 2024 10:45am - 11:00am HST
South Pacific 1

10:45am HST

ORGH 2 - Effect of Plastic Mulch, Living Mulches and Cover Crops on Soil, Weeds and Yield in Artichokes Production
Thursday September 26, 2024 10:45am - 11:00am HST
Standard organic farming production practices for specialty crops frequently involve the use of polyethylene plastic mulch or mechanical soil disturbance to reduce weed competition and enhance crop yields. Although successful, these practices come with environmental consequences, including soil pollution and loss of soil organic matter. As such, alternative methods that prioritize the long-term health of the soil and minimize environmental impact are needed. We performed a field experiment to assess and compare the influence of five soil management systems on soil characteristics, weed pressure and yield in globe artichokes production. Artichoke (Cynara scolymus L.) seedling cvs. Tavor were established on raised beds as: A) intercropped with white clover (Trifolium repens L.) as living mulch, or B) intercropped with crimson clover (Trifolium incarnatum L.) as living mulch, or C) transplanted into mixture of buckwheat (Fagopyrum esculentum M.) and pea (Pisum sativum L.) cover crop residue or D) intercropped with Kurapia (Lippia Nodifera L.) as living mulch, or E) transplanted in PE plastic mulch. Results show that white clover increased soil organic matter (SOM), soil potassium and manganese content, water extractable carbon, soil respiration (CO2), soil nitrate, ammonium and total soil nitrogen compared to plastic mulch at 360 DAS (Days After Seeding). White clover weed suppression ability did not differ from crimson clover and buckwheat/pea mixture. Crimson clover increased SOM at preharvest sampling. Both clovers decreased artichokes yield per plant when compared to plastic mulch. Kurapia increased soil sodium content compared to plastic. Cover crop/reduce tillage system increased SOM at 120 DAS compared to plastic. Due to biomass decomposition, the suppression ability of this mixture decreased over time. Plastic mulch increased copper and iron soil concentration. Artichoke yield from plants grown on plastic mulch had comparable bud weight and yield to buckwheat/pea mixture and Kurapia. The potential to enhance soil nitrogen and carbon levels over a longer period of white clover makes it a valuable choice in systems aiming to improve soil fertility. Crimson clover emerges as the most promising among the clovers, exhibiting less competition compared to white clover, effective weed control, and, although the yield is lower than that achieved with plastic mulch, it maintains a well-balanced crop load. The reduced tillage system has shown promising results, successfully managing weeds adequately and allowing for a satisfactory level of production. No detrimental impact on yield were found intercropping artichokes with Kurapia and, but its effect on soil health was limited.
Speakers
avatar for Arianna Bozzolo

Arianna Bozzolo

Rodale Institute
Co-authors
AS

Andrew Smith

Rodale Institute
NA
JP

Jacob Pecenka

Rodale Institute
NA
Thursday September 26, 2024 10:45am - 11:00am HST
South Pacific 4

10:45am HST

PB 3 - Leaf Culture and Regeneration in Hydrangea Macrophylla
Thursday September 26, 2024 10:45am - 11:00am HST
Hydrangea is a genus of flowering plants that includes a diverse range of species and cultivars. These plants are known for their large, showy flower heads and are commonly grown as ornamental shrubs in gardens and landscapes. Hydrangea macrophylla, commonly known as bigleaf hydrangea, is a popular ornamental shrub in the hydrangeaceae family, well-known for its large, showy flower heads and broad leaves. Tissue culture regeneration techniques offer a promising avenue for rapid propagation, genomic study, and biotech breeding, including genome editing and genetic transformation. However, literature on hydrangea macrophylla regeneration and transformation/genome editing report is limited. This study aims to investigate the influence of various tissue culture conditions on the regeneration efficiency of Hydrangea macrophylla 'Blaumeise,' 'H2020-59,' and 'H15298' by assessing the impact of different culture conditions and hormonal treatments on the regeneration of selected varieties in vitro leaf cultures. The first three open leaves from 4-week-old in vitro cultures were collected and cultured on Murashige and Skoog (MS) medium, supplemented with varying concentrations of 6-Benzylaminopurine (BAP) (0, 0.5, 1, 2 mg/L) combined with 1-Naphthaleneacetic Acid (NAA) (0.01 mg/L). The cultures were maintained in a growth chamber with varying light (dark or light) and photoperiod conditions. Regeneration parameters, including regeneration rate, regeneration number, and root development, were recorded over a 4-week period. Preliminary results indicate a significant influence of BA concentrations and light conditions on shoot regeneration rate and number. The combination of BA at 2 mg/L and NAA at 0.01 mg/L under dark conditions resulted in the highest regeneration efficiency. Rooting was observed when the cultures were transferred to a hormone-free MS medium.
Speakers
KD

Kedong Da

North Carolina State University
Director of plant transformation lab at North Carolina State University
Co-authors
AN

Anna Nelson

NC State University
NA
CN

Callie Nix

North Carolina State University
NA
HL

Huani Leng

North Carolina State University
NA
JN

John Nix

NC State University
NA
KM

Keren Morales

NC State University
NA
SM

Sydney McLennan

North Carolina State University
NA
TR

Thomas Ranny

North Carolina State University
NA
WL

Wusheng Liu

North Carolina State University
Thursday September 26, 2024 10:45am - 11:00am HST
Nautilus

10:45am HST

PNM 2 - Understanding the Boron-Yield Relationship in Pistachio Orchards
Thursday September 26, 2024 10:45am - 11:00am HST
Micronutrients like boron, similar to essential macronutrients (nitrogen, phosphorus, and potassium), play a crucial role in plant growth and productivity, even though they are required in smaller quantities. In California’s pistachio production, boron deficiency was initially identified as a concern. However, more recently, the issue has shifted to excess boron in soils and water, potentially affecting the plants as boron toxicity. The current study is investigating the relationship between soil and leaf boron levels, leaf surface area damage and yield in pistachio drip irrigated orchard. Soil, leaf and yield data were collected from a second year running salinity management trial on an eight-year-old pistachio orchard (established in 2015) on the west side of the San Joaquin Valley. Our preliminary findings indicate that while soil boron levels significantly reduced pistachio yield, no significant correlation was found between leaf boron level or percentage of leaf damage (indicative of boron toxicity) and yield. This indicates that the decrease in yield with increasing soil boron is not caused by a reduction in active photosynthetic area. Based on these findings, focusing on monitoring and maintaining optimal soil boron levels might be the most effective strategy for minimizing potential yield losses associated with boron issues in pistachio orchards.
Speakers
MM

Mukesh Mehata

University of California, Davis
Co-authors
BM

Blake Mccullough Sanden

University of California Davis
NA
GB

Gary Banuelos

USDA ARS
NA
GM

Giulia Marino

University of California, Davis
NA
JC

Joseph Coehlo

Valley Orchard LLC
NA
LF

Louise Ferguson

University of California, Davis
NA
MC

Mae Culumber

University of California, Davis
NA
MS

Marta Saludes

Universidad de Salamanca
NA
Thursday September 26, 2024 10:45am - 11:00am HST
Coral 1

10:45am HST

POM 3 - Characterizing Unique Apple Selections for U-Pick Growers in the Midwest Using Descriptive Analysis, Consumer Liking Tests, and Phytochemical Analysis
Thursday September 26, 2024 10:45am - 11:00am HST
The apple U-Pick market in Ohio lacks diversity in varieties to meet consumer demand outside of those typically available at grocery stores. Apple growers want new cultivars that are suited for growth in the Midwest, ripen across the picking season, and intrigue customers with unique flavors, textures, and traits. These diverse and unique tasting apples exist, but it is difficult to market these apples without a comprehensive understanding of the traits and consumer desirability of these fruits. This project aims to identify and characterize sensory traits in 33 up-and-coming apple selections including commercial, in-development, and wild varieties with novel characteristics suited for local production. Apple selections were chosen in conjunction with apple specialists at The Ohio State University and local apple growers. Consumer perception and apple traits were evaluated through two sets of sensory experiments: consumer hedonic testing and descriptive analysis. Consumer testing was conducted in private sensory booths, where apple slices were provided in a randomized, blinded order to mitigate order effects. One hundred participants rated apples on their appearance, texture, flavor, and overall liking on a 9-pt hedonic liking scale (i.e., dislike extremely to like extremely). Descriptive analysis was conducted by 12 trained panelists who used references as anchors on a 10-pt scale to score important appearance, aroma, flavor, and texture fruit characteristics. Measured characteristics were decided in collaboration with the panel organizer, trained panelists, and included traits of particular interest to growers. The trained panelists rated 26 traits like red color, floral notes, sweetness, and crispness. Anchors were carefully selected to provide precise references along the scale, such as sucrose solutions of varying concentration to calibrate judgements of sweetness. To compare how different factors of the apple related to each other, correlation analyses were run on the datasets. Flavor liking had the strongest positive correlation with overall liking, followed by texture liking, while appearance liking showed a weaker positive correlation. Sweetness exhibited a slight positive correlation with overall liking, whereas sourness showed the opposite. Using mean separation tests, we identified 15 apple selections liked equivalently to Honeycrisp, a top commercial apple. Further phytochemical analysis will enable gaining insights on nutritional quality profile and its relation to consumer preference. Our goal is to provide information on novel apples that will enable apple growers to diversify their offerings, which will also benefit producers and consumers.
Speakers
avatar for Lydia Balogh

Lydia Balogh

PhD Candidate, The Ohio State University
Co-authors
CS

Christopher Simons

The Ohio State University
NA
DM

Diane Miller

The Ohio State University
NA
JC

Jessica Cooperstone

The Ohio State University
NA
JF

Jonathan Fresnedo Ramirez

The Ohio State University
NA
Thursday September 26, 2024 10:45am - 11:00am HST
South Pacific 2

10:45am HST

TECH 2 - Enhancement of air quality in agricultural facility using particulate matter reduction systems
Thursday September 26, 2024 10:45am - 11:00am HST
In agricultural facility, which are equipped with mechanical and closed ventilation systems, have faced the challenge to reduce fine dust concentration for enhancing working environment. Among the dust sources, fruit fuzz, characterized by its dense and needle-like structure, can induce allergic symptoms in agricultural workers upon exposure to their respiratory systems and skin, adversely impacting their health and deteriorating the work environment. The focus of this research is the development of a fine dust reduction system aimed at enhancing the working conditions. The system operates by generating a downward airflow to prevent fine dust from reaching the workers' respiratory systems. To assess the efficacy of the fine dust reduction system, real-time measurements of dust concentrations were conducted at commercial peach sorting stations, both before and after the operation of this system. The findings revealed that during peach sorting task, the total dust concentration was 6.89 times higher than the normal condition, representing the critical need for reducing fine dust levels. The deployment of a particulate matter reduction system specifically within the fruit sorting area, a section identified for substantial dust generation due to the removal process of fruit covering bags, has led to a substantial decrease in airborne particulate concentrations. This targeted intervention resulted in an 80.4% reduction in Total Suspended Particulate (TSP) levels and a 60.3% decrease in PM-10 concentrations at the site of implementation. Additionally, a broader assessment across the entire sorting facility revealed a significant decline in fine dust levels, with TSP concentrations diminishing by 67.6% and PM-10 concentrations by 52.2%. This research underscores the efficacy of targeted fine dust control measures within agricultural facilities, markedly enhancing air quality and the occupational environment for agricultural laborers.
Speakers
HS

hyojae Seo

Department of Rural Construction Engineering, Jeonbuk National University
Co-authors
IS

Il-Hwan Seo

Associate Professor
Thursday September 26, 2024 10:45am - 11:00am HST
Kahili

10:45am HST

WCPM 3 - Herbicide-Resistant Italian Ryegrass in Oregon Hazelnut Orchards: Evaluating Nonchemical and Chemical Methods
Thursday September 26, 2024 10:45am - 11:00am HST
Herbicide-resistant Italian ryegrass (Lolium multiflorum Lam.) presents a significant challenge in hazelnut orchards across Oregon, with confirmed resistance to multiple herbicide modes of action groups (1, 2, 9, 10, 15, and 22). Four field studies were conducted in 2023 to evaluate nonchemical and chemical methods for controlling Italian ryegrass during spring. Tested treatments included mowing at 2 km h-1, electric weeding control (EWC) at 15 MJ ha-1 (2 km h-1), and glufosinate application at 1.68 kg ai ha-1, administered once or twice. Furthermore, combinations of EWC with mowing or glufosinate were examined, resulting in eleven treatments. EWC was performed using alternating current and 30 kW (EH-30 Thor, ZassoTM), treating swaths 1.2 m wide. Assessments conducted 56 days after initial treatment (DAIT) revealed that single mowing showed no significant difference compared to untreated plots. However, when mowing was performed twice, it led to a 30% reduction in inflorescence density and an 84% reduction in weight. EWC, applied once or twice, resulted in significant decreases in Italian ryegrass inflorescence density (51-58%), weight (55-73%), and shoot weight (45-75%) compared to untreated plots, with no significant differences observed between single or double applications. Similarly, glufosinate applied once or twice substantially reduced Italian ryegrass inflorescence density (68 to 86%) and weight (73 to 93%). Combinations of EWC with mowing or glufosinate demonstrated high efficacy, achieving control rates of 89 to 96% and exhibiting comparable efficacy to two applications of glufosinate (96%). These findings suggest that EWC, when applied during the spring period, can effectively control Italian ryegrass, offering comparable efficacy to glufosinate and superior efficacy to mowing.
Speakers
MM

Marcelo Moretti

Oregon State University
Thursday September 26, 2024 10:45am - 11:00am HST
Lehua Suite

11:00am HST

CE 5 - Shade-Avoidance Responses of Kale and Lettuce Elicited by Far-Red Light Can Persist Under High-Light Intensity
Thursday September 26, 2024 11:00am - 11:15am HST
Far-red (FR; 700–750 nm) light induces shade-avoidance responses such as stem and leaf elongation and an increase in specific leaf area (SLA). Previous studies have reported that a high photon flux density (PFD) can mitigate the effects of FR light. However, limited research has explored the impacts of individual waveband PFDs on the effects of high total PFD (TPFD) in regulating FR-light responses. To address this gap, we conducted an experiment hypothesizing that the effects of a high FR fraction [FR-PFD divided by the sum of red (R; 600–699 nm) and FR PFD] on shade-avoidance responses would persist when the TPFD increases were solely from increases in R and FR PFDs. We grew kale (Brassica oleracea var. sabellica) ‘Red Russian’ and lettuce (Lactuca sativa) ‘Rex’ and ‘Rouxai’ under 12 lighting treatments with a 24 h∙d−1 photoperiod, TPFDs of 85, 170, 255, or 340 µmol∙m−2∙s−1, and FR fractions of 0.00, 0.17, or 0.33. The blue (400-499 nm) PFD was constant in all treatments and the alterations in the TPFDs were solely due to R and FR PFDs. Based on preliminary results, high FR fractions increased the leaf length of kale to a similar degree at all TPFDs except for no increase at the TPFD of 85 µmol∙m−2∙s−1. High FR fractions increased the leaf length of lettuce ‘Rex’ and ‘Rouxai’ to a similar degree at all TPFDs. In contrast, the SLA of kale did not respond to the FR fraction at any of the TPFDs. The SLA of lettuce ‘Rex’ and ‘Rouxai’ was increased by high FR fractions to a similar degree at all TPFDs except for no increase at the TPFD of 85 µmol∙m−2∙s−1. Contrary to the paradigm, our results suggest that FR-fraction effects can persist under a high TPFD when R and FR PFDs are elevated. Moreover, the lack of response of kale leaf length and lettuce SLA to the FR fraction at the lowest TPFD implies that a low R and FR PFD attenuates the effect of the FR fraction in eliciting shade-avoidance responses.
Speakers
avatar for Jiyong Shin

Jiyong Shin

Michigan State University
Co-authors
ER

Erik Runkle

Michigan State University
NA
Thursday September 26, 2024 11:00am - 11:15am HST
South Pacific 3

11:00am HST

FRBR 1 - A Genome-Wide Association Study To Identify Loci Underlying Fruit Color In Red Raspberry
Thursday September 26, 2024 11:00am - 11:15am HST
Red raspberry (Rubus idaeus L.) is a high-value crop, acclaimed for its fruit quality characteristics and putative health benefits. Among fruit quality characteristics, color is a critical trait in determining market acceptability and consumer preference. Red raspberry fruit encompasses a wide array of colors, notably yellow, orange, and red. Red fruited cultivars are the most common in commercial settings and market selection is dependent on the color intensity: while the processing industry needs dark berries for most applications, the fresh market requires bright red and non-darkening fruit. Anthocyanins, a group of water-soluble phenolic compounds, are regarded as the major contributors to raspberry red fruit color. Knowledge on the genetics of raspberry fruit pigmentation would be valuable for breeding programs, but to date the genetic control of the different red intensities of raspberries remains elusive. This research aims to map the genetic regions underlying the red shades of raspberry fruit through a genome-wide association study (GWAS). Fruits from 765 red raspberry cultivars and selections – including red-, orange-, and yellow-fruited genotypes – were harvested over four seasons (2018-2021) and analyzed for total anthocyanin content and color. Total anthocyanins were measured through the pH differential methods and color was assessed using a high-throughput digital phenotyping protocol. Leaves from all genotypes were harvested in summer 2022 and used for genomic DNA extraction. Whole-genome sequencing of DNA samples was achieved through Illumina NovaSeq6000, with an average coverage of 30×. Sequences were aligned to the ‘Malling Jewel’ reference genome using BWA-MEM and single nucleotide polymorphisms (SNPs) were identified following the GATK pipeline. Total anthocyanin content ranged between zero (yellow genotypes) and 113.21 mg/100 g fresh weight (FW) of peonidin-3-O-glucoside equivalents (P3OG eq.) and averaged 42.09 mg/100 g FW P3OG eq. Color coordinates L* (lightness) varied between 11.99 and 48.21 and averaged 21.21, a* (red-green) spanned -1.18 and 38.38 and averaged 26.85, b* (yellow-blue) ranged between 4.57 and 30.04 and averaged 18.05. The association between the detected genetic variants and the phenotypic data (fruit color and total anthocyanins) will enable the identification of SNP markers that explain the variation in observed red shades of berries. Such markers will be used in raspberry breeding programs to facilitate the development of cultivars with desired fruit color.
Speakers
CB

Claudia Baldassi

University of British Columbia
Co-authors
MD

Michael Dossett

BC Berry Cultivar Development Inc.
NA
SC

Simone Castellarin

The University of British Columbia
NA
Thursday September 26, 2024 11:00am - 11:15am HST
South Pacific 1

11:00am HST

ORGH 2 - Eastern South Dakota Early Season Soil Tarping Impacts on Soil Microbiology
Thursday September 26, 2024 11:00am - 11:15am HST
Solarization and occultation are weed management strategies used by growers across the globe. However, there is not a large amount of literature discussing the impacts of this weed management practice on soil health. This study evaluated the impact of tarp materials and duration of tarp coverage on soil microbiology. Field experiments were conducted in the 2023 growing season in Brookings, South Dakota. Solarization was conducted using clear tarps secured with sandbags and buried edges. Clear tarps were placed early spring for six, four, and two weeks before tarp removal in May. Immediately following tarp removal, each plot was tilled, and rows of onion transplants were planted. Occultation was conducted using white side up and black side up silage tarps, both applied for six, four, and two weeks before removal and planting onions. These treatments were organized in a randomized complete block design with four blocks and ten treatment plots per block including a control with no tarp. Temperature and moisture data were taken in treatment plots using HOBO temperature and moisture sensors during tarping as well as during the growing season. Soil samples were taken before tarp application to observe organic matter and basic nutrients. Samples were also collected in each treatment plot after tarping and at the end of the growing season to determine differences in organic matter, basic nutrients, soil respiration, permanganate oxidizable carbon, and nitrogen. Solarized plots showed trends of higher temperatures during tarping compared to occultation plots. Solarized plots showed higher soil moisture trends during tarping and lower moisture trends during the growing season. Occultation tarp treatments showed trends of lower moisture during tarping and higher moisture during the growing season. No significant differences were seen between tarp treatments for soil respiration, permanganate oxidizable carbon, and nitrogen. While soil tarping can manipulate soil microbiology, more research is needed to determine the full extent of these impacts.
Speakers
HV

Hannah Voye

South Dakota State University
Co-authors
KL

Kristine Lang

South Dakota State University
RB

Rhoda Burrows

South Dakota State University
NA
Thursday September 26, 2024 11:00am - 11:15am HST
South Pacific 4

11:00am HST

PB 3 - Immature Embryo Germination of Camellia sinensis (L) O. Kuntze.
Thursday September 26, 2024 11:00am - 11:15am HST
Camellia sinensis (L.) O. Kuntze is a woody perennial, evergreen shrub or small tree native to Southwest China, whose leaves are processed into various types of teas for consumption. Harvesting mature tea seeds typically requires 12 to 14 months, with an additional 2 to 3 months needed for germination using traditional methods. In an effort to expedite this breeding cycle, we conducted aseptic germination experiments on immature embryos of Camellia sinensis fruits collected from different months, spanning from May to September. Visible embryos were observed in immature fruits harvested in late July, exhibiting an average size of 2.17 ± 0.33 cm, and demonstrated germination capabilities only after mid-August. These embryos were excised and cultured on Murashige and Skoog (MS) medium supplemented with 3% sucrose and 0.65% agar. Cultures were maintained in a growth chamber set at 24°C under a 16-hour photoperiod. To enhance the germination process, cultures were kept in darkness for the initial two weeks. Immature embryos initiated germination approximately one to two weeks after the initiation of culture. After two months, plantlets were transplanted into a substrate consisting of peat moss and perlite (1:1 v/v) and acclimatized in a mist system within a greenhouse. Five month post-culture initiation, the average shoot length, root length, and leaf number of transplanted plantlets were recorded as 2.24 ± 0.89 cm, 5.61 ± 4.58 cm, and 8.36 ± 2.84, respectively. Preliminary findings suggest promising outcomes, demonstrating the feasibility of in-vitro embryo germination in tea plants. This methodology holds the potential to mitigate late-term abortion of hybrid embryos and significantly shorten the breeding cycle, critical aspects in breeding triploid tea varieties through crossbreeding diploid and tetraploid tea plants.
Speakers
SP

Sarita Paudel

University of Georgia
Co-authors
DZ

Donglin Zhang

University of Georgia
Thursday September 26, 2024 11:00am - 11:15am HST
Nautilus

11:00am HST

PNM 2 - Growth Responses of Hydroponic Vegetable Transplants to Nutrient Solution Concentrations Made with Food Waste Liquid Ana
Thursday September 26, 2024 11:00am - 11:15am HST
Food waste liquid anaerobic digestates (FWLAD) have received much public attention for its potential as an organic fertilizer source as they are rich in mineral elements. However, FWLAD can contain high salinity and high NH4 concentration, and thus, the optimum application rates need to be determined to deliver required plant nutrients without excessive salt and NH4 level. The objective of this study was to evaluate the effects of nutrient solution concentration made from FWLAD on the growth of leafy vegetable seedlings. The seeds of lettuce (Lactuca sativa) ‘Rex’, ‘Muir’, and ‘Roxy’, Swiss chard (Beta vulgaris subsp. vulgaris) ‘Rhubarb’, bok choy (Brassica rapa subsp. chinensis) ‘Mei Qing Choi’, and kale (Brassica oleracea var. sabellica) ‘White Russian’ were sown in rockwool plug and grown at 22 °C under sole-source LED lighting with an 18-h photoperiod at a photosynthetic photon flux density of 200 µmol∙m-2∙s-1. After germination, the seedlings were sub-irrigated with nutrient solution made with either crude or processed FWLAD at electrical conductivities (ECs) of 1, 2, 3, or 4 dS·m–1. Four weeks after treatment, when using crude FWLAD, shoot fresh mass of three lettuce cultivars decreased by 76-92% as EC increased from 1 to 4 dS·m–1. In contrast, with processed FWLAD, lettuce ‘Adriana’ and ‘Roxy’ showed 68-1080% greater shoot fresh mass at an EC of 2 dS·m–1 compared to an ECs of 1, 3, or 4 dS·m–1. Shoot fresh mass of lettuce ‘Muir’ at an EC of 2 dS·m–1 was similar with that at an EC of 1 dS·m–1 but 380-516% greater than those at ECs of 3 or 4 dS·m–1. In lettuce, the EC of FWLAD had similar effects on leaf area as it did on shoot fresh mass, but it had minimal effects on leaf number, relative chlorophyll concentration, and shoot dry mass. In kale, Swiss chard, and bok choy, the EC of FWLAD had little effects on plant growth attributes. Our results suggest that leafy vegetable seedlings vary in their responses to nutrient solution concentrations derived from FWLAD, with lettuce exhibiting greater sensitivity than Swiss chard, bok choy, and kale. In lettuce, lower concentrations of FWLAD (at an EC ≤2 dS·m–1) increased shoot fresh mass.
Speakers
EW

Emily Webb

Arizona State University
NA
Co-authors
YP

Yujin Park

Arizona State University
ZC

Zhihao Chen

Arizona State University
NA
Thursday September 26, 2024 11:00am - 11:15am HST
Coral 1

11:00am HST

POM 3 - Selection and Patenting of New, Grower Friendly Apple Trees by the Maryland Tree Architecture Project
Thursday September 26, 2024 11:00am - 11:15am HST
The Maryland Tree Architecture Project (MD-TAP) used classical plant breeding methods to create, identify, select and then patent grower-friendly apple trees. The project began in 1991 with the open pollination of 'McIntosh Wijcik' trees set in an isolated 'Gala' block. Elite seedlings resulting from that initial cross then served as male parents in an open-pollination of commercial cultivars well-adapted to the warm, wet, windy, Mid-Atlantic climate. Two scion-dwarfed, apple trees producing good quality fruit and demonstrating a reduced susceptibility to fire blight resulted from this effort. These two selections were patented as 'MD-TAP1' and 'MD-TAP2' in 2023. A replicated field trial was set in 2016 to compare these two scion-dwarfed selections, with their wild-type siblings also from this program. Trees were budded onto 'M.111,' a semi-dwarfing rootstock to assess their growth habit and tree size without the benefit of trellis support or sustained annual pruning. Trees were set at a 2.75 by 4.25 m (9 by 14 ft) spacing and are still manageable. Despite annual pruning, they are similar in height to trees in an adjacent tall-spindle planting budded onto dwarfing rootstocks. The University of Maryland concluded two Materials Transfer Agreements (MTAs) with other universities before the patents were allowed. After patenting, the University began contacting commercial nurseries in the Mid-Atlantic Region for future testing and licensing.
Speakers
CW

Chris Walsh

University of Maryland
Chris Walsh is a Professor Emeritus in Horticulture. He currently maintains research and educational programs in tree fruit production and apple tree breeding, and in fresh-market produce safety.
Thursday September 26, 2024 11:00am - 11:15am HST
South Pacific 2

11:00am HST

TECH 2 - Experience with New Generation Horticultural Education, Research and Production Through Indoor Ag.
Thursday September 26, 2024 11:00am - 11:15am HST
These days it has become almost impossible to depend on climate for agricultural production of any crops mainly horticultural crops. Unpredictable climate conditions have been a significant challenge to growers. Therefore, it is an urgent need for horticultural educators, researchers, and growers to come up with new approach to explore new farming techniques. This abstract is to discuss over 8 years experiences of research and education on Indoor Ag includes hydroponics with vertical, horizontal, fully automated, or partially automated farming techniques. It has enormous potential to overcome all challenges that is claimed to grow plants and global food security due to population growth, unpredictable climate, water scarcity, space, labor, and food safety related. Indoor Ag is mainly soilless, it is controlled environment agriculture (CEA). Opening educating opportunities to new generation who can come up with new innovative designs with new techniques to improve it for better. In recent times Indoor Ag has come up with very high expectation, and capable of growing plants from several hundred times more than traditional farming per year. Besides, Indoor Ag (IA) facility or controlled environment agriculture could produce the best quality crops. With the experiences in Indoor Ag along with traditional outdoor Ag, the conclusion is we need to develop education, research, and extension curricula about Indoor Ag, urgently. Indoor Ag as a new discipline it has a few challenges but could be overcome easily by our intelligent next generation students. They can take Indoor Ag education, research and production techniques as the future Horticulture. At present, globally a limited number of faculties and researchers has been involved that needed to be increased through interest and hands-on training in this new technology. It has been observed, most of the Indoor Ag is run by business owners and for business secret they cannot share their true success story to increase competition that we all agree. But we researchers who have been working for the better future to overcome multifaceted challenges can see the Indoor Ag as potential alternative. Therefore, now is the time we should adopt Horticultural education, research, and production through Indoor Ag. We need to develop academic courses, education, and research activities from K-12 to undergraduate and graduate programs in college and Universities. So, whoever involved in agricultural research and education at this moment Indoor Ag should be our goal to make it future global horticulture education, research, and production method.
Speakers
BB

BIPUL BISWAS

FORT VALLEY STATE UNIVERSITY
Thursday September 26, 2024 11:00am - 11:15am HST
Kahili

11:00am HST

WCPM 3 - Limiting Liverwort Growth by Allelopathic Effects of Organic Mulches in Ornamental Production
Thursday September 26, 2024 11:00am - 11:15am HST
Liverwort (Marchantia polymorpha) is one of the problematic weeds in ornamental crop production that deteriorates the quality and aesthetic value of ornamentals. To study the effectiveness of allelopathic properties of organic mulch extracts, six different organic mulch materials including rice hull (RH), cocoa hull (CH), pine bark (PB), maple leaf (ML), shredded cypress (SC) and red hardwood (HW) were used for obtaining mulch extracts. The extracts were prepared by following the modified EPA 1312 synthetic precipitation procedure. In the lab experiment, the mulch extracts obtained were used to impregnate agar media at an increasing dose at either 1x (2ml), 2x (4ml), 3x (6ml), and 4x (8ml) rates. Ten gemmae were transferred to the culture medium in each petri dish and all petri dishes containing gemmae were maintained inside the growth chamber. Data was recorded for number of gemmae germinating in each petri dish and at the end of experiment, the length and width of the thallus derived from each gemmae were measured. For greenhouse experiment, the mulch extracts were applied to nursery containers filled with standard substrate and amended with controlled-release fertilizer for assessing the postemergent liverwort control in nursery containers. Either RH, HW, CH, ML, SC or PB mulch extracts were applied to each of the container uniformly at either 1X (15ml), 2X (30ml), 3X (45ml), and 4X (60ml) rates, at the beginning of experiment and bi-weekly until 10 weeks. Control set without any mulch extract was included as well. Percent of substrate surface covered by liverwort thalli was visually estimated bi-weekly until 10 weeks after first treatment. Fresh biomass of the thalli and number of gemmae cups in each pot were also recorded at the end of the experiment. Both lab and greenhouse experiments had four replications per treatment and were arranged in a randomized complete block design. After 1 week in the growth chamber, ML followed by SC, PB and RH extracts showed maximum suppression of liverwort gemmae germination. At 2 weeks, all rates of ML provided complete inhibition of liverwort. In the greenhouse, all the mulch extracts were able to provide complete liverwort control for the first two weeks. PB and HW mulches showed excellent liverwort control and minimum biomass of liverwort after 10 weeks as compared to other mulches. Hence, the allelopathic potential of the organic mulches can be a promising option for biopesticidal control of liverwort, and a component of integrated liverwort management.
Speakers
MS

Manjot Sidhu

Michigan State University
Co-authors
DS

Debalina Saha

Michigan State University
Thursday September 26, 2024 11:00am - 11:15am HST
Lehua Suite

11:15am HST

CE 5 - Does Intermittent and Continuous Nutrient Flow Affect the Growth and Phytochemicals of Culinary Herbs in NFT Hydroponics
Thursday September 26, 2024 11:15am - 11:30am HST
Hydroponic cultivation has emerged as an innovative method for efficient and sustainable production of different crops because of year-round production and precise nutrient delivery. Light plays a major role when plants are grown in a controlled environment. Supplemental light is necessary for the physiological function of crops when grown in a hydroponics system. In nutrient film technique (NFT) hydroponic production, crops are usually produced with continuously flowing nutrient solutions. However, intermittent flow, where nutrient solutions are paused for periods of time instead of continuous cycling, has been proposed as a more efficient hydroponic system. Intermittent flow of nutrients increases the efficiency of hydroponic systems as it reduces the cost of running pumps continuously. Culinary herbs can be grown easily in NFT hydroponic systems. These herbs are a high-value crop and are a rich source of vitamins, nutrients, fibers, and phytochemicals that are known to fluctuate in concentration in different production systems. Yet it is not known if intermittent irrigation will impact phytochemicals in culinary herbs with or without supplemental lights in NFT production. This experiment investigated the effect of intermittent and continuous flow of nutrients in two culinary herbs, cilantro (Coriandrum sativum) and parsley (Petroselinum crispum) with or without supplemental lights. To regulate nutrient solution flow, the pump was turned on continuously in the continuous flow treatment, whereas it was turned on and off periodically for 30-minute intervals in the intermittent flow system. The herbs were grown for a month and different plant growth parameters like plant height, plant fresh weight, dry weight, root length (RL), total phenolic content (TPC), total flavonoid content (TFC) and proline were measured. Interestingly, nutrient delivery only affected plant height and plant fresh weight in cilantro. Plant height was greater in intermittent flow whereas plant fresh weight was greater in continuous flow. However, nutrient flow did not show any differences in other studied growth parameters in both herbs. Supplemental light significantly increased the root length, plant fresh weight, and dry weight of both herbs. TFC of cilantro was affected by the interaction of supplemental light and nutrient flow system with greater flavonoids in a continuous flow without supplemental light. In parsley, supplemental light increased the proline content. These findings suggest that cilantro and parsley can be grown easily in intermittent flow by reducing the associated cost of production. However, supplemental lighting is necessary to increase the yield of herbs.
Speakers
AR

Abishkar Regmi

Graduate Research Assistant, Texas Tech University
Co-authors
CS

Catherine Simpson

Texas Tech University
NA
HL

Haydee Laza

Texas Tech University
NA
LS

Lindsey Slaughter

Texas Tech University
NA
NM

Naima Moustaid Moussa

Texas Tech University
NA
Thursday September 26, 2024 11:15am - 11:30am HST
South Pacific 3

11:15am HST

FRBR 1 - Relatedness of Luther Burbank’s Plum (Prunus sp.) Introductions based on Genotyping by Sequencing (GBS)
Thursday September 26, 2024 11:15am - 11:30am HST
The renowned horticultural artist and plant breeder Luther Burbank worked with many different species of plants. During his 50-year career, he introduced over 800 cultivars, including more than 150 accessions of plums (Prunus spp.) in the late 1800’s and early 1900’s. Burbank preferred utilizing wide, interspecific crosses to create a vast range of phenotypic variation and then artificially select from the extremes. While a very great artist, Burbank was a substandard scientist because he was derelict in pedigree note-taking. Though many of his introductions are extinct, hobbyists, enthusiasts, and international collections retain nearly a third of the economically viable cultivars he bred. For a century, many of his hybridizations remained inscrutable mysteries until modern genomic and computational tools developed their resolution and statistical power. Today, genotyping by sequencing (GBS) is a useful tool for pedigree reconstruction in the absence of reliable records. GBS can inform principal component analyses (PCA), identity by descent (IBD) kinship, and phylogenetic admixture, revealing complex relationships among taxa. In this study, whole genome sequencing was performed on 53 Prunus taxa used by Luther Burbank in his breeding experiments in the most comprehensive genetic survey of his work to date. Exact parent-offspring relationships between this population may be impossible to discern due to years of back crossing, sibling mating, and open pollination. However, the proportion of genomic similarity amongst these taxa provides information on the relatedness of the genotypes in Burbank’s Prunus experiments, defining four primary lineages within his breeding population. These lineages are comprised primarily of P. salicina and P. simonii, but also have influences from P. americana, P. cerasifera, P. domestica, and P. rivularis. The prevalence of P. simonii in Burbank’s Prunus introductions appears to have been vastly underreported, indicating that some of the seedstock founders of his breeding population could have been P. salicina x P. simonii hybrids at the inception of his career. This research has implications for pedigree reconstruction and prioritizing conservation in collections curation for future studies.
Speakers
avatar for Rachel Spaeth

Rachel Spaeth

Research Horticulturalist, USDA-ARS-NCGR-Davis
Dr. Rachel Spaeth is currently serving as a postdoc with the USDA-ARS-NCGR as the Interim Curator of the Prunus collection. Prior to that she was the Curator at the Luther Burbank Home & Gardens in Santa Rosa, CA for 15 years.  She is the co-host on KSRO's Garden Talk Radio two Saturdays... Read More →
Co-authors
DP

Daniel Potter

University of California at Davis
NA
DP

Domininque Pincot

University of California at Davis
NA
JP

John Preece

USDA-ARS-NCGR Emeritus
NA
PJ

Pat J Brown

University of California at Davis
NA
TG

Tom Gradziel

University of California at Davis
Thursday September 26, 2024 11:15am - 11:30am HST
South Pacific 1

11:15am HST

PB 3 - Development of an In Vitro Transformation System for Gene Editing Powdery Mildew Resistance in Gerbera jamesonni
Thursday September 26, 2024 11:15am - 11:30am HST
Gerbera is among the significant players in the global cut flower market, valued at 30 billion USD in 2023. Gerbera daisies, along with chrysanthemums are the largest segment of the cut flower market with a share of 40%. The quality and quantity of gerbera cut flower production is negatively impacted by the fungal disease powdery mildew causing a significant loss of revenue. Effects from powdery mildew infection include reduced flower quality, stunted growth, decreased flower longevity, and decreased marketability. Powdery mildew is currently controlled using fungicides which increases the cost of cut flower production and has the potential for the fungus to develop resistance to the fungicides. One strategy is to use gene editing and CRISPR technology to produce gerbera plants resistant to powdery mildew. The gene “mlo” which stands for “Mildew Locus O” plays a crucial role in the plant’s defense against powdery mildew infections. Plants with mutations in the “mlo” gene exhibit a type of broad-spectrum resistance providing protection against various strains of powdery mildew. We developed a tissue culture regeneration and transformation system for the Gerbera jamesonii cultivar ‘Flori Line Maxi Yellow’ which is sensitive to powdery mildew. The Agrobacterium tumefaciens strain GV3101 containing a binary plasmid encoding for an enhanced GFP marker gene and hygromycin selection gene was used to develop the transformation system. Young, 10mm sized in vitro leaves with part of the petiole were used as explants. A sensitivity test with the explants showed hygromycin at 7.5 mg/L was optimal for selection of callus with positive GFP expression. The next step is to regenerate GFP plants to confirm successful transformation and design CRISPR constructs to inactivate the “mlo” gene in the powdery mildew sensitive gerbera cultivar via gene editing.
Speakers
HG

Heather Gladfelter

University of Georgia
Co-authors
DW

Dayton Wilde

University of Georgia
NA
KT

Khuram Tanveer

University of Georgia
NA
Thursday September 26, 2024 11:15am - 11:30am HST
Nautilus

11:15am HST

PNM 2 - Foliar Boron Nutrition in Grafted Watermelon: Impact on Fruit Development, Yield, and Quality
Thursday September 26, 2024 11:15am - 11:30am HST
Grafting is an effective management strategy in watermelon crop against soil borne pathogens. Carolina strongback (SB) rootstock used for grafting, is resistant to both fusarium wilt and root knot nematodes which are devastating soil borne pests of watermelon. However, recent trials have shown that SB grafted plant bear fruits 7-10 days later than regulate plants leading to farmers losing early market which is more profitable. Further, tissue boron content in SB grafted plants were reported to be lower than regular watermelon nursery plants. Boron is the key micro-nutrient involves in cell wall and cell membrane, pollination, pollen germination, cell division, translocation of carbohydrates and fruit development. We hypothesize that foliar application of boron will cure the boron deficiency in grafted plants and leads to early fruit set similar to regular watermelon nursery. To test this hypothesis, a field experiment was conducted at Edisto Research and Education Centre, SC with the objective to evaluate the impact of foliar boron applications on pollen viability, pollination, fruit set, and periodic fruit yield as compared to regular watermelon nursery. The experiment was comprised of four treatments including a regular watermelon nursery control, in randomized complete block design. The soils had medium to low boron content of 0.1 pounds/acre. The soils were medium in potassium (133 pounds/acre), zinc (5.2 pounds/acre) and manganese (13 pounds/acre). Within first 25 days of transplanting, we did not observe any difference in the watermelon aboveground growth and biomass accumulation, in different treatments. Further, we will evaluate the impact of foliar boron application on pollen viability, pollination, watermelon fruit set, fruit yield and quality in SB grafted nursery.
Speakers
BJ

Bhupinder Jatana

Clemson University
Co-authors
TS

Tom Sanders III

Clemson University
NA
Thursday September 26, 2024 11:15am - 11:30am HST
Coral 1

11:15am HST

POM 3 - Effects and Interactions of Water Stress and Rootstock on Physiological Responses and Ambrosia Beetle Colonization of Apple Trees
Thursday September 26, 2024 11:15am - 11:30am HST
Rapid apple decline (RAD), a phenomenon that causes sudden decline and death of young apple trees in high-density orchards, is a pressing issue. This problem has been associated with abiotic (flood, drought, freeze) and biotic stressors (fungi, bacteria, and insects). Ambrosia beetles (AB) (Xylosandrus spp.) have been linked to stressed trees suffering from RAD. However, the direct association is still not clear. We evaluated the effects and interactions of rootstock (‘B. 9’, ‘M. 7’, and ‘G. 41’) and water stress (flood, drought, control) on physiological responses and AB colonization. Specifically, a greenhouse experiment was performed in spring 2023 on 14-month-old potted ‘MAIA1’ trees. Trees were subjected to water stress for 20 d. Water stress treatments consisted of a saturated pot-in-pot system for flood, water with-held for the duration of the experiment for drought, and irrigation based on soil moisture, maintaining the pots between 0.7 and 1 water fraction volume for control trees. The experiment had a randomized complete block design, was replicated 10 times, and had a factorial treatment structure. Measurements were made every 2 d for soil moisture, fluorometry, and spectrometry data, every 4 d for leaf gas exchange and midday water potential, at 7 and 14 d for ethanol volatiles, and at the termination of the experiment for AB colonization. Under control conditions, ‘G. 41’ trees had higher transpiration, stomatal conductance, and assimilation rates than ‘B. 9’ and ‘M.7’ trees. However, after 4 d of stress, ‘G. 41’ showed a more rapid decline in leaf gas exchange parameters relative to other rootstocks. Drought-stress trees from the three rootstocks declined 4 d faster than flood trees during the first 12 d. However, this decline occurs more abruptly in ‘G. 41’ and ‘M. 7’ trees. From 16 to 20 d, drought and flooded trees have a similar response. Under control conditions, all three rootstocks have similar quantum efficiency values. Conversely, under water stress, ‘G. 41’ and ‘M. 7’ declined faster than ‘B. 9’ trees, with a more severe response to drought for ‘G. 41’ and ‘M. 7’ trees. Chlorophyll index (Ci) showed lower values for flood and drought trees after 10 d for ‘G. 41’ and ‘M. 7’ trees. For ‘B. 9’, this was only true in drought trees. Flooded trees had AB tunnels three times longer than control, and drought trees were the only ones where AB larvae were observed, which was linked to higher ethanol levels.
Speakers
MM

Melissa Munoz

NC State University
Co-authors
CR

Christopher Ranger

USDA-Agricultural Research Service
NA
TM

Thomas M. Kon

NC State University
NA
Thursday September 26, 2024 11:15am - 11:30am HST
South Pacific 2

11:15am HST

WCPM 3 - Effect of Application History on Preemergence Herbicide Persistence
Thursday September 26, 2024 11:15am - 11:30am HST
Preemergent herbicides are commonly applied to control many annual weed species in turfgrass systems. Oxadiazon and prodiamine are pre-emergent herbicides that effectively inhibit the growth of emerging annual grasses and broadleaf weeds without harming certain turfgrass species. However, in recent years, a decline in the efficacy of oxadiazon and prodiamine has been observed by golf course managers, leading to an increase in application rates in an attempt to mitigate the issue. Therefore, the objective of this study was to characterize degradation processes that affect oxadiazon and prodiamine persistence and efficacy in order to identify solutions or mitigation strategies. Soil samples were collected from unique sites throughout North Carolina. Field studies were organized as a randomized complete block design containing 3 replications and 2 experimental runs. Treatments were arranged in a split-split plot design, where the whole plots consisted of 4 sites with histories of continuous oxadiazon or prodiamine use (never applied, applied 1-2 years, ~7 years, > 15 years), the sub-plots were 2 treatments (non-sterilized and sterilized), and the sub-sub-plots were 6 collection timings (14, 28, 42, 56, 112, and 168 days after treatment). Herbicide residue quantifications were determined using high-performance liquid chromatography. Data were recorded and converted into a percentage of the applied rate. A higher percent of oxadiazon was observed for sterilized soil (79.2%) compared to non-sterilized soil (73.7%). In the non-sterilized soil, at 14 DAT there were no differences between periods of use. However, at 28 DAT, the soil with no use history presented a higher percentage of oxadiazon (83.0%) compared to 1 and 15 years (75.5%, and 77.1% respectively). Furthermore, at 42 and 56 DAT, the soil with no history of application exhibited the highest percentage of oxadiazon among all periods of use. Findings of this study suggest that there is higher concentration of oxadiazon, meaning less degradation, in the soils with no history of application.
Speakers
TG

Travis Gannon

NC State University
Co-authors
AV

Alex Veverka

NC State University
NA
EG

Estefania Gomiero Polli

NC State University
NA
KA

Khalied Ahmed

NC State University
NA
RR

Ronald Rogers

NC State University
NA
Thursday September 26, 2024 11:15am - 11:30am HST
Lehua Suite

11:30am HST

CE 5 - Adjusting Supplemental LED Light Intensities Based on Real-time Chlorophyll Fluorescence Measurements in a Greenhouse
Thursday September 26, 2024 11:30am - 11:45am HST
Precise and efficient control of supplemental lighting is vital to minimize electrical energy costs in controlled environment agriculture. Even though various environmental factors such as temperature, vapor pressure deficit, CO2 concentrations, and water status influence photosynthetic capacity, current supplemental light control strategies are controlled only based on ambient sunlight conditions. Meanwhile, chlorophyll fluorescence is widely used as an indicator of environmental stress and photosynthetic capacity on account of its easy and non-invasive measurement. A chlorophyll fluorescence-based biofeedback system has been proposed as an innovative approach for precise control of supplemental LED light intensities. The biofeedback system can dynamically optimize LED light intensities based on real-time measurements of chlorophyll fluorescence while allowing plants to decide the amount of supplemental light they need. The biofeedback system has been previously validated in a growth chamber, but its application in an actual greenhouse condition remains unexplored. The objective of this research was to implement the biofeedback system in a greenhouse environment for real-time control of supplemental light intensities based on photosynthetic activity. Additionally, the productivity and energy efficiency of the biofeedback strategy were evaluated and compared to conventional light control strategies. Two fluorometers (MINI-PAM; Heinz Walz, Effeltrich, Germany) were used to monitor the electron transport rate (ETR) and quantum yield of photosystem II (ΦPSII) every 10 minutes, and the Biofeedback system adjusted supplemental LED light intensities until the predefined target ETR and ΦPSII were achieved. Three popular greenhouse crops [lettuce (Lactuca sativa), sweet basil (Ocimum basilicum), and spinach (Spinacia oleracea L.)] were grown under five supplemental light conditions. Specific targets of 1) electron transport rate (ETR), 2) quantum yield of photosystem II (ΦPSII), 3) photosynthetic photon flux density (PPFD), 4) daily light integral (DLI), and 5) no control (ambient sunlight) were used to control supplemental light intensities. In contrast to conventional lighting control methods, the biofeedback system tailored supplemental light intensities according to not only sunlight levels but also temperature and humidity. The result underlines the effectiveness and energy efficiency of the biofeedback system that could integrate variable environmental factors in the greenhouse and apply them to adjust supplemental light intensities precisely.
Speakers
avatar for Suyun Nam

Suyun Nam

PhD student, University of Georgia
Co-authors
LB

Leonardo Bastos

University of Georgia
NA
MH

Mark Haidekker

University of Georgia
NA
MY

Melanie Yelton

Grow Big CEA Consultants
NA
RF

Rhuanito Ferrarezi

University of Georgia
NA
SN

Savithri Nambeesan

University of Georgia
NA
Thursday September 26, 2024 11:30am - 11:45am HST
South Pacific 3

11:30am HST

FRBR 1 - A Deep Learning‐based Smartphone App for Blueberry Yield Prediction
Thursday September 26, 2024 11:30am - 11:45am HST
The global blueberry market has been expanding vastly driven by consumer demand for healthier food. As a top blueberry producer, United States generated a revenue of $932 million in 2020. A profitable blueberry industry relies on continued cultivar improvement. One challenge faced by blueberry breeders, researchers, and growers, is yield data collection. Measuring blueberry yield by manual sampling is labor-intensive and time-consuming. We developed a smartphone application leveraging deep learning techniques to automate yield prediction and maturity assessment for different blueberry cultivars under field conditions. State of the art YOLOv8 models were fine-tuned and evaluated using a dataset of side-view images of various southern highbush and rabbiteye blueberry cultivars. The best performing DL model of YOLOv8-x achieved a mean average precision of 0.708 and 0.372 under 0.5 and 0.5-0.95 Intersection over Union thresholds on validation datasets, respectively. Blueberry yield was predicted using non-linear regression-based machine learning models using the image-derived mature berry count multiplied by user-defined average berry weight and cultivar as explanatory variables with satisfactory accuracy. This proposed smartphone app can enable image-based yield prediction for blueberry growers and breeders, which is valuable for management decision making and accelerated selection for high-yielding cultivars.
Speakers
SR

Sushan Ru

Auburn University
Co-authors
PS

Puranjit Singh

University of Delaware
NA
YB

Yin Bao

University of Delaware
NA
Thursday September 26, 2024 11:30am - 11:45am HST
South Pacific 1

11:30am HST

PB 3 - Declining Phosphorus Availability Increases Sucrose Synthase Activity and Storage Root Formation in Sweetpotato cv Beauregard Adventitious Roots
Thursday September 26, 2024 11:30am - 11:45am HST
Sucrose Synthase (SuSy) plays a crucial role in sugar metabolism mainly in the sink tissues of plants. In sweetpotato, increased SuSy activity has been associated with increased storage root development and correlated with sink strength. However, little is known about the specific variables associated with increased SuSy activity. Evidence from model systems supports the hypothesis that phosphorus (P) starvation is associated with increased accumulation of carbohydrates in roots. In the first study, we measured SuSy gene expression in ‘Beauregard’ sweetpotato grown in a split root system and subjected to the following P treatments: positive control ( / ), negative control (0/0), declining P (-/-), and split P ( /-). The declining P treatment corresponded to 25, 50, 75 and 0% progressive reduction in P and was imposed on days 6, 9, 12, and 15, respectively. A second study was conducted to measure storage root development at 50 days. The (-/-) treatment was associated with increased SuSy activity in developing adventitious starting at 11 days after planting. Moreover, plants grown with the declining P treatment produced storage roots with larger diameter (>2cm) significantly higher than the positive control. Decreased SuSy activity was associated with reduction in storage root number among P-deficient (0/0) plants. Taken together, these results support the hypothesis that P availability in the root zone is associated with sink strength and storage root formation signaling in adventitious roots. These findings can be used to develop tools and management practices to increase P fertilizer efficiency for consistent storage root yields in sweetpotato.
Speakers
avatar for Marissa Barbosa

Marissa Barbosa

Lousiana State University
Co-authors
AV

Arthur Villordon

LSU Agcenter
CG

Cole Gregorie

LSU AgCenter Sweetpotato Research Center
NA
DL

Don La Bonte

Louisiana State Univ
NA
LA

Lisa Arce

Louisiana State University
MA

Mae Ann Bravo

Louisiana State University
Thursday September 26, 2024 11:30am - 11:45am HST
Nautilus

11:30am HST

POM 3 - The Role of Photosynthesis in the Regulation of Early Fruit Growth of Apple
Thursday September 26, 2024 11:30am - 11:45am HST
Photosynthesis is well-known to not only occur in leaves but also other tissues like stems, sepals, and fruits. Fruit photosynthesis has been documented in cucumber, tomatoes, satsuma mandarins, prickly pear, wheat, and apple. Fruit photosynthesis occurs in these instances not only to contribute to carbon assimilation but to support other metabolic processes, the synthesis of metabolites, and seed development. Early fruit growth in apple is regulated by energy-intensive cell division that lasts for approximately five weeks before switching to a phase of predominantly cell expansion-driven growth. Thus, fruit photosynthesis during early fruit development in apple could function to fulfill the resource and energy requirements necessary for the growth and development of fruit tissues. To examine this potential contribution of photosynthesis to apple fruit metabolism, shade bags made of 30%, 65%, and 80% shade cloth were placed on fruitlets at 16 days after full bloom. The effects of fruit shading on fruit tissue plastid ultrastructure, metabolite composition and tissue transcriptomes were analyzed. Using transmission electron microscopy (TEM), we found that plastids in the peel and cortex overall resembled that of photosynthetically active plastids; they contained stromal and granal thylakoids similar to those found in leaves. Spatially, pith plastids displayed unique hypergranal features , with increased granal thylakoids and a significantly reduced presence of stromal thylakoids. When compared to the control, 80% shaded peel plastids contained more plastoglobuli, and 80% shaded pith plastids displayed prolamellar bodies, which are indicative of disassembly. Further, significantly lower chlorophyll a concentration was observed in shaded fruit. Metabolite analyses indicated that sorbitol was significantly greater in shaded fruit than in the control. Transcriptome analyses indicated substantial changes associated with carbohydrate metabolism in the fruit cortex and peel in response to fruit shading. Together, these analyses indicate a significant contribution of fruit photosynthesis to early fruit growth and development in apple.
Speakers
BR

Bayleigh Roussel

University of Georgia
Thursday September 26, 2024 11:30am - 11:45am HST
South Pacific 2

11:45am HST

CE 5 - Interactions of Far-Red Photons with Orange Photons or Red Photons: Photosynthetic Response, Morphology and Fruit Yield
Thursday September 26, 2024 11:45am - 12:00pm HST
Plant response from the interaction between far-red and orange photons were rarely known, compared to that of far-red and red photons. Recent previous studies have found application of supplemental orange photons increases the openness of tomato plant architecture, resulting in improved dry weight than supplemental blue, green and red photons. However, limited information is available on the effects of orange photons on plant growth, morphology, and photosynthetic efficiency. Thus, our objective was to quantify the effects of orange photons on growth and photosynthetic responses during long term crop cultivation, compared to red photons. Dwarf tomatoes ‘Red Robin’ were grown in a walk-in chamber with controlled environmental conditions for 96 days after sowing (day temp. 24.3 ± 0.4℃ / night temp. 19.8 ± 0.5℃ and RH 60.5 ± 3.5%). Four light spectral treatments were applied as follows: 1) B25G25O200 (orange), 2) B25G25R200 (red), 3) B25G25O165FR35 (O FR), and 4) B25G25R165FR35 (R FR) (subscripts denote photon flux densities in µmol m² s-1). All spectral treatments had the same total light intensity of 250 µmol m² s-1 with a 18-h photoperiod. Leaf photosynthetic rate was measured before the fruit stage under sole-source orange or red light, as well as under combination lights (RGB or OGB), in a random order. Plant height and main stem length significantly increased under the two spectral treatments with far-red photons (i.e., O FR or R FR), compared to treatments without far-red photons (i.e., orange and red treatments). In comparison between orange and red treatments (without far-red), total dry weight of orange treatment was significantly higher than in red. However, the trend was opposite in the treatments with far-red photons (O FR treatment was lower than R FR treatment). In comparison between with and without far-red photons, total leaf area and fruit dry weight under far-red photons were significantly higher than those in the treatments without far-red photons, whereas stem weight was lower. Brix° under with far-red photons was higher than the treatment without far-red, and that of orange treatment was higher than in the red. Photosynthesis rate under sole-source orange photons was higher than under red photons, but no significant difference was observed among under combination lights. Overall, our results indicated that application of orange photons instead of red photons led to improved biomass and fruit yields in dwarf tomato, resulting in enhanced openness in the canopy structure; however, the trends were reversed with the application of far-red photons.
Speakers Co-authors
SZ

Shuyang Zhen

Texas A
NA
Thursday September 26, 2024 11:45am - 12:00pm HST
South Pacific 3

11:45am HST

FRBR 1 - Utilizing Optical Sorting Technology for High-Throughput Phenotyping in Sweet Cherry Breeding
Thursday September 26, 2024 11:45am - 12:00pm HST
Phenotyping remains a bottleneck in many breeding programs, including sweet cherry. Current fruit evaluation protocols require extensive manual sorting and visual evaluation, which reduces throughput and is subject to evaluator bias and fatigue. The Washington State University Cherry Breeding Program is seeking more efficient methods of evaluating fruit quality. In 2023, the program acquired an optical fruit sorter. Our objective was to customize the sorter parameters according to breeding program needs and compare the results of the sorter with traditional methods. Our Tomra InVision 2 sorter has the same optics, software and computer hardware as a commercial sorter, but operates on a single lane. Fruit are loaded onto an infeed system which passes fruit in single file into the detection area. A combination of fruit rotation, multiple cameras and mirrors is designed to image the entire surface of individual fruit. Both visual and infrared images are captured, generally > 24 images per fruit at a rate of approximately 15 fruit per second. The sorter software identifies fruit and classifies them according to a set of tunable quality parameters or grades. Air-actuated valves then eject the fruit into one of four grade-determined exits. The sorter generates reports that include the fruit size profile as well as the percentage of fruit sorted into the various exits and/or grades. The sorter shipped with a pre-loaded map (sorting algorithm), which we modified by updating with data from representative images of various quality parameters. We then used the sorter to grade fruit from Phase 2 variety trials. We analyzed 50-fruit subsamples in the traditional manner for size and defects. All remaining fruit from each sample were analyzed via the sorter. Out of 20 samples evaluated, the average number of fruit per sample evaluated by the sorter was 154, vs. 50 for manual evaluation. Overall, the sorter detected a lower percentage of cracking, doubles (polycarpy), and pitting vs. manual evaluation, and a higher percentage of skin blemishes. Continued testing will be required to determine whether these differences are due to the effects of small sample size or bias due to the methods themselves (human evaluator vs. sorter). While the sorter required a similar number of personnel as for manual evaluation, it required less time to evaluate each sample even though more fruit were analyzed. We will expanding the use and testing of the sorter in 2024, including evaluation of postharvest quality.
Speakers
PM

Per McCord

WASHINGTON STATE UNIVERSITY
Co-authors
MM

Marcella Magby

Washington State University
NA
Thursday September 26, 2024 11:45am - 12:00pm HST
South Pacific 1

12:00pm HST

NUTS 2 - A Look at Heat Stress on Micro-propagated Pecan Trees
Thursday September 26, 2024 12:00pm - 12:15pm HST
Carya illinoinensis (pecan) belongs to the Juglandaceae family, and the native region extends from Illinois, USA to Oaxaca, Mexico. Pecan is a valuable economic crop due to its nutritious and tasty nuts, and the United States produced 275 million pounds of pecans in 2022. As temperatures are increasing it is important to understand the impact on pecan trees. By 2100, the average U.S. temperature is projected to increase by about 3°F to 12°F. Plants deal with heat stress in several different ways including the production of heat shock proteins (HSPs) and their transcription factors known as heat shock factors (HSFs). HSFs initiate the transcription of genes that encode heat shock proteins (HSPs), that deal with heat stress by initiating protein folding and aid in the repair or removal of damaged proteins. In this study, we aim to look at the genetic networks that are impacted when multiple genotypes are subjected to high-heat environments. For this study, seedstocks from multiple genotypes that span the geographic region of North America were introduced into micropropagation. These include seedstocks from ‘Elliott’, ‘Apache’, ‘Cape Fear’, ‘Mahan’, ‘Giles’, ‘Sioux’, ‘Wichita’, ‘Western’, and native seedstocks of unknown genetics from Ohio. A preliminary heat stress assay was performed on a micropropagated ‘Elliott’ line by subjecting three small trees to 43°C for two hours prior to flash freezing in liquid nitrogen and comparing these to the same clonal line (three trees) that remained at 23°C. Real time quantitative reverse transcription PCR (QRT-PCR) was performed on the heat stress and control trees. Normalized gene expression indicated that CiHSP1 expression was 2X higher in the heat-treated pecan trees than CiHSP1 expression of the control trees. The additional micropropagated seedstocks listed above are being subjected to heat stress at different temperature ranges and time intervals. The replicated assays will be analyzed using RNA-Seq and qRT-PCR to determine differential gene expression of control and heat-treated trees especially between the HSPs and HSFs. These assays will help determine the gene networks that pecan trees use as they experience heat stress and will help determine how different pecan genetics that originate in different geographic regions react to heat stress.
Speakers
avatar for Doris Alexa Arnedo

Doris Alexa Arnedo

New Mexico State University
Co-authors
AH

Angelyn Hilton

USDA ARS Southern Plains Agricultural Research Center
NA
JR

Jennifer Randall

New Mexico State University
NA
KC

Kimberly Cervantes

New Mexico State University
NA
SP

Sahithi Pulicherla

New Mexico State University
Thursday September 26, 2024 12:00pm - 12:15pm HST
Lehua Suite

12:15pm HST

NUTS 2 - Unraveling the role of LEA(Late embryogenesis abundant) genes in pecan stress resilience
Thursday September 26, 2024 12:15pm - 12:30pm HST
Late embryogenesis abundant (LEA) proteins, encoded by a family of LEA genes, are vital in conferring stress tolerance in plants through their unique intrinsically disordered structure that can stabilise cellular components under desiccated conditions. While the protective capabilities of LEA proteins are well-documented across various crops, their specific roles in pecan (Carya illinoinensis), a highly nutritious and economically significant nut crop, remain largely unexplored. This gap of knowledge needs to be addressed as pecan yields face threats from escalating drought and salinity issues, intensified by ongoing climate change. This study represents the first comprehensive analysis of LEA genes within the pecan genome. We have successfully identified 332 LEA genes distributed across 15 of the 16 chromosomes in four genomes of pecan, categorized into 8 distinct subgroups based on their conserved motif regions. Synteny analysis provided a deeper understanding of their evolutionary trajectories. Utilizing extensive transcriptomic datasets, we explored the tissue-specific expression patterns of LEA genes in pecan, discovering diverse expression profiles across various tissues. Ongoing studies include promoter analysis and assessments of gene expression under abiotic stress conditions. To specifically address the impact of drought, heat and salinity, clonal pecan plants are being subjected to these stressors under controlled conditions in tissue culture and greenhouse settings. This approach aims to directly observe the physiological and molecular responses of LEA genes under realistic stress simulations. The presence of LEA genes across a vast majority of pecan chromosomes and their diverse subgroup classifications suggests a genome-wide defense mechanism potentially key to enhancing the stress tolerance of pecan trees. By understanding and harnessing these genes, our research seeks to elucidate plant stress responses at the molecular level allowing the development of genetic strategies to ensure the sustainability of pecan by mitigating adverse environmental impacts on its production. This knowledge could also be applied in a diverse array of other economically significant crops.
Speakers
avatar for Sahithi Pulicherla

Sahithi Pulicherla

PhD Candidate, New Mexico State University
Co-authors
AA

Alexa Arnedo

New Mexico State University
CM

Chris Mattison

United States Department of Agriculture
NA
JR

Jennifer Randall

New Mexico State University
NA
Thursday September 26, 2024 12:15pm - 12:30pm HST
Lehua Suite

12:15pm HST

WUM 3 - Assessing Grapefruit Responses to Different Irrigation Rates for Managing Salinity Water Under Greenhouse-Controlled Con
Thursday September 26, 2024 12:15pm - 12:30pm HST
Coastal agriculture frequently relies on surface water for irrigation. However, in Florida, surface water availability can become limited during the dry season, leading growers to switch to groundwater. Groundwater in coastal areas often contains high salt concentrations which can negatively affect crop production. Citrus species, one of the most cultivated crops in Florida, are sensitive to salt stress. Among other strategies, irrigation management is used to mitigate salinity buildup in soil by leaching salts away from the root zone. Increased irrigation rates with water sources in the ‘slight’ to ‘moderate’ range of salinity (0.7 to 3 dS/m) have been shown to reduce salt accumulation in the soil without affecting production. However, when the water has high salinity concentrations (>3 dS/m), increasing the irrigation rate beyond 125%-130% of the crop evapotranspiration (ETc) is not sustainable due to the high-water usage. Conversely, a limited volume of water applied for leaching the salts can exacerbate the accumulation. In coastal Florida, where often only high salinity water is available during the dry season, evaluating short-term strategies to maintain crop production is crucial. The objective is to understand how irrigation water with high salinity concentrations and different irrigation rates impact plant performance and soil salinity accumulation. In this study, one-year-old ‘Ruby Red’ grapefruit trees grafted on ‘US-942’ rootstock were planted in a weighing lysimeter phenotyping platform (“Plant Array”) under greenhouse-controlled conditions. Irrigation water with high salinity concentration (5 dS/m) was precisely applied at three different irrigation rates: 75% (deficit), 100% (regular), and 125% (excessive) of the ETc. A control treatment with water at a low salinity concentration (0.3 dS/m) was applied at 100% ETc for comparison. Transpiration, plant net weight, soil moisture and soil electrical conductivity (EC) were recorded daily. Bulk leaf water potential, osmotic potential, and dark-adapted chlorophyll fluorescence were measured at the beginning and at the end of the experiment. Results showed that ETc and net weight decreased for those plants irrigated with high salinity concentration compared to the control. Salt EC was higher for those trees irrigated with 75% ETc under high salinity concentration resulting in the lowest ETc rates. Plants irrigated with 100% and 125% ETc rates showed similar results, likely due to decreasing transpiration of trees upon high salinity treatment application. Different plant performance under different irrigation rates emphasized the need of evaluating irrigation strategies in mitigating salt stress in citrus, particularly in region with limited water resources.
Speakers
NA

Neus Alcon Bou

University of Florida
Co-authors
GS

Gerard Sapes

University of Florida
NA
JF

John-Paul Fox

University of Florida
LR

Lorenzo Rossi

University of Florida
SG

Sandra Guzman

University of Florida
NA
WH

William Hammond

University of Florida
NA
Thursday September 26, 2024 12:15pm - 12:30pm HST
Coral 2

12:30pm HST

NUTS 2 - Discovery of Early Biomarkers for the Scab Resistance of Pecan Seedlings Using Metabolomic Analysis Combined with Machin
Thursday September 26, 2024 12:30pm - 12:45pm HST
Pecans (Carya illinoinensis (Wangenh.) K. Koch) are globally consumed nuts and an important agricultural commodity in the United States. Scab is a devastating pecan disease, which necessitates the application of numerous fungicide sprays in the growing season of pecans. Even with the control measures, in wet years, scab infection results in great yield loss (over 50% loss in susceptible varieties) and deterioration of nut quality. Although there have been various efforts to alleviate the scab, the development of scab-resistant pecan cultivars is the most effective method to control the disease. However, current methods to assess pecan scab resistance require multiple years of field screening and complicated laboratory (microscopic) techniques. Thus, a simple and reliable method that can rapidly evaluate pecan scab resistance at an early stage of infection is necessary. In this study, metabolomic analysis with machine learning algorithms was utilized to identify early biomarkers for the scab resistance of pecan seedlings. Two pecan seedlings with contrasting scab resistance ('Pawnee' and 'Desirable') were inoculated with water (control), Pa-OK-11 (isolated from 'Pawnee'), and De-Tif-11 (isolated from 'Desirable') for 7 days. 'Desirable' seedlings exhibited resistance to Pa-OK-11, while 'Pawnee' seedlings showed moderate resistance to De-Tif-11. Both cultivars were susceptible to their respective isolates. Leave samples from each seedling were collected at different time points (0, 1, 2, 3, 4, 5, 7 days). For the metabolomics work, liquid chromatography‒mass spectrometry (LC‒MS) was employed to analyze metabolites in samples, which can cover a wide range of primary and secondary metabolisms, including carbon fixation, glycolysis, citric acid cycle, amino acid metabolism, phenylpropanoid, monolignol, and flavonoid biosynthesis. Different machine learning algorithms were compared to find differentially regulated metabolites (biomarkers) between scab-resistant and -susceptible seedling groups. With a combination of machine learning models, we obtained reliable potential biomarkers, e.g., phenolic acids, flavonoids, plant hormones, and their intermediates and precursors, involved in the early stage of scab infection. The selected markers are expected to be used to classify scab resistance levels in pecan seedlings within a week after infection, which may replace the conventional method (phenotype-based mass selection) for pecan breeding selection. In short, this research breaks the bottleneck of resistance screening in pecans and will help facilitate the early selection of scab-resistant pecan cultivars to achieve breeding goals.
Speakers
avatar for Min Jeong Kang

Min Jeong Kang

Graduate Research Assistant, University of Georgia
Hello! I am a 5th year Ph.D. candidate in the Food Science and Technology Department at the University of Georgia.My research interests are Metabolomics, using Machine Learning Algorithms to discover the biomarkers. My recent work involves evaluating pecan quality, looking at biomarkers... Read More →
Co-authors
JS

Joonhyuk Suh

University of Georgia
NA
LW

Lenny Wells

University of Georgia
NA
PC

Patrick Conner

University of Georgia
RP

Ronald Pegg

University of Georgia
NA
Thursday September 26, 2024 12:30pm - 12:45pm HST
Lehua Suite

12:30pm HST

WUM 3 - Irrigation trials examine yield, water productivity, and nitrogen uptake of summer cauliflower
Thursday September 26, 2024 12:30pm - 12:45pm HST
Replicated irrigation trials were performed on cauliflower (Brassica oleracea var. botrytis cv. Symphony) in California’s Salinas Valley during 2018 and 2019. The CropManage online decision-support system was used to guide evapotranspiration-based irrigation scheduling. Overhead sprinklers were used to establish the crop with 60-70 mm of water, followed by surface drip for the remaining crop cycle. A randomized complete block design, with six replications, was used to administer four treatments near 50%, 75%, 100% and 150% of estimated full crop water requirement (T50, T75, T100, T150) during the drip phase. An additional drip treatment at 125% (T125) was added in 2019. Applied water totals across treatments ranged from 199-410 mm in 2018 and 179-369 mm in 2019 (plus 35 mm of precipitation). No significant differences were observed between total curd (head) yields from T100 and T150 in year 1 (> 30 Mg ha-1), although marketable yield from T150 was greater. Total yield of T100 and T125 were significantly greater than T150 during year 2, but marketable yield was similar among T100-T150. No significant difference was observed in fresh or aboveground dry biomass production from T100 and T150. Significant reductions in yields and biomass production were observed in T50 and T75 for both years. T100 and T150 had the highest irrigation water productivity with respect to marketable yield. Nitrogen uptake and fertilizer N recovery were highest in T100 and T150 during 2018, but no significant treatment differences were observed in 2019. These field trials demonstrated that estimating crop evapotranspiration and irrigation requirements of cauliflower through a decision support service such as CropManage can be a reliable tool for irrigation scheduling.
Speakers
MC

Michael Cahn

UC Cooperative Extension
Co-authors
LJ

Lee Johnson

NASA ARC-CREST/California State University Monterey Bay
NA
SB

Sharon Benzen

USDA-ARS
NA
Thursday September 26, 2024 12:30pm - 12:45pm HST
Coral 2

12:45pm HST

NUTS 2 - Developmental Transcriptomics of Pecan Fruit in ‘Mahan’ and ‘Tiny Tim’
Thursday September 26, 2024 12:45pm - 1:00pm HST
Pecan (Carya illinoinensis) is a nut crop native to the United States and Mexico which is becoming an increasingly important crop globally. Juglandaceous nuts are uniquely high in antioxidants among nuts and a conversion equivalent derived from studies in mice indicates that consumption of 22-38 pecans per day may reverse metabolic disorder in an individual weighing 132 pounds, implying a role in a healthy diet. Despite this importance, relatively little is known about the molecular basis of pecan nut ontogeny compared to other nut crops, leading to difficulties in understanding the physiological issues which plague growers. Susceptibility to various biotic and abiotic disorders including pecan scab, vivipary, water split, and shuck decline are dependent upon the stage of development the pecan nut is in. To better understand the molecular basis and timing of pecan nut development, developmental time-course RNA-Seq was carried out on nuts collected from cultivars ‘Mahan’ (a large nut bearing pecan from Mississippi) and ‘Tiny Tim’ (a small nut bearing native pecan from Missouri) approximately biweekly through the growing season of 2022. Using this data, genes were grouped together into distinct developmental phases, connecting transcriptional changes to the already well-characterized ontogenic stages of pecan nut development.
Speakers Co-authors
WC

Warren Chatwin

USDA ARS Southern Plains Agricultural Research Center
NA
Thursday September 26, 2024 12:45pm - 1:00pm HST
Lehua Suite

12:45pm HST

WUM 3 - Growth Morphology as Indicators of Salt Water Tolerance in Watermelon Cultivars
Thursday September 26, 2024 12:45pm - 1:00pm HST
Saltwater intrusion into coastal areas is a major problem that reduces acreage under vegetable production. Cultivating salt-tolerant varieties is one of the approaches to overcome this problem. The long-term goal of this project is to screen and identify salt-tolerant watermelon germplasm. We assessed the impact of salinity stress from natural brackish water collected in Charleston, South Carolina (32o47’38” N and 80o3’25” W), on the growth morphology of four watermelon cultivars to identify one discriminatory concentration to be used for evaluating hundreds of watermelon accessions available in USDA-ARS Germplasm Resources Information Network. Watermelon plants were hydroponically grown in a Nutrient Film Technique (NFT) system at various EC levels (natural brackish water diluted with de-ionized water to generate 5.5, 10, 12, 14, and 19 dS/m and control, 0 dS/m) and plant growth and shoot morphology were monitored. All cultivars failed to withstand salinity stress at 19 dS/m. Surprisingly watermelon cultivars tolerated fairly high levels of salinity (5.5-14 dS/m ⁓3,530 - 8,960 ppm salt concentration) with inhibited growth. Increasing EC levels correlated with decreased growth parameters such as plant height, leaf number, and shoot fresh and dry weight. Chlorophyll content and electrolyte leakage values increased with higher brackish water concentrations, peaking at 14 dS/m. These values were notably elevated, with chlorophyll content and electrolyte leakage being 5 and 2 times higher than the control, respectively. Cultivar Sugar Baby had significantly greater shoot length, chlorophyll content, and electrolyte leakage compared to other cultivars (Crimson Sweet, Charleston Grey, and Black Diamond). The other growth parameters were similar across all cultivars. Further research to identify an optimal EC between 14 and 19 dS/m for use in large-scale evaluation of germplasm accessions will be needed.
Speakers
AS

AZEEZAHMED SHAIK

Clemson University
Co-authors
Thursday September 26, 2024 12:45pm - 1:00pm HST
Coral 2

1:00pm HST

NUTS 2 - Pistachio Orchard Productivity Enhancement Through Molecular Marker Preselection
Thursday September 26, 2024 1:00pm - 1:15pm HST
There is significant variation in tree size, which determines productivity, in commercial pistachio orchards planted with UCB-1 seedling rootstocks. It has been unclear to extent to which this is due to genetic differences or environmental variation. Nurseries have tried to tackle this problem by rogueing young seedlings before they are planted in orchards. However, our data previously demonstrated that performance in the first year is a poor predictor of later tree size. Genotyping by sequencing data from experimental and commercial orchards and genome wide association studies (GWAS), combined with our chromosome-scale, high quality, genome assemblies for the parental Pistacia atlantica and P. integerrima trees resulted in two highly informative molecular markers for vigor. Based on the genomic sequence information, we developed an inexpensive, quick, and easy qPCR protocol for single nucleotide polymorphism (SNP) marker analysis. We were able to predict the improved size distribution that extant orchards would have had if this marker had been used to rogue seedlings prior to planting in the orchards. We want this marker to make it available for nurseries to rogue out trees which would exhibit low vigor and productivity later in an orchard.
Speakers
avatar for Ewelina Jacygrad

Ewelina Jacygrad

University of California Davis
Co-authors
DG

Deborah Golino

University of California Davis
NA
JE

John E. Preece

University of California, Davis
NA
KC

Keri Cavanaugh

University of California, Davis
NA
RM

Richard Michelmore

University of California Davis
NA
RH

Robert H. Beede

UCCE Kings County, CA
NA
Thursday September 26, 2024 1:00pm - 1:15pm HST
Lehua Suite

1:00pm HST

WUM 3 - Assessment of Salinity Tolerance in Cucumber Cultivars Using NFT System
Thursday September 26, 2024 1:00pm - 1:15pm HST
Increasing salinity levels pose significant challenges to coastal vegetable cultivation, particularly impacting salt-sensitive crops like cucumber, leading to reduced growth, development, yield, and quality. This study assessed the responses of six commercial cucumber cultivars to different salinity levels. Cucumber plants were grown in a hoop house hydroponically using various dilutions of brackish water in a Nutrient Film Technique (NFT) system at EC levels 3, 6, and 12 dS/m, along with adequate controls (0 dS/m). Increasing salinity levels caused a significant decline in plant growth parameters (shoot length, biomass, leaf number). Overall a 59% reduction in shoot length and 52% decrease in dry biomass was observed at 12 dS/m compared to control. The cultivar, Stripped Armenian had significantly greater shoot length (163 cm) and dry biomass (59 g), compared to the others (Diva, Katrina, Lemon, H-19 Little Leaf, and Suyolong) by 52-207% and 126-409%, respectively. Additionally, Stripped Armenians dry weight exceeded the control by 120%, 115%, and 25% in 3, 6, and 12 dS/m treatments, respectively. Gaseous exchange parameters measured with Licor 6850 (photosynthetic rate, stomatal conductance, transpiration rate, and intercellular CO2 concentration) declined significantly with increasing salinity at vegetative and reproductive stages. The photosynthetic rate and stomatal conductance showed reductions of 15-17% and 13-50%, at salinity levels of 3 dS/m, 6 dS/m, and 12 dS/m, compared to the control treatment respectively. Similar reductions were also observed at the reproductive stage. Stripped Armenian consistently exhibited higher photosynthetic rate (4-27%), stomatal conductance (7-75%), and transpiration rate (6-56%) compared to other cultivars at vegetative and reproductive stages. In conclusion, Stripped Armenian demonstrated substantial tolerance to 12 dS/m salinity compared to other cultivars and may prove useful in saline environments, however further research is needed.
Speakers
AS

AZEEZAHMED SHAIK

Clemson University
Co-authors
Thursday September 26, 2024 1:00pm - 1:15pm HST
Coral 2

1:15pm HST

NUTS 2 - Fatal Flaws of Experimental Almond Varieties and Selections
Thursday September 26, 2024 1:15pm - 1:30pm HST
The California almond industry has funded multiple, multi-site almond variety evaluation trials over the last several decades. These field trials have previously evaluated many of the varieties that are now the most widely planted in California. Although, field evaluation trials are helpful for revealing which varieties are promising, they are, perhaps, most valuable to the industry for revealing which varieties/selection have serious flaws and should not be planted by growers. Thirty named cultivars and numbered breeder selections were planted in three replicated commercial orchards across California’s Central Valley in 2014. Of these 30, as of April 2024, one numbered selection Y116-161-99 from the USDA has been commercially released as ‘Yorizane’. However, nine of the 30 varieties/selections were dropped from further evaluation in the trial in 2022 for a variety of reasons: low yield (five), lack of interest by the breeder (two), extremely early bloom timing (one), and poor harvestability (one). Of the 21 still being evaluated in 2024, many have one of these major flaws, or additional flaws, that will likely prevent commercial adoption, including a high percentage of double kernels, susceptibility to bacterial blast (Pseudomonas syringae pv. syringae), Botryosphaeria canker disease susceptibility, hull rot susceptibility, and a high percentage of kernel creases or twins, just to name some of the additional flaws. Even if a variety/selection has high yield, good kernel quality, and none of these major flaws documented after ten years of evaluation (e.g. Y117-91-03 from USDA), further observation in the UC trial sites or in the orchards of early adopters may reveal important flaws that prevent sustained and widespread variety adoption. This long-term challenge is why some believe it takes decades to prove a new scion variety. The wide diversity of potentially fatal flaws underscores the need for cultivar evaluation to take place by a third-party like UC Cooperative Extension in long-term replicated trials to reduce substantial financial risk to the grower to the greatest extent possible. Keywords: Prunus dulcis, almond, variety evaluation, breeding, nut crop
Speakers
LM

Luke Milliron

University of California Agriculture Natural Resources
Co-authors
PG

Phoebe Gordon

University of California Cooperative Extension
RD

Roger Duncan

UC Cooperative Extension
NA
Thursday September 26, 2024 1:15pm - 1:30pm HST
Lehua Suite

1:15pm HST

WUM 3 - Influence Of Deficit Irrigation And Biochar Application On Soil Water Depletion, Roots Distribution, And Water Use Effic
Thursday September 26, 2024 1:15pm - 1:30pm HST
A rapid decline in water table of the Ogallala aquifer necessitates water conservation farming practices in Texas High Plains (THP). Deficit irrigation (DI) and biochar amendment strategies are widely adopted to sustain agriculture in semi-arid regions like THP. Although these practices are studied individually, research involving the combined effect of these factors is lacking, especially in THP. The goal of this study was to investigate the effect of DI and biochar application on soil water depletion, root distribution, and water use efficiency of cucumber in West Texas. A two-year field study was conducted in a split-plot design with irrigation levels as the main plots: I1[100% crop evapotranspiration (ETc) replacement before mid-season (EBM))-100% ETc replacement after mid-season (EAM), I2 (80% ETc EBM- 60% ETc EAM), I3 (60% ETc EBM - 80% ETc EAM), I4 (40% ETc EBM-40% ETc EAM)] and biochar rates [ 0 t/ha,15 t/ha, and 20 t/ha] as sub-plots with four replications. Results showed that I4 had the largest and I1 had the least soil water depletion, and the differences in water depletion among irrigation levels were significant up to 1-m soil depth. Root length density (RLD) and root surface area density (RSAD) were significantly higher in I1 followed by I2 and I3, and these parameters were the least in I4. Water Use Efficiency (WUE) showed I2 being the most water productive DI treatment with an average increase of 5% compared to I1. Biochar didn't influence water depletion, RLD, and WUE but significantly increased RSAD compared to non-amended plots. Thus, deficit irrigation level I2 can be a potential alternative irrigation to full irrigation for enhancing water productivity of cucumber in the THP. More pronounced biochar effects could be expected in long term studies.
Speakers
avatar for Sukhbir Singh

Sukhbir Singh

Texas Tech University
NA
Co-authors
AK

Arjun Kafle

Texas Tech University
CS

Catherine Simpson

Texas Tech University
NA
GR

Glen Ritchie

Texas Tech University
NA
MS

Manpreet Singh

University of California Agriculture and Natural Resources
NA
PB

Preetaman Bajwa

Texas Tech University
NA
SD

Sanjit Deb

Texas Tech University
NA
Thursday September 26, 2024 1:15pm - 1:30pm HST
Coral 2

1:30pm HST

WUM 3 - Assessing Resource-use Efficiency Affected by Irrigation Management Practices in Processing Onion Production
Thursday September 26, 2024 1:30pm - 1:45pm HST
This study aimed at conducting an impact evaluation of irrigation management practices in processing onion production. A three-year experiment was carried out in 15 commercial processing onion fields under different irrigation methods of furrow, solid-set sprinkler, and subsurface drip. The experimental sites were located in the Imperial Valley, California’s low desert region. All fields were on a 40-inch bed, six plant rows per bed with a spacing of 2.5-in between planting lines. The fields had a variable soil type with predominate soil texture from fine sandy to silty clay loam. Water, nitrogen, and energy used, bulb weights, soil moisture, soil nitrate and salinity, and actual evapotranspiration were measured in each site. A wide range of seasonal irrigation water applied was observed across the experimental sites. Irrigation water applied varied from 3.3 ac-ft/ac in a drip irrigated field to 6.9 ac-ft/ac in a furrow irrigated field. The results demonstrated that utilizing subsurface drip irrigation in processing onions could conserve 0.8 and 2.4 ac-ft/ac water in compared with solid-set sprinkler and furrow irrigation systems, respectively. The water productivity, the ratio of onion bulb weight to water applied, was determined 4.9, 4.3, and 2.7 t/ac-ft for the drip, sprinkler, and furrow irrigated fields, respectively. A greater nitrogen use efficiency was found in the drip irrigated fields compared to the sprinkler (15.2% points) and furrow (62.1% points) irrigated fields. The findings illustrated a higher salt accumulation on the topsoil (0-6 in. depth) in the drip irrigated fields. In other words, drip irrigation could cause salinity impacts in desert processing onions, and therefore, more frequent light irrigation events may be an effective tool to manage salinity. More nitrate leaching was also observed from the topsoil in the sites irrigated by sprinklers. Energy productivity, the ratio of onion bulb weight to fuel consumption, was 48.3% points higher in the drip fields than the sprinkler fields. The results revealed that irrigation practice has a significant impact on resource-use efficiency and environmental issues.
Speakers
AM

Ali Montazar

University Of California Cooperative Extension
Thursday September 26, 2024 1:30pm - 1:45pm HST
Coral 2

1:45pm HST

CE 6 - Timing Kale Growth for Peak Nutrition and Energy Efficiency in a Vertical, Hydroponic Indoor Container Farm
Thursday September 26, 2024 1:45pm - 2:00pm HST
As entrepreneurs look to find new ways to shorten the gap between farm and table in urban communities, many are considering vertical farming as an answer to the problem of limited growing space. The aim of this experiment is to determine the optimal harvest time in weeks for vertically grown, hydroponic kale (Brassica oleracea var. acephala cv. ‘Toscano’) based on morphological data, phytonutrient concentrations, energy, and yield. After a four-week germination period, kale was grown for up to eight weeks and harvested at eight different stages of growth, based on the number of weeks spent in the vertical system. When harvested, morphological parameters were measured, and samples were collected to analyze mineral nutrient content. Electrical Energy usage data was collected and presented as: Lighting, HVAC, and Other. Data was analyzed as a Randomized Complete Block Design with three blocks. Mean plant height, fresh leaf mass, and leaf dry mass all increased with growth stage, with the largest plants being observed at stage eight. Additionally, the greatest mean quantity of dead, diseased, or unconsumable leaves of 3.27 leaves per plant was observed at stage eight. Mineral nutrient concentrations of calcium, sulfur, and manganese increased through seven weeks (stage seven), after which a decrease was observed in stage eight. Decreases in concentration during stage eight was also observed for phosphorus, potassium, and magnesium, with negligible differences in the younger stages. No differences in energy data existed for the daily mean lighting, HVAC, and Other electrical consumption across all eight stages. Harvest data collected indicates that plants should be harvested prior to stage eight to maintain mineral nutrient content and minimize dead leaves and should be considered with total energy consumption to optimize farm productivity, energy efficiency, and nutritional content of plants. Further analysis of other primary and secondary metabolites alongside total energy consumption cost is necessary to identify the best stage of harvest maturity and nutritional quality for consumers relative to energy usage and production cost.
Speakers
SB

Skyler Brazel

University of Tennessee - Knoxville
Co-authors
CS

Carl Sams

University of Tennessee
DV

Devin Vitello

University of Tennessee - Knoxville
NA
KR

Katelynn Rector

University of Tennessee - Knoxville
NA
Thursday September 26, 2024 1:45pm - 2:00pm HST
Coral 1

1:45pm HST

PUBHORT/Hort Industry - Enhancing Public Garden Experiences: Utilizing QR Codes and Videos for Plant Identification and Education
Thursday September 26, 2024 1:45pm - 2:00pm HST
Public gardens play a crucial role in promoting horticultural education and appreciation. Proper plant signage can further enhance a visitor’s learning experience. This project provides partner gardens with trusted horticulture information while further utilizing Oklahoma Gardening content, produced by Oklahoma State University Extension. Oklahoma Gardening, a research-based, how-to gardening television show, airs weekly on Oklahoma Educational Television Authority (OETA), a PBS affiliate. This project created a virtual, educational experience for visitors of participating gardens. Eleven public gardens and educational demonstration gardens located in rural and urban settings throughout Oklahoma were provided with 5-15 signs depending on the size of the garden, the availability of in-season plant material, and the applicable video content. This approach leverages the recent widespread adoption of QR codes, allowing visitors to access plant information effortlessly from Oklahoma Gardening. Many of the selected gardens provide free entrance to the public, offering a horticultural experience to all. However, this can reduce the garden’s operation budget and limit their ability to provide adequate educational signage. The objective of this project is to help these public gardens increase their horticulture educational interpretation. These QR code signs not only provide gardens with seasonally appropriate plant identification signage but also offer visitors videos about the plants they are observing. Furthermore, for open-access public gardens it can be difficult to quantify visitation. By utilizing dynamic QR codes the quantity and time of scans is captured. This allows for tracking of the usage of each sign and which plants are most popular. This information is then shared with participating gardens. Public gardens are often visited by tourists as well. This project expands Oklahoma Gardening and OSU Extension beyond television and YouTube to reach an audience in the public garden space. The dynamic QR code scans provide the phone’s registered city, state, and country, giving approximate geographic locations of garden visitors. After a year of placing the signs, we have identified clicks from 23 states, and 5 additional countries. This project was funded by Oklahoma Department of Agriculture, Food, and Forestry Specialty Crop Block Grant.
Speakers
avatar for Bailey Singleton

Bailey Singleton

Oklahoma State University
Co-authors
CH

Casey Hentges

Oklahoma State University
NA
Thursday September 26, 2024 1:45pm - 2:00pm HST
Lehua Suite

1:45pm HST

VSF 4 - First They’re Sweet, Then They’re Sour: The Impact of Cultivar, Berry Maturity, and Phytohormones on Blueberry Quality U
Thursday September 26, 2024 1:45pm - 2:00pm HST
Fruit quality parameters are typically reported by growers and researchers as an average. However, for small fruits such as blueberries, berry-to-berry variability in texture and flavor also impacts the consumer eating experience. The objective of this project was to capture how fruit quality uniformity varies by 1) cultivar, 2) berry maturity, and 3) exogenous phytohormone applications. From 2022-2023, analyses were conducted on individual blueberries from multiple studies carried out in commercial fields in Michigan. First, we compared the uniformity of berry weight, diameter, firmness, and total soluble solids in six northern highbush blueberry cultivars: “Duke,’ ‘Bluecrop,’ ‘Draper,’ ‘Calypso,’ ‘Elliott,’ and ‘Aurora.’ Second, we evaluated how changes in berry maturity due to delayed harvest and sequential harvest dates affected the uniformity of berry weight, diameter, firmness, total soluble solids, pH, total acidity, and aroma volatile concentrations in: ‘Duke,’ ‘Draper,’ ‘Calypso,’ and the uniformity of berry weight, diameter, firmness, and total soluble solids in ‘Bluecrop,’ ‘Elliott,’ and ‘Aurora,’ respectively. The implications of delayed harvest on the uniformity of consumer liking scores will also be discussed. Finally, we tested whether exogenous application of multiple phytohormones impacted the uniformity of berry weight, diameter, firmness, and total soluble solids in ‘Bluecrop,’ ‘Elliott,’ and ‘Aurora’. We conclude that “uniformity” is an important component of fruit quality in blueberry.
Speakers
MG

Michael Gasdick

Michigan State University
Co-authors
DD

Daniel Dick

Michigan State University
JV

Josh VanderWeide

Michigan State University
Thursday September 26, 2024 1:45pm - 2:00pm HST
Nautilus

1:45pm HST

WUM 3 - Assessing Drip Irrigation as an Alternative to Micro-sprinklers During Strawberry Establishment in Southern California
Thursday September 26, 2024 1:45pm - 2:00pm HST
The escalating regulatory pressure to achieve sustainable groundwater use in California will demand improved irrigation efficiency. Even though approximately 80 to 90% of the sprinkler-applied water to a strawberry crop is lost through runoff, deep percolation and evaporation, all the strawberry fields in Ventura County are still irrigated with overhead sprinklers during crop establishment. This study quantified differences in water use, yield, canopy coverage and root depth between drip tape and micro-sprinkler irrigation during crop establishment at a commercial field located in Oxnard, CA during the 2023-2024 growing season. Treatments consisted of three irrigation methods used during the first five weeks: 1) primarily drip tape (DT), 2) micro-sprinklers only (MS), and 3) a combination of drip tape and micro-sprinklers (C). The irrigation scheduling of the MS treatment was defined by the irrigator (grower standard), while the DT and C treatments were guided by tensiometers and field observations. All other production practices remained the same. Each treatment was replicated four times in a randomized complete block design, with an area of approximately 1.7 acre per plot (40 beds of 350ft long). Treatments were carried out for 35 days from planting (Oct 5), after which drip irrigation became the only irrigation method. Total water use during establishment was very similar among treatments: 3.9, 3.6 and 4.0 acre-in for DT, C and MS, respectively. With four plant rows and three drip lines per bed, the DT treatment was irrigated for longer than anticipated to assure uniform soil moisture around the plant roots. Marketable yield until Mar 14 was 4,583, 4,229 and 4,297 lb/acre for DT, MS and C, respectively. Although not statistically significant, DT yield was 8.4% greater than MS (p-value = 0.802), and 6.7% greater than C (p-value = 0.865). Canopy cover trends were very similar between DT and C, while MS was between 13 and 29% lower than DT from 48 to 61 days after planting. Canopy coverage equalized at 90 days after planting after significant precipitation during Dec and Jan. Average root depth of DT was 38 and 19% greater than MS for 15 and 28 days after planting, respectively. In summary, this study found equal or superior crop performance of DT compared to MS during strawberry establishment. We expect that increasing the number of drip tape per bed from three to four would significantly decrease the irrigation time needed to provide ideal soil moisture, consequently decreasing water use.
Speakers
AB

Andre Biscaro

UC Cooperative Extension
Co-authors
MV

Maripaula Valdes Berriz

University of California Cooperative Extension
NA
OD

Oleg Daugovish

University of California Cooperative Extension
RC

Raul Coronado

GoodFarms
NA
SZ

Siomara Zendejas

University of California Cooperative Extension
NA
Thursday September 26, 2024 1:45pm - 2:00pm HST
Coral 2

2:00pm HST

CE 6 - Effects of Beneficial Bacterial Endophytes on Growth of Lettuce Plants, Transcriptome, and Root Microbiome in Hydroponic Systems
Thursday September 26, 2024 2:00pm - 2:15pm HST
Controlled environment agriculture will play an important role in feeding the increasing world population as urbanization is expanding, and arable land is decreasing. Higher yields will help offset the initial high cost for building hydroponic production facilities. Beneficial bacterial endophytes have been receiving more attention in sustainable agriculture practices because they can promote plant growth, enhance nutrient uptake, and inhibit pathogen growth. The Institute for Advanced Learning and Research has established a bacterial endophyte library of more than 2000 strains and found that some bacterial endophytes significantly increased the growth of tall fescue KY31 in vitro, up to 8-fold compared with untreated control plants. In previous paper, we reported that Pseudomonas psychrotolerans IALR632 significantly promote lettuce growth in hydroponic systems. In this study, we investigated the molecular and microbiological mechanisms these bacteria exhibit for plant growth promotion in hydroponic systems through plant gene expression with RNAseq and root bacterial community changes through microbiome analysis after bacterial inoculation. Lettuce (Lactuca sativa) cultivar ‘Green Oakleaf’ was inoculated with Pseudomonas psychrotolerans IALR632 one week after seeds were sown and transplanted to nutrient film technique (NFT) hydroponic units one week after bacterial inoculation. Samples were taken at 4, 10, and 15 days after lettuce seedlings were transplanted for gene expression analysis. Root samples were taken 15 days after transplantation for microbiome analysis. Anosim, NMDS, and PCoA analyses indicated bacterial community changes in inoculated plants. The top genus relative abundance was unclassified bacteria with 87% in IALR632 treatment and 85% in control (p=0.0136). In the next top 24 genus’s relative abundance, IALR632 inoculation dramatically increased Sediminibacterium, Hyphomicrobium, Sphingobium, Devosia, Mycobacterium, Rhodoplanes, and Runella by 68%, 114%, 72%, 158%, 513%, 103% and 1920%, respectively, and reduced Methylotenera, Rhizobium, and Sphingomonas by 68%, 62% and 45%, respectively. RNAseq data showed that there were 135, 2059, and 9319 DEG between the control and bacterial treatment at 4, 10, and 15 days, respectively. These DEG are being analyzed for pathways involved in plant growth promotion.
Speakers
CM

Chuansheng Mei

Institute for Advanced Learning and Research
Co-authors
RC

Robert Chretien

Institute for Advanced Learning and Research
NA
SA

Sajeewa Amaradasa

Institute for Advanced Learning and Research
NA
SL

Scott Lowman

Institute for Advanced Learning and Research
NA
Thursday September 26, 2024 2:00pm - 2:15pm HST
Coral 1

2:00pm HST

CITR 3 - A Glimpse of The Future of Citrus in Florida – The Millennium Block
Thursday September 26, 2024 2:00pm - 2:15pm HST
For the past two decades, Florida citrus production has undergone a 75% reduction due to Huanglongbing (HLB), a disease caused by Candidatus Liberibacter asiaticus and vectored by the Asian Citrus Psyllid (ACP, Diaphorina citri). To combat this threat, breeding programs have been developing new varieties, seeking those tolerant to HLB while possessing other desirable traits and providing a long-term solution for the citrus industry. The Indian River Research and Education Center is leading this effort by planting new scion and rootstock varieties in four independent trials at the Millennium Block in 2019. One trial consists of 18 grapefruit-pummelo hybrid scions grafted onto three rootstock varieties, totaling 54 combinations (Trial 1). The other three trials are rootstock trials, where ‘Ray Ruby’ grapefruit (Trial 2), ‘Glenn Navel’ sweet orange (Trial 3), and ‘UF-950’ mandarin (Trial 4) varieties are grafted onto 32 rootstocks. The Millennium Block is home to 5,500 trees. Complete data for the 2023/24 season was collected, evaluating fruit yield, weight, size, and juice quality across all trials except for the mandarins, which have yet to set and keep a harvestable crop. Fruits were categorized into “good fruit” (based on shape, size, and maturity) and “bad fruit” (including visually HLB-affected fruit and off-bloom fruit). One of the 18 scions in Trial 1, a grapefruit-orange hybrid with golden flesh and high juice content called ‘Triumph,’ was discovered through a fortuitous mistake, yielding over 19,000 lb/ac of “good fruit” when grafted onto X-639, and had a Brix of 8.18. ’Triumph’ exhibits visual tolerance to HLB, with minimal to no affected fruit and no leaf symptoms. Of the red flesh grapefruit, ‘UF-914’ grafted onto ‘US-942’ and ‘X-639’ yielded close to 12,000 lb/ac of “good fruit” each, with juice Brix between 8-9. The traditional ‘Ray Ruby’ grapefruit has produced more boxes per acre grafted onto UFR-15 (close to 8,000 lb/ac) than US-942 and Sour Orange. Meanwhile, ‘Glenn Navel’ sweet orange yields more boxes when grafted onto US-942 (approximately 3,800 lb/ac), UFR-17, and Kuharske. The rootstock trials reveal that grapefruit and sweet orange scions require distinct rootstock characteristics to achieve the best yields. Data gathered by these trials are essential for growers to make informed decisions about which varieties to plant compared to the available conventional scions.
Speakers
avatar for Flavia Tabay Zambon

Flavia Tabay Zambon

University of Florida - IFAS - IRREC
Co-authors
MH

Macselynia Hossain

University of Florida
NA
MA

Mark A. Ritenour

University of Florida
NA
RD

Ronald D. Cave

University of Florida
NA
Thursday September 26, 2024 2:00pm - 2:15pm HST
South Pacific 2

2:00pm HST

HSMP 2 - Hydroponic Production of Seed Ginger Rhizomes in Virginia
Thursday September 26, 2024 2:00pm - 2:15pm HST
The length of field growing season in the temperate and subtropical regions of the United States including Virginia, does not allow ginger (Zingiber officinale) rhizomes to mature naturally. As a result, saving rhizomes as seeds is often impossible and the supply of seed ginger rhizomes (seeds) has been mostly from Hawaii. To mitigate this challenge, Cooperative Extension at Virginia State University attempted to produce ginger seeds hydroponically in a greenhouse for two years. In 2022/23, cultivar Chinese Ginger (4-6 buds/rhizome) was presprouted in the greenhouse using 1-gallon pots filled with soilless media in January and transplanted into 20-gallon fabric containers filled with soilless media or pine bark on May 6 or 17, 2023. Plants were fertigated on weekdays with a nutrient stock solution containing 6 oz 4-18-38 plus micros, 3 oz magnesium sulfate and 8 oz calcium nitrate per gallon. Seed harvests took place from January 15 to March 18, 2024. The yield was significantly higher with soilless media (12.7 lb./plant) than with pine bark (11.1 lb./plant) although the marketable yield was not statistically different. Plants in soilless media were difficult to harvest (heavy and wet soil, tangled roots). Marketable yield was the highest for plants harvested from 240-269 days after transplanting (DAT), followed by 270-289 DAT. Harvests after 290 DAT had 37-53% culls. The overall yield was not different in terms of transplanting dates, but May 6 transplanting had significantly less marketable rhizomes compared to May 14 transplanting. The first-year results favored using pine bark and harvesting 260-290 DAT. In 2023/24, ‘Blue Ring’ and ‘Yellow Ginger’ were added. Pre-sprouting started in March and transplanting occurred in late May 2023 with only pine bark as the media type. Fertigation and irrigation were discontinued in mid-December to allow media to dry. The yield of ‘Chinese Ginger’ raged from 11.3 lb./plant in early November 2023 to 13.7 lb./plant in late February 2024, indicating possible early harvests and curing if storage space is available, which would avoid heating greenhouse in deep winter. ‘Chinese Ginger’ had the highest yield (13.8 lb./plant), followed by ‘Yellow Ginger’ (12.5 lb./plant) and ‘Blue Ring’ (9.7 lb./plant). All three cultivars had 10-20% culls due to rotting (disease) and scarring. Our results proved the feasibility of ginger seed production in local greenhouses and the great yield with a hydroponic system. We will refine the system and test the quality of seeds in field and high tunnels in 2024.
Speakers Co-authors
CM

Christopher Mullins

Virginia State University
SG

Sanjun Gu

Virginia State University
Thursday September 26, 2024 2:00pm - 2:15pm HST
Kahili

2:00pm HST

NUR 2 - Fine-tuning Substrate Stratification Ratios for Shrubs and Flowers
Thursday September 26, 2024 2:00pm - 2:15pm HST
The ornamental production industry utilizes either controlled greenhouse or open-air nursery production systems. Both rely upon the use of soilless substrates, with regular application of water and mineral nutrients, to maintain profitability and quality crop growth and development. However, the leading base substrates components used, peat moss and bark, present sustainability concerns for producers. Peat moss sustainability concerns surround harvest, supply, and cost (environmental, social, and economic; three tiers of sustainability) of the material. Pine bark sustainability in production is due to inefficiency in water and mineral nutrient retention (environmental, social, and economic). Nevertheless, a solution to help improve the sustainability of both substrates across the greenhouse and nursery industry has developed. Soilless substrate stratification is a practical management strategy that entails layering two unique substrates, either derived from the same substrate or different substrates, atop one another in the container. Stratifying substrates has been shown to reduce peat use and reliance in the greenhouse industry by upwards of 50%. Moreover, stratifying substrates can reduce irrigation and fertilizer applications by 25- and 20%, respectively. To date, stratified substrate research has utilized an even 50:50 stratified depth layer partition. As growers adopt this technique, more understanding of the balance and opportunities is needed. Thus, a series of experiments was developed to explore varying ratios of stratification. In two experiments, popular greenhouse (Petnas) and nursery (Rosa) crops were grown in different stratified depth layer ratios with peat-based (greenhouse) and bark-based (nursery) systems. Ratios included a non-stratified treatment (100% filled), a 75:25 percent by vol. layer partition, a 50:50, and a 25:75. In the greenhouse experiment, peatlite mix was layered over unscreened bark and irrigation was lysimeter-actuated. In the nursery experiment, fine bark particles were layered over coarse particles. Moreover, different fertilizer rates were applied (low, medium, high). The results showed in the greenhouse study, a Pentas crop can be grown with equal growth (and similar quantities of water) as traditional greenhouse crop when ≥50% peatlite is used by vol. In the nursery experiment, low fertilizer application rates can be used to grow a crop similar to a traditional nursery-grown crop when grown in a stratified system. While there are discrete differences, it primary take away is that stratification does not need to be overly technical to generate impact and improve efficiency; however, there is a limit to the ability to use “filler” material which tends to be about 50% of the volume.
Speakers
JF

Jeb Fields

LSU AgCenter Hammond Research Station
Co-authors
KC

Kristopher Criscione

LSU AgCenter Hammond Research Station
Thursday September 26, 2024 2:00pm - 2:15pm HST
South Pacific 4

2:00pm HST

PUBHORT/Hort Industry - Educational Signage in a Community Garden can Assist in Volunteer Learning
Thursday September 26, 2024 2:00pm - 2:15pm HST
Volunteering issues in community gardens have been an ongoing problem and have resulted in high turnover and untrained volunteers that may not have the skills to appropriately staff a community garden. The problem of having to train or have dedicated staff at a garden to assist volunteers is that often community gardens are not funded, or garden staff are stretched too thin. To inspect factors in volunteerism in community gardens, researchers sent out a ten-question survey to head community garden leaders (N=51) across the U.S. Overall, researchers found that many gardens perceive educational opportunities and the people that attend the garden as successful elements, while volunteer retention and education, along with signage issues, were the most prevalent problem. Finally, when asked about signage, most signs turned out to be purely informative and attractive, with few playing educational roles. Researchers concluded that educational signage may play an important role in the garden that many community gardens are missing. To understand further how educational signage plays a role in people’s understanding of a subject, researchers have developed another survey that is currently being distributed to the public. The data from this survey will allow researchers to more effectively use signage to not only attract but educate and train volunteers to relieve some of the burden from community garden staff.
Speakers
JT

Jonah Trevino

Texas Tech University
NA
Co-authors
CS

Catherine Simpson

Texas Tech University
NA
LF

Laura Fischer

Texas Tech University
NA
LT

Leslie Thompson

Texas Tech University
NA
VB

Vikram Baliga

Texas Tech University
NA
Thursday September 26, 2024 2:00pm - 2:15pm HST
Lehua Suite

2:00pm HST

VCM 5 - Evaluation of Wireworm Resistant Sweetpotato Cultivars in Western Washington
Thursday September 26, 2024 2:00pm - 2:15pm HST
Sweetpotato (Ipomoea batatas) is a nutritious, productive, and resilient crop that is grown worldwide and is gaining popularity throughout the U.S. In western Washington, wireworms (Agriotes lineatus, A. obscurus, and Limonius canus) are the primary pest impacting sweetpotato production. Wireworm resistant cultivars can provide an effective and sustainable pest management tool for growers. A field experiment in Mount Vernon, WA included nine sweetpotato cultivars and breeding lines: wireworm-susceptible cultivars Bayou Belle, Beauregard, Covington, and Orleans; wireworm-resistant cultivars Cascade and Monaco; and wireworm-resistant breeding lines USDA-04-136, USDA-04-284, and USDA-04-791. Storage roots were graded according to USDA sweetpotato categories and root weight, number, and wireworm damage [Wireworm-Diabrotica-Systena (WDS) severity index] were measured. Marketable yield ranged from 22 t/ha (USDA-04-136) to 57 t/ha (‘Bayou Belle’) (p
Speakers
LS

Laura Schulz

Graduate Research Assistant, Washington State University
I am a PhD student at Washington State University working with Carol Miles on introducing sweetpotato as a new crop in western Washington.
Co-authors
CM

Carol Miles

Washington State University
JB

Jacob Blauer

Washington State University
NA
LM

Laurel Moulton

Washington State University
NA
LN

Louis Nottingham

Washington State University
NA
PW

Phil Wadl

United States Department of Agriculture, Agricultural Research Service
SS

Srijana Shrestha

Washington State University
NA
Thursday September 26, 2024 2:00pm - 2:15pm HST
South Pacific 1

2:00pm HST

VSF 4 - Phytohormone and Plant Growth Regulator Use in Blueberry Production – A Review
Thursday September 26, 2024 2:00pm - 2:15pm HST
Plant growth regulators (PGRs) are natural or synthetically derived plant hormones that play a significant role in shaping plant growth and development. In tree fruit and table grape production, PGRs are commonly employed to address production challenges, including modulating crop load and improving fruit size, coloration, and quality. Meanwhile, their use in berry crops such as blueberry remains limited despite the prevalence of production challenges and the availability of registered PGRs for other fruit crops. This review summarizes the existing literature regarding PGR use in blueberry, as well as the current needs for research on PGRs going forward. First, considering the large increase in U.S. blueberry production over the past decade, we highlight the lack of PGRs registered and utilized in blueberry compared to other fruit crops. Second, we summarize the current literature on the utility of PGRs to mitigate challenges in blueberry production, including cold hardiness and frost protection, dormancy release, fruit size and crop load management, fruit quality improvement, post-harvest shelf-life extension. Finally, this work presents future opportunities for research involving PGRs in blueberry production. As blueberry production continues to increase in the U.S. and globally, the need to mitigate production challenges using PGRs will likely also increase.
Speakers
DD

Daniel Dick

Michigan State University
Co-authors
JV

Josh VanderWeide

Michigan State University
Thursday September 26, 2024 2:00pm - 2:15pm HST
Nautilus

2:15pm HST

CE 6 - Soybean Speed Breeding: Optimizing Photoperiod for Maximizing Yield and Minimizing Time
Thursday September 26, 2024 2:15pm - 2:30pm HST
Speed breeding is a cutting-edge technology, that utilizes controlled environments to significantly reduce plant generation time, thereby accelerating breeding and research programs. The manipulation of temperature, irrigation, phytohormones, and light are the main ways to reduce plant cycles in speed breeding programs. However, changing these factors can result in decreased yield efficiency, which can also affect the quality of a speed-breeding program. This study aimed to increase seed production without increasing harvest time in soybean plants, a short-day plant, by using different photoperiod regimes. Two soybean (Glycine max) varieties, S16-14801C and CZ7570LL, were grown from seeds in 11-L pots containing peat moss-based substrate in growth chambers with controlled temperature (27 ± 0.5 ˚C), CO2 (475 ± 15 µmol mol-1), humidity (70 ± 5.0%), and light (300 ± 5 µmol m-2 s-1 at table; 20% blue, 10% green, 70% red). One week after germination, seedlings were exposed to four different photoperiod regimes: i) 10 h (0 w at 18 h); ii) two weeks at 18 h and then 10 h (2 w at 18 h); iii) four weeks at 18 h and then 10 h (4 w at 18 h) and iv) six weeks at 18 h and then 10 h (6 w at 18 h). The light fixtures were not adjusted over plant height following industry practices. The plants were harvested ten days after 95% of the pods had attained maturity (R8 stage). For both varieties, the number of pods and seeds and seed weight per plant increased linearly, with the increase in the number of weeks at 18 h. Thus, the number of pods, seeds, and seed weight of plants at 6 w at 18 h were at least 5-fold higher than in plants at 0 w at 18 h. Similarly, plants grown at 6 w at 18 h presented 4-fold higher biomass than plants grown at 0 w at 18 h. However, the increased seed yield and biomass accumulation did not result in a longer plant cycle; plants of both varieties at 6 w at 18 h were harvested 32 days before plants at 0 w at 18 h. Here, we demonstrated that seed yield can be increased and harvest time decreased by manipulating the photoperiod. These findings can help plant breeders in identifying the most suitable method for growing soybean plants in a shorter period, while also ensuring high seed production.
Speakers
avatar for Cristiane da Silva

Cristiane da Silva

Postdoctoral Research Scholar, North Carolina State University
I'm Cristiane, a plant physiologist with experience in plant biochemistry and plant responses to abiotic stress. Currently, I'm a post-doc at NCSU studying the effects of light on plant life cycles to expedite breeding purposes in crop and tree species. When I'm not working, I enjoy... Read More →
Co-authors
CC

Cristian Collado

North Carolina State University
NA
RH

Ricardo Hernandez

North Carolina State University
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
Coral 1

2:15pm HST

CITR 3 - Lessons from Evaluating New Varieties for the Indian River Grapefruit Industry
Thursday September 26, 2024 2:15pm - 2:30pm HST
Citrus greening is one of the deadliest bacterial diseases in citrus production. Caused by Candidatus Liberibacter asiaticus (CLas) and vectored by the Asian Citrus Psyllid (ACP, Diaphorina citri), the disease has devastated Florida’s citrus industry, reducing production by over 75% during the last twenty years. The Indian River Region, known for its premier grapefruit production, has suffered an intense decline in yield and acreage. Growers in the region have been fighting the pathogen and its insect vector, however, a long-term solution is required for sustainable grapefruit production. As no HLB resistance is known in commercially available cultivars, the University of Florida Breeding Program has bred new grapefruit hybrids with potential HLB tolerance. Plants developed through the program need to be field-tested. This study was initiated to evaluate new fresh grapefruit scion and rootstock breeding materials for HLB-tolerant. In collaboration with twelve growers across the state, a large trial was planted between 2020 and 2022 with 40 plots, each with forty-two scion/rootstock combinations totaling 12,000 trees. Among other tree growth data collected, fruit yield and quality were measured this season between October 2023 and March 2024. Results confirm that 'Jackson' grapefruit has some HLB tolerance, possibly due to its vigorous nature. However, its high fruit drop and inconsistent fruit set are persistent grower concerns. Among the newly developed grapefruit hybrids, 'UF N40-16-11-7' grafted onto SuperSour #1 and UFR-5, and the pummelo hybrid 'UF KW-50-1' grafted onto X-639 had low HLB disease indexes, equivalent to ‘Jackson’. On trees fruiting for the first time, the pummelo hybrid ‘UF KW-1-50’ grafted onto SuperSour #1 had the highest yield, mainly due to the pummelo heritage, followed by red grapefruit ‘UF N40-16-11-7’ also grafted onto SuperSour #1 and ‘Rio Red’ onto US-942. With tree ages ranging from 2 to 4 years, further data collection is needed to determine sustained yield and fruit quality. These results can help determine which combinations are most HLB-tolerant and best for planting in the Indian River Region.
Speakers
avatar for Flavia Tabay Zambon

Flavia Tabay Zambon

University of Florida - IFAS - IRREC
Co-authors
AG

Andres GonzalezNeira

University of Florida
MA

Mark A. Ritenour

University of Florida
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
South Pacific 2

2:15pm HST

HSMP 2 - Enhancing Monoterpene Indole Alkaloid Production in Catharanthus roseus Through Controlled Environment Cultivation and Hormone Applications
Thursday September 26, 2024 2:15pm - 2:30pm HST
The monoterpene indole alkaloids (MIAs) Vincristine and Vinblastine are medicinally important anti-tumor chemotherapy drugs derived from Catharanthus roseus metabolites, but the production of these alkaloids is difficult due to low levels in plant tissue and cost-prohibitive extraction methods. Cultivation of C. roseus in controlled environment systems could allow for increased production of desirable metabolites. There currently is a lack of knowledge concerning hydroponic and controlled environment production of C. roseus for alkaloid production. In two separate experiments, C. roseus was grown in deep water culture hydroponics (DWC) to determine its suitability for hydroponic cultivation and the effect of applying the plant hormones jasmonic and salicylic acids on MIA levels. In experiment 1, two cultivars, ‘Sunstorm Mix’ and ‘Cora Mix’, were cultivated under greenhouse conditions in DWC with two substrates, rockwool (Grodan AO 36/40) or 75% peat: 25% coir ( Jiffy Preforma *HP* DJ) and two fertilizer solution concentrations [150 or 300 mg/L N using a 15N-2.2P-12.4K water-soluble fertilizer (Jack’s Professional® LX 15-5-15 Cal-Mag LX)]. Shoot and root fresh and dry weight (SFW, SDW, RFW, RDW), leaf chlorophyll (CCI) and anthocyanin content (ACI), and total alkaloids (TA) were analyzed. The most favorable combination for many plant growth parameters measured was ‘Sunstorm Mix’ with Jiffy at 150 mg/L N, showing higher SFW, SDW, RFW, and RDW compared to other combinations. In experiment 2, ‘Sunstorm Apricot’ was cultivated under greenhouse conditions in DWC with the same75% peat: 25% coir using a modified Sonneveld solution at 150 mg/L N. Jasmonic and salicylic acids were applied at three rates and at two time points [34 and 41 days after transplant (DAT)]. Two sets of leaf samples were collected at 6,12,18 and 24 hours after application (HAA) and analyzed for the MIAs Vincristine and Vinblastine. Plants were destructively harvested 47 DAT for measurement of growth parameters FSW, FRW, DSW, and DRW. Together, these experiments assisted in improving the crop production for alkaloid use in healthcare and other applications.
Speakers
MH

Matthew Housley

Research Paraprofessional, Graduate Student, University of Georgia
Co-authors
AM

Anish Malladi

University of Georgia
NA
JL

Jason Lessl

University of Georgia
NA
RF

Rhuanito Ferrarezi

University of Georgia
NA
RB

Robin Buell

University of Georgia
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
Kahili

2:15pm HST

NUR 2 - Engineered Substrates Improve Nitrogen, Phosphorus, and Water Retention in Nursery Container Production
Thursday September 26, 2024 2:15pm - 2:30pm HST
Container nursery production is the fastest-growing sector in the nursery industry. High volumes of runoff containing nitrogen (N) and phosphorus (P) from container production result in wasted high-quality fresh water, loss of costly applied fertilizer, and increased risk of nutrient management regulations, especially near receiving waters prone to eutrophication. The authors hypothesize that stratified substrates, in which a fine textured substrate is placed atop a coarse substrate amended with ferrous sulfate (FeSO4), can reduce water use and decrease N and P losses while yielding a high-quality container crop. This research was conducted at the Horticulture Teaching and Research Center in Holt, Michigan on three replicate simulated nursery pads per treatment, each having 45 containers consisting of Buddleja x ‘Miss Violet’, Ilex crenata ‘FARROWSK6’, Hydrangea paniculata ‘Limelight’, Physocarpus opulifolius ‘Seward’, Cornus sericea ‘SMNCSBD’, Cotinus coggygria ‘MINCOJAU3’, Rosa x ‘ChewDelight’. Substrate treatments consisted of an 85:15 (by vol.) pine bark:sphagnum peat uniform profile (Conv), an 85:15 pine bark:sphagnum peat uniform profile fully amended with 3 kg/m3 FeSO4 (Conv Fe), stratified substrate (Strat) in which fine sphagnum peat amended bark substrate was atop a coarse bark substrate, and stratified substrate with the coarse bark layer amended with 3 kg/m3 FeSO4 FeSO4 (Strat Fe). All plants were micro-irrigated with a spray stake. Irrigation water usage, N, and P leaching were quantified and compared. Preliminary results indicate that lower amounts of N leached from Strat (12 mg L-1, p = 0.03) and Strat Fe (13 mg L-1, p = 0.02) compared to Conv (23 mg L-1). Similarly, lower P was found in leachate from Strat (6.33 mg L-1, p = 0.01) and Strat Fe (6.74 mg L-1, p = 0.02) compared to Conv (11.78 mg L-1). These preliminary results, in addition to leaching fraction and growth index, will be discussed in this presentation.
Speakers
avatar for Henry Gonzalez

Henry Gonzalez

Research Assistant/Ph.D. Student, Michigan State University
Co-authors
JS

Jacob Shreckhise

USDA-ARS, U.S. National Arboretum
JO

James Owen

USDA-ARS
Jim Owens is a USDA-ARS Research Horticulturist located at the Application Technology Research Unit in Wooster, OH. Jim received his B.Sc. in Plant and Soil Science at the University of Kentucky, his M.Sc. in Environmental Science at the University of Rhode Island, and Ph.D. at North... Read More →
RF

Rodney Fernandez

Michigan State University
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
South Pacific 4

2:15pm HST

PUBHORT/Hort Industry - Marigolds - An Overlooked Cut Flower Alternative
Thursday September 26, 2024 2:15pm - 2:30pm HST
Especially the floral industry is dependent on fashion trends and changes in taste that dictate the colors and styles of arrangements. As it turns out, when it comes to marigold cut flowers, certain customers have been traditionally underserved in the southeastern United States. Research conducted by the Louisiana State University and Mississippi State University indicate that Marigolds are not only a very viable alternative to traditional cut flowers but also a worthwhile investment for commercial growers. Further research indicates that specific cultures and religions prefer marigolds for celebrations and holidays representing a relatively large customer base with considerable purchasing power that has previously gone unnoticed by the floral industry in the southeastern United States. Findings suggest marigolds have the potential to increase the floral industry’s market share and attract new customers that it previously failed to attract. Additionally, many celebrations and holidays for which marigolds are desired are during a time of the year when demand for flowers is typically low. Marigolds should therefore be considered for season extension.
Speakers
AH

Alessandro Holzapfel

Extension Associate, Louisiana State University Agricultural Center
Co-authors
AA

Achyut Adhikari

Louisiana State University Agricultural Center
NA
KF

Kathryn Fontenot

LSU AgCenter
Thursday September 26, 2024 2:15pm - 2:30pm HST
Lehua Suite

2:15pm HST

VCM 5 - Variation in Toxic Element Presence in Sweetpotato Storage Roots From A Small Plot Trial: Sampling Implications
Thursday September 26, 2024 2:15pm - 2:30pm HST
The overarching goal of FDA’s Closer to Zero (C2Z) action plan is to reduce dietary exposure to contaminants, in foods commonly eaten by babies and young children, to as low as possible while maintaining access to nutritious foods. In addition to establishing action levels for specific toxic elements (TEs), C2Z proposes to develop new and improved testing methods to measure lower levels of contaminants in food and monitor levels over time to determine potential adjustments to proposed action levels. These proposed testing and monitoring activities represent potential added costs to the producer. The sweetpotato (Ipomoea batatas L.) is a leading baby food raw product but very little information is available on the appropriate frameworks for optimal sampling procedures to ensure accuracy and precision of surveys, especially at the field scale. A field trial to investigate the role of commonly used soil amendments in reducing storage root accumulation of arsenic (As), cadmium (Cd), and lead (Pb) revealed interesting trends that merits further investigation. Three random U.S. No.1-sized storage roots were sampled from each of three random plants from each of two unamended (control) plots (plot size=12’ x 3.3’) and analyzed for TE presence at a commercial laboratory. The Pb and Cd content of storage roots from cultivars ‘Bayou Belle’ (BB) (SDs: Cd=1.1, Pb=1.3) and ‘Beauregard’ (BX) (SDs; Cd=1.8 Pb=1.3, Cd=) showed more variability relative to As (SDs: BB=0.5, BX=0.6). There were no differences between two cultivars for all TEs measured. A possible follow-up study could investigate plant- or soil-based variables that contribute to variation in Pb and Cd accumulation. Such findings can be used to improve the accuracy and precision of sampling approaches to enable producers to meet C2Z goals, especially as it concerns sampling of storage roots for monitoring and enforcement purposes.
Speakers
avatar for Arthur Villordon

Arthur Villordon

Professor, Louisiana State University AgCenter
No roots left behind! The sweetpotato's root system architecture integrates internal, environmental, and management determinants of storage root yield, quality, and shape attributes. Root architectural adaptations to biotic and abiotic stress variables provide insights about traits... Read More →
Thursday September 26, 2024 2:15pm - 2:30pm HST
South Pacific 1

2:15pm HST

VGBR 2- Genome-wide Association Study and Genome Prediction of Bolting Trait in Spinach
Thursday September 26, 2024 2:15pm - 2:30pm HST
Spinach (Spinacia oleracea L.) stands as a globally significant vegetable celebrated for its rich array of nutritional and health-promoting compounds. Bolting, a crucial trait in spinach cultivation across diverse seasons and regions, is heavily influenced by photoperiod sensitivity. The premature induction of bolting in spinach due to extended daylight exposure can render the plant unsuitable for market. This study aimed to conduct a comprehensive genome-wide association study (GWAS) to pinpoint single nucleotide polymorphism (SNP) markers associated with late bolting in spinach and to perform genomic prediction for this trait. GWAS was executed on a panel of 295 USDA spinach germplasm accessions, utilizing 16,563 SNPs derived from whole-genome resequencing. Various statistical models, including GLM, MLM, FarmCPU, and BLINK, were deployed in the analysis using the GAPIT 3 tool. A significant quantitative trait locus (QTL) region on chromosome 6 was identified, with three SNP markers — SOVchr6_13545609, SOVchr6_13545882, and SOVchr6_13545887 — located between 13,545,609 bp and 13,545,887 bp, demonstrating robust associations with late bolting. Additionally, the gene SOV6g004620, encoding a TTF-type domain-containing protein and situated at 13,566,721 bp to 13,567,164 bp on chromosome 6, emerged as a potential candidate for regulating bolting. Genomic prediction exhibited a high prediction ability (GA) with an r value of 0.85. The identified SNP markers and GA metrics present valuable tools for breeders to selectively cultivate late-bolting spinach plants and lines through marker-assisted selection (MAS) and genomic selection (GS), thereby facilitating enhanced spinach breeding endeavors.
Speakers
HA

Hanan Alkabkabi

University of Arkansas
NA
Co-authors
avatar for Ainong Shi

Ainong Shi

Associate Professor, University of Arkasnas
Dr. Ainong Shi is a faculty member in the Department of Horticulture at the University of Arkansas. His research laboratory specializes in plant breeding and genetics, particularly focusing on vegetable crops such as arugula, cowpea, and spinach for cultivar and germplasm development... Read More →
BM

Beiquan Mou

USDA-ARS
NA
GB

Gehendra Bhattarai

University of Arkansas
HX

Haizheng Xiong

University of Arkansas
IA

Ibtisam Alatawi

University of Arkansas
NA
KC

Kenani Chiwina

University of Arkansas
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
South Pacific 3

2:15pm HST

VSF 4 - Postharvest Quality of ‘Calypso’ Blueberry After Hand and Machine Harvest
Thursday September 26, 2024 2:15pm - 2:30pm HST
The 'Calypso' blueberry has emerged as a popular variety widely planted in the Pacific Northwest. Its reputed storage quality and reasonable firmness suggest its suitability for mechanical harvesting in the fresh market using over-the-row machine harvesters. To explore its postharvest quality after both hand and machine harvest, we conducted a comprehensive study in a commercial, 7-year old 'Calypso' field in Oregon. Additionally, a drop test was employed to simulate machine harvesting for fresh market blueberries. Throughout a 4-week period of cold storage, fruit firmness generally remained stable, with occasional increases noted, while berry size remained consistent, indicating 'Calypso' maintains good storage quality. Examination of fruit internal bruise damage (IBD) by cutting berries along the equator revealed consistent levels of IBD throughout cold storage, elucidating why 'Calypso' enjoys a good shelf life. The drop test demonstrated 'Calypso's' resilience to damage from drops, with a similar pattern of fruit IBD development observed between drop-tested and machine-harvested fruits. This study highlights the slow rate of IBD development in 'Calypso' fruit as a crucial factor contributing to its success in machine harvesting for fresh market operations.
Speakers
WY

Wei Yang

North Willamette Res
Co-authors
SD

Sarah Doane

North Willamette Res
NA
Thursday September 26, 2024 2:15pm - 2:30pm HST
Nautilus

2:30pm HST

CE 6 - Energy Modeling and Management to Improve the Sustainability of Indoor Farming
Thursday September 26, 2024 2:30pm - 2:45pm HST
Controlled environment agriculture (CEA) is considered one of the most efficient ways of crop production. CEAs have the ability to control environmental conditions to maximize crop production. Indoor farms are considered one of the CEA systems that precisely control the environment, leading to high energy consumption in lighting, heating, cooling, and humidity control requirements. Enhancing the energy use efficiency (EUE) of indoor farms requires a better understanding of the energy characteristics of the system and crop production is needed. In this study, a steady state energy model and a machine learning based crop growth model were developed to evaluate energy-saving strategies for indoor lettuce production. The strategies included shifting photoperiod, utilizing heat tolerant crops, and adjusting air temperature settings at four different locations (Phoenix, AZ, Los Angeles, CA, Jacksonville, FL, and Boston, MA). The results showed that cultivar selection plays an important role in EUE improvement. Using high temperature settings with heat tolerant cultivars can increase the EUE of the system. However, increasing temperature setting alone does not significantly reduce energy consumption because of the increasing amount of energy needed for dehumidification. The geographical location of the indoor farm also affects energy consumption because of the different outdoor climate conditions. Boston, MA, which has the coldest outdoor air temperature, had the lowest energy consumption overall compared to the other three locations. Lastly, changing the photoperiod schedule from daytime to nighttime can reduce the electricity costs dramatically by avoiding the peak rate of electricity despite not having a significant reduction in energy consumption.
Speakers
YZ

Ying Zhang

University of Florida
Co-authors
GS

German Sandoya

University of Florida
KH

Kale Harbick

USDA-ARS
NA
NB

Nikolay Bliznyuk

University of Florida
NA
TL

Tanapol Leelertkij

University of Florida
NA
Thursday September 26, 2024 2:30pm - 2:45pm HST
Coral 1

2:30pm HST

CITR 3 - Florida Citrus Rootstock Selection 5th Edition: Artificial Intelligence Enhanced Mobile Application for Growers
Thursday September 26, 2024 2:30pm - 2:45pm HST
Florida citrus production has declined by 81% in total tonnage since 2020, mainly due to the deadly citrus greening caused by Candidatus Liberibacter asiaticus (CLas), a fastidious, phloem-limited, unculturable, gram-negative, α-proteobacterium vectored by the Asian Citrus Psyllid (ACP). Over $1.5 billion in funds have been mobilized since 2006 to overcome this disease. As an innate immune response, the infected plant deposits callose and p-protein in the phloem sieve pore, decreasing the flow of photoassimilates, leading to a rapid decline and, eventually, a plant collapse. The high cost of production has economically devastated Florida citrus growers. Using HLB tolerant rootstocks is one alternative to mitigate CLas effects, and the growers depend on the University to provide the most up-to-date recommendations. To address this, we have developed a convenient mobile application that uses artificial intelligence (AI) to assist growers in making the best rootstock selection for their groves based on horticultural traits, abiotic tolerances, and specific disease/pest incidences. The Florida Citrus Rootstock Guide Expert System 5th Edition is planned to be released by 2025 and is based on the information released in the previous editions. In addition to the release of the mobile application on all major platforms, an interactive web-based rootstock table has been updated with recent field data and newly released rootstocks. Historical and unavailable rootstocks are excluded from the selection list, increasing the incidence rate for a well-suited rootstock selection. Users can download, send, and retrieve rootstock reports on their mobile devices. The app’s design was generated from grower/user surveys to be as user-friendly as possible. The expert system is built on the ES-Builder Web application, McGoo Software, and is developed utilizing Google’s Dart programming language. The University of Florida is committed to establishing an AI-based university. The app's scalability will allow it to fully integrate into future AI projects to combat epidemics like citrus greening.
Speakers
AG

Andres Gonzalez Neira

University of Florida - IFAS - IRREC
Co-authors
FT

Flavia Tabay Zambon

University of Florida - IFAS - IRREC
JC

John Chater

University of Florida
MR

Mark Ritenour

University of Florida - IFAS - IRREC
NA
Thursday September 26, 2024 2:30pm - 2:45pm HST
South Pacific 2

2:30pm HST

HSMP 2 - Multipronged Strategies to Combat Seed-Piece and Soil-borne Diseases of Ginger
Thursday September 26, 2024 2:30pm - 2:45pm HST
Ginger (Zingiber officinale Roscoe) is esteemed for its diverse uses in flavoring beverages, enhancing cuisines and offering medicinal benefits such as aromatherapy and home remedies. Yet, its global production struggles to meet demand due to persistent seed-piece and soil-borne diseases (SSDs) caused by fungi, bacteria, oomycetes and nematodes. Lack of genetic diversity because of vegetative propagation exacerbates the situation. This study explored the efficacy of hot water treatment (HWT, 47°C for 30 minutes or 52°C for 10 minutes), Trichoderma-based biocontrol products (BPs, RootShield®, RootShield®Plus) and chitosan (1 or 5g/L in 1% HCl) alone or in combination with each other using ‘Chinese’ variety grown in a 10-lber grow-bags in a high tunnel. Fusarium oxysporum f.sp. zingiberi) was inoculated (2 X 103 conidial suspension/ml) prior to and after HWT, BPs and / or Chitosan. Results showed significantly higher mortality when seed-pieces were treated and then inoculated with pathogen before planting than vice versa. In one of the experiments, ginger plants grew significantly taller when treated chitosan (5g/L) when compared with non-treated control. Dipping seed-pieces in BPs also showed significantly higher growth and yield compared to only HWT or the non-treated control. The research contributes components that can be added towards developing integrated preventative and curative measures to mitigate SSDs. Recently, leaf spot caused by Curvularia sp. and postharvest infections by Pythium sp. and Penicillium sp. are under investigation. Scouting research plots in high tunnels and a grower’s greenhouse also revealed arthropod damages by grasshoppers, caterpillars, mites and sucking insects in protected systems.
Speakers
ZM

Zelalem Mersha

Virginia State University
Thursday September 26, 2024 2:30pm - 2:45pm HST
Kahili

2:30pm HST

NUR 2 - A 2-Dimensional Analysis of How Root Architecture and Morphology Are Influenced by Stratified Substrate Systems
Thursday September 26, 2024 2:30pm - 2:45pm HST
Soilless substrates serve an important role in both the sustainability of specialty crop production and supporting healthy containerized root growth. The requirements and tolerance of containerized roots are essentially what dictates the (i) physiochemical limitations of the substrate, (ii) how production practices are managed (i.e., quantity and quality of irrigation / fertilization), and (iii) the performance of high-quality shoot growth and development, emphasizing the importance of both substrates and roots. Nevertheless, most horticultural crop research primarily focuses on shoot growth and dismisses important root growth traits, often only reporting root biomass at study culmination or during destructive harvests. Information regarding how roots grow throughout the substrate matrix is evidently sparse. More research is needed to develop better understandings of spatial and temporal root development, such as root architecture, which describes how (and where) roots invests carbon throughout the 3-Dimentional substrate matrix. Research regarding popular engineered substrate systems, stratified substrates (i.e., layering different media atop each other), has began to dive deeper into how roots grow in time and space, where stratified-grown roots grow differently than traditionally grown (non-stratified) cropping systems. However, no research to date as explored root architecture, temporally or spatially, in stratified systems. The study herein explored root architecture in time and space using clear acrylic-based RhizoBoxes (8-L vol.). Several different types of crops (nursery- hibiscus; greenhouse- basil; representative crop- sunflower) were grown in different non-stratified and stratified substrate systems, including bark- [non-stratified: 100% unscreened bark; stratified- fine bark (< 6.3 mm) layered over coarse bark (> 6.3 mm)] and peat-based [non-stratified: 100% peat-lite (7:3); stratified: peat-lite layered over unscreened bark] substrates. Root growth was traced frequently and analyzed quantitatively for total visible root length and growing angle, and qualitatively for general shape and patterns. The results showed that stratified grown crops, across cropping systems, had a wider root distribution spreading angle, growing wider and more outward than crops grown in non-stratified systems. Moreover, stratified grown crops typically grew in the upper stratified layer longer than crops grown traditionally, growing more sequentially than continuously. In most cases, stratified-grown crops had longer visible roots growing against the acrylic glass in the upper 50% of the profile. Stratified-grown roots were often longer and finer than non-stratified grown crops. In all, this study highlights that stratified grown crops have superior root growth and development and that RhizoBoxes are a useful tool in studying root architecture in soilless substrate systems.
Speakers
avatar for Kristopher Criscione

Kristopher Criscione

LSU AgCenter Hammond Research Station
Co-authors
JF

Jeb Fields

LSU AgCenter Hammond Research Station
Thursday September 26, 2024 2:30pm - 2:45pm HST
South Pacific 4

2:30pm HST

PUBHORT/Hort Industry - Improving Military Community Reintegration: The Effects of Plant-related Jobs on Military Service Member Mental and Physical Health
Thursday September 26, 2024 2:30pm - 2:45pm HST
Military members are a unique and diverse group making up 7% of the U.S. population. After completing their military service many return home and struggle with reintegration back into civilian life due to mental and physical ailments they obtained during enlistment. One of the first steps of civilian reintegration is acquiring a job. A type of job that military members enter is in plant-related fields. Research on the passive and active interaction with plants and its benefits, has been conducted extensively. However, it is not yet known how specific jobs that require working with plants or being in nature can help improve military member health and if they have therapeutic benefits. To evaluate this, part 1 of an online survey ascertained demographics and part 2 was created based on the National Veteran’s Survey and the VR-36 which looked at participants’ physical (PCS) and mental wellness (MCS). Results show that most of the military participants (N=148) were in the 25-30 year and 40-50-year-old range, Caucasian (70.9%) males (68.9%) involved in Army (44.6%) and Marine (24.3%) branches of the military and honorably discharged or retired. Military members in plant-related jobs scored in the top 3 job categories for PCS (49.1) and MCS (45.0), while Health related jobs were top for MCS (53.6) and those retired were top for PCS (49.7). Overall, those in plant, health, and retired jobs described them as relaxing, easy, and physical. Military in rural locations also had lower MCS in comparison to those living in urban centers. The findings from this research suggest that plant-related jobs could offer military members an opportunity to improve their mental and physical health, while helping with job retention and community reintegration.
Speakers
avatar for Alicia Thomas

Alicia Thomas

Assistant Professor of Practice, Texas Tech University
Thursday September 26, 2024 2:30pm - 2:45pm HST
Lehua Suite

2:30pm HST

VCM 5 - Striving to stay clean: Production of sweetpotato nuclear stock used for certified seed growers in North Carolina
Thursday September 26, 2024 2:30pm - 2:45pm HST
The Micropropagation and Repository Unit (MPRU) produces, maintains and distributes meristemmed-tip culture, virus-tested, indexed, true-to-type sweetpotato nuclear plants to certified seed growers in NC. Under the certification program, seed growers use nuclear plants for production of G0 plants in greenhouses, and subsequently G1 and G2 plants and storage roots (seed) in the field. All these materials are inspected and certified by NC Crop Improvement Association, Inc. (NCCIA). The MPRU is a clean center for sweetpotato under the National Clean Plant Network (NCPN) umbrella. It works closely with the NC State sweetpotato breeding and genetics program to clean advanced selections yearly. The MPRU distributes about 90,000 nuclear plants to NC certified seed growers every year. It is estimated that about 70% of the commercial sweetpotato acreage in NC is planted annually with stocks derived from the MPRU. It is known that the accumulation and perpetuation of viruses in sweetpotato is a major constraint for production of seed and the commercial crop. The aphid-transmitted potyvirus complex is prevalent in NC and comprises Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), Sweet potato virus C (SPVC) and Sweet potato virus 2 (SPV2). In order to evaluate the performance and quality of clean seed after it had been integrated into commercial sweetpotato operations, NCPN field trials were carried out in 2021 and 2023 with Covington and Beauregard as evaluated varieties. Because sweetpotato is vegetatively propagated, viruses and mutations can accumulate readily which can lead to cultivar decline. G1 seed was used as a reference to compare the yield and virus incidence of growers’ generation 2 (G2), generation 3 (G3) and generation 4 (G4) seed roots (grown in the growers’ seed production fields 1, 2 or 3 years following the year of clean seed production). Virus detection data suggested a low incidence of viruses (mainly SPFMV) on G1 material. Potyviruses (mainly SPVG, SPVC and SPFMV) started to be prevalent on G2 and G3 material. In the older generation evaluated (G4), all potyviruses (SPVG, SPVC, SPFMV and SPV2) were detected. In general, the prevalence of four potyviruses was associated to higher seed generations, indicating a buildup over the years on clean seed regardless of the variety. Yield data suggested a negative impact due to virus infections in Beauregard. This study will allow us to understand the impact of clean seed on the economic value of the crop to educate growers and stakeholders.
Speakers
CA

Christie Almeyda

MPRU Director, North Carolina State University
Co-authors
CY

Craig Yencho

North Carolina State University
NA
DA

Dustin Auman

North Carolina Crop Improvement Association, Inc
NA
KP

Kenneth Pecota

North Carolina State University
NA
Thursday September 26, 2024 2:30pm - 2:45pm HST
South Pacific 1

2:30pm HST

VGBR 2 - Towards the Improvement of Lettuce for Heat Tolerance Adapted to Controlled Environment Agriculture
Thursday September 26, 2024 2:30pm - 2:45pm HST
Lettuce (Lactuca sativa L.) is one of the top ten most consumed vegetables in the United States. In Controlled Environment Agriculture (CEA), lettuce is one of the most cultivated vegetables. The crop yield is severely affected by heatwaves during production. As a result of severe warmer temperatures, lettuce develops physiological disorders such as bolting and tipburn and consequently less marketability and yield. In order to reduce cooling costs and extend the growing season of lettuce crops, breeding heat-tolerant germplasm is imperative. In this research our aim was to confirm heat tolerance in lettuce identified in fields when grown in hydroponics. Initial screenings were conducted at the North Florida Research and Education Center- Suwannee Valley. One hundred and four lettuce accessions from four morphological types (Boston, Latin, leaf, and romaine) were planted in a Nutrient Film Technique (NFT) hydroponic system in a passively vented greenhouse in two experiments. Germplasm included commercial cultivars, plant introductions, legacy cultivars, and breeding lines from the University of Florida /Institute for Food and Agricultural Sciences (UF/IFAS) Lettuce Breeding Program. Data was collected on head weight and related characteristics including marketability, head height, density and width, and core length. Presence of disorders such as bolting, chlorosis and tipburn were also registered as indicators on the negative effects of warmer temperatures. Germplasm with tolerance to warmer temperatures were identified within each of the lettuce types used on this research. This germplasm had an acceptable head weight with less plants that bolted and insignificant presence of tipburn. Several of the germplasm considered heat tolerant are commercial cultivars currently used by the industry in CEA. Similarly, breeding lines from the UF/IFAS Lettuce Breeding Program showed better tolerance than commercial germplasm and are candidates for breeding and genetics studies to decipher mechanisms of heat tolerance in lettuce for this specific environment. Mapping and breeding populations will soon be developed to first study the genetics of tolerance to warmer temperatures and to select germplasm in this specific environment. While tolerant germplasm will aid to decrease cost production for CEA, additional management strategies should be optimized to decrease even further cost of production for growers.
Speakers
GS

German Sandoya Miranda

Associate Professor, University of Florida EREC
Co-authors
RH

Robert Hochmuth

University of Florida
NA
WL

Wanda Laughlin

University of Florida
NA
Thursday September 26, 2024 2:30pm - 2:45pm HST
South Pacific 3

2:30pm HST

VSF 4 - Preliminary Findings from the Evaluation of New Cranberry Cultivars in Massachusetts
Thursday September 26, 2024 2:30pm - 2:45pm HST
Cranberry growers in Massachusetts still rely primarily on heritage cultivars, such as Howes (1843) and ‘Early Black’ (1852). The research aims to increase the profitability and sustainability of the Massachusetts cranberry industry by evaluating twelve new hybrid cultivars for improved yield, fruit quality, disease resistance, and size. The research project was initiated in March 2021 with the prorogation of the new cultivars in a greenhouse. At the same time, the renovation of a 0.75-acre cranberry bog was initiated. The renovation included stripping off the top 0.25 m of the bog and replacing it with new sand. A new irrigation and drainage system was also installed. The new cultivars were planted in June 2021 at the Cranberry Station in East Wareham, Massachusetts. The new cultivars were planted in a randomized, complete block design with four replications per cultivar and buffer zones between the plots. Standard commercial cultural practices for new plantings regarding irrigation, fertilization, pest control, and canopy management were followed. Fruit was removed from the vines to allow maximum resource allocation for canopy growth in 2022, and the first fruit harvest was in 2023. Yield was measured by picking all fruit within a 0.09 m 2 quadrat. The fruit samples were then sieved through an 8-mm opening to remove undersized berries; the remaining berries represented the yield of marketable berries. Additional samples (≈500 g) were collected from each treatment replication for fruit quality analysis. Fruit color was measured using total anthocyanin content (TAcy). Regarding yield, Haines® (353 barrels/acre), Welker™ (287 barrels/acre), and Crimson King (243 barrels/acre) were the most productive, while Vassana® (112 barrels/acre) and HyRed® (117 barrels/acre) performed poorly, with the other cultivars in the mid-range. Scarlet Knight® (81 TAcy), HyRed® (65 TAcy), and Midnight 8 (58 TAcy) had the best fruit color, while Badger (16 TAcy), Granite Red (22 TAcy), Sundance (24 TAcy), and Pilgrim King (26 TAcy) had poor fruit color. The highest fruit rot incidence was observed in HyRed® (37%), Welker™ (52%), and Vassana® (63%), while Granite Red (11%), Mullica Queen® (13%), Badger (18%), and Sundance® (19%) had the lowest incidence. The fruit size measured as fruit diameter was largest in Badger (20.3 mm), Granite Red (20.3 mm), Crimson King (19.8 mm), and Haines® (19.5 mm). In conclusion, first-year harvest data showed differences in the performance of the cultivars under MA growing conditions. Additional data from multiple years are still needed to provide growers with recommendations.
Speakers
GM

Giverson Mupambi

University of Massachusetts Amherst
Co-authors
HS

Hilary Sandler

University of Massachusetts Amherst
NA
LU

Leela Uppala

University of Massachusetts Amherst
NA
PJ

Peter Jeranyama

University of Massachusetts Amherst
NA
Thursday September 26, 2024 2:30pm - 2:45pm HST
Nautilus

2:45pm HST

CE 6 - Increasing Circularity in Controlled Environment Agriculture using Anaerobic Digester Effluent as an Organic Fertilizer
Thursday September 26, 2024 2:45pm - 3:00pm HST
As global population and stress on our natural resources increases, we need to rethink how/where we produce food with emphasis on recycling resources such as carbon, water, and nutrients. Controlled environment agriculture (CEA) is gaining increasing attention due to its potential for improving resource use efficiency compared to traditional field-based agriculture. This project investigated a novel approach for treating hydroponics irrigation water and recovering nutrients from vegetable waste for reuse in CEA systems. An integrated anaerobic/aerobic biological treatment process was investigated. Anaerobic digester effluent was nitrified via an aerobic membrane bioreactor process to produce a liquid organic fertilizer supplement (nADE). The nADE was evaluated as a nutrient source for indoor hydroponic and greenhouse soilless drip-irrigation lettuce cultivation. Lettuce yield, tissue nutrient content, water quality, and nutrient uptake efficiency were compared between the nADE treatment and a commercial fertilizer control for each CEA system. The lettuce grown on nADE demonstrated similar or higher yields, more leaves, and elevated tissue nutrient content than the control. The nADE media improved N and P uptake efficiency in the drip-irrigation system but decreased K, Ca, and Mg uptake efficiency, possibly from the over-application of these nutrients. Further research is needed to optimize the integrated treatment system as well as nADE dosing. The study demonstrates a circular bioeconomy approach to decrease dependency on inorganic fertilizers while benefiting crop yield and quality.
Speakers
AM

Ana Martin Ryals

University of Florida
Co-authors
HB

Haimanote Bayabil

University of Florida
NA
KV

Kelsey Vought

University of Florida
NA
Thursday September 26, 2024 2:45pm - 3:00pm HST
Coral 1

2:45pm HST

CITR 3 - Australian Microcitrus-Derived Hybrids: Field Performance in Florida Under HLB Endemic Conditions
Thursday September 26, 2024 2:45pm - 3:00pm HST
At the Queensland Department of Agriculture and Fisheries, the breeding program used native Australian citrus species (C. australasica, C. australis, C. garrawayi, and C. inodora), collectively referred to as Microcitrus, and cultivated Citrus. Commencing in 1998, this program aimed to introduce desirable Microcitrus traits into cultivated citrus, resulting in hybrids with pedigrees ranging from 12.5% to 100% Microcitrus. Previous studies suggest that specific Microcitrus accessions may exhibit resistance to huanglongbing (HLB), a disease associated with Candidatus Liberibacter asiaticus (CLas). To assess this resistance, we conducted tests on these Microcitrus-derived seedlings in a Florida field site where HLB and its vector, the Asian Citrus Psyllid (Diaphorina citri; ACP), are prevalent. Seeds were received in August 2015 and grown into field-ready seedling trees at the USHRL greenhouse. In August 2018, these trees were planted in a randomized layout at the Fort Pierce USDA grove, comprising 53 Microcitrus-derived populations alongside grafted Clementine and Hamlin standards. During 2020 and 2021, a subset of these plants underwent 24 assessments for ACP colonization, focusing on periods of abundant citrus flush and active D. citri presence. Data collected included observations of eggs, nymphs, and 5th instars, indicating D. citri's ability to complete development on the plant. Statistical analysis assessed variations in egg and nymph abundances concerning scion and date, revealing differing nymph counts across dates and scion types, with Hamlin and Arrufatina X 09Q048 displaying the highest nymph counts. Additionally, all trees were evaluated for CLas levels in October 2021 and no significant differences were found. The study encompassed seedling development, field planting, and standard citrus production practices, with minimal pesticide usage to determine the tolerance of Australian-derived hybrids to HLB.
Speakers Co-authors
ES

Ed Stover

Retired (USDA,ARS)
NA
FT

Flavia Tabay Zambon

University of Florida - IFAS - IRREC
Thursday September 26, 2024 2:45pm - 3:00pm HST
South Pacific 2

2:45pm HST

HSMP 2 - Seed emergence of Fagonia indica, a plant with potential chemistry active against breast cancer.
Thursday September 26, 2024 2:45pm - 3:00pm HST
Phytochemicals from the genus, Fagonia, have potential beneficial effects on human health. Fagonia indica is a Pakistani traditional herbal medicine thought to be useful for the prevention and treatment of breast cancer Acid-hydrolyzed extracts of Fagonia indica have bioactivity on breast cancer MCF-7 cells in vitro. Horticultural production of Fagonia indica is largely undeveloped. Seeds planted without special treatment show poor emergence and come up slowly over many weeks. Seed treatments with vernalization, scarification, gibberellic acid soaking and their interactions were tested. Seed were treated and planted into mulch. Less than 1 percent of untreated seed emerged within 3 weeks of planting. Both seed scarification and gibberellic acid greatly enhanced emergence. Vernalization had a small effect on total emergence but did increase seedling emergence during the first two weeks following planting, Scarification and gibberellic acid could be refined by making variations in these practices.
Speakers
CS

Clinton Shock

Scientific Ecological Services
Thursday September 26, 2024 2:45pm - 3:00pm HST
Kahili

2:45pm HST

NUR 2 - Predicted Drought Tolerance of Cephalanthus occidentalis L. for Use in Managed Landscapes
Thursday September 26, 2024 2:45pm - 3:00pm HST
Buttonbush (Cephalanthus occidentalis) is a valuable landscape shrub revered for its prominent white, globe-shaped blooms which can later develop into brilliant red aggregate fruits. This North American native shrub occurs almost exclusively in riparian habitats, typically in standing water in the wild, but it is curiously adaptable to a range of landscape conditions in cultivation. Because this species appears to perform well when grown using average soil-moisture conditions, we questioned where the limits of drought tolerance occur for this riparian-adapted species. The objective of this study was to evaluate USDA-GRIN germplasm of buttonbush to compare unique provenances representing different regions of the native range of the taxon to generate a relative scale of predicted drought tolerance for the species. Utilizing vapor pressure osmometry, this study examined seasonal osmotic adjustment and predicted leaf water potential at the turgor loss point (ᴪpo) among ten Cephalanthus occidentalis populations grown at the Morton Arboretum in Lisle, Illinois. All populations evaluated demonstrated a minor ability to osmotically adjust (Δᴪ𝝿100) throughout the growing season. NA 79917 exhibited the most osmotic adjustment (-0.22 MPa) whereas NA 61271 exhibited the least (-0.08 MPa). Estimated spring ᴪpo and summer ᴪpo across populations was -1.75 MPa and -1.91 MPa, respectively. NA 79705 exhibited the highest ᴪpo in both spring (-1.56 MPa) and summer (-1.68 MPa). NA 82190 exhibited the lowest ᴪpo in spring (-1.92 MPa ), whereas NA 73814 exhibited the lowest in summer (-2.17 MPa). These data indicate that drought tolerance in buttonbush varies across populations, suggesting that this trait can be improved in landscape selections through selective breeding efforts.
Speakers
avatar for John Larsen

John Larsen

Graduate Student, University of Minnesota
John works with winter hardy landscape plants, with a special emphasis on Salix pellita (Satiny Willow). A major interest of John's is looking at the horticultural potential of certain native flora, hoping this could lead to new means of conservation for Minnesota's threatened sp... Read More →
Co-authors
BM

Brandon Miller

University of Minnesota
KS

Kim Shearer

The Morton Arboretum
NA
Thursday September 26, 2024 2:45pm - 3:00pm HST
South Pacific 4

2:45pm HST

PUBHORT/Hort Industry - Evaluating the Impacts of Climate Change on Urban Tree Performance and Survival
Thursday September 26, 2024 2:45pm - 3:00pm HST
Climate change is expected to lead to the increased frequency and intensity of natural disasters, which will adversely affect urban tree populations. As a result of rising surface temperatures, USDA Hardiness Zones are projected to shift northward. Healthy urban trees can offer benefits which may offset some of the effects of warming. Therefore, species adaptability to urban conditions needs to be considered, and we need to understand the predicted impacts of warming better in order to design and plant more resilient urban forests. Thus, in the Fall of 2022, protocols began developing to evaluate the following areas of concern: 1: Identify underutilized tree species that might perform well in future climates. A state-wide survey was distributed to green industry professionals to guide species selection for field trials across three hardiness zones in Florida (8b, 9a, and 10b). 2: Analyze the variability of commonly used irrigation technologies on tree establishment. The project compares two commonly used irrigation bags (i.e., TreeDiaper and Treegator) to hand watering to determine labor inputs, time to establishment, and overall tree performance. 3: Determine the effects of increased temperatures on tree species commonly planted in Florida. Temperature-controlled greenhouse experiments will be used to determine the heat tolerance of 6 tree species based on future climates. 4: Analyze parking lot plantings and evaluate the impact of the mitigation of the urban heat island effect. Several randomly selected parking lots in Florida will be looked at to determine their suitability for planting based on the adverse growing conditions associated with urban heat islands. The above studies offer a proactive approach to better understanding the potential effects of warming and provide practical solutions to minimize the impact.
Speakers
avatar for Teagan Young

Teagan Young

PhD Research Assistant, University of Florida
Hi there! I come from the lovely town of Kalamazoo, MI, where my love for taking care of nature through horticulture first took root. In 2019, I made my way down to Gainesville, FL, enticed by the opportunity to join the respected University of Florida's Environmental Horticulture... Read More →
Co-authors
GH

Gail Hansen

University of Florida
NA
LW

Laura Warner

University of Florida
NA
RK

Ryan Klein

University of Florida
NA
SW

sandra wilson

University of Florida
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
Thursday September 26, 2024 2:45pm - 3:00pm HST
Lehua Suite

2:45pm HST

VCM 5 - Effects on yield, quality, sugar content and soil health indicators of foliar and soil applied Chlorella vulgaris in ‘Beauregard’ sweetpotato (Ipomoea batatas [L.] Lam).
Thursday September 26, 2024 2:45pm - 3:00pm HST
Commercial sweet potato production has seen a recent surge in both fresh market and processing acreage in South Carolina. Producing quality conventionally and organically grown sweetpotatoes is a challenge in South Carolina due to numerous biotic and abiotic factors. One of the most important deciding factors on sweetpotato yield is germplasm and fertility. In this study we examined effects on yield and quality of foliar and soil applied Chlorella vulgaris (CV) in ‘Beauregard’ sweetpotato (Ipomoea batatas [L.] Lam). Chlorella vulgaris (EnSoil Algae, Enlightened Soil Corp) is marketed under the USDA/APHIS category of soil amendments and Plant Growth Enhancers (PGE). This study was conducted in 2022-2023 in a randomized complete block full factorial design with 4 replications and a total of 17 treatments with a product rate of 250ml/Ac, including the following: 1) Unfertilized Control, 2) 100 % Preplant Granular Fert. (PGF), 3) Soil Algae Application (SAA), 4) Foliar Algae Application (FAA), 5) 100% PGF SAA, 5) 100% PGF SAA, 6) 100% PGF FAA, 7) 100% PGF SAA FAA, 8) SAA FAA, 9) 25% PGF SAA 75% Drip Irrigation Fert.(DIF), 10) 25% PGF FAA 75% DIF, 11) 25% PGF SAA FAA 75% DIF, 12) 25% PGF SAA, 13) 25% PGF FAA, 14) 25% PGF SAA FAA, 15) 25% PGF 75% DIF, 16) 75% DIF, 17) 25% PGF. Results were mixed over time with 2022 being a better growing year. In 2022, USDA grade Jumbo roots were 10% numerically greater in SAA treated plots, than 25% PGF SAA 75% Drip Irrigation Fert. (DIF) and 9% over SAA and FAA. In 2023 there were similar trends, with USDA grade Number
Speakers
BW

Brian Ward

Clemson University CREC
Co-authors
KA

Karin Albornoz

Clemson University
NA
MH

Matt Horry

Clemson University
NA
PW

Phillip Wadl

USDA, ARS, U.S. Vegetable Laboratory
Thursday September 26, 2024 2:45pm - 3:00pm HST
South Pacific 1

2:45pm HST

VGBR 2 - Root Phenotyping in Chile Pepper: Key Steps and Challenges with the RhizoVision Explorer
Thursday September 26, 2024 2:45pm - 3:00pm HST
Genetic studies of root architecture provide valuable insight into the overall yield potential of chile pepper (Capsicum annuum L.) under various biotic and abiotic conditions. Phytophthora root rot , caused by soil born pathogen Phytophthora capsici, is one of the most destructive diseases of chile pepper that incur huge losses under severe infection. Rotting of the roots and crown are the primary symptoms with lesions on stem, wilting, and necrosis leading to the plant death. RhizoVision Explorer is a high throughput phenotyping tool that facilitates precise and in-depth phenotyping of root architecture. In this study, four chile pepper cultivars were planted in three replications under greenhouse conditions. A virulent isolate ‘6347’ was used to inoculate the cultivars. At maturity, shoots were removed, and roots were thoroughly washed to prepare them for scanning. A flatbed scanner was used where a transparent plastic flat allowing roots to be submerged in the water was set up to proceed with scanning and analysis using the RhizoVision Explorer. Analysis of variance (ANOVA) demonstrated significant differences between the treated and control groups coupled with strong positive correlation (r > 0.90; P < 0.001) for maximum number of roots (MNR), number of root tips (NRT), total root length (TRL), depth (DPT), maximum width (MAXW), and width-to-depth ratio (WDR). Preliminary results provided insights into root architecture under P. capsici infection and the optimization of key procedures such as root washing and scanning. Overall, the efficiency of root phenotyping using the RhizoVision Explorer under pathogen infection could be improved by modifying specific steps related to the washing and processing of chile pepper samples. Keywords: High throughput phenotyping, Phytophthora blight, root architecture
Speakers
EK

Ehtisham Khokhar

New Mexico State University (NMSU)
Co-authors
DN

Dennis Nicuh Lozada

New Mexico State University
Thursday September 26, 2024 2:45pm - 3:00pm HST
South Pacific 3

3:00pm HST

CE 6 - Utilizing Deep Learning for Hydroponic NFT Channel Spacing Optimization
Thursday September 26, 2024 3:00pm - 3:15pm HST
In controlled environment agriculture (CEA), maintaining effective plant spacing throughout the crop growth cycle is crucial for efficient resource (light, water, space, and nutrients) utilization to achieve optimal crop yield and quality. Overcrowded or overlapping plant leaves could cause inefficient light exposure to plants/parts of plants, negatively affecting their growth. Additionally, reduced airflow makes overcrowded plants prone to diseases and foliage damage. Meanwhile, sparse plant spacing could result in inefficient space and light utilization. Traditional plant spacing adjustment relies on expert knowledge and manual labor, which is time-consuming, labor-intensive, and costly. Computer vision-based automatic plant space adjustment could help with data-driven decision-making and reduce labor dependency. This study aims to develop a deep learning-based computer vision approach to estimate the effective plant spacing by extracting the morphological characteristics of plants and NFT (nutrient film technique) channels during different plant growth stages. A total of 576 lettuce plants were grown in an NFT channel-based hydroponics system in a controlled environment. Then, RGB-D information of these plants and NFT channels was collected each day for three weeks from planting to harvesting. Then, CNN (convolutional neural network) was employed to extract the plant and NFT channel feature information. Then, the spatial pyramid pooling approach was used to encode and decode the contextual information and segment the plants and NFT channels. This approach helped to achieve an F1-score of 0.90 on the test dataset to estimate space between plants and NFT channels. These results show the potential of the proposed approach for automated plant space adjustment for efficient resource utilization.
Speakers
AZ

Azlan Zahid

Assistant Professor, Texas A&M University
AI and Robotics for CEA
Thursday September 26, 2024 3:00pm - 3:15pm HST
Coral 1

3:00pm HST

CITR 3 - The Citrus Genome Database: A Resource for Citrus Research and Crop Improvement
Thursday September 26, 2024 3:00pm - 3:15pm HST
The Citrus Genome Database (CGD, www.citrusgenomedb.org) is a crop community database tailored for citrus researchers and breeders. CGD includes the Breeding Information Management System (BIMS) for both private breeding program management and publicly available phenotype and genotype data. Genetic data include genetic markers, maps, QTL, and GWAS curated from published and integrated with associated data in the database. The data is accessible via several search interfaces. Genetic maps can be viewed through the MapViewer tool, that also visualizes gene and genome data where available. CGD has over 40 genomes of Citrus and other genera in the Rutaceae family. For plant genomes, additional functional annotation and synteny analyses are conducted and made available to search. The genomes can be viewed in JBrowse, sequences searched using BLAST, genome synteny viewed with Synteny Viewer, and metabolic pathways for representative genomes can be viewed and users can overlay -omics data in CitrusCyc. Expression data associated with genes or mRNA of genomes in CGD are also available to view in the Expression Heatmap tool and on the feature page for the corresponding gene/mRNA. Ten bacterial genomes from Ca. Liberibacter and Liberibacter species are also available to search in the database, view in JBrowse, and search the sequences using BLAST. Researchers can also prepare and submit published data to the database using Excel based templates.
Speakers
avatar for Jodi Humann

Jodi Humann

Research Associate, Washington State University
Co-authors
CH

Chun Huai Cheng

Washington State University
NA
DM

Dorrie Main

Washington State University
FG

Fred Gmitter

University of Florida
NA
KB

Katheryn Buble

Washington State University
NA
PZ

Ping Zheng

Washington State University
NA
RT

Ronald Tapia

University of Florida
SJ

Sook Jung

Washington State University
NA
TL

Taein Lee

Washington State University
NA
Thursday September 26, 2024 3:00pm - 3:15pm HST
South Pacific 2

3:00pm HST

HSMP 2 - Impact of Polyploid Induction on Apigenin Production in Parsley
Thursday September 26, 2024 3:00pm - 3:15pm HST
Apigenin, an anticancer secondary metabolite, is produced in fruits, vegetables, and herbs, and has been used to prevent patient resistance to cancer treatments. Petroselinum crispum (parsley) is one of the highest natural producers of apigenin. Three parsley cultivars, ‘Darki’, ‘Giant of Italy’, and ‘Wega’, were trialed in an indoor vertical hydroponic system to determine biomass production and apigenin accumulation. The cultivar ‘Giant of Italy’ was selected as the superior cultivar with 0.16 mg apigenin accumulated in each plant and significantly higher biomass than the other cultivars. A viable strategy for increasing secondary metabolite production in plants is through polyploid induction. Although polyploid induction has not previously been used to increase apigenin, it has been used to increase production of other secondary metabolites including quercetin and kaempferol. ‘Giant of Italy’, which has been reported as 2n = 2x = 22, was induced to form tetraploid tissue by treating seeds with an antimitotic agent. Seed germination decreased with increasing treatment concentration and the surviving seeds were grown to maturity in a greenhouse. New leaf tissue was harvested for analysis, and tetraploid cells were confirmed using flow cytometry. Polyploid induction of ‘Giant of Italy’ in this study suggests potential for elevated apigenin production.
Speakers
avatar for Rebekah Maynard

Rebekah Maynard

University of Georgia
Co-authors
JS

Joonhyuk Suh

The University of Georgia
NA
LL

Leonardo Lombardini

The University of Georgia
NA
SO

Samuel Ogundipe

The University of Georgia
NA
Thursday September 26, 2024 3:00pm - 3:15pm HST
Kahili

3:00pm HST

NUR 2 - Comparative microbial diversity analysis and isolation of plant growth-promoting rhizobacteria from roundleaf buffaloberry (Shepherdia rotudifolia)
Thursday September 26, 2024 3:00pm - 3:15pm HST
The world is haunted by climate change and global warming, posing critical challenges to plant health and productivity. Hence, it is now imperative to think about ecosystem resilience and conservation. Microbiomes from extreme environments with plant growth-promoting and stress-relieving properties can be used as inoculum for growing plants during stress. Hence, our study aims to explore the root and soil microbiome of native and hardy Shepherdia species available in Utah, USA. The native Shepherdia species, S. rotudifolia was selected for the study. We compared the microbial diversity of S. rotudifolia from three different locations in Utah. The plants' bulk soil, rhizosphere, and root were collected for the study from Torrey, Colorado City, and Cannonville in Utah and brought to the Utah State University, Logan, for further processing. DNA extraction was done from all the samples and sequenced for 16S rRNA region. The bulk soil of roundleaf buffaloberry from Torrey is highest in organic matter, while that from Colorado City is highest in salinity but lowest in NPK and most micro-nutrients. Bulk soil and rhizosphere bacterial alpha diversity differ significantly (p=0.05) among the locations of roundleaf buffaloberry; however, there is no difference in root endosphere alpha diversity among the locations. The bacterial community composition of roundleaf buffaloberry from Torrey is significantly different from the other two locations. Proteobacteria and Actinobacteriota are the dominant phyla in the bulk soil and rhizosphere of roundleaf buffaloberry from all three locations; however, Actinobacteriota dominates in root in all three locations. The genus composition of bulk soil, rhizosphere, and root of roundleaf buffaloberry is very diverse among the three locations. Frankia, the well-known nitrogen-fixing bacteria, is prevalent in the root samples of S. rotundifolia from Cannonville and has lesser abundance in the other two locations. Fifty-seven bacteria were isolated from the rhizosphere of the S. rotudifolia on different nutrient media. These isolates are being tested for eight plant growth-promoting traits, such as the production of indole acetic acid, siderophore, catalase, protease, ACC deaminase activity, nitrogen fixation, phosphate solubilization, and sulfur-oxidizing activity
Speakers
avatar for Amita Kaundal

Amita Kaundal

Assistant Professor, Utah State University
Thursday September 26, 2024 3:00pm - 3:15pm HST
South Pacific 4

3:00pm HST

PUBHORT/Hort Industry - Managing Drift in Vegetable Operations: Extension Risk Management Herbicide Workshops
Thursday September 26, 2024 3:00pm - 3:15pm HST
Herbicide drift from the site of application into non-target areas can be devastating to the environment and to neighbor operations. Crop injury will occur from drift and improper management of herbicides within an operation. Environmental conditions, applicator off-label usage and accidents are often the cause of herbicide drift. Prevention and communication are the most important strategies in managing off target application of herbicides. Two workshops were held in Louisiana. Vegetable producers, Department of Agriculture inspectors, county agents, and crop producers were invited to both workshops. Pre and post tests were given to all participants to measure general herbicide application and rule knowledge. The workshops consisted of fields showcasing tomatoes and squash with 4 herbicides sprayed on them to showcase what drift looks like. Control (non-sprayed plants) were also in the field. All plots were replicated but only half labeled. The participants learned what the symptoms looked like, then worked in teams to identify the non-labeled plots. Participants also learned how to properly clean tanks and nozzles, as well as listened to speakers about the economic loss from off target herbicide drift, and rules and regulations from Louisiana Department of Ag and Forestry specialists. 77% of the participants could identify round up damage by the end of the workshop, whereas only 40% could identify 2, 4D damage. All participants increased knowledge in tank cleaning and cross contamination prevention by the end of the workshop. and All participants gained knowledge in the documentation of crop loss economic questions at the end of the workshops.
Speakers
KF

Kathryn Fontenot

LSU AgCenter
Co-authors
AH

Alessandro Holzapfel

Louisiana State University Agricultural Center
MB

Maria Bampasidou

LSU AgCenter
NA
RS

Ronald Strahan

LSU AgCenter
NA
Thursday September 26, 2024 3:00pm - 3:15pm HST
Lehua Suite

3:00pm HST

VCM 5 - The Effect of Potassium Fertilization on Potato Tuber Nutrition in the Columbia Basin of Oregon
Thursday September 26, 2024 3:00pm - 3:15pm HST
Potato (Solanum tuberosum L.) crops require a high amount of potassium (K) to achieve the ideal yield and quality. However, the effect of K fertilization on potato tuber nutritional value is largely unknown. Based on the tubers from two-year field trials on a Quincy loamy fine sand soil in the Columbia Basin of Oregon, we evaluated yield, specific gravity, nutritional contents (i.e., ascorbic acid, tyrosine, chlorogenic acid, tryptophan, phenylalanine), and nutrient contents (nitrogen [N], phosphorus [P], K, and sulfur [S]) of three potato varieties (Clearwater Russet, Russet Burbank, and Umatilla Russet) under three K rates (0, 448, and 897 kg ha-1). Our results showed that the K application increased the yield of >170 g tubers but had no considerable effect on the total tuber yield. The application of K tended to decrease specific gravity regardless of varieties and years. Russet Burbank had the lowest specific gravity while Clearwater Russet had the highest one. Most of the nutritional contents were higher in 2020 than in 2021. Russet Burbank generally had the highest nutritional contents except for ascorbic acid compared to two other varieties. The application of K generally did not affect tuber nutritional contents but reduced the amounts of tyrosine in Clearwater Russet and Umatilla Russet in 2020. Fertilization of K resulted in an enhanced K content in the tuber, with the highest K application rate exhibiting a 35% increase in K compared to the control. However, it did not have any discernible effects on N, P, and S contents in the tubers. The tuber P and S were lower in Russet Burbank than other varieties. In general, there is no strong relationship between K fertilization and tuber nutritional contents.
Speakers
RQ

ruijun qin

OSU-HAREC
Co-authors
AG

Aymeric Goyer

Oregon State University
NA
ST

Shahram Torabian

Virginia State University
NA
Thursday September 26, 2024 3:00pm - 3:15pm HST
South Pacific 1

3:00pm HST

VGBR 2 - Genome-wide Association Study and Genome Prediction of Tallness Trait in Spinach
Thursday September 26, 2024 3:00pm - 3:15pm HST
Spinach (Spinacia oleracea L.) is a highly nutritious leafy green known for its abundance of health-promoting components. Plant height (tallness), particularly relevant for efficient machine harvesting, is a critical trait of interest in spinach cultivation. This study aimed to conduct a genome-wide association study (GWAS) to identify single nucleotide polymorphism (SNP) markers associated with tallness in spinach and to perform genomic prediction for this trait. GWAS was conducted on a panel of 307 USDA spinach germplasm accessions, utilizing 15,058 SNPs derived from whole-genome resequencing. Various statistical models, including GLM, MLM, FarmCPU, and BLINK, were employed in the analysis using the GAPIT 3 tool. Significant quantitative trait loci (QTL) were identified on chromosome 2, along with two QTL on chromosome 6. Specifically, the SNP marker SOVchr4_38323167 at 38,323,167 bp on chromosome 4, and two SNPs, SSOVchr6_8139833 and SOVchr6_91175684 at 8,139,833 bp and 91,175,684 bp respectively on chromosome 6, exhibited robust associations with tallness. Genomic prediction demonstrated high accuracy, with a prediction ability (GA) represented by an r value of 0.71 in the panel. The identified SNP markers and genomic prediction metrics provide valuable tools for breeders to select spinach plants and lines with desired tallness traits through marker-assisted selection (MAS) and genomic selection (GS), thereby enhancing spinach breeding efforts.
Speakers
IA

Ibtisam Alatawi

University of Arkansas
NA
Co-authors
avatar for Ainong Shi

Ainong Shi

Associate Professor, University of Arkasnas
Dr. Ainong Shi is a faculty member in the Department of Horticulture at the University of Arkansas. His research laboratory specializes in plant breeding and genetics, particularly focusing on vegetable crops such as arugula, cowpea, and spinach for cultivar and germplasm development... Read More →
BM

Beiquan Mou

USDA-ARS
NA
GB

Gehendra Bhattarai

University of Arkansas
HX

Haizheng Xiong

University of Arkansas
HM

Hanan Mohammedsaeed Alkabkabi

University of Arkansas
NA
KC

Kenani Chiwina

University of Arkansas
NA
Thursday September 26, 2024 3:00pm - 3:15pm HST
South Pacific 3

3:15pm HST

CE 6 - Modeling Evapotranspiration in Greenhouse and Indoor Cutting Propagation
Thursday September 26, 2024 3:15pm - 3:30pm HST
Current mist irrigation practices in plant propagation do not represent the variable rate of water loss experienced in a greenhouse environment and often rely on grower experience for adjusting irrigation settings. Automated control logic for these systems can be improved by considering climate data to predict the real-time water loss in the propagation environment. The objectives of this study were to 1) identify the impacts of environmental parameters on the water loss of young plants in greenhouses and indoor environments and 2) develop an evapotranspiration model based on the key parameters identified to achieve weather-based mist irrigation control for resource-efficient plant propagation in controlled environment agriculture. Data sets that include climate data, water applied, and water loss were collected in greenhouse sunlight and indoor sole-source LED environments with unrooted chrysanthemum cuttings. Trials were completed in June and September in 2023 and February in 2024 to collect diverse minute-by-minute data in each environment. Measurements using load cells indicated highly variable water loss in the greenhouse environment. Conversely, in the indoor environment with lower and constant photosynthetic photon flux density (PPFD) and reduced vapor pressure deficit via a fog system, rate of water loss was lower and consistent over time. The key parameters for modeling water loss, found using stepwise regression, were PPFD, leaf temperature, and air vapor pressure (temperature and relative humidity). These climate parameters were correlated with water loss data over time to yield a simple evapotranspiration equation that could be programmed into commercial environmental control systems to improve current irrigation scheduling programs. By improving the control of mist irrigation to take climate data into account, growers have the potential to reduce crop losses (“shrinkage”), reduce rooting time, and improve water use efficiency.
Speakers
DC

Daniel Crawford

University of Florida
Thursday September 26, 2024 3:15pm - 3:30pm HST
Coral 1

3:15pm HST

CITR 3 - Comparative Transcriptomic and Metabolomic Studies Provide Insights into Early Tolerance Response of Citrus to CLas Infection
Thursday September 26, 2024 3:15pm - 3:30pm HST
Citrus Huanglongbing (HLB, or citrus greening disease) has caused over 90% production losses since it was first reported in Florida in 2005. The unknown pathogenicity of the causative pathogen CLas hinders the development of sustainable disease management. Thus, understanding citrus host response to CLas, particularly at initial infection stage, is important for early disease detection and effective long-term HLB management. In this study, transcriptomic and metabolomic studies were conducted in a 2-day-post-inoculation (dpi) window, between HLB-tolerant LB8-9 Sugar Belle ® mandarin-like hybrid (SB; Citrus reticulata) and HLB- sensitive Valencia sweet orange (VAL; C. sinensis). CLas inoculation treatments included two controls no asian citrus psyllid (ACP) and CLas-negative ACP, plus CLas-positive ACP. Data were collevted at four time points: 2-, 12-, 24-, and 48-hour-post-inoculation (hpi). The results reveal that SB indicates immediate transcriptomic-level response from 2 hpi, compared with the delayed response in VAL from 24 hpi. The initial CLas-responsive differentially expressed genes (DEGs) in SB are related to plant defense response to Gram-negative bacterium, kinase activity and protein-kinase derived complex. DEGs that are categorized in plant defense response to Gram-negative bacterium are mostly associated with the pectinesterase inhibitors (PEIs) family which primarily alters the localized pH of the cell wall and strengthens cell wall integrity. On metabolomic level, SB shows rapid and high flavonoid content accumulation that reduces CLas-triggered stress and counteracts the initial infection. In VAL, the low flavonoid content accumulation removes reactive oxygen species (ROS) less efficiently which leads to more stress and cell death. Further investigation and validation on the proposed pathway are needed to confirm the early stage transcriptomic and metabolomic response of citrus tolerance response to CLas infection.
Speakers
ZW

Zimmy Wang

UF CREC
Co-authors
FG

Frederick Gmitter

University of Florida
NA
JL

Jingwen Li

University of Florida
NA
RT

Ronald Tapia

University of Florida/IFAS Citrus Research and Education Center
YW

Yu Wang

University of Florida
Thursday September 26, 2024 3:15pm - 3:30pm HST
South Pacific 2

3:15pm HST

HSMP 2 - Alzheimer’s Disease: Prospecting for Sterubin in California Yerba Santa
Thursday September 26, 2024 3:15pm - 3:30pm HST
California yerba santa (Eriodictyon californicum) is a chaparral shrub of western California and south western Oregon. Its leaves are rich sources of natural flavonoids. Leaves collected from wild stands in general contain the flavonoids homoeriodictyol, eriodictyol, hesperetin, and smaller amounts of other flavonoids. These flavonoids are of possible medical value and are subjects of intensive medical research. California yerba santa leaves containing substantial amounts of the flavonoid sterubin would be of special interest due to sterubin’s potential activity against the enzymatic and inflammatory pathways leading to Alzheimer’s disease in humans as discovered by the Salk Institute of La Jolla, California. We collected leaf samples from SW Oregon through California over the range of plant distribution. Not all areas were sampled. Total flavonoid content in excess of 10 percent of leaf dry weight were common. Leaves with sterubin content were relatively rare. Sterubin content of several samples exceeded 5 percent of leaf dry weight.
Speakers
CS

Clinton Shock

Scientific Ecological Services
Co-authors
MW

Mei Wang

USDA, ARS, NPURU
Thursday September 26, 2024 3:15pm - 3:30pm HST
Kahili

3:15pm HST

NUR 2 - Navigating the Interplay of Climate Stress and Pest Pressure in Shade Tree Nursery Production: Insights from Oregon and Tennessee
Thursday September 26, 2024 3:15pm - 3:30pm HST
The plant nursery production industry in Oregon and Tennessee faces escalating challenges from climate change, particularly concerning shade trees like red oak (Quercus rubra) and red maple (Acer rubrum). This research investigated the physiological responses of these species to fluctuations in soil moisture, vapor pressure deficit (VPD), and leaf temperature (Tleaf) through field experiments in Oregon's Willamette Valley and Tennessee's nursery regions. Monitoring stomatal conductance (gs) and stem water potential (Ψs) under varied conditions revealed distinct responses between the two species, with red maple exhibiting greater sensitivity to soil moisture and VPD compared to red oak. Additionally, a novel correlation between VPD and maple gas exchange underscores the significance of atmospheric moisture dynamics in plant water management strategies. Furthermore, assessing the impact of abiotic stressors on flatheaded borer (FB) attacks, we found that drought-stressed red maple trees experienced the highest borer infestations. Plant growth was adversely affected by all stressors, with drought stress exhibiting the most detrimental impact. Our findings underscore the complexity of plant responses to climate stress and highlight the necessity of informed water management practices for sustainable nursery production in diverse regional contexts. Bridging knowledge gaps in plant hydraulic physiology can empower growers to adapt to evolving environmental conditions and ensure the resilience of shade tree production systems. Further research is crucial to deepen our understanding of plant hydraulic physiology and its implications amidst climate change-induced challenges.
Speakers
avatar for Lloyd Nackley

Lloyd Nackley

oregon state university
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
Co-authors
AL

Anthony LeBude

north carolina state university
NA
AW

Anthony Witcher

Tennessee State University
NA
DM

Dalyn McCauley

Oregon State University
KA

Karla Addesso

Tennessee State University
NA
Thursday September 26, 2024 3:15pm - 3:30pm HST
South Pacific 4

3:15pm HST

PUBHORT/Hort Industry- Native Trees for Public Gardens: Building a University Teaching Collection for Increased Student Learning, Visitor Engagement, and Carbon Sequestration
Thursday September 26, 2024 3:15pm - 3:30pm HST
Changing climate patterns challenge the long-term health and survivability of common mid-Atlantic U.S. tree species, including climax species such as oaks, elms, and beeches. Evidence of tree loss in natural and managed ecosystems and residential areas demonstrates the need for public gardens to consider alternative species that will adapt to changing conditions, maximize carbon sequestration, and provide aesthetic value. University-affiliated Rutgers Gardens has long served to demonstrate landscape best practices and species selection for students, industry professionals, and homeowners; additionally, carbon sequestration has become a primary function. Continuing a tradition of education, Rutgers Gardens is creating a Native Trees teaching collection including over one hundred native species selected for their ecosystem functions, ecological niche, and landscape aesthetics, on an approximately four-acre site with the goal of maximizing carbon sequestration and educational value. Selected specimens include those native to New Jersey and the wider mid-Atlantic region and/or southeastern United States. This allows for a comprehensive collection that supports larger ecosystem functions, especially as tree species composition in the broader region is likely to shift with time. As major tree species are lost due to climate-influenced changes in pest, disease, and environmental pressures, preparing for continuous carbon sequestration by including species likely to thrive in our changing climate will maximize the environmental benefit. By including a mix of small, medium, and large (at maturity) trees, the design maximizes ecosystem niches occupied throughout the planting area and provides a comprehensive demonstration for students, homeowners, and industry professionals, modeling native trees for consideration in landscape plantings throughout the state. Specimens include straight species, as well as cultivars within the genera to demonstrate variability in true native trees and “nativars,” or cultivars of native trees. A density of approximately 25 trees per acre planted allows for the integration of new trees with existing specimens, including trees and shrubs that represent historical iterations of present-day Rutgers Gardens, and accommodates the design of accessible paths and gathering spaces between plantings to maximize educational opportunities. Public gardens present many opportunities for education and demonstration, especially within a university setting. Yet, challenges exist when considering complex land use history, student and faculty needs, visitor expectations, and the interests of diverse stakeholders such as members, volunteers, and staff of public gardens. Lessons learned include the importance of positive and clear communication among stakeholders to ensure project benefits are recognized and shared for educational and ecological success in public spaces.
Speakers
LE

Lauren Errickson

Director of Rutgers Gardens & Campus Stewardship, Rutgers, the State University of New Jersey
Co-authors
MM

Maxine Marvosa

Rutgers, the State University of New Jersey
NA
Thursday September 26, 2024 3:15pm - 3:30pm HST
Lehua Suite

3:15pm HST

VCM 5 - Predicting Potato Tuber Yield Through Hyperspectral Signals and Machine Learning
Thursday September 26, 2024 3:15pm - 3:30pm HST
Potato production is crucial for global food security, and with an increasing demand for food and a diminishing supply of fertile land, there is a need to boost production. Remote sensing technologies, such as high-resolution hyperspectral sensors, have the potential to provide valuable insights into potato growth, yield, and quality. Narrow spectral bands captured by these sensors are directly linked to biophysical parameters and can accurately estimate crop parameters. Recent studies have utilized hyper-spectral imagery acquired from proximal sensor such as ASD FieldSpec to estimate various crop parameters and yield. The results from these studies are promising, indicating that hyper-spectral sensors have the potential to improve crop management and agricultural practices. Moreover, the integration of remote sensing data with advanced analytical techniques, such as machine learning, helps in accurately estimating yield and yield components. In this study we are testing two machine learning such as PLSR and RF to predict biomass and N uptake in-season. Results from this indicate that PLSR performs better in predicting biomass and N uptake in potatoes. Moreover, yield can be best estimated at tuber bulking stage.
Speakers
avatar for Ravinder Singh

Ravinder Singh

Graduate Research Assistant, UF/Bayer
Co-authors
LS

Lakesh Sharma

University of Florida
Dr. Lakesh Sharma is an assistant professor of soil fertility and sustainable agriculture at the University of Florida in Gainesville, FL. Lakesh has been farming since he was a child on his own farm. His academic school journey started in 2000. He is currently working on nutrient... Read More →
RS

Rajkaranbir Singh

University of Florida
NA
SK

Sehijpreet Kaur

Agronomy, UF
NA
SS

Simranpreet Sidhu

University of Florida
NA
Thursday September 26, 2024 3:15pm - 3:30pm HST
South Pacific 1

3:15pm HST

VGBR 2 - Capitalizing on the Global Capsicum Core Collection to Advance Pepper Breeding
Thursday September 26, 2024 3:15pm - 3:30pm HST
Unlike other crops, access to genetic and genomic tools enabling more efficient breeding is limited in pepper. The majority of the research in pepper is based on analyzing traits in biparental populations, and in addition, limited access to pathogen strains or races reduces the wide-scale applicability of the developed molecular markers across populations and breeding programs. In contrast to research in bi-parental populations, genome-wide association studies utilizes the broad range of genetic diversity present in natural populations, including historical recombination events, which allows for the identification of more alleles potentially associated with the trait. A well-designed core collection captures the diversity that is present in an entire germplasm collection, which is crucial for preserving unique alleles and traits and facilitates more efficient phenotyping and GWAS. A core collection of 423 accessions was assembled representing the genetic diversity present in the G2P-SOL global collection of 10,038 wild and cultivated Capsicum accessions from 10 major genebanks .The G2P-SOL Capsicum core collection has been phenotyped for resistance to anthracnose, bacterial wilt, phytophthora blight, and Chili leaf curl virus, as well as for heat stress component traits in several locations in Asia. Genome wide association studies have revealed multiple significant loci associated with the individual traits. These loci are being utilized in the breeding program to more efficiently develop and release cultivars.
Speakers
avatar for Derek Barchenger

Derek Barchenger

World Vegetable Center
Co-authors
HZ

Herbaud ZOHOUNGBOGBO

World Vegetable Center
NA
MK

Manoj Kumar Nalla

World Vegetable Center
NA
RS

Roland Schafleitner

World Vegetable Center
NA
SL

Shihwen Lin

World Vegetable Center
NA
TL

Tsunghan Lin

World Vegetable Center
NA
YW

Yanwei Wang

World Vegetable Center
NA
YL

YaPing Lin

World Vegetable Center
NA
Thursday September 26, 2024 3:15pm - 3:30pm HST
South Pacific 3

3:30pm HST

CE 6 - The Impact of Extreme Low Irradiance on the Wholesale Market Volume of Major Horticultural Crops in Korea
Thursday September 26, 2024 3:30pm - 3:45pm HST
Tomatoes, strawberries, paprika, and Korean melons, which are major fruit vegetables in Korea, are primarily grown in protected horticultural greenhouses, and their production is significantly influenced by seasonal and climatic factors. Extreme low irradiance caused by abnormal weather conditions not only reduces light input but also affects the internal temperature and relative humidity of greenhouses, thereby greatly impacting the growth and production of fruit vegetables. In 2024, fluctuations in production due to prolonged abnormal low irradiance during the flowering, fruit-setting, and fruit-enlargement periods (January to March) have become a significant issue in Korea. The duration of irradiance hours in the winter of 2024 (December to February) was 427.8 hours, a 20% decrease compared to the average of 535.4 hours (1990-2020). In particular, in February, it decreased sharply by 42.1% to only 104.7 hours. Additionally, there were two occurrences of low irradiance lasting more than five days, with the longest period extending up to 11.6 days. As a result, the market volume of strawberries, paprika, and Korean melons from February to April decreased by 19.3%, 29.4%, and 46.8%, respectively. The average selling price of strawberries increased by 1.3 times during this period. Therefore, there is an urgent need to develop environmental control and crop cultivation techniques to mitigate the damage caused by reduced yields due to abnormal low irradiance.
Speakers
JK

Jinhyun Kim

Rural Development Administration
Co-authors
HW

Hyeon Woo Jeong

Rural Development Administration
JH

Jae Han Lee

Rural Development Administration
JW

Ji Woong Bang

Rural Development Administration
MH

Min Hee Han

Rural Development Administration
Thursday September 26, 2024 3:30pm - 3:45pm HST
Coral 1

3:30pm HST

CITR 3 - Exploring Leaf Nutrients and Fruit Quality Attributes Relationship in Fresh Market Citrus Using Artificial Neural Networks and Linear Regression Models
Thursday September 26, 2024 3:30pm - 3:45pm HST
The market value of fresh citrus fruit is greatly influenced by the internal and external fruit qualities, such as peel color, total soluble solids (TSS), titratable acid (TA), and fruit size. Abundance or deficiency of mineral nutrients in citrus trees are among the most important key factors that affect fruit qualities. Various regression models using leaf nutrient parameters and quality indices have been suggested, but their accuracy and generalization performance in estimating fruit quality remain insufficient. In this research, we used both artificial neural network models (ANN) and a multiple linear regression model to explore the effects of leaf nutrient concentration on citrus fruit quality. For ANN models, we applied two transfer functions and five different training functions to establish the model with best prediction accuracy using TensorFlow framework through Python software. The models were evaluated using statistical performance evaluation criteria including the coefficient of determination (R2), root mean square error (RMSE), mean absolute error (MAE), and mean absolute relative error (MARE). Sensitivity analysis of the prediction models was conducted to discern the significant contribution of leaf mineral nutrients to the respective fruit quality parameters. The response surface analysis determined the optimal range of these mineral elements, which is critical for guiding precision fertilization in fresh market citrus fruit for improving fruit quality. Comprehensive results will be presented during the conference. Keywords: artificial neural network, fruit quality, citrus, mineral nutrients, sensitivity analysis
Speakers
avatar for Shankar Shrestha

Shankar Shrestha

PhD Candidate, University of Florida
Co-authors
AS

Arnold Scumann

University of Florida
NA
Thursday September 26, 2024 3:30pm - 3:45pm HST
South Pacific 2

3:30pm HST

HSMP 2 - Genomic Variation in Wild Sabadilla (Schoenocaulon officinale, Melanthiaceae) Populations for Key Phenotypic Traits of Interest for Domestication and Breeding
Thursday September 26, 2024 3:30pm - 3:45pm HST
Sabadilla (Schoenocaulon officinale), a perennial geophytic species with various medicinal properties and historical uses as a natural insecticide or “green pesticide”, has been used by human cultures in the Americas for >2,000 years. Its history parallels the domestication of pyrethrum (Chrysanthemum cinerariifolium) in Europe with similar green pesticidal properties, although the active ingredients differ. Alkaloids extracted from sabadilla seeds have been used to control many insect pests also killed by pyrethrum as well as additional insect pests. With the renewed consumer interest in botanically derived products and the growth of organic chemical industries, S. officinale has re-emerged as a viable source for insect management. To meet market demands, rapid crop domestication must occur. However, sabadilla is an herbaceous perennial geophyte (tunicate bulbs) with an extended juvenility period of at least 64 wks and little is known about the phenotypic and genetic structure of wild populations, alkaloid content variation, and flowering times from seed. Current production is limited to wild-harvested seed (open-pollinated) in Venezuela which is threatening native populations. The purpose of this study was to assess phenotypic and genotypic structure of wild sabadilla populations and seed lots; species comparison with S. texanum were also performed. Through introduction of wild-sourced composite seed into a modern breeding and cropping system, phenotypic traits (rate of seed germination, growth rates, factors of flowering, timing of seed maturity, seed yield, and alkaloid content) were assessed in multiple locations. Genotypic analyses (GBS; DArTseqLD) were used to identify low density SNPs and determine genetic structure within and among wild species populations. Seed lots from varying locations in Venezuela showed distinct SNP arrays with little overlap. SNP-trait association of seed germination weeks was an unexpected, rather tight linkage. Both species are genetically distinct from each other. Phenotypic and genotypic data will be integrated with a genome-wide association study (GWAS) to identify SNP-trait associations and aid in marker-assisted selection.
Speakers
avatar for Albert Radloff

Albert Radloff

University of Minnesota
Co-authors
NA

Neil Anderson

University of Minnesota
NA
Thursday September 26, 2024 3:30pm - 3:45pm HST
Kahili

3:30pm HST

NUR 2 - The Effects of Supplemental Nickel on Mouse Ear Disorder of Three Diospyros Species
Thursday September 26, 2024 3:30pm - 3:45pm HST
American persimmon (Diospyros virginiana L.) is a multipurpose tree endemic to the eastern United States with potential for broader use in managed landscapes or for producing desirable fruits. Whereas most members of this genus originate from tropical and subtropical regions, the American persimmon could expand landscape diversity and fruit production applications in northern climates. Due to purported challenges with transplant success, American persimmon is likely best suited to cultivation in containers. Recent observations of container-nursery crop production indicates American persimmon is susceptible to mouse ear disorder (MED), a function of nickel deficiency. We hypothesized that American and Asian-origin persimmon species are susceptible to MED and that supplementing nickel with a foliar spray will ameliorate the disorder. Our objectives were to characterize symptoms of non-treated MED with American (D. virginiana), Japanese (D. kaki), and dateplum (D. lotus) persimmon as well as to determine if MED could be corrected by foliar application of nickel or other compounds presumed to interact with the urease metabolic pathway, such as urea. In a randomized greenhouse study, seedlings of American, Japanese, and dateplum persimmons were evaluated by comparing a non-treated control (H2O spray), to foliar spray treatments of NickelPlus® (169 ppm), NiCl2 (169 ppm), urea (0.325 g/L), and combined NiCl2 (169 ppm) and urea (0.325g/L). Following treatment, plants were evaluated using a MED severity rating scale, leaf characterization metrics (greenness, count, surface area, dry mass, and specific area), as well as metrics characterizing stem traits (elongation and dry mass). Compared to the non-treated control, leaf surface area increased by ~56%, ~61%, ~25%, and ~52% for the Nickel Plus®, NiCl2, Urea, and combined NiCl2 Urea treatments, respectively, when pooled across species and cultivar. These results suggest nickel supplements are effective at increasing important growth metrics like leaf surface area for Diospyros species displaying MED symptoms. This study offers valuable insights for improving the cultivation of persimmons in container nursery production settings, contributing to the development and advancement of American persimmon as an emerging specialty crop.
Speakers
AH

Alyssa Headley

University of Minnesota-Twin Cities
Co-authors
BM

Brandon Miller

University of Minnesota-Twin Cities
Thursday September 26, 2024 3:30pm - 3:45pm HST
South Pacific 4

3:30pm HST

PUBHORT/Hort Industry - Future Directions of Horticultural Research Among Botanical Gardens and Arboreta in the United States
Thursday September 26, 2024 3:30pm - 3:45pm HST
Botanical gardens and arboreta maintain globally important collections for conservation and education with efforts to constantly strive for excellence in propagation, cultivation, and collection preservation. Methods of cultivating plants, learning from successes and challenges, with the ability to disseminate that knowledge is paramount for improving techniques and outcomes. However, the underlying field of horticultural research is not well defined, and results of plant cultivation techniques are often only shared informally rather than published. We explored how horticultural research practitioners perceive the field of horticulture research and excellence, how they are involved, and the most urgent needs of future horticultural research among gardens and arboreta. We conducted an internet-based survey of the status of horticultural research amongst the United States members of the American Society for Horticultural Research (ASHS), American Public Garden Association (APGA), Botanical Garden Conservation International (BGCI), and the Interactive Community of Arboreta (ArbNet), Level II, III, and IV members. 128 respondents from 116 institutions across 34 of the United States completed the survey. As conservation needs, changing agricultural paradigms, and climate change impacts continue to increase, we find future research needs are increasingly holistic and focus on species and variety conservation, ecology, and mitigating pests and diseases. The respondents were variously involved in horticulture research and the main challenges were funding, time, and personnel resources. Horticultural knowledge is largely practical and shared informally and there is a need for recognition and means of sharing practical research as well as technical research. This study presents a new framework for horticultural research supporting the horticulture community with the conceptualization, communication, and implementation of horticultural research.
Speakers
avatar for Michael Opgenorth

Michael Opgenorth

National Tropical Botanical Garden
Co-authors
DR

David Rae

Stanley Smith (UK) Horticultural Trust
NA
JA

Julia Avila

National Tropical Botanical Garden
NA
NR

Nina Ronsted

National Tropical Botanical Garden
NA
SB

Sarah Bryce

National Tropical Botanical Garden
NA
Thursday September 26, 2024 3:30pm - 3:45pm HST
Lehua Suite

3:30pm HST

VCM 5 - Evaluating King Stropharia Mushroom as an Intercrop in Asparagus and Tomato Production
Thursday September 26, 2024 3:30pm - 3:45pm HST
Stropharia rugosoannulata (L.), the King Stropharia or Wine Cap mushroom, is a wood-loving fungus that grows well on organic mulches. Some vegetables can be successfully grown using organic mulches like woodchips or straw. As a result, farmers may be able to enhance their income by intercropping Stropharia mushrooms with their vegetable crops. However, no study has been identified that assesses this strategy's potential or effect on vegetable yields. Thus, a Stropharia-asparagus intercrop was evaluated by applying woodchips at three depths (4, 8, and 12 in), and a Stropharia-tomato intercrop was evaluated using woodchips, wheat straw, and soy straw (all at 6 in depth). Both experiments utilized a randomized complete block design (RCBD) with four replications and included bareground controls. The tomato study also included a positive mulch control using black plastic. In the fall of 2021, black plastic, inoculated wheat straw, and uninoculated soy straw and woodchip mulch provided earlier harvest than unmulched plots, while the soy treatments and bareground and black plastic controls increased total fruit numbers. In 2022, overall tomato production decreased, resulting in no marketable fruit. Across both 2022 and 2023 asparagus harvest began earlier with decreasing depths of mulch, and therefore lasted longer. Inoculated plots also produced more marketable spears than uninoculated plots. And, 12 in woodchip mulch significantly inhibited asparagus emergence and is therefore not recommended. These results suggest that a Stropharia-tomato intercrop may not be feasible without additional work, though a Stropharia-asparagus intercrop shows great promise. In fact, in 2023, mushrooms were observed in uninoculated plots demonstrating the gregarious growth of Stropharia in woodchip mulch on asparagus plots. The relative success in asparagus plots supports a need for further research to evaluate other Stropharia-vegetable [or fruit] intercrop candidates and/or strategies to improve compatibility.
Speakers
avatar for Olalekan Sipasi

Olalekan Sipasi

Ph.D. Candidate, Kansas State University
Sipasi Olalekan Ayodele is a Ph.D. Candidate at the Department of Horticulture and Natural Recourses at Kansas State University, ONE Champion 2017, Fellow Thinking School Africa, 2016 Winner of the African Youth Award in Agriculture, a seasoned NYSC SDGs Facilitator, The Future Award... Read More →
Co-authors
CL

Calvin Liu

Kansas State University
NA
JC

Jeremy Cowan

Kansas State University
NA
Thursday September 26, 2024 3:30pm - 3:45pm HST
South Pacific 1

3:30pm HST

VGBR 2 - Private-public Partnership for Sustainable Cucurbit Breeding and Production in Asia
Thursday September 26, 2024 3:30pm - 3:45pm HST
The global cucurbit breeding program of the World Vegetable Center (WorldVeg) focuses on tropical pumpkin (Cucurbita moschata) and four gourds: bitter gourd (Momordica charantia), ridge gourd (Luffa acutangula), sponge gourd (Luffa aegyptica = cylindrica) and bottle gourd (Lagenaria siceraria). This breeding program uses the diversity of hitherto unexploited landrace collections to develop high yielding and disease resistant lines and F1 hybrids with a range of fruit types suitable for various market segments. The program supports breeding research of partners from national agricultural research and extension systems organizations and the private seed industry to develop better cucurbit cultivars for the benefit of stakeholders along the vegetable value chain. To facilitate these partnerships, the WorldVeg cucurbit team displays improved cucurbit lines and F1 hybrids during the cucurbits open field days at the WorldVeg East and Southeast Asia Research and Training Station, located on the campus of the Kasetsart University in Kamphaeng Saen, Thailand. This annual event attracts breeders, pathologists, product development managers, marketing and sales managers, R
Speakers
avatar for Narinder Dhillon

Narinder Dhillon

Principal Plant Breeder - Cucurbits & Okra, World Vegetable Center
Narinder Dhillon leads the cucurbits and okra breeding program of the World Vegetable Center. He works on the development of  gourds, tropical pumpkin, and okra inbred lines and hybrids for the tropics, with emphasis on improved fruit yield and quality, multiple disease resistance... Read More →
Thursday September 26, 2024 3:30pm - 3:45pm HST
South Pacific 3

3:45pm HST

VGBR 2 - Characterization of A Novel Locus for Fruit Flavor Aroma in Tomato
Thursday September 26, 2024 3:45pm - 4:00pm HST
Tomato flavor has become an important trait for targeted crop improvement. Because of the historical emphasis on yield and other agronomically important traits, many modern tomato varieties have lost their rich flavor, leading to consumer dissatisfaction. While volatile compounds play an important role in defining the distinct tomato flavor, little is known about their biochemical pathways, making it difficult to build a desirable volatile profile. Identifying the genes involved in volatile production can help us better understand the biochemistry as well as accelerate the breeding process. This study focuses on two consumer-desired volatiles, 1-nitro-2-phenylethane and phenylacetaldehyde, and has mapped a novel QTL on chromosome 8 by combining results from linkage mapping and GWAS (genome-wide association study). A cluster of Amino Acid Decarboxylases (AADCs) were identified as the candidate genes underlying this QTL and a total of four SV haplotypes of the AADC cluster were found in the Varitome collection. Among these haplotypes, Type III was lost during domestication and is a likely beneficial allele to increase the concentrations of phenylacetaldehyde and 1-nitro-2-phenylethane in tomato fruits. Preliminary data of transgenic plants created by CRISPR/Cas9 suggested a positive involvement of this AADC locus in volatile production. Enzymatic analysis of the AADC proteins and incorporation of the beneficial allele into modern tomato varieties is in progress. The outcome of this study will provide breeders valuable tools to facilitate the selection process for better tomato flavor. Characterization of volatile pathways will also give us insights on plant secondary metabolite biosynthesis and the evolution history during adaption and domestication. This research is funded by NSF IOS 2151032.
Speakers
QF

Qian Feng

Institute of Plant Breeding, Genetics and Genomics, University of Georgia
NA
Co-authors
AH

Austin Hart

University of Georgia
DT

Denise Tieman

University of Florida
EV

Esther van der Knaap

Institute of Plant Breeding, Genetics, and Genomics, University of Georgia
NA
LP

Lara Pereira

Center for Applied Genetic Technology, University of Georgia
NA
MS

Manoj Sapkota

University of Georgia
NA
WD

William Dobson

University of Florida
NA
Thursday September 26, 2024 3:45pm - 4:00pm HST
South Pacific 3

4:00pm HST

PGR 2 - Quantifying Growth Control of Ornamental Millet ‘Jester’ with Ancymidol, Ethephon, Flurprimidol, Paclobutrazol, and Unic
Thursday September 26, 2024 4:00pm - 4:15pm HST
Plant growth regulators (PGRs) are a valuable tool in the ornamental industry. Whether it is for promoting or controlling growth, PGRs give growers the opportunity to produce high quality crops in the face of their production or shipping challenges. Often, substrate drench applications provide greater growth control, require less labor, and have shortened re-entry intervals than spray applications. Current PGR recommendations for ornamental millet (Pennisetum glaucum ‘Jester’) are for spray applications; therefore, the objectives of this study were to evaluate the efficacy of different PGRs applied as substrate drenches to improve marketability and control growth of ornamental millet ‘Jester.’ Seeds were received from a commercial supplier and sown into 288-cell plug trays (5-mL individual cell vol.) filled with a pre-moistened commercial soilless propagation substrate. After 24 d, young plants of similar heights, basal diameters and culm were transplanted with one plant per 11.4-cm-diameter container filled with a commercially available peat-based substrate. At 7 d after transplant, plants received 59-mL aliquots of solution containing 0 (deionized water control),1, 2, 4, 8, or 16 mg·L–1 ancymidol, flurprimidol, paclobutrazol, or uniconazole or 25, 50, 75, 100, or 200 mg·L–1 ethephon. Plants were grown at bench-level in a glass-glazed greenhouse with an air temperature set point of 23 °C, and supplemental day-extension lighting provided by light-emitting diode lamps from 0600 to 2200 hr (16-h photoperiod) to achieve a daily light integral of ~14 mol·m–2·d–1. Data were collected four weeks after drench. For each chemical, effects of PGR concentration were analyzed independently, and means were separated using Tukey’s honestly significant differences. For all analyses, a P ≤ 0.05 was used to determine significant effects. In general, ancymidol and ethephon provided the best growth control, while flurprimidol and uniconazole were found to be inadequate for drenches at the concentrations investigated due to unmarketable plants. Paclobutrazol resulted in unmarketable plants at concentrations ≥ 1 mg·L–1. Ancymidol substrate drenches containing 1 to 16 mg·L–1 resulted in plants that were 3% to 21% shorter and 3% to 14% smaller plants, respectively, than untreated plants. Similarly, increasing ethephon substrate drench concentrations from 1 to 16 mg·L–1 resulted in plants that were 7% to 36% shorter and 27% to 41% smaller plants compared to the untreated control. Results from this study establish substrate drench recommendations for ornamental millet ‘Jester’; however, further investigations are needed to assess growth control responses of other ornamental millet cultivars.
Speakers
LS

Lauren Seltsam

The Ohio Sate University,
Co-authors
GO

Garrett Owen

The Ohio State University
Thursday September 26, 2024 4:00pm - 4:15pm HST
South Pacific 4

4:15pm HST

PGR 2 - Controlling growth of Brunnera macrophylla L. ‘Jack Frost’ with Uniconazole Substrate Drenches or Sprays
Thursday September 26, 2024 4:15pm - 4:30pm HST
Heartleaf brunnera (Brunnera macrophylla L.) is a popular herbaceous perennial that is often used in the landscape. With large leaves and a mounding habit, growth control is often needed during greenhouse production. Plant growth regulators (PGR) applied as substrate drenches or foliar sprays can control growth necessary to produce compact, high-quality containerized plants. Our objectives were to evaluate the efficacy and growth control provided by uniconazole substrate drenches or sprays. Rooted liners of heartleaf brunnera ‘Jack Frost’ were transplanted into containers (16.6-cm; 2.8 L) filled with a commercially formulated peat-based substrate. After 10 d, eight single-plant replicates received either a substrate drench or foliar application of uniconazole. For substrate drenches, 296-mL aliquots of solution containing deionized water (0 mg·L–1; control) or 0.25, 0.875, 1.75, 2,5, 5.5, 7.5, or 10.0 mg·L–1 uniconazole were applied across the substrate surface. For foliar sprays, 0, 2.5, 5.0, 7.5, 10.0, or 20.0 mg·L–1 uniconazole were applied at a rate of 1.89 L/ 9.29 m2. Plants were grown in a glass-glazed greenhouse at 23 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈120 µmol·m–2·s–1 delivered from light-emitting diode lamps from 0600 to 2200 HR (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At 7 weeks after treatment, data were collected and plants were destructively harvested. In general, uniconazole significantly controlled plant height, diameter, and dry mass for each uniconazole application method. Plant height and diameter were 15% to 51% (2.2 to 7.6 cm) shorter and 22% to 40% (7.4 to 13.5 cm) smaller, respectively, than untreated plants as uniconazole drench concentration increased from 0.875 to 5.0 mg·L–1, respectively. Plants treated with 0.875 to 5.0 mg·L–1 developed 3 to 7 fewer leaves. Shoot dry mass was 39.5% lower than untreated plants as uniconazole drench concentration increased from 0.875 to 5.0 mg·L–1, respectively. For foliar applications, plant height and diameter were both reduced but to varying degrees. Plant height was reduced by 6% (~1 cm) but the greatest amount of control observed was in plant diameter which was reduced by 15 to 21% (4.8 to 7.2 cm) as concentrations increased from 5.0 to 10.0 mg·L–1. Collectively, these results indicate that drenches of 0.875 to 5.0 mg·L–1 uniconazole or foliar sprays of 5.0 to 10.0 mg·L–1 uniconazole may be used to control growth of ‘Jack Frost’ heartleaf brunnera.
Speakers
WR

William Rich

The Ohio State University
Co-authors
GO

Garrett Owen

The Ohio State University
Thursday September 26, 2024 4:15pm - 4:30pm HST
South Pacific 4

4:30pm HST

PGR 2 - Uniconazole Substrate Drenches Control Growth of Buddleia Cultivars
Thursday September 26, 2024 4:30pm - 4:45pm HST
The increasing diversity of butterfly bush (Buddleia × hybrida) cultivars presents new challenges for growers, particularly in adjusting plant growth retardants (PGRs) to manage plant size effectively. Therefore, the objective of this study was to evaluate uniconazole substrate drench concentrations for growth control of two popular cultivars of butterfly bush (Buddleia × hybrida). Liners of ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush were individually transplanted into containers (16.5-cm; 1.7 L) filled with a commercially formulated bark-based substrate. After 10 d, eight single-plant replicates received a substrate drench of 266-mL aliquots of solution containing deionized water (0 mg·L–1; untreated) or 0.25, 0.5, 1, 2, or 4 mg·L–1 uniconazole. Plants were grown in a glass-glazed greenhouse at 20 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈125 µmol·m–2·s–1 delivered from light-emitting diode arrays from 0600 to 2200 HR (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At 5 weeks after drench, data were collected. Plant height, plant diameter, growth index (GI), and shoot dry weights were unaffected by cultivar or cultivar × uniconazole concentration interaction but varied by uniconazole concentration (P < 0.0001); therefore, all data were pooled and analyzed by uniconazole concentration. Increasing uniconazole substrate drench concentrations effectively controlled ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush plant height, plant diameter, GI, and shoot dry weights. Plant height and diameter were 16% to 32% (6.9 to 13.8 cm) shorter and 10% to 24% (6.9 to 16.9 cm) smaller than untreated plants as uniconazole drench concentration increased from 1 to 4 mg·L–1, respectively. Shoot dry mass was 24% to 34% (5 to 7 g) lower than untreated plants as uniconazole drench concentration increased from 1 to 4 mg·L–1, respectively. Overall, these results indicate that 1 to 4 1 to 4 mg·L–1 uniconazole applied as a substrate drench may be used to control growth of ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush. Time to visible bud and flower was not negatively influenced by increasing uniconazole concentrations; however, growers should trial drench concentration and adjust as needed for desired market dates. Additionally, further investigations with uniconazole are warranted for other butterfly bush cultivar introductions because it is the is the preferred PGR for perennial growth control.
Speakers
LW

Lark Wuetcher

The Ohio State University
Co-authors
GO

Garrett Owen

The Ohio State University
Thursday September 26, 2024 4:30pm - 4:45pm HST
South Pacific 4

4:45pm HST

PGR 2 - Effects of Weather Conditions on the Efficacy of ACC as a Peach Thinner
Thursday September 26, 2024 4:45pm - 5:00pm HST
1-aminocyclopropane-1-carboxylic acid (ACC) is the immediate precursor of ethylene in plants. Accede SG containing ACC as active ingredient has been registered as a chemical thinner in the US for stone fruit and apple. The objective of this study was to investigate the effects of weather parameters on Accede SG efficacy. In a series of experiments in Oregon and California in the field and growth chambers, we evaluated the relationship between flower/fruitlet abscission caused by ACC and weather parameters in peaches. In field trials, ACC at 300 mgL-1 and 600 mgL-1 was sprayed on a daily basis to different set of peach trees throughout the bloom period and correlated fruit set data with daily weather parameters. From these field trials, it became apparent that flower/fruitlet abscission caused by ACC is in negative relationship with daily minimum and maximum temperatures. These findings were confirmed by greenhouse studies where increase in nighttime temperature reduced thinning efficacy of ACC. No close relationship between thinning efficacy and relative humidity was found. We created three models to predict ACC thinning efficacy using weather parameters and ACC spray concentration.
Speakers
JR

Jozsef Racsko

Valent USA
Co-authors
AK

Al Kovaleski

University of Wisconsin-Madison
NA
AK

Alec Karayan

Fresno State University
NA
GB

Gurreet Brar

Fresno State Univ.
NA
PF

Poliana Francescatto

Valent BioSciences LLC.
NA
SM

Steven McArtney

Valent BioSciences LLC.
NA
Thursday September 26, 2024 4:45pm - 5:00pm HST
South Pacific 4

5:00pm HST

PGR 2 - Mode of Action and Uptake Investigations of ACC as a Peach Thinner
Thursday September 26, 2024 5:00pm - 5:15pm HST
1-aminocyclopropane-1-carboxylic acid (ACC) is assumed to cause flower abscission via the ethylene pathway when used as a chemical thinner in peaches. The objectives of this study were to investigate the uptake of ACC via flower parts, and determine if ethylene is the main cause of flower abscission by ACC. In a series of field trials in Oregon, we determined that ACC is a non-mobile compound when applied as a foliar spray to peach trees. ACC does not translocate between branches and movement of externally applied ACC is very limited even between flower parts. When the ACC solution was applied via paintbrush to various parts of the flowers, it became evident that for sufficient flower thinning activity, the presence/uptake of ACC is needed through the pedicel and/or Abscission Zone tissues of the pedicel (AZ1-2). Application of ACC to the petals only, resulted in petal drop only but not in flower abscission. When evaluating the mode of action of ACC, we established a close relationship between ethylene production of the flowers and flower abscission. However, when ethylene production of the flowers was reduced with the addition of ACC oxidase inhibitors (2-picolinic acid, pyrazinecarboxylic acid) in the ACC spray solution, the flower abscission rate remained the same as in the ACC application alone. These results indicate that ethylene might not be the only factor in flower abscission caused by ACC.
Speakers
JR

Jozsef Racsko

Valent USA
Co-authors
PF

Poliana Francescatto

Valent BioSciences LLC.
NA
Thursday September 26, 2024 5:00pm - 5:15pm HST
South Pacific 4

5:15pm HST

PGR 2 - Physiological Mechanism of Silicon’s Enhancement of Drought and Heat Tolerance in Creeping Bentgrass
Thursday September 26, 2024 5:15pm - 5:30pm HST
Creeping bentgrass is an important cool-season turfgrass species widely used for golf course putting greens, however it experiences summer stress and quality decline in the U.S. transition zone and other regions with similar climates. Silicon (Si) may improve abiotic stress of creeping bentgrass, but mechanism of its impact on plant drought and heat tolerance has not well understood. The objectives of this study were to investigate physiological mechanism of Si on tolerance to drought and heat stress in creeping bentgrass under growth chamber and field conditions. The five treatments from two Si products (Potassium silicate at 0.95 and 1.91 mL m-2, and Ortho-Si at 0.16 and 0.32 mL m-2) were applied biweekly to creeping bentgrass, and treated grass was subjected to heat and drought stress for 56 days and also the treatments were applied to creeping bentgrass putting green in the field conditions. Turfgrass quality, physiological parameters and root growth characteristics were evaluated biweekly. Deficit irrigation was applied to induce drought stress in June and July in the field plots. Foliar application of the Si products improved turf quality, photochemical efficiency, leaf chlorophyll and carotenoid content, antioxidant enzyme activity and endogenous Si content. The Si treatments at the high rates also improved root biomass, length, surface area, volume, and root viability when compared to the control. The results from the field study confirmed the findings in the growth chamber study. The exogenous Si may improve drought and heat tolerance by enhancing root growth and viability, Si uptake by roots, and up-regulation of antioxidant activity, protecting photosynthetic function. The results of this study suggest that foliar application of Si products may be considered as an effective approach to improve turf quality and physiological fitness of creeping bentgrass during the summer months in the U.S. transition zone and other regions with similar climate.
Speakers
XZ

Xunzhong Zhang

Virginia Tech
Co-authors
JG

James Goatley

Virginia Tech
NA
Thursday September 26, 2024 5:15pm - 5:30pm HST
South Pacific 4

5:30pm HST

PGR 2 - Effect of Light Quality and Intensity on Cannabis Photosynthetic Activity
Thursday September 26, 2024 5:30pm - 5:45pm HST
Among numerous abiotic environmental factors, varying light quality and intensity elicit photosynthetic responses that can play vital roles in the optimization of crop production in controlled environment agriculture. Earlier and preliminary studies on photosynthetic activity reported that amber light (595 nm) induces higher photosynthetic rates and quantum yield of plants is a wavelength-dependent response. To resolve the most accurate ePAR curves in cannabis (Cannabis sativa), this study investigated the spectral response of photosynthesis by examining the effects of the leaf versus the whole plant on the impact of photosynthetic activity. A customized CO2 chamber equipped with relative humidity, temperature, and CO2 was used to collect leaf and whole plant photosynthetic data from 5 week old clones with different monochromatic wavelengths (380–750 nm) using the LI-6800 Portable Photosynthesis System (LI-COR) equipped with the Large Leaf and Needle Chamber (LI-COR 6800-13). Differences and correlation between photosynthetic activity at the leaf level and the whole plant were determined. Subsequent studies will involve the combinations of different wavelengths at different ratios. Findings will expand the current understanding of the photosynthetic response of plants to light and provide highly resolved spectral quantum yield curves.
Speakers
PW

Philip Wiredu Addo

McGill University
Co-authors
AR

AnneSophie Rufyikiri

McGill University
NA
ML

Mark Lefsrud

McGill University
NA
MD

Mohamed Debbagh

McGill University
NA
SM

Sarah MacPherson

McGill University
NA
Thursday September 26, 2024 5:30pm - 5:45pm HST
South Pacific 4

5:45pm HST

PGR 2 - Enhancing the quality of novel greenhouse crops through dynamic LED lighting
Thursday September 26, 2024 5:45pm - 6:00pm HST
The adoption of supplemental lighting in horticulture has allowed greenhouse growers to increase the yield of multiple crops by at least 10%, with a 300% yield increase documented for cucumbers when transitioning from unlit to lit production. Since then, horticultural lighting has advanced significantly to now include dynamic LED lighting, which provides unparalleled control over the light intensity, spectrum and zoning within the greenhouse. This has allowed greenhouse growers to further maximize crop productivity, but also to target improvements in crop quality and to diversify their production. For example, the greenhouse industry has seen the introduction of multiple berry crops, leafy crops, Asian cucumbers, etc. in recent years, all of which have varying lighting requirements ranging from 12 to 25 mol of light per square meter per day. The ideal spectrum also differs between crops, as do the light saturation points and target intensities. Beyond enhancing photosynthesis and increasing crop productivity, dynamic LED lighting can also be used to improve the nutritional quality and taste of various crops through spectral adjustments during the growth cycle. In a trial comparing the impact of broad and narrow spectra on basil, a broad spectrum produced a flavor profile stronger in eucalyptol whereas a narrow spectrum produced an estragole-dominant crop. This resulted in a milder flavor under a broad spectrum and a stronger flavor under a narrow spectrum. With dynamic lighting, growers can adjust the spectrum to target different flavors and thus different markets. Further, the application of high levels of blue light during the last week of production has been repeatedly shown to enhance the antioxidant capacity of red leafy greens through the bioaccumulation of anthocyanin. The Brix, or sweetness, of fruiting crops has also been improved under dynamic lighting, with commercial trials showing a minimum of 7% increase in Brix in speciality cherry tomatoes compared to fixed spectrum lighting. This increase could potentially be enhanced with end-of-day (EOD) light treatments, which early trials have suggested to enhance the translocation of sugars from leaves to fruit. As such, dynamic LED lighting can improve both the productivity and nutritional quality of greenhouse crops, allowing forward-thinking growers to meet the growing population’s needs in terms of both quality and quantity.
Speakers
RS

Rose Seguin

Agronomist, Sollum Technologies
Rose Séguin is an agronomist specializing in controlled environment agriculture, with previous experience in indoor agriculture, agricultural innovation systems, and agricultural development in remote areas of Canada. She holds a bachelor's degree in agro-environmental sciences and... Read More →
Thursday September 26, 2024 5:45pm - 6:00pm HST
South Pacific 4
 


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