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Tuesday, September 24
 

10:00am HST

CE 1 - Transcriptomic Analysis of Kale (Brassica oleracea) Grown Under Different Light Emitting Diode Wavelengths Revealed Potential Genes Responsible for Phenotypic Changes
Tuesday September 24, 2024 10:00am - 10:15am HST
Light emitting diodes (LEDs) of different wavelengths significantly influenced kale growth, morphology, and nutrient content. The importance of indoor agriculture is being recognized, but few studies have investigated the influence of LEDs, particularly green wavelengths, on crops at the transcriptome level. The objective of this study was to use RNA sequencing technology to elucidate the genetic response of kale to blue (BV), green (G), and red (RF) LEDs compared to the combination of all the LEDs (RFBVG), control. Results revealed total amount of differentially expressed genes (DEGs) was 1373 for kale grown under BV LEDs, 924 under G LED, and 133 under the RF LED treatments. DEGs enriched in kale grown under RF LEDs played roles in regulating hormone metabolic processes and oxidoreductase activity. In the BV treatment, several enzymes in the phenolic biosynthetic pathway were upregulated compared to the control which may explain previous results reporting higher levels of phenolic content in kale grown under BV LEDs. In the G LED treatment, the expression of genes related to photosynthesis, heme binding, and oxidoreductase activity were upregulated compared to those in the control group. These results may support previous findings of higher iron content in kale grown under G LEDs. Further, the G LED treatment upregulated the expression of cytochrome P450 enzymes, which play key roles in plant growth and stress responses. Understanding the molecular mechanisms underlying the effects of different LED wavelengths by RNAseq provides information to improve indoor cultivation practices that optimize crop growth and nutrient value.
Speakers
TS

Tristan Sanders

West Virginia University
NA
Co-authors
JT

Janet Tou

West Virginia University
NA
NW

Nicole Waterland

West Virginia University
NA
YM

Youyoun Moon

West Virginia University
NA
Tuesday September 24, 2024 10:00am - 10:15am HST
Coral 1

10:00am HST

CHEX 1 - A comprehensive analysis of Vidalia Onions transplanting and its impacts
Tuesday September 24, 2024 10:00am - 10:15am HST
Onions are a key crop in the United States. In 2023, 138,000 acres were cultivated in the country with onions. Georgia harvested 11,700 acres in 2023, reaching an average production of 129,000 tons. The onion transplanting process is crucial to the crop cycle and is directly linked to the production potential and quality of the bulbs. Every year, thousands of workers are employed to transplant onion seedlings, which results in a wide variation in operational performance and quality of execution between them. These factors are influenced by the experience and conditions in which the workers operate, which can lead to failures in the process, such as double plants, partially transplanted and plants that have fallen to the ground. Furthermore, manual work is slow and requires many workers, increasing the cost of the operation. Therefore, we aimed with this study to assess the time required to manually transplant onions, the quality of manual transplanting, and the impact of inadequate transplanting on crop development. To assess how much time it takes to transplant an acre of onions, and the quality of transplanting, twenty-five people were observed during their work at a commercial field in Glennville-GA. To assess the impact of poor-quality transplanting, an experiment was carried out in four 10ft replications (10x4ft beds) in Reidsville-GA, simulating four situations observed in the commercial field. Treatments were: T1: 25% of the plants in the plot laying on the ground, T2: 25% partially transplanted, T3: 100% properly transplanted, T4: 25% multiple transplanted, T5: 100% laying on the ground. The difference in operational efficiency between workers exceeded ~20 hours per acre. Results indicated that, in average, one person transplanted 1 acre in approximately 30 hours. The fastest person in the crew transplanted in 22 hours, while the slowest took around 40 hours to transplant 1 acre. Poor-quality transplanting of seedlings exceeded up to 11%. The average number of multiple seedlings was 1%, partially transplanted seedlings was 6%, and laying on the ground was 5.5%. Plant development was assessed based on the number of leaves. Properly transplanted seedlings generated a greater number of leaves compared to the other treatments. Higher leaf number was observed in treatment 3 with an average of 7.33 leaves per plant. All the treatments differed from treatment 5, which had an average of 4.6 leaves per plant. Results indicate that good practices on transplanting can increase onion yield.
Speakers
avatar for Regimar dos Santos

Regimar dos Santos

University of Georgia
Bachelor's degree in agronomic engineering from the Federal University of Mato Grosso do Sul, Brazil at 2021. Master's degree in plant production with an emphasis on computational intelligence in genetic improvement at 2022, with a doctorate in progress at the state university of... Read More →
Co-authors
LO

Luan OIiveira

University of Georgia
NA
LS

Lucas Sales

University of Georgia
Agronomy Engineer graduated from the Federal University of Paraíba. With experience in the management and cultivation of Ornamental Plants, through a year of experience working in Greenhouses in the state of New Hampshire, USA. Experienced in the management and cultivation of vegetables... Read More →
MB

Marcelo Barbosa

University of Georgia
Tuesday September 24, 2024 10:00am - 10:15am HST
South Pacific 2

10:00am HST

MKEC - Consumer Shopping Destination Preferences For Outdoor Garden Plants In The United States
Tuesday September 24, 2024 10:00am - 10:15am HST
Outdoor garden plants are integral products in the nursery and garden stores industry in the United States. Industry reports indicate that home improvement centers and big-box stores pose a significant threat to small garden centers, nursery stores, and ornamental farmers through price competition while small local ornamental businesses tend to focus on personalized products and services to compete with chain retail stores. Identifying the key characteristics of consumer clusters that influence consumer shopping destination preferences can be useful for industry players to devise efficient marketing plans for their niche markets. This study employs cluster analysis techniques and multinomial logistic regression on the cross-sectional data collected from an online survey of 609 consumers to estimate the influence of consumer economic and socio-demographic characteristics on their shopping destination choices. The results from this study indicate that retail consumers of outdoor garden plants can be categorized broadly into four clusters: home improvement center shoppers (47.4%), big-box center shoppers (13.5%), local garden center shoppers (21.2%), and farmers’ market shoppers (17.9%). This study also finds that age, ethnicity, education, household income, number of children in the household, urbanicity, housing arrangements, and political inclination are useful predictors of shopping destination preferences for outdoor garden plants. This study adds valuable information to the market research literature for the retail ornamental horticulture industry.
Speakers
VB

Vivek Bist

Agricultural & Natural Resources Agent, University of Georgia
Co-authors
BC

Benjamin Campbell

University of Georgia
JM

Jeffrey Mullen

University of Georgia
NA
Tuesday September 24, 2024 10:00am - 10:15am HST
South Pacific 1

10:00am HST

NUR 1 - Seventy Years of Evaluations and Selections of Ornamentals by the NDSU Woody Plant Improvement Program.
Tuesday September 24, 2024 10:00am - 10:15am HST
The North Dakota State University (NDSU) Woody Plant Improvement Program has been servicing the Northern Great Plains for 70 years, beginning germplasm trial evaluations in 1954. NDSU purchased an 80-acre (~32 hectares) farm in the early 1970s to be established as the NDSU Horticulture Research Farm near Absaraka, ND and began trial plantings in fall of 1974. This research farm provides ideal horticultural soil for evaluation and breeding projects for ND. Approximately 45 acres (~18 hectares) of this farm is used for evaluation, selection and breeding of woody ornamental plants including a 35-acre (~14 hectares) research arboretum. This research arboretum is the most extensive collection of woody ornamental plants in North Dakota and in the Northern Great Plains. There have been over 15,000 accessions obtained, evaluated, and developed since planting began in 1974. Accessions have been collected from local, regional, national, and international sources. After 50 years, this program has introduced 62 superior ornamental woody plants for production and sale with 44 active registered trademarks with the U.S. Patent and Trademark Office. NDSU woody plant introductions have a nursery wholesale sale value of over $2.0 million and a $6.0 million value in retail sales for 2022 alone. Introductions are currently being propagated for sale by commercial wholesale firms in four countries: Australia, Canada, England, and the United States (22 states, including 35 nurseries). The primary focus of this program is with increasing the diversity and availability of woody plants with increased disease/insect resistance and winter hardiness for landscapes throughout North Dakota, region, and nation. One issue that this program is addressing is that native woody (trees and shrubs) plant species diversity is extremely low in the central United States, especially in North Dakota. Most of the available trees and shrubs in the specialty crop nursery trade in North Dakota are non-native introductions. Many non-native plants have been shown to be invasive to native environments. Woody plant research has reacted to this issue utilizing sterility breeding. This results in new cultivars that are not considered invasive and are allowed to be utilized by the commercial nursery and landscape industry, even in states where they are banned. Sterility breeding through polyploid induction has become a focus of the NDSU Woody Plant Improvement Program. The research focus of this project is to induce, or develop, polyploids produce sterile cultivars to be used in the nursery and landscape trade.
Speakers
avatar for Todd West

Todd West

North Dakota State University
Dr. Todd P. West is currently a Professor at North Dakota State University and director of the NDSU Woody Plant Improvement Program. He earned his Ph.D. from Southern Illinois University at Carbondale. The NDSU Woody Plant Improvement Program focuses on the development of new woody... Read More →
Tuesday September 24, 2024 10:00am - 10:15am HST
South Pacific 3

10:00am HST

PNM 1 - Evaluating Nitrogen Application Rates on Open-field Fresh-market Tomato Production in North Mississippi: Preliminary Results
Tuesday September 24, 2024 10:00am - 10:15am HST
Nitrogen (N) is an essential crop nutrient and is a major production requirement for vegetable crops, critical for optimum yield and fruit quality. An adequate supply of N improves plant growth and health, reduces plant susceptibility to diseases, and minimizes the risk of groundwater and surface water pollution. There is limited information on the N requirements for commercial vegetable production systems in Mississippi (MS). This project aims to establish the critical N application rate for open-field fresh-market tomato production in northeast Mississippi. The study was conducted at North Mississippi Research and Extension Center, Verona MS. The evaluated treatments (0, 73, 109, 145, 218, and 290 kg/ha-N) were arranged in a randomized complete block design with three replicates per treatment. For each treatment, the total required amount of nitrogen application was applied at a split rate of 50% preplant (ammonium nitrate, 33-0-0 and fertigation (Calcium nitrate, 15.5-0-0). Fertigation was applied weekly starting at 6 weeks after transplanting. Both potassium and phosphorus were the same for all treatments and applied at 100% pre-plant using 0-46-0 and 0-0-60 formulations respectively. Yield data were collected at fruit maturity and analyzed for statistical differences among treatments. Preliminary results suggest significant differences (p < 0.05) among treatments for leaf tissue N concentration. The total marketable yield and extra-large fruit categories were highest (p < 0.05) at 290 kg/ha-N compared to other treatments. The results also clearly demonstrated that the observed yield increase at a higher N rate (290 kg/ha-N) was attributed to increase in total fruit number at maturity and bigger fruit size. The observed yield for the unmarketable fruit category was highest at N application rate of ≤ 73 kg/ha. Based on the preliminary results obtained, the optimum N application rate for open-field fresh-market tomato production in northeast MS could be up to 290 kg/ha. However, more studies are currently being conducted to validate these preliminary results.
Speakers
avatar for Timothy Ayankojo

Timothy Ayankojo

Assistant Professor, Mississippi State University
Co-authors
JW

Jeff Wilson

Mississippi State University Extension
TH

Thomas Horgan

Mississippi State University
NA
Tuesday September 24, 2024 10:00am - 10:15am HST
Kahili

10:00am HST

POM 1 - Prohexadione Calcium Does Not Affect Thinning Efficacy of 1-aminocyclopropane-1-carboxylic Acid in ‘Golden Delicious’
Tuesday September 24, 2024 10:00am - 10:15am HST
Apple’s (Malus × domestica Borkh.) tendency towards biennial bearing necessitates management strategies such as fruit thinning and vigor control. Applications of plant growth regulators to manage crop load and vigor overlap in the spring. A precursor to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC; Accede®) was recently registered as a chemical fruit thinner in the USA. Prohexadione-calcium (P-Ca) is a gibberellin biosynthesis inhibitor widely used to manage vigor. It is suspected that P-Ca may interfere with ACC precursors, decreasing thinning efficacy of ACC. We evaluated the effects and interactions of ACC and P-Ca on shoot growth, ethylene evolution, leaf area, and yield responses of mature ‘Golden Delicious’. The experiment was conducted in 2023, in Mills River, NC, USA. Treatments included ACC (400 mg∙L-1), P-Ca (250 mg∙L-1), ACC P-Ca, and an untreated control. Application of P-Ca occurred on three dates. ACC was applied when average fruit diameter was ~20 mm. Across all measured responses, there were no interactions between ACC and P-Ca. P-Ca had a negative main effect on shoot growth rate (48.7–75.4% reduction). ACC reduced leaf number of spurs 4 and 9 days after treatment (DAT). Ethylene evolution in fruit and spurs was increased by ACC 1, 4, and 9 DAT (spur: 1.1e4%, 5300%, and 515%, respectively; fruit: 9200%, 725%, and 222%, respectively). ACC had a negative effect on fruit number, yield, and crop density (60.1%, 56.5%, and 60.3% reduction, respectively). These results indicate that ACC and P-Ca can be used simultaneously to manage crop load and vigor, respectively
Speakers
AV

Annie Vogel

North Carolina State University
Co-authors
CC

Christopher Clavet

North Carolina State University
NA
JL

James Larson

Utah State University
TK

Thomas Kon

North Carolina State University
NA
Tuesday September 24, 2024 10:00am - 10:15am HST
Nautilus

10:15am HST

CE 1 - Blue Light Mediates Far-Red Light Effects on Increasing Leaf Area and Shoot Mass of Kale and Lettuce
Tuesday September 24, 2024 10:15am - 10:30am HST
There are contrasting effects of far-red (FR; 700–750 nm) light on leaf area and biomass in plants. These differences have been attributed to photon flux density (PFD) and species/cultivar differences. In a previous experiment, total PFD (TPFD) did not mediate the influence of FR light on leaf area and shoot mass when the TPFD alterations were only of red (R; 600–699 nm) and FR light. Therefore, we hypothesized that blue (B; 400–499 nm) light controls the influence of TPFD in regulating the effects of FR light on leaf area and shoot mass. We cultivated kale (Brassica oleracea var. sabellica) ‘White Russian’ and lettuce (Lactuca sativa) ‘Rex’ and ‘Rouxai’ under 12 lighting treatments with a 24 h∙d−1 photoperiod and TPFDs of 85, 170, 255, or 340 µmol∙m−2∙s−1 and FR fractions [FR-PFD divided by the sum of R and FR PFD] of 0.00, 0.17, or 0.33. The alterations in the TPFDs were solely due to B-PFD; the sum of R and FR PFD was constant in all treatments. Preliminary results indicate that elevated FR fraction did not increase leaf area and shoot mass of all three crops in the absence of B light, when the TPFD was 85 µmol∙m−2∙s−1. However, a high B-PFD and thus TPFD amplified the effects of a high FR fraction at increasing leaf area and shoot mass of all three cultivars. These high FR-fraction effects were correlated with increased biomass partitioning to leaves at a high B-PFD and thus TPFD. These results imply that the contrasting effects of FR light on leaf area and biomass in previous studies could be attributed to the B-PFD. In addition, the influence of TPFD on FR-fraction effects is primarily influenced by the B-PFD.
Speakers
avatar for Jiyong Shin

Jiyong Shin

Michigan State University
Co-authors
ER

Erik Runkle

Michigan State University
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
Coral 1

10:15am HST

CHEX 1 - Is Winter Squash a Potential Alternative Cucurbit Vegetable Crop to Combat Whitefly and Whitefly-Transmitted Viruses for Fall Production in Southern Georgia?
Tuesday September 24, 2024 10:15am - 10:30am HST
The predominant cucurbit vegetable crop during fall in Georgia is summer squash with production value of around $94.08 million on 7,757 acres in 2022 while winter squash acreage was insignificant. Whitefly and whitefly-transmitted viruses (WTV) account for 30-50% summer squash yield losses on average and threaten squash production during fall in the region. Cucurbit leaf crumple virus (CuLCrV), Cucurbit yellow stunting disorder virus (CYSDV) and Cucurbit chlorotic yellows virus (CCYV) are the prominent WTV in southern Georgia. We carried out an experiment during fall 2023 in Tifton, Georgia to evaluate tolerance of winter squash varieties for whitefly and WTV and to study their potentiality for fall production in the region. We compared ten commercial hybrid varieties of which two were acorn types (‘Tay Belle’ and ‘Table Ace’), five were butternut types (‘Waltham’, ‘Ceres’, ‘Atlas’, ‘Ultra HP’ and ‘Genesis’), and one each of a hubbard type (‘Golden Hubbard’), a kabocha type (‘Sweet Mama’) and a calabaza type (‘La Estrella’). We collected data on whitefly number, silver leaf disorder, virus incidence and severity, and fruit yield. In addition, we ran quantitative polymerase chain reaction (qPCR) and quantitative reverse transcription polymerase chain reaction (RT-qPCR) on leaf samples to detect and quantify viruses. There were significant differences between winter squash varieties for whitefly feeding preference, silver leaf disorder, virus severity, virus loads and marketable yield. ‘La Estrella’ had the lowest number of whitefly adults per cm2 leaf area followed by all other butternut types (Genesis, Ultra HP, Waltham, Ceres, Atlas), and highest in ‘Tay Belle’, followed by ‘Table Ace’ and ‘Golden Hubbard’. We found significantly severe leaf silvering in ‘Golden Hubbard’ and ‘Sweet Mama’ followed by acorn types. We observed 100% virus incidence in all the varieties, however severity was lowest for ‘Ceres’, ‘Genesis’, ‘La Estrella’, ‘Sweet Mama’, ‘Ultra HP’ and ‘Waltham’. CCYV loads was found highest in ‘Sweet Mama’ and lowest in ‘Genesis’, ‘La Estrella, ‘Ceres’ and ‘Ultra HP’. CYSDV and CuLCrV loads were highest in ‘Table Ace’ and ‘Tay Belle’ and negligible in other varieties. We observed the highest marketable fruit yield in ‘Ceres’ (7,139 count/acre) and ‘Genesis’ (7,109 count/acre). Although ‘La Estrella’ was less infested with whitefly and WTV, it had poor fruit yields. Overall, we found butternut types mainly ‘Ceres’ and ‘Genesis’ as potential alternative cucurbit vegetable crops for fall production in southern Georgia with lower whitefly and WTV infestation resulting in the highest marketable fruit yields.
Speakers
NA

Nirmala Acharya

University of Georgia
Co-authors
DG

David G Riley

University of Georgia
NA
JC

Juan Carlos Diaz Perez

University of Georgia
MK

Manish Kumar

University of Georgia
NA
SB

Sudeep Bag

University of Georgia
NA
TM

Ted McAvoy

University of Georgia
NA
TC

Timothy Coolong

University of Georgia
Tuesday September 24, 2024 10:15am - 10:30am HST
South Pacific 2

10:15am HST

MKEC - Producer Awareness and Treatment of Ambrosia Beetle: Evidence from a Producer Survey
Tuesday September 24, 2024 10:15am - 10:30am HST
Ambrosia beetles are creating a larger negative impact on tree crops throughout the U.S. As such, research is on-going to better understand ambrosia beetles and the impact of varying treatment methods. However, little is known about awareness and the treatments currently being utilized by producers throughout the U.S. This research takes an in-depth look at producer awareness, treatments utilized pre- and post-ambrosia beetle infestation, and expenditures associated with treating ambrosia beetles. Utilizing a survey of producers throughout the U.S., most producers were aware of ambrosia beetles; however, treatments to control ambrosia beetles varied considerably. Interestingly, many producers chose not to treat, which implies many producers currently do not see a positive benefit/cost to treat. A reason for lack of treatment could be the lack of consistency of ambrosia beetle infestations as many producers indicated ambrosia beetles were not a problem each year. Further, this research does provide stakeholders with information on what treatment methods are preferred and means to increase information dissemination about new ambrosia beetle treatments.
Speakers
BC

Ben Campbell

University of Georgia
Co-authors
AR

Adam Rabinowitz

Auburn University
NA
AL

Alicia L Rihn

University of Tennessee
avatar for Julie Campbell

Julie Campbell

University of Georgia
Tuesday September 24, 2024 10:15am - 10:30am HST
South Pacific 1

10:15am HST

NUR 1 - Tea Plant Propagation for Nursery Production
Tuesday September 24, 2024 10:15am - 10:30am HST
Tea (Camellia sinensis) is the second most popular beverage worldwide and the U.S. annually imports 240 million pounds of tea. The limited availability of tea cultivars and limited knowledge for tea plant propagation are primary barriers for tea production in Washington and the U.S. overall. Time of year and section of shoot for propagation cuttings were tested in northwest Washington for tea cultivar Minto Pacific. Shoots were collected on 8 and 21 Sep, 6 and 24 Oct, 3 and 21 Nov, and 8 Dec 2022, and 18 Jan and 8 Feb 2023, then processed into top, mid, and bottom section cuttings. The bottom end of each cutting was scored (1-2 inches depth) using a knife, dipped into rooting hormone for 5-10 seconds, and placed into a treepot filled with propagation media (5:3:2 ratio peatmoss, vermiculite and perlite, pH 4.5) with the bottom node leaves resting on the mix line. Treepots were placed in a mist chamber with 50% shade and 70-80% relative humidity for 4 months. Survival rate was greatest for shoots collected from 21 Sep through 8 Dec 2022: 99.5% on average 4 months after collection. Cuttings from 8 Sep 2022 had the lowest survival rate overall: 77% at 4 months after collection. Top, mid and bottom section cuttings had an average survival of 96.7%, 95.8% and 94.7% at 4 months after collection. Plant height at 4 months after collection was greatest for cuttings collected on 8 Feb (6.6 cm) and lowest for all other dates (4.5 cm on average). Overall, cuttings from the mid and bottom sections had the greatest plant height at all times: average 5.0 cm at 1 month, average 5.1 cm at 2 months, average 5.2 cm at 3 months, and average 5.6 cm at 4 months. The number of new leaves measured in June 2023 was greatest for top and mid sections of the shoot (3.8 leaves on average) while the bottom section had the lowest number of new leaves (2.8 leaves on average). The overall health rating up to 4 months after collection was highest for cuttings collected on 6 and 24 Oct, and 8 Dec (more than 4.5 on average for all months). The top section of the shoot had the highest rating for overall health in all months (≥ 4.5). Keywords: Camellia sinensis, Cuttings, Northwest Washington, Vegetative
Speakers
CM

Carol Miles

Washington State University
Co-authors
SS

Srijana Shrestha

Washington State University
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
South Pacific 3

10:15am HST

PNM 1 - Effect of Bacterial Biostimulant Applied at Different N Rates in Potatoes
Tuesday September 24, 2024 10:15am - 10:30am HST
Nitrogen is a crucial macronutrient for potato production, as it plays a vital role in promoting photosynthesis, chlorophyll synthesis, and overall plant growth, ultimately contributing to higher crop yield. However, the shallow root system of potato plants and the sandy soil conditions in this region make applied nitrogen unavailable to the crop, resulting in reduced nitrogen use efficiency (NUE). An alternative and eco-friendly solution is to integrate microbial consortium inoculation in nutrient management plans. This approach entails the introduction of a mixture of beneficial microorganisms known as plant growth promoting rhizobacteria (PGPR), into the soil to promote plant growth. These N2-fixing microbes can increase soil N availability which could meet N demand of potato crop, hence can help in reducing N fertilizer input rate. Therefore, a commercial microbial biostimulant was applied with five different N rates 0, 78, 157, 235, and 314 kg ha-1. We found that microbial biostimulant did not increase tuber yield but improved NUE. Increasing N rate increased tuber yield, biomass and NUE significantly.
Speakers
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 →
Co-authors
SS

Simranpreet Sidhu

University of Florida
NA
WD

Winniefred D Sharma

University of Florida
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
Kahili

10:15am HST

POM 1 - Carbohydrate Status of Apple Fruitlets following Chemical Thinner Application Informs Sink Strength and Fruit Set
Tuesday September 24, 2024 10:15am - 10:30am HST
Crop load management of apple (Malus x domestica Borkh.) is one of the most important orchard management practices to ensure adequate fruit size and quality. Fruitlets are most sensitive to thinner applications early in the season, between 6mm and 20mm fruitlet diameter. During this time, abscission is associated with environmental and biological factors that influence fruitlet development, growth and sink strength. The carbohydrate economy of the fruitlet and its position within the cluster (king flower vs. lateral flowers) are primary factors contributing to the sink strength of individual fruitlets. We evaluated the relationship between the non-structural carbohydrate status of apple fruitlets in three different size classes (i.e., 90th, 50th, and 10th percentile of the population) and their respective likelihood to persist throughout the season. Persistence probabilities of these size classes were generated by an empirical fruit set prediction model based on the distribution of fruitlet mass and confirmed by actual measures of fruit set. Soluble carbohydrates and starch were quantified with an enzymatic assay procedure. Following chemical thinner application, the concentration of soluble sugars (glucose, fructose, sucrose, and sorbitol) was significantly reduced on a gram / gram fresh weight basis. Fruitlets in the 10th percentile generally had the lowest concentration of soluble sugars and starch and the slowest recovery rate following chemical thinner application. Fruitlets in the 90th percentile generally had the highest concentrations of soluble sugars and starch. Our data support that differences in the carbohydrate concentration of fruitlets contribute to their sink strength and abscission fate as predicted by a fruit set prediction model.
Speakers
LH

Laura Hillmann

Michigan State University
Co-authors
TS

Thomas Sharkey

Michigan State University
NA
TE

Todd Einhorn

Michigan State University
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
Nautilus

10:15am HST

TCHG 1/ADMIN - FFAR Fellows: Opportunities for Horticulture PhD Students
Tuesday September 24, 2024 10:15am - 10:30am HST
The Foundation for Food and Agriculture (FFAR) Fellows Program was launched in 2018 and has become the premier professional development program for food and agriculture doctoral students. The FFAR Fellows offers leadership and professional development training for PhD students studying food and agriculture-related sciences in the U.S. and Canada. North Carolina State University leads the initiative, which provides Fellows with training, networking opportunities, and peer support. The objectives of the program are to 1) develop leadership competencies that enhance current and future individual productivity and well-being, and enhance Fellows capacity to contribute to the public good, 2) connect young scientists across research domains and geographic areas to promote multi-disciplinary understanding and problem-solving, and 3) broaden students understanding of their career options and create links to sectors beyond academia (industry, government, NGO). Over a 3-year period members of each cohort (25-30 Fellows) attend four in-person meetings plus monthly virtual sessions, create and execute annual professional development plans, and network and establish mentor-mentee relationships with industry scientists and others outside of academia. Eligible students are those who have completed their MS degrees before the program starts or current PhD students with at least three years remaining in the program. FFAR provides 50% of the funds with the rest matched from industry, NGOs, commodity organizations, or other sources of non-federal funds. Deadlines are generally late February for the Stipend Professional Development Category (providing professional development $50,000/year in support) and mid April for the Professional Development Category (providing professional development). Application requirements will be discussed in the presentation. The research program of each Fellow must address one or more of the six FFAR challenge areas, five of which relate to horticulture: Soil Health, Sustainable Water Management, Next Generation Crops, Urban Food Systems, and Health-Agriculture Nexus. Approximately 7% of the 139 Fellows are from horticulture programs. There are opportunities for more horticulture PhD students to take advantage of this program.
Speakers
JD

John Dole

North Carolina State University
Co-authors
RD

Rebecca Dunning

North Carolina State University
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
South Pacific 4

10:15am HST

WCPM 1 - Evaluation of Plant Hormones and Other Seed Treatments to Reduce Injury Caused by Preemergent Herbicides on Direct-seed
Tuesday September 24, 2024 10:15am - 10:30am HST
Poor competitive ability and limited herbicide options make weed management of Brassica crops difficult. Growers often adopt the use of transplants, which is less efficient in terms of time, material, and labor when compared with direct seeding, resulting in higher prices per unit. Seed treatment with protective compounds could decrease crop injury from preemergent (PRE) herbicides making it profitable to direct-seed Brassica plants for production. Research was conducted to evaluate the ability of three candidate safeners [24-epibrassinolide, melatonin, and ascorbic acid (AsA)] to reduce injury caused by four herbicides (S-metolachlor, pyroxasulfone, halosulfuron, and mesotrione) applied PRE on the collard green cultivar Top Bunch and turnip cultivar Purple Top White Globe. Two independent greenhouse trials were conducted at the Clemson University Coastal Research and Education Center in Charleston, SC. Visual injury of the treated plants was evaluated weekly and dry mass was collected 21 days after treatment. Seed treatment did not reduce injury efficiently caused by pyroxasulfone, halosulfuron, and mesotrione; all doses were lethal for both crops. However, collard seeds treated using melatonin and AsA had 66% and 54% less injury caused by S-metolachlor at 514 g⋅ha–1 a.i., respectively. On turnips, melatonin was the only treatment that reduced the S-metolachlor damage on seedlings, with 43% less injury than untreated seedlings. Plant injury and plant weight correlated significantly for both Brassica crops. The reduction in injury caused by S-metolachlor when seeds were treated with melatonin and AsA validated those compounds’ protective ability. Seed treatment with melatonin could be combined with PRE applications of S-metolachlor to overcome the low weed competitive ability of these species early in the season.
Speakers
MC

Matthew Cutulle

Clemson
Weed control in vegetables and small fruits
Co-authors
SB

Sandra Branham

Clemson University
NA
Tuesday September 24, 2024 10:15am - 10:30am HST
Lehua Suite

10:30am HST

CE 1 - Interactions Between Blue Light and Far-Red Light on Growth of Culinary Herbs
Tuesday September 24, 2024 10:30am - 10:45am HST
Light quality can regulate growth and quality characteristics of young plants, but responses of culinary herb transplants are not well understood. Blue light generally inhibits extension growth while far-red light promotes stem elongation and leaf expansion. The objective of this study was to investigate the interaction between blue (400-499 nm) and far-red (700-750 nm) light on six culinary herb species, basil ‘Nufar’, cilantro ‘Santo’, parsley ‘Giant of Italy’, sage ‘Extraka’, mint ‘Spearmint’, and oregano ‘Greek’, with the goal of producing high-quality transplants with compact growth. Six indoor lighting treatments were tested with blue light photon flux densities (PFDs) of 20, 60, or 100 µmol∙m−2∙s−1 and far-red light of 0 or 60 µmol∙m−2∙s−1, with red light (600-699 nm) added so that the total PFD was 210 µmol∙m−2∙s−1 in all treatments. Seeds were sown in 72-cell trays at a constant 23 °C under a 16-h photoperiod and grown for 28-44 days until harvest. As expected, treatments with the highest far-red and lowest blue light PFDs had the greatest extension growth and those with no far-red and high blue light were the most compact. Preliminary results indicate basil, cilantro, and mint exhibited the greatest leaf area under high blue and far-red light. Generally, all species had the highest shoot fresh mass when grown with far-red light. We conclude that blue light and far-red light interact to regulate plant height and leaf area, especially in basil and sage. Therefore, including blue and far-red in the light spectrum should be considered to manage the morphology of young culinary herb plants.
Speakers
BK

Bridget Knight

Michigan State University
Co-authors
ER

Erik Runkle

Michigan State University
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
Coral 1

10:30am HST

CHEX 1 - Evaluating Onsite Nitrate and Potassium Sensors
Tuesday September 24, 2024 10:30am - 10:45am HST
Destany Westlake, Paul Fisher, Josh Tebow, and Ryan Dickson Maintaining nutrient balance in hydroponic systems reduces the need to dump nutrient solution, thereby reducing water and fertilizer cost, and the resulting environmental impact. Laboratory testing to monitor nutrient concentrations is reliable, however it typically requires shipment and days to weeks of processing. The objective was to test the accuracy of handheld and inline ion-selective nitrate and potassium sensors compared with laboratory analysis of these nutrients. The methodology consisted of a factorial design with four reservoirs containing two water qualities and two fertilizer recipes with one nutrient film technique (NFT) system per reservoir. Nitrate and potassium concentration was measured twice per week during a 6-week hydroponic trial with basil, using handheld sensors, inline sensors, and Lachat QuickChem 8500 Series 2 analysis by a commercial horticulture laboratory. Based on the laboratory testing, NO3-N ranged from 142 to 272 mg.L-1 and K ranged from 111 to 271 mg.L-1 during the trial. The average error ± one standard deviation for the handheld sensor minus the laboratory concentration was -26.5 ± 18.8 mg.L-1 and -9.4 ± 13.1 mg.L-1 for N and K, and for the inline sensors was 3.5 ± 27.5 mg.L-1 and -15.2 ± 32.1 mg.L-1 for N and K, respectively. Therefore, we conclude that the handheld and inline sensors provided a useful and rapid estimation of N and K levels, but replicated samples should be taken and these levels should be verified by periodic laboratory analysis. Onsite testing could be an important tool for effective nutrient management to reduce nutrient loss and waste.
Speakers
DW

Destany Westlake

University of Florida
First- year Graduate Environmental Horticulture student.
Co-authors
JT

Josh Tebow

University of Arkansas
NA
PF

Paul Fisher

Floriculture Specialist at the University of FL
NA
RD

Ryan Dickson

University of Arkansas
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
South Pacific 2

10:30am HST

MKEC - Consumer Awareness, Treatment Perception, and Purchasing Response to Flathead Borer
Tuesday September 24, 2024 10:30am - 10:45am HST
Flathead borers cause extensive damage for specialty crop producers throughout the U.S. As specialty crop producers attempt to mitigate damage, various treatments are being utilized. Furthermore, flathead borers cause damage in landscapes. To this end, this research examines the impact of consumer awareness and perception of flathead borer, consumer views on potential treatments in their landscape and in specialty crop production systems, and how the purchasing decision for a tree, bush, etc. might change given different probabilities of the tree, bush, etc. being impacted by flathead borer. An online survey on a representative sample of U.S. consumers conducted in 2024 found that there is little consumer awareness of flathead borer, but consumer’s recognized damage when shown pictures of what damage looked like. However, consumers had definitive opinions about flathead borer treatments, notably negative opinions about chemical treatments, though this view was heterogenous in nature. Finally, purchase decisions were impacted by the probability of a tree, bush, etc. being impacted, such that consumers were more accepting of a higher probability for minor damage, but a low probability of major damage would decrease the probability of purchase. From this research, stakeholders and researchers get a better understanding of which treatments may have a negative purchasing impact.
Speakers
BC

Ben Campbell

University of Georgia
Co-authors
AL

Alicia L Rihn

University of Tennessee
MD

Mounata Dahal

The University of Georgia
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
South Pacific 1

10:30am HST

NUR 1 - Establishment of Fraser Fir Christmas Tree Plantations in Response to Mulch and Root Dips
Tuesday September 24, 2024 10:30am - 10:45am HST
In the Great Lakes region of the United States Christmas tree plantations are established by planting seedlings or transplants. Reducing plant moisture stress after planting is crucial to successful establishment of these small conifers. A myriad of products have been marketed to Christmas tree producers with claims to improve transplant success by limiting transplant shock. Since 2021, we have conducted a series of field trials in collaboration with Michigan Christmas tree growers to evaluate the effect of root dips, mulching and other cultural practices on transplant survival and growth. Root dip products applied immediately prior to planting included: DieHard™ Root Dip (endo/ecto mycorrhizae polymer), MycoApply® Injector Ecto (ectomycorrhizae), SoilMoist™ Fines, and Roots® Terra-Sorb® Fine Planting Gel (polymer). Cultural treatments that were applied following planting included: foliar antitranspirant spray (Wilt-Pruf® [25% di-1-p-menthane]), wood chip mulch, shade blocks (20.3 cm x 30.5 cm mesh screen), controlled release fertilizer, and biochar. Root dips did not affect tree survival or growth in any of the trials. Mulch and shade blocks increased shoot growth at several farms. Improved survival of trees under mulch was associated with improved soil moisture. Mulch did not affect foliar nitrogen (N) concentration, indicating that mulch did not ‘tie-up’ N. The application of Wilt-Pruf reduced transpiration but also reduced photosynthetic rate, resulting in a net decrease in shoot growth. Fertilization at planting significantly reduced survival on two of four sites. Overall, the results suggest that cultural treatments, especially mulch, are more likely to improve plantation establishment than root dips.
Speakers
avatar for Bert Cregg

Bert Cregg

Michigan State University
Dr. Bert Cregg is a professor of Horticulture and Forestry at Michigan State University. He conducts research and extension programming on the physiology and management of trees in landscapes and nursery and Christmas tree production.
Co-authors
RJ

Riley Johnson

Michigan State University
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
South Pacific 3

10:30am HST

PNM 1 - Evidence of Downregulation in Atmospheric Nitrogen-Fixation Associated with Native Hawaiian Sugarcane
Tuesday September 24, 2024 10:30am - 10:45am HST
The study of nitrogen fixation in sugarcane has a long history that has demonstrated high potential but with substantial variation in results. This 32-month study sought to assess the response of nitrogen fixation associated with sugarcane (Saccharum officinarum L. cvs. ‘Akoki, Honua’ula, and ‘Ula) to available soil nitrogen. Plants were grown in large pots of perlite along with a fixing and a non-fixing plant control and administered liquid fertigation with varying amounts of isotopically enriched nitrogen. Assessment of nitrogen fixation utilized nitrogen isotope tracing and acetylene reduction assay in the target and control plants. Isotope enrichment and acetylene reduction assay both indicated that nitrogen fixation peaked under low nitrogen application, and declined with higher application rates, with agreement between the two methods. These results suggest that sugarcane engages in a downregulation of nitrogen fixation under high nitrogen availability, potentially explaining the high variation in published experimental results. This suggests that nitrogen management and fertilization strategy can impact the atmospheric inputs of nitrogen in sugarcane cultivation, and the potential to improve nitrogen application efficiency in cropping systems utilizing sugarcane.
Speakers
NL

Noa Lincoln

Associate Professor - Indigenous Crops, University of Hawaii at Manoa
Noa Kekuewa Lincoln is an Associate Professor with a focus on Indigenous Crops and Cropping Systems, in the College of Tropical Agriculture and Human Resources at the University of Hawai'i at Mānoa, and the PI of the Indigenous Cropping Systems Laboratory.  He is the President and... Read More →
Tuesday September 24, 2024 10:30am - 10:45am HST
Kahili

10:30am HST

POM 1 - Performance of a reflectance spectroscopy model to predict apple fruitlet thinning efficacy
Tuesday September 24, 2024 10:30am - 10:45am HST
Post-bloom apple chemical thinning relies on the application of plant bioregulators to induce fruitlet abscission, reducing crop load to improve fruit quality and promote return bloom. Abscission rates following chemical thinner application are influenced by carbohydrate status of the tree and thus widely variable. Multiple applications are often needed for growers to reach a desired crop load. However, trees are only perceptive to chemical thinners for a 3 to 4 week period shortly after bloom. Rapid prediction of chemical thinner efficacy is critical to allow growers to make necessary applications in this narrow period of time without the risk of over-thinning. In 2021 and 2022 a predictive model using reflectance spectroscopy measured with a handheld spectrometer (Felix F-750; Felix Instruments; Camas, WA, USA) was developed to predict chemical thinner efficacy for ‘Honeycrisp’ in North Carolina, USA. This model was found to predict chemical thinner efficacy with greater than 85% accuracy as early 3 days following a chemical thinner application. In 2023 and 2024 validation of this model occurred on multiple cultivars: ‘Red Delicious’, ‘Granny Smith’, ‘Gala’, and ‘Fuji’; and in multiple growing regions: Michigan, New York, and North Carolina, USA. Performance of the developed model to predict chemical thinning efficacy in this wide range of situations will be discussed to determine commercial applicability of the model.
Speakers
JL

James Larson

Utah State University
Co-authors
LH

Laura Hillmann

Michigan State University
LG

Luis Gonzalez Nieto

Cornell University
NA
TR

Terence Robinson

Cornell University
NA
TK

Thomas Kon

North Carolina State University
NA
TE

Todd Einhorn

Michigan State University
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
Nautilus

10:30am HST

TCHG 1/ADMIN - Nurturing Knowledge: The Impact of Assuming Professional Role in Achieving Learning Objectives in Upper-Level Horticulture Courses
Tuesday September 24, 2024 10:30am - 10:45am HST
Practical experience is invaluable to students majoring in plant-related fields including horticulture. Most times students with no prior practical experience acquire the required knowledge and skills to succeed in horticulture field through college education. However, there is limited literature on the impact of courses implementing experiential learning through students assuming horticulture-related professional roles on achieving learning objectives. Hence, the current study investigated the pedagogical approach of practical learning by incorporating students undertaking management role in achieving learning objectives of upper-level horticulture courses within a classroom setting. The methodology involves implementing this student-centered activity of assuming professional role as greenhouse manager and hydroponics operation manager in two different 3000-level courses (urban horticulture and hydroponics and soilless crop production, respectively) and assessing their impact on learning outcomes. Each student assumed the role of manager for a week and experienced real-world problem solving in greenhouse and hydroponics operation management settings. Quantitative and qualitative data collection methods, including surveys, and observational analysis, are utilized to evaluate the effectiveness of the approach in enhancing students' understanding and attainment of course objectives. Preliminary findings indicate that incorporating assumption of horticulture professional role activities fosters deeper engagement, critical thinking, and practical application of theoretical concepts. Students reported increased confidence in their abilities to apply learned principles in real-world scenarios, as well as a greater appreciation for the complexities of urban horticulture and hydroponics crop production. Overall, this research highlights the potential of experiential learning strategies, such as horticulture professional role simulations, to effectively support the achievement of learning objectives while providing students with valuable insights into professional practice. Finally, the findings contribute to the ongoing discourse on innovative pedagogical approaches and their impact on student learning outcomes in higher education settings.
Speakers
SK

Shivani Kathi

Assistant Professor, Oklahoma State University
Tuesday September 24, 2024 10:30am - 10:45am HST
South Pacific 4

10:30am HST

WCPM 1 - Flaming, Cultivation, and Handweeding Weed Control in Organic Carrot Production Systems with Different Fertilizer Types
Tuesday September 24, 2024 10:30am - 10:45am HST
Weed management is a common weed management practice in organic weed control, however, this practice is expensive. Other integrated weed management practice could include flaming and cultivation. The study objective is to investigate flaming, cultivation, and hand weeding to develop an integrated weed control program in organic carrot. The study was conducted in an organic certified field at the North Florida Research and Education Center Suwanee County, Live Oak, FL. Treatments were a factorial design with 5 weed management programs and 2 fertilizer types. Weed management treatments were (1) flaming preseeding weekly cultivation, (2) flaming preseeding weekly cultivation 1 handweeding event, (3) flaming preseeding flaming preemergence weekly cultivation (4) flaming preseeding flaming preemergence weekly cultivation 1 handweeding event, (5) flaming preseeding flaming preemergence weekly cultivation 2 handweeding events. Fertilizer treatments were pelleted poultry litter and 50% feather meal 50% poultry litter. Carrot ‘Uppercut’ were seeded on December 3, 2020 and were harvested on May 3, 2021. Eight rows of carrot were planted on a 0.9 m bed top. Fertilizer was applied immediately after seeding. Weeds were counted by species in two 0.5 m2 quadrats prior to each basket weeder cultivation between the rows. Carrots were cultivated 6 times before the carrot were too large and would be injured. Fertilizer type were not different for weed counts at all dates. Cutleaf evening primrose (Oenothera laciniata) was the only weed species in the plots from the beginning of the trial through harvest. The inclusion of flaming preplant and preemergence delayed the emergence of cutleaf evening primrose, however at 6 weeks after planting all the treatments were similar. Mid-season weed species included henbit (Lamium amplexicaule) and common chickweed (Stellaria media), however, these weed species were not present late-season. Purple toadflax (Linaria purpurea) and old world diamond flower (Oldenlandia corymbosa) were the most common weed species late-season. Single handweeding had excellent control early-season, but two handweeding events controlled both the cool and warm season weeds. Early season weed control should include flaming. Between row weed management was best with cultivation. Handweeding is necessary for late season weed control when flaming and cultivation are not available.
Speakers
PD

Peter Dittmar

University of Florida
Co-authors
DT

Danielle Treadwell

University of Florida
NA
GM

Gabriel Maltais-Landry

University of Florida
NA
Tuesday September 24, 2024 10:30am - 10:45am HST
Lehua Suite

10:45am HST

CE 1 - Blue and Green Light and Temperature Interactively Regulate Growth, Morphology, Physiology, and Phytochemicals of Lettuce
Tuesday September 24, 2024 10:45am - 11:00am HST
Substituting green (G; 500-600 nm) for blue (B; 400-500 nm) light can enhance crop yield through increasing leaf expansion and photon capture in indoor farming. In addition to yield, the concentration of phytochemicals may also be influenced by varying B to G light ratios. Those responses to B and G light are primarily mediated by cryptochrome photoreceptors. However, cryptochrome activity is further dependent on temperature. We hypothesized that B and G light and temperature could interactively regulate plant morphology, physiology, and secondary metabolites, consequently impacting crop yield and nutritional quality. Two cultivars of lettuce (Lactuca sativa L.), ‘Rouxai’ and ‘Rex’, were grown under three temperatures (20, 24, and 28 ℃) and five spectral treatments composed of B, G, and red (R; 600-700 nm) light (B40G0R60, B30G10R60, B20G20R60, B10G30R60, and B0G40R60). The subscript number following each light type represents its percentage in total photon flux density (TPFD; 400-800 nm). TPFD was maintained at a constant level of 200 μmol·m-2·s-1, with R photon flux of 120 μmol·m-2·s-1 (60% of TPFD) in all treatments. Results revealed that light spectra and temperature interactively influenced plant morphology. Specifically, in Rouxai, increasing G light from 0% to 40%, coupled with decreasing B from 40% to 0%, linearly increased total leaf area at all three temperatures. Notably, the substitution of G for B light caused the greatest leaf expansion at 24 ℃ (a 64% increase at 20 ℃, a 90% increase at 24 ℃, and a 32% increase at 28 ℃). In Rex, substituting G light for B light up to 30% increased total leaf area at 20 and 24 ℃, but not at 28 ℃. Similar to Rouxai, the spectral effect on the leaf expansion of Rex was greater at 24 ℃, compared to 20 ℃. Shoot dry weight responded to spectral and temperature treatments similarly as total leaf area. Secondary metabolites (e.g., phenolics and flavonoids) and antioxidant capacity consistently decreased with increasing G light (or decreasing B from 40% to 0%), but the decline was more pronounced at warmer temperatures. Without significant interaction between light spectrum and temperature, chlorophyll and carotenoid contents decreased with increasing G light. Thus, we concluded that the proportion of B and G light and temperature interactively regulated plant morphology and secondary metabolites, ultimately affecting crop yield and nutritional quality. Our study emphasizes the importance of considering the interaction between light spectrum and temperature in optimizing production systems.
Speakers Co-authors
Tuesday September 24, 2024 10:45am - 11:00am HST
Coral 1

10:45am HST

CHEX 1 - Filling the Gaps for Informed Adoption of Carolina Strong Back Grafted Nursery: Transplanting Time and Spacing Optimization
Tuesday September 24, 2024 10:45am - 11:00am 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 pest of watermelon. In addition, recent studies have shown higher vigour of SB grafted plants than regular nursery plants. However, grafted watermelon nursery is 4-5 times more expensive than regular nursery which leads to reluctance among farmers for adoption of this effective management strategy. Further, recent trials showed that grafted plant bear fruits 7-10 days later than regulate plants leading to farmers losing early profitable watermelon market. To fill these gaps for informed adoption of SB grafted nursery, a field experiment was conducted at Blackville SC with the objective to evaluate the optimum transplanting time and density of SB grafted watermelons nursery to have equivalent fruit yield and harvesting window to that of regular nursery. The experiment comprised of three transplanting times and four transplant densities in a split plot design. We will evaluate the impact of transplanting time and transplanting density on watermelon fruit yield, fruit quality, number of fruits per plant, periodic fruit harvesting yield and plant vigour.
Speakers
SK

Sukhman Kaur

Clemson University
Co-authors
BJ

Bhupinder Jatana

Clemson University
TS

Tom Sanders III

Clemson University
NA
Tuesday September 24, 2024 10:45am - 11:00am HST
South Pacific 2

10:45am HST

MKEC - Market Research to Reinvigorate the Processed Vegetable Industry using Consumer Sensory Evaluations
Tuesday September 24, 2024 10:45am - 11:00am HST
In an effort to understand perceived quality and purchase interest in processed frozen vegetables vs. their fresh counterparts, consumer sensory evaluations were conducted with Oregon consumers (n=108, 68% female, aged 18 and over). Consumers were served blind coded samples to investigate consumer preference for fresh vs. frozen select processed vegetables in appearance, aroma, color, overall liking, flavor, and texture. Utilizing hedonic scales and just-about-right methodology, consumers both rated their liking for each and assessed the ideal sweetness, texture, and moisture content. Additionally, the survey was used to probe the best strategies for increasing consumer awareness and marketability of processed vegetables and to understand consumer purchasing behavior and motivation when it relates to buying processed vegetables. Consumers also responded to questions about quality, purchase intent and ideal packaging size for processed vegetables. Consumer perception of frozen processed broccoli, while not as high as fresh, was positive. When asked about the characteristics of produce that most influence their purchasing decisions, quality and freshness were the two most important considerations to these consumers. Seventy-five percent responded either yes or depends on the price when probed about their interest in a frozen vegetable and fruit consumer supported agriculture (CSA) model. Consumers were also asked which reasons would most convince them to join a frozen vegetable and fruit CSA. The most frequently chosen options were 1) to support the livelihoods of growers and their communities, 2) frozen produce reduces waste and 3) frozen produce tastes fresher than off season produce. These ideas could be leveraged to encourage consumers to support the purchase of processed frozen vegetables as well as support a subscription service to high quality frozen produce.
Speakers
AC

Ann Colonna

Oregon State University Food Innovation Center
Co-authors
EP

Edward Peachey

Oregon State University
NA
JM

James Myers

Oregon State University
Tuesday September 24, 2024 10:45am - 11:00am HST
South Pacific 1

10:45am HST

NUR 1 - Cultivating Control: Effective Suppression Methods for Jumping Worms in Container Nursery Production
Tuesday September 24, 2024 10:45am - 11:00am HST
Keywords: Amynthas spp., Biological Controls, Invasive Species, Soil Health, Temperate Ecosystems Jumping worms (Amynthas spp.) present a significant threat to biodiversity and overall soil health across temperate ecosystems. In forest systems, jumping worms alter ecological dynamics by impacting the organic litter layer, soil structure and chemistry, food web functionality, and nutrient cycling processes. These annual, hermaphroditic worms reproduce through parthenogenesis and inhabit the top few inches of moist soils. They survive extreme temperatures in their cocoon stage with the possibility of remaining dormant for several growing seasons. One inadvertent method of jumping worm spread is through container-grown nursery stock and horticultural substrates. In nursery production, jumping worms modify plant quality by consuming organic matter such as roots, altering substrate structure and chemistry in the container, and contributing to excessive nutrient leaching. The rapid movement of these worms may also impact consumer buying potential and preference. There are currently no products listed for controlling jumping worms in the United States, leading to challenges with the management of their spread. We hypothesize that control methods not yet listed for jumping worms in the United States have the potential to effectively suppress jumping worm populations in container-grown crops. Our objective was to further evaluate chemical and biological approaches for managing jumping worms in container nursery production systems. Treatments included a non-treated control, BotaniGardⓇ (2 Tbsp/gal), Thiophanate-methyl fungicide (0.625 mL/400mL), Sodium lauryl sulfate (2 mL/L ), Cedarwood oil (1.5625 mL/L), ConserveⓇ (0.317 mL/400mL), Castaway 3-0-1 Tea Seed Meal Fertilizer (2.7 g/pot), Slug MagicTM (0.5 oz/pot), and SevinⓇ (8.75 mL/400mL). The results of this work suggest differential efficacy between treatments and highlight options with potential for application in horticultural production. Identifying effective control methods benefits the scientific community and the horticultural industry by providing a foundation for future research activities centered on jumping worm management as well as limiting their spread through horticultural products. These findings support growers by outlining potential management practices that demonstrate efficacy for controlling jumping worms in the Amynthas genus.
Speakers
avatar for Jenna Simon

Jenna Simon

Research Assistant, University of Minnesota - Twin Cities
Jenna Simon studies invasive jumping worms (Amynthas spp.) with a focus on containerized production. She has a strong passion for the nursery profession and strives to bridge the gap between horticulture and ecology. She believes that ecology should be viewed from many different lenses... Read More →
Co-authors
BM

Brandon Miller

University of Minnesota - Twin Cities
EB

Erin Buchholz

University of Minnesota
NA
JG

Josef Gorres

University of Vermont
NA
MN

Maryam Nouri Aiin

University of Vermont
NA
Tuesday September 24, 2024 10:45am - 11:00am HST
South Pacific 3

10:45am HST

PNM 1 - Nitrate Leaching Potential of UAN and Organic Soybean Extract Fertilizers Applied to Lettuce
Tuesday September 24, 2024 10:45am - 11:00am HST
In California, lettuce (Lactuca sativa) production generates over $1.8 billion in revenue. As a leafy green vegetable, Nitrogen (N) fertilizer applications can reach as much as 280 kg N/ha. The relative shallow root systems and frequent irrigation can enhance Nitrate (NO3) Leaching Potential (NLP) when the crop is grown on Sandy Loam soil. Because of economic, health, and environmental concerns, growers are exploring the option of using organically approved fertilizers such as water-soluble N derived from soy protein hydrolysate (GS) as an alternative to Urea Ammonium Nitrate (UAN). The objective of this study was to compare the NLP of equivalent rates of UAN and GS applied to a (1) soil-column study (Phase 1) and (2) greenhouse lettuce crop with 3 Irrigation regimes x 2 Fertilizers x 4 Rates as a factorial experiment replicated four times (Phase 2). In the Phase 1 study, approximately 2,150 ml of water containing a chloride (Cl) tracer and fertilizers at rates of 0, 56, 112, and 168 kg N/ ha were applied to a fixed volume of soil at a bulk density of 1.35 g/cm3. The chloride concentrations in the leachate from both fertilizer treatments were similar, and the water balance accounted for 95% of the solution applied. The concentration and amount of NO3 in the leachate collected from soil treated with GS were lower or at least equal to that obtained from the soils treated with UAN. In contrast, the amount of residual soil NO3 was significantly higher in the soil receiving the UAN, ranging from 2 to 4 times as the application rates increased from 56 to 168 kg N/ha, respectively, implying a relatively higher NLP for the UAN. In the case of the lettuce experiment (Phase 2), there were no significant differences in the chlorophyll content based on the choice of fertilizer or application rates. Lettuce yields, expressed on a dry matter basis, were not significantly (p=0.11) different for fertilizer type, with similar fertilizer rate response curves being obtained for both UAN and GS. Finally, the mean %N and %C in the lettuce leaves were 3.22% and 40%, respectively, regardless of whether the lettuce was grown with synthetic UAN or organically derived soybean hydrolysate (GS). These preliminary findings justify the need to investigate further the impact of higher irrigation rates and even saturated conditions on the NLP of vegetables subjected to the two fertilizers used in the current study.
Speakers
avatar for Dave Goorahoo

Dave Goorahoo

Professor, California State University, Fresno
Co-authors
FC

Florence Cassel S

California State University, Fresno
GS

Govind Seepersad

The University of the West Indies- Trinidad
NA
KG

Konner Gilman

California State University, Fresno
NA
WC

Wesley Chun

Grower's Secret Inc.
NA
Tuesday September 24, 2024 10:45am - 11:00am HST
Kahili

10:45am HST

POM 1 - Overexpression of the Coding Sequence of Ma1 Decreases Fruit Acidity in ‘Royal Gala’ Apple
Tuesday September 24, 2024 10:45am - 11:00am HST
Vacuolar accumulation of malic acid, the predominant organic acid in apple (Malus domestica) and many other fleshy fruits, largely determines fruit acidity, a key trait for fruit taste and flavor. ALUMINUM-ACTIVATED MALATE TRANSPORTER 9 (ALMT9/Ma1) underlies a major genetic locus, Ma, for fruit acidity in apple. A natural mutation at base 1455 leads to a pre-mature stop codon that truncates the Ma1 protein by 84 amino acids to ma1, and this truncation significantly reduces Ma1’s malate transport activity by disrupting a conserved C-terminal domain, leading to low fruit acidity in recessive homozygous ma1ma1 genotypes. However, it remains unclear how Ma1 functions to transport malate across the tonoplast membrane. When the coding sequence of Ma1 was overexpressed in ‘Royal Gala’ apple (Ma1ma1) to determine its in planta function, to our surprise, the transgenic fruit had drastically reduced fruit acidity compared with the wild-type (WT). This led us to uncover that Ma1 undergoes alternative splicing. Two isoform proteins are generated by alternative splicing: Ma1beta being 68 amino acids shorter with much lower expression than the full-length protein Ma1alpha. Ma1beta does not transport malate itself, but interacts with the functional Ma1alpha, creating synergy with Ma1alpha for malate transport in a threshold manner when Ma1beta is equal to or exceeds 1/8 of Ma1alpha. In WT ‘Royal Gala’, Ma1 operates at this threshold. Overexpression of Ma1alpha triggers feedback inhibition on the native Ma1 expression via transcription factor MYB73, decreasing the Ma1beta level well below the threshold that leads to significant reductions in Ma1 function and malic acid accumulation in fruit. Overexpression of Ma1alpha and Ma1beta or genomic Ma1 increases both isoforms proportionally and enhances fruit malic acid accumulation. These findings reveal an essential role of alternative splicing in Ma1-mediated malate transport underpinning apple fruit acidity.
Speakers
LC

Lailiang Cheng

Cornell University
Co-authors
CL

Chunlong Li

Cornell University
NA
KX

Kenong Xu

Cornell University
NA
MZ

Mengxia Zhang

Cornell University
MP

Miguel Pineros

Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University
NA
SK

Srinivasan Krishnan

Cornell University
NA
Tuesday September 24, 2024 10:45am - 11:00am HST
Nautilus

10:45am HST

TCHG 1/ADMIN - Mid-semester Teaching Evaluations to Enhance Course Communication
Tuesday September 24, 2024 10:45am - 11:00am HST
Effective course communication is critical to foster a positive learning environment. One way communication can be improved is by scheduling a mid-semester teaching evaluation to capture student perspectives on what aspects of the course are going well and what could be improved. By providing students with a platform to express their opinions mid-semester, instructors have access to timely feedback to improve their teaching methods while the course is still ongoing. In this study, a mid-semester evaluation was conducted in an asynchronous, online Fruit Production course with 27 undergraduate students and one graduate student. The students were given a link to an online survey to respond to specific questions about the course structure and an open-ended question for actionable feedback. The evaluations were voluntary, anonymous, and confidential to solicit honest student responses. By having students respond individually, it was possible to capture unique student viewpoints and consensus statements among the class with a 96% response rate. Students responded positively to some aspects of the course such as the use of hands-on assignments; however, course modifications were made only in response to critiques. The most notable feedback was 14.8% of the students responding that the course material did not feel manageable with 44.4% of the class spending more than the expected time on lecture assignments. Additionally, students requested more clarity on the assigned projects. The survey responses were summarized for the students along with specific ways the course would be adjusted to better meet the student's needs and enhance their learning experience. To address the students’ concerns, the course workload was reduced, and students were provided with a clear explanation of their expected level of engagement. Recorded instructions along with detailed written descriptions and templates of the projects were also provided to aid in transparency about course assignments. Overall, students were well receptive of the mid-semester evaluation and reported it improved their satisfaction with the course. Because students found the mid-semester evaluation valuable to their learning, the course modifications will be maintained for future semesters.
Speakers
avatar for Rebekah Maynard

Rebekah Maynard

University of Georgia
Tuesday September 24, 2024 10:45am - 11:00am HST
South Pacific 4

10:45am HST

WCPM 1 - Tolerance of Peppermint to Herbicides Applied Post-Harvest
Tuesday September 24, 2024 10:45am - 11:00am HST
After harvest, peppermint is vulnerable to weed interference due to the loss of crop canopy. However, few herbicides are registered for use during this critical time in the production cycle. In response to this, we conducted research trials in 2023 at two commercial peppermint production fields in Indiana (North Judson and Fair Oaks) to determine peppermint response to preemergence and postemergence herbicides. Preemergence herbicide treatments included Zidua (1.84 fl oz/a), Optogen (3 fl oz/a), Spartan (4 fl oz/a), Chateau EZ (4 fl oz/a), Dual Magnum (1 pt/a), Fierce EZ (10 fl oz/a), and Tenacity (3 fl oz/a). Postemergence herbicide treatments included Basagran (2 pt/a), Reviton (2 fl oz/a), Tough (24 fl oz/a), Sharpen (2 fl oz/a), Anthem Flex (4.5 fl oz/a), Aim (1 fl oz/a), and Tough (24 fl oz/a) plus either Optogen (1.5 fl oz/a), Tenacity (1.5 fl oz/a), or Basagran (2 pt/a). Visible crop injury on a scale of 0 (no injury) to 100% (crop death), as well as crop height, was recorded every other week after treatment. Eight weeks after treatment, the greatest injury was observed was from the Group 14 herbicides: Reviton (81-84%), Sharpen (81-88%), and Aim (33-54%). Injury from Group 27 herbicides, Optogen and Tenacity, was more severe at Fair Oaks (63% and 64%, respectively) than at North Judson (28% and 12%, respectively). However, combining a half rate of these herbicides with Tough greatly increased crop injury at both locations (>73%). Injury from Chateau EZ and Fierce EZ differed by location; injury was lower at North Judson (13% and 7%, respectively) than at Fair Oaks (42% and 55%, respectively). Crop injury from Zidua, Dual Magnum, Spartan, Basagran, and Tough plus Basagran were similar to, or less than, Tough applied alone (the registered grower standard). Peppermint height and end-of-season aboveground biomass followed similar trends.
Speakers
avatar for Stephen Meyers

Stephen Meyers

Associate Professor, Purdue University
Co-authors
CL

Carlos Lopez Manzano

Purdue University
NA
CC

Celia Corado Mendoza

Purdue University
NA
EC

Emmanuel Cooper

Purdue University
NA
JA

Jeanine Arana

Purdue University
JC

Josue Cerritos

Purdue University
NA
Tuesday September 24, 2024 10:45am - 11:00am HST
Lehua Suite

11:00am HST

CE 1 - Supplemental Blue and UV-B Light Enhances Amino Acid-Derived Flavor Compounds in Greenhouse-Grown Tomatoes
Tuesday September 24, 2024 11:00am - 11:15am HST
Tomato production under controlled environmental conditions presents challenges due to the selective permeation of solar radiation within enclosed structures or the limited wavelengths produced by artificial light sources. Despite these challenges, growers increasingly opt for such production systems due to the enhanced uniformity and yield of fruit compared to open-field cultivation. However, controlled environment conditions, particularly greenhouses, often limit specific wavelengths of light, including blue and UV-B radiation. This limitation has the potential to alter flavor and overall fruit quality. Therefore, the present investigation examined how supplemental blue and UV-B light, independently and in combination, influence the levels of amino acid–derived flavor compounds, particularly those derived from branched-chain and aromatic amino acids, in two tomato varieties, Plum Regal (PR, commercial) and TAM HOT-Ty (THT, Texas A
Speakers
SB

Samikshya Bhattarai

Graduate Research Assistant, Texas A&M University
Co-authors
Tuesday September 24, 2024 11:00am - 11:15am HST
Coral 1

11:00am HST

CHEX 1 - Substrate Hydro-Physical Properties in Soilless Agriculture: Investigating the Role of Container Geometry on Substrate Air and Water Profiles
Tuesday September 24, 2024 11:00am - 11:15am HST
The cultivation of specialty crops in soilless growing systems has emerged as a pivotal practice in modern agriculture. The adoption of container-based production, particularly through soilless culture systems, is witnessing a significant uptrend among specialty crop producers. The challenges associated with cultivating plants in containers are extensively documented, particularly in navigating the delicate balance between insufficient and excess water. Shallow containers often result in excessive water, limiting air availability, while the confined volume of containers imposes restrictions on the water supply for optimal plant growth. Air and water capacity (AWC) model was utilized to determine basic physical properties, such as total porosity (TP), air space (AS), and container capacity (CC), for a substrate in specific-sized and shaped containers. AWC models offer a comprehensive tool for estimating hydrophysical properties across multiple substrate/container combinations simultaneously. The existing literature lacks direct reporting on these specific container types, primarily focusing on modeling the air and water profiles of traditional containers that the floriculture industry utilized, leading to a notable gap in data concerning the dynamic interplay between air and water profiles within these containers and their impact on the rooting environment. 19 substrates and 30 commercially used container selections were modeled to understand their air-water profiles. The results underscore the effect of container geometry on substrate air-water profiles, necessitating different management approaches for the same substrate in different containers. Container height stands out as a critical factor, exerting a substantial influence on substrate characteristics and subsequently affecting air and water values.
Speakers
BS

Brandan Shur

PhD Student, Virginia Tech
Co-authors
BJ

Brian Jackson

North Carolina State University
NA
WF

William Fonteno

North Carolina State University
NA
Tuesday September 24, 2024 11:00am - 11:15am HST
South Pacific 2

11:00am HST

MKEC - Consumer Preferences for Commercially Available Poinsettia Cultivars in South Mississippi
Tuesday September 24, 2024 11:00am - 11:15am HST
Mississippi State University’s South Mississippi Branch Experiment Station began hosting a Poinsettia Open House in 2021. The goal of this event was to provide retail consumers and commercial producers with up-to-date information about poinsettias currently available for production. The first two events were single day events in early December (December 2, 2021 and December 1, 2022). Due to the success of the first two events, a decision was made to expand the event to two days in 2023 (December 1-2, 2023) and include educational presentations. Photography backdrops with poinsettia enhancements have been provided each year for anyone wishing to use them for Christmas card photos or to simply commemorate their visit. Attendees were given the opportunity to participate in several surveys at each open house. Participants completing a survey were allowed to choose and take home a poinsettia. Attendees were allowed to walk through the production greenhouse, view the poinsettia cultivars, and record their personal favorites. Participants viewed 35, 52, and 40 poinsettia cultivars in 2021, 2022, and 2023, respectively. In 2021, attendees identified Ice Punch, Orange Glow, Premium Ice Crystal, Superba New Glitter, and Autumn Leaves as their top five favorites. In 2022, attendees identified Superba New Glitter, Ice Punch, Norwin Orange, Prestige Maroon, and Grande Italia as their top five. In 2023, attendees identified J’Adore Soft Pink, Premium Picasso, Christmas Feelings Merlot, Christmas Spirit, and Tapestry as their top five.
Speakers
PK

Patricia Knight

Mississippi State University
Co-authors
AB

Anthony Bowden

University of Arkansas
BP

Ben Posadas

Mississippi State University
NA
CC

Christine Coker

Mississippi State University
NA
HW

Haley Williams

Mississippi State University
JD

James DelPrince

Mississippi State University
NA
JR

Jenny Ryals

Mississippi State University
SL

Scott Langlois

Mississippi State University
Tuesday September 24, 2024 11:00am - 11:15am HST
South Pacific 1

11:00am HST

NUR 1 - Effects of Water Quality and Fertilization Practices on Container Tree Growth in Nurseries
Tuesday September 24, 2024 11:00am - 11:15am HST
The Covid-19 pandemic and ensuing lockdowns led to an increase in revenue and production for green industry products in early 2020. In Study 1. an evaluation of fertigation (liquid feed, quick release) and controlled release fertilizers (CRFs, slow release) were applied to container-grown (7 gallon) live oak (Quercus virginiana) and Nutall oak (Quercus nuttallii) trees (100% Liquid feed, 0% CRF, 67% Liquid feed, 33% CRF, 33% Liquid feed, 67% CRF, 100% Liquid feed, 0% CRF). Live oak trees fertilized with CRFs had increased stem calipers (>30%). Nuttall stem caliper and height were significantly increased by 62% and 58%, respectively, with substrate incorporation of CRFs. Live oak tree height was increased by 35% and stem caliper when CRFs were incorporated. In study 2, the effect of alkaline water quality on live oak tree production was initiated at a nursery in Point Coupee Parish. Ca and Mg sources were used to study the impact of water quality on live oak tree container-growth and study the benefits of using different rates of lime and gypsum [0% dolomitic lime (Ca, Mg), 100% gypsum (Ca) Epsom salt (Mg), 25% dolomitic lime (Ca, Mg), 75% gypsum (Ca) Epsom salt (Mg), 50% dolomitic lime (Ca, Mg), 50% gypsum (Ca) Epsom salt (Mg), 75% dolomitic lime (Ca, Mg), 25% gypsum (Ca) Epsom salt (Mg), 100% dolomitic lime (Ca, Mg) 0% dolomitic lime]. Live oak tree growth measurements increased with the reduction of dolomitic lime and increase of Epsom salt and gypsum applications. Leaf Na content was significantly reduced using higher proportions of gypsum and Epsom salt. Soil pH was also reduced by more than 1 pH unit after a growing season. Soil pH did increase when irrigated with highly alkaline water. Growers using alkaline water need to manage irrigation water and soil pH and consider using gypsum and Epsom salt reducing dolomitic lime rates as a source of Ca and Mg. All Ca and Mg sources provided greater than the threshold levels of leaf Ca and Mg content.
Speakers
ZD

Zachary Davis

LSU AgCenter
Co-authors
EB

Edward Bush

LSU AgCenter
Tuesday September 24, 2024 11:00am - 11:15am HST
South Pacific 3

11:00am HST

PNM 1 - Evaluating the N Status of Tomato Supplied with Soluble and Controlled-release Urea Formulations
Tuesday September 24, 2024 11:00am - 11:15am HST
Matching crop nitrogen (N) demand and supply is necessary to increase crop N use efficiency (NUE) and reduce environmental impact. Proximal optical sensors such as the Soil Plant Analysis Development (SPAD) meter have been found to be useful in monitoring the crop N status, providing insight into the effects of N fertilization practices in cropping systems. High N rate applications are common in conventional tomato production, where loss of N, more specifically NO 3 - , from the rootzone can decrease water quality. Thus, optimal N management of fertigated vegetable crops requires frequent and rapid assessment of the crop N status to quickly adjust application of N when required. A two-year field study was conducted in north Florida to evaluate the crop N status based on N fertilization practices associated with soluble urea and polymer coated controlled-release urea (CRU) for fall and spring tomato (‘HM 1823’) grown in sandy soils under a plastic-mulched bed system. In addition to a no N fertilizer treatment, three urea N sources [one soluble source and two polymer-coated CRU sources with different N release durations of 60 (CRU-60) and 75 (CRU-75) days] were applied at three N rates (140, 168, and 224 kg ha -1 ), where 224 kg ha -1 is the recommended N rate for tomato production in Florida. Soluble urea was split applied weekly over the 13-week growing season, whereas CRUs were applied at the full rate once at preplant. For all seasons, biweekly SPAD meter readings were taken and sampling periods coincided with the vegetative, flowering, fruit set, fruit growth, and harvest growth stages. Overall, minimal differences in tomato N status were observed among the tested N rates and N sources, indicating that all N fertilizer practices tested maintained similar N use. Thus, irrespective of the N source, this study found that tomato N demands could be met at a 38% reduction of the recommended N rate, potentially enhancing NUE in tomato production systems cultivated on sandy soils in north Florida.
Speakers
LJ

Laura Jalpa

University of Florida
Co-authors
RM

Rao Mylavarapu

University of Florida
NA
Tuesday September 24, 2024 11:00am - 11:15am HST
Kahili

11:00am HST

POM 1 - Carbohydrate And Nitrogen Storage Are Inversely Affected By Crop Load For 'Honeycrisp' And 'Gala' Apples
Tuesday September 24, 2024 11:00am - 11:15am HST
Biennial or alternate bearing is characterized by an abundance of blooming and fruiting in “on” years and a lack of blooming and fruiting in “off” years. Biennial bearing in fruit tree production has been extensively studied. However, it continues to be problematic in certain crops and cultivars. Fundamental physiological mechanisms controlling this behavior are still poorly understood. Along with carbohydrates in plant tissues, reserve nitrogen influences early-season growth in apples, with the percent contribution of reserve nitrogen being dependent on the current nitrogen supply. Because flowering and fruit set occur in spring alongside bud break, reserve nitrogen can significantly affect these processes too. We sought to understand the role carbohydrate and nitrogen storage in various plant tissues has on biennial bearing for ‘Honeycrisp’ apple. Apical buds, terminal shoots, and one-year-old spurs were collected in 2022
Speakers
TC

Thiago Campbell

Washington State University
Co-authors
LK

Lee Kalcsits

Washington State University
NA
Tuesday September 24, 2024 11:00am - 11:15am HST
Nautilus

11:00am HST

TCHG 1/ADMIN - Evaluation of Packback - an AI-Assisted Writing Program for Student Assignments in Horticulture Courses
Tuesday September 24, 2024 11:00am - 11:15am HST
The use of Artificial Intelligence (AI)-supported writing tools in higher education has been a hot topic since OpenAI introduced ChatGPT in 2022. These AI-supported writing tools are intended to analyze written materials and provide feedback on the writing , including grammar, vocabulary, content, and structure. Packback (https://www.packback.co/) is one of the AI-supported online platforms that intends to improve student curiosity, communication skills, and critical thinking, and provides ease of assessment for instructors. Two instructors in the Department of Horticultural Sciences at Texas A
Speakers
NM

Navreet Mahal

Instructional Assistant Professor, Texas A&M University
Co-authors
Tuesday September 24, 2024 11:00am - 11:15am HST
South Pacific 4

11:00am HST

WCPM 1 - Developing a Biobased, Compostable Mulch that Crops Grow Through
Tuesday September 24, 2024 11:00am - 11:15am HST
Plastic mulch films and geotextile landscape fabrics are not compatible with specialty crops grown at high densities with narrow in-row spacing. As a result, many growers resort to hand weeding these specialty crops, including leafy greens, carrots, and matted-row strawberries. Our objective was to develop and test value-added weed barrier mulches designed specifically for these crops to grow on and root through. We have conducted 13 trials across 3 crops (lettuce, carrot, and strawberry) and 3 years to evaluate 9 different biobased, compostable weed barrier mulches (BCMs) that include polylactic acid (PLA) resin. The BCMs tested varied in weight basis and material composition including: 1) PLA-only (80, 120, and 180 g/m2), 2) PLA embedded organic fertilizers (soybean meal and composted turkey litter; 150 and 210 g/m2), and 3) PLA paper (105 and 210 g/m2). The BCMs are installed in the field like a typical mulch film roll but are then covered with a 1 to 2.5 cm layer of compost (or other weed-free media) and crop seeds. Data was collected to evaluate effects of BCMs on weed density, soil nitrogen availability, moisture, and temperature, microbial abundance, and crop establishment, yield, and quality. Across all crops and site-years, BCMs reduced weed emergence by 80% to 97% compared to bare soil, and weed suppression was best in PLA paper. The BCMs immobilized some available soil nitrogen and embedded fertilizers in the BCM did not affect this outcome. In carrot, BCMs increased mycorrhizal fungi abundance by up to 59% compared to bare soil. In strawberry, BCMs increased crop canopy area by up to 51%. Yields were usually not different between BCMs and bare soil because weeds were removed weekly after counting. However, poor seedling establishment on BCMs due to heavy rainfall after planting in 2022 reduced carrot yield by 13% and lettuce yield by 20%. To address this issue, lettuce in 2023 was planted in two shallow seed furrows filled with compost on the BCM (instead of broadcast planting across the entire BCM bed top as in previous years). Lettuce establishment in the furrows was two times greater than in bare soil due to improved tilth and reduced erosion, and yield was not different from bare soil. Volumetric soil moisture in BCM compost seed furrows was 27.1% compared to 35.7% in bare soil, highlighting differences in texture and the importance of irrigation in the BCM system during establishment.
Speakers
SW

Samuel Wortman

University of Nebraska - Lincoln
Co-authors
CW

Caleb Wehrbein

University of Nebraska - Lincoln
CP

Chris Proctor

University of Nebraska - Lincoln
NA
CR

Claudio Rojas

University of Costa Rica
NA
EJ

Elizabeth Jeske

University of Nebraska - Lincoln
NA
IK

Ignatius Kadoma

3M Company
NA
LD

Lisa Durso

USDA ARS
NA
MU

Manuel Umana

University of Costa Rica
NA
ML

Mia Luong

University of Nebraska-Lincoln
NA
RD

Rhae Drijber

University of Nebraska - Lincoln
NA
Tuesday September 24, 2024 11:00am - 11:15am HST
Lehua Suite

11:15am HST

CE 1 - Characterizing the effect of blue light on water relations of unrooted cuttings during indoor acclimation
Tuesday September 24, 2024 11:15am - 11:30am HST
Managing water loss of unrooted cuttings (URC) during acclimation is critical to decrease crop losses and shorten rooting time. Vertical indoor propagation (VIP) systems that use indoor-farming technologies enable the opportunity to optimize the environment for URC acclimation. However, recommend environmental setpoints for VIP systems are unknown. Light quality affects various morphological and physiological processes in plants, and blue light in particular, has an effect on stomatal opening and plant size, both of which regulate water relations of plants. Therefore, the objective of this study was to characterize short-term effects of increasing percentages of blue light on water relations of Chrysanthemum ‘Crystal Bright’ and Begonia ‘Dark Britt’ URC. Four light-quality treatments were evaluated: 15%, 30%, 45%, or 60% blue light. All treatments provided a photosynthetic photon flux density of 70 µmol·m–2·s–1 delivered by broadband and monochromatic-blue light-emitting diode fixtures. Ambient temperature, relative humidity, and carbon dioxide concentration were set at 22 °C, 70%, and 420 μmol·mol–1. Water uptake and water loss were evaluated by placing individual URC in vials with and without water, and exposing them to each treatment for 24 or 48 h, respectively. Changes in water loss were also recorded at various intervals for 24 h. Water uptake of Chrysanthemum linearly increased as blue-light percentages increased. In contrast, water uptake followed a quadratic response for Begonia, which peaked at 45% blue light. Water loss also followed a quadratic response for begonia, with increasing values up to 30% blue light. Water loss of Chrysanthemum followed linear response to increasing blue light. After 24 h, water loss of Chrysanthemum linearly increased with increasing blue light, from 0.65 to 0.76 g under 15% and 60% blue light, respectivey. There were no treatment differences for stomatal conductance, but leaf vapor pressure deficit linearly increased with increasing blue light, regardless of species. These findings show that blue light affects water relations of URC, which should be considered when making lighting recommendations for VIP systems.
Speakers
AS

Ana Sofia Gomez

Purdue University
Co-authors
CG

Celina Gomez

Purdue University
Tuesday September 24, 2024 11:15am - 11:30am HST
Coral 1

11:15am HST

CHEX 1 - Kenaf (Hibiscus cannabinus) Compost As An Alternative To Peat
Tuesday September 24, 2024 11:15am - 11:30am HST
Global growing media demand is projected to increase 400% by 2050. Growers are interested in alternative substrates due to the restrictions placed on peat harvesting, as well as transportation and supply chain issues associated with peat. Kenaf (Hibiscus cannabinus), a tropical fibrous plant that was grown and composted in Florida, was evaluated to determine its potential as a horticultural substrate. Research trials were conducted in South Florida to determine effectiveness of kenaf as an alternative substrate for seed germination and plant establishment when compared to a commercially available compost and commonly used growing media. Seed germination trials consisted of planting arugula (Erica sativa) in seed trays filled with either (1) kenaf compost [KC], (2) commercially available compost [CC], or (3) ProMix HP [PM]. Germination was monitored daily, and mean emergence was determined. To evaluate plant establishment, a container trial was conducted using Lantana (Lantana camara) plants that were originally planted in Metro-Mix and transplanted from 1-gallon to 3-gallon plastic containers filled with either KC, CC or PM. Plant visual quality, percent wilt and volumetric water content(VWC) were evaluated weekly and root biomass was determined when plants were deconstructed at the end of the three-month trial. Results show that there were no treatment differences for percent seed emergence of arugula, with all emergence reaching over 80%. Plant establishment in the first field trial found KC and CC treatments increased VWC when compared to PM. Higher visual quality ratings of plants in KC and CC substrates may be explained by the increase in VWC. Lantana plants transplanted and grown in KC were uniform and grew equally as well as CC and better than PM on 13 of 14 rating dates. These data show there is no difference in arugula seed emergence when planted in CC, PM or KC. Lantana establishment in KC was comparable in CC and better than in PM growing media.
Speakers
avatar for Shawn Steed

Shawn Steed

University of Florida
Co-authors
AW

AC Wilkie

University of Florida
NA
CA

Conner Austin

University of Florida
DC

DG Clarik

University of Florida
NA
EB

E Babaeian

University of Florida
NA
GL

G Landry- Maltais

University of Florida
NA
LF

Liz Felter

University of Florida
NA
MM

mica mcmillan

University of Florida
NF

N Franklin

University of Florida
NA
Tuesday September 24, 2024 11:15am - 11:30am HST
South Pacific 2

11:15am HST

MKEC - Understanding the Characteristics of Ethnic Markets and Help Small Growers to Find Niche
Tuesday September 24, 2024 11:15am - 11:30am HST
Many small and socially disadvantaged producers grow fruit and vegetables. These farmers start small to satisfy family needs and support a preferred lifestyle. However, many small and socially disadvantaged farmers aim to be economically sustainable and want to create a feasible operation rooted in their communities. Since 2016, we have gathered information from over 3,000 small and socially disadvantaged farmers in the Southeastern region of the US who seek opportunities to improve wealth and health for individuals and communities. Information includes types of operations, family compositions, and needs of training and assistance. In particular, many of these farmers went through a series of experiential training programs to grow medicinal crops originated in Asia. These specialty fruit and vegetables are not familiar to most of the local farmers, and these specialty fruit and vegetables have high potential to serve as medicinal crops based on scientific studies. This presentation will introduce the components in this series of training linking production to market, financial assessment, risk evaluation, and niche opportunities to improve long-term health outcomes. The presentation will focus on connections and characteristics of ethnic markets, where most of these specialty fruit and vegetables are sold to diverse populations, from cultural and health perspectives. Market prices, consumer behaviors, and communication strategies will also be shared as examples to support small and socially disadvantaged farmers in breaking the barriers to access the ethnic market. Since 2016, this training program has assisted more than 1,000 producers to grow Asian medicinal crops, and successfully engaged in market activities serving diverse customers across the US.
Speakers
avatar for ChyiLyi Liang

ChyiLyi Liang

WK Kellogg Distinguished Professor and Director of Center for Environmental Farming Systems, NCA&T
My work involves multifunctional agriculture (integrations across production, value added, agritourism, and community engagement), interdisciplinary food systems, and entrepreneurship in general. My programs serve farmers, community organizations, and government agencies particularly... Read More →
Tuesday September 24, 2024 11:15am - 11:30am HST
South Pacific 1

11:15am HST

PNM 1 - Understanding Nitrogen Uptake Potential of Two Wetland Plants Under Varied Water Temperatures and Nitrogen Concentrations
Tuesday September 24, 2024 11:15am - 11:30am HST
Excessive use of commercial fertilizers in nursery production results in substantial fertilizer runoff, leading to surface and groundwater contamination. Therefore, to prevent contamination and comply with regulations, irrigation return flow (runoff water) is generally collected in a retention pond before it can be safely discarded or released. Nitrogen, applied as nitrate compounds is among the highest used fertilizer and is prone to leaching and runoff. Employing a phytoremediation strategy to remediate irrigation return flow (runoff water) has the potential to lower nitrate concentrations in water before release. In this study, we assessed the suitability of growing Helianthus maximiliani (maximilian sunflower) and Asclepias speciosa (showy milkweed) in a floating treatment wetland system (FTW) and evaluated the nitrate uptake capacity of these plants grown in three different nitrogen concentrations i.e., 10, 20, and 30 mg/L and two water temperatures of 75°F and 85°F. Increasing water temperature increased growth index for both species and increased dry weight for Asclepias speciosa. However, for Helianthus maximiliani, increasing temperature had a lesser effect on total dry weight. The accumulation of nitrate nitrogen in plant tissue was higher in Helianthus maximiliani at the nitrate nitrogen concentration of 20 mg/L under both temperature treatments. However, in Asclepias speciosa, the accumulation of nitrate nitrogen in plant tissue was higher at the high temperature treatment of 85⁰F and 20 mg/L nitrate nitrogen concentration. The nitrate nitrogen uptake from both plants in this study indicated suggests that Helianthus maximiliani ‘maximilian sunflower’ and Asclepias speciosa ‘showy milkweed’ can be grown as FTW and be used to remove nitrogen from a nursery retention pond.
Speakers
avatar for Saroj Burlakoti

Saroj Burlakoti

Utah State University
Co-authors
SP

Shital Poudyal

Utah State University
NA
Tuesday September 24, 2024 11:15am - 11:30am HST
Kahili

11:15am HST

POM 1 - Striking the Right Balance: Innovative PGR Strategies for Fruit Drop Mitigation and Color Enhancement in Apples
Tuesday September 24, 2024 11:15am - 11:30am HST
In apple orchards, addressing pre-harvest fruit drop in early-maturing, commercially valuable cultivars like ‘Honeycrisp’ and ‘Gala’ is crucial. This issue is largely linked to ethylene, a ripening hormone that, despite its role in enhancing fruit qualities, triggers premature fruit drop. From 2018 to 2021, extensive field trials were conducted across commercial and experimental orchards to refine the application of two ethylene-inhibiting products, ReTain (AVG-15%) and Harvista (1-MCP-1.3%), in mitigating this challenge in ‘Gala’ apples. Our findings confirmed AVG’s effectiveness in reducing fruit drop and stem-end splitting; however, AVG application consistently resulted in diminished fruit coloration. In the subsequent seasons of 2023 and 2024, our research pivoted towards identifying plant growth regulator (PGR) formulations that could balance the dual objectives of minimizing fruit drop and preserving color development in ‘Honeycrisp’ and ‘Gala’ apples. Key findings include: a) the multiple applications of Accede (ACC-10%) and Motivate (Ethephon-21.7%) starting from three weeks before harvest significantly enhanced red color formation in ‘Honeycrisp’ and ‘Gala’ apples, surpassing control and ReTain treatments, though Motivate increased the rate of fruit drop; b) ReTain, both alone and in combination with Accede, notably reduced fruit drop, with the ReTain-Accede mix also enhancing fruit coloration; c) combining ReTain and Motivate neither decreased fruit drop nor enhanced color; d) the positive impact of the ReTain-Accede mix on color was biochemically and molecularly validated; e) Accede's color-enhancing effect appears to be ethylene-independent. This research underscores the potential of specific PGR mixes in achieving a harmonious balance between reducing fruit drop and enhancing fruit coloration.
Speakers
avatar for Sherif M. Sherif

Sherif M. Sherif

Associate Professor, Virginia Tech
Dr. Sherif M. Sherif is an Associate Professor at Virginia Tech, where he channels his fervent zeal for life sciences and educational outreach into his specialization in tree fruit physiology and molecular biology. His career is defined by a dedication to overcoming the biological... Read More →
Co-authors
KJ

Khalil Jahed

Virginia Tech
NA
MT

Mohammad Tipu

Virginia Tech
NA
Tuesday September 24, 2024 11:15am - 11:30am HST
Nautilus

11:15am HST

TCHG 1/ADMIN - Evolution Of An Undergraduate Tropical Crop Production Systems Course
Tuesday September 24, 2024 11:15am - 11:30am HST
TPSS 300 Tropical Production Systems is a four-credit undergraduate crop production course. It has two lectures and one lab period a week. In Spring 2023, there were 16 undergraduate students registered for this every Spring offered course—12 TAE students, one NREM student, one Interdisciplinary Studies student, one Botany student, and one Hawaiian student. In Spring 2024, there were nine undergraduate students—six TAE students, one Botany student, one Journalism student, and one Elementary Education & Special Education student. The objective is to describe the improvements made to TPSS 300 based on student interests and emerging new technologies and disciplines in horticulture. Various teaching techniques were used including flipped classroom, small group discussions, class discussions, in-class activities, lectures, guest speakers, field trips, YouTube videos, and laboratories. With a BYOD format, students could review assigned materials and look up information on the Internet to aid group discussions. New topics were added such as agricultural drone technology and crop sensors and equipment for monitoring plant status. Besides inviting our department graduate students as guest speakers, department extension agents and faculty and faculty and graduate students from other departments were invited. A TPSS faculty with another department’s faculty discussed the regulations for drone use and gave a demonstration of flying drones. The TPSS graduate students spoke on breadfruit tissue culture and industrial production in Hawaii; innovative agroforestry in ancient ways; and taro in aquaponics. Extension agents spoke about food safety. A PEPS graduate student spoke on invasive pests impacts on palm species with a focus on the Pacific and Israel. Two GEO students demonstrated their experimental growth chambers and artificial lighting set up. The manager of our college’s greenhouse facilities provided a tour of the facilities, explaining maintenance and irrigation. The rigor of this course was increased through incorporating more mathematics and quantitative reasoning, growth analysis, yield analysis, crop modeling and simulation, computer applications in horticulture, and high technology in horticulture. Students commented that TPSS 300 was a valuable learning experience. The course provided diverse learning experiences and hands-on activities. The integration of graduate students, extension agents, and the greenhouse manager as guest lecturers into the course worked well, providing benefits to both the speakers and the students.
Speakers
avatar for Kent D. Kobayashi

Kent D. Kobayashi

Interim Dept. Chair, TPSS Dept., Univ. of Hawaii at Manoa
Tuesday September 24, 2024 11:15am - 11:30am HST
South Pacific 4

11:15am HST

WCPM 1 - Evaluating Application Approaches for Enhancing the Weed Suppression Effectiveness and Crop-Safety of Preemergence Herbi
Tuesday September 24, 2024 11:15am - 11:30am HST
Preemergence herbicide application under plastic mulch is an effective strategy for managing weeds in vegetable plasticulture production. However, applying herbicides under plastic mulch in raised beds carries the inherent risk of crop phytotoxicity. This underscores the importance of exploring crop-safe methods for herbicide application in beds covered with plastic mulch. The study aimed to evaluate the efficacy of preemergence herbicide S-metolachlor alone or in combination with super absorbent polymer, soil binding agent, or compost in effectively controlling weeds in plastic mulched tomato beds without impacting the crops. During trials, I and II, preemergence S-metolachlor was applied either as blanket sprays or in combination with super absorbent polymer, soil binding agent, and compost on raised beds before installing plastic mulch. Results from trial II showed that S-metolachlor soil binding agent and S-metolachlor compost mix suppressed weed density by over 85% and 68%, respectively. Similarly, treatments including S-metolachlor alone, S-metolachlor super absorbent polymer, S-metolachlor soil binding agent, and S-metolachlor compost led to a reduction in weed biomass by over 50% compared to the non-treated control. Importantly, these treatments did not significantly impact tomato crop vigor and chlorophyll content during trials I and II, nor did they affect tomato crop biomass and yield. In conclusion, utilizing preemergence S-metolachlor along with different application approaches tested shows promise for controlling tough weeds such as nutsedge in tomato plasticulture beds.
Speakers
RK

Ramdas Kanissery

University of Florida
Co-authors
RT

Ruby Tiwari

University of Florida
NA
Tuesday September 24, 2024 11:15am - 11:30am HST
Lehua Suite

11:30am HST

CE 1 - Shedding Light on Nutrition: The Influence of Supplemental Lighting on Glucosinolate Concentrations in Brassica Plants and Their Potential Anticarcinogenic Effects in Human Diets
Tuesday September 24, 2024 11:30am - 11:45am HST
Brassica plants contain important secondary metabolites, such as glucosinolates, and provide a nutritious addition to the human diet. Glucosinolates, when hydrolyzed, yield isothiocyanates which can affect the carcinogenesis process, and further research into increasing glucosinolate concentrations in plants is important for determining anticarcinogenic properties of brassicas in human diets. Kale (Brassica oleracea var. acephala cv. ‘Toscano’ ) and Arabidopsis (Arabidopsis thaliana, Col-0) were grown in the greenhouse under natural light (control) and subjected to three additional supplemental light treatments to determine the impact of supplemental LED lighting on glucosinolate concentrations. Treatments included no supplemental light (control), 75:25 Red:Blue LED, 50:50 Red:Blue LED, and Warm White LED light at 100 μmol.m-2.s-1 each. Plants were harvested when the first kale treatment group reached a leaf number of 7, and when half of all Arabidopsis flowers began opening. Harvested plants were analyzed for glucosinolate and mineral nutrient concentration. Statistical analysis on Arabidopsis data revealed significant differences among light treatments in glucosinolate concentrations, particularly glucoraphanin and gluconasturtiin. Additionally, significant differences were found in leaf and petiole mass and leaf number of both kale and Arabidopsis at harvest. The no supplemental light control produced the lowest harvest mass compared to plants receiving supplemental light. Preliminary qPCR analysis of Arabidopsis displays variations in the relative expression of genes CYP79B2 and CYP83A1, varying across treatment when compared to the control. Glucosinolate analysis of kale resulted in no statistically significant differences among all four light treatments. However, glucosinolates, including gluconapin, glucoraphanin, gluconasturtiin, and several unknowns, were found to be present across all four treatments. As glucosinolates are stress-response compounds, their lack of variation in kale and significant variation in Arabidopsis under different light environments indicate that other environmental factors also play a crucial role in their production. Further research is necessary to identify abiotic and biotic factors influencing their concentration in the greenhouse environment for both species.
Speakers
SB

Skyler Brazel

University of Tennessee - Knoxville
Co-authors
CZ

Caleb Zepeda

University of Tennessee - Knoxville
NA
CS

Carl Sams

University of Tennessee
SN

Samantha Nuzzi

Donald Danforth Plant Science Center
NA
TB

Tessa Burch-Smith

Donald Danforth Plant Science Center
NA
Tuesday September 24, 2024 11:30am - 11:45am HST
Coral 1

11:30am HST

MKEC - Consumers' WTP on Sustainability Turfgrass Attributes with Consideration of Aesthetic Attributes and Water Conservation Policies
Tuesday September 24, 2024 11:30am - 11:45am HST
This study estimates consumers’ willingness to pay (WTP) for sustainability turfgrass attributes such as low-input and stress-tolerance attributes, while considering potential trade-off relationships between aesthetic attributes and sustainability attributes. To address our objectives, our study conducts a choice experiment and estimates two mixed logit models. The first model includes low-input, winter kill, and shade-tolerance attributes as predictor variables, and the second model extends the first model by adding interaction terms between aesthetic and sustainability attributes. Another choice experiment is conducted under water policies with various water rate increase and watering restriction scenarios. Results from the mixed logit models show that overall, higher low-input cost reduction, less winter-damaged, and more shade-tolerance grasses are preferred, the direct effect of aesthetic attributes on consumers’ preference is strong, but the indirect effect represented by the interaction terms are generally statistically insignificant. Our results indicate that consumers like to have a pretty lawn, but no strong consideration is given to the aesthetics of their lawn when selecting low-input and stress-tolerance turfgrasses. Our choice experiment under water policy scenarios suggests that water pricing is more effective than watering restriction in increasing consumer demand for water-conserving turfgrasses. Our findings provide useful implications for future research in turfgrass breeding and evaluation of consumer preference for turfgrass. Many researchers have discussed potential degradation of aesthetic characteristics when developing input-saving turfgrass varieties. However, to the best of our knowledge, no earlier studies have investigated the effect of aesthetic deterioration caused by enhanced low-input and stress-tolerance attributed on consumers’ valuation of turfgrasses. Our findings suggest that aesthetic attributes need to be considered when conducting choice experiments for the valuation of the enhanced grasses, but limiting trade-offs may not be as important as enhancing low-input/stress-tolerance attributes when developing future turfgrasses. Another contribution might be the water policy outcomes from our choice experiment. Our experiment finds that the water pricing is more effective than the watering restriction in increasing consumer demand for water-conserving grasses, which could help develop better water policies in the future.
Speakers
CC

Chanjin Chung

Oklahoma State University
Co-authors
HJ

Hyojae Jung

Oklahoma State University
NA
Tuesday September 24, 2024 11:30am - 11:45am HST
South Pacific 1

11:30am HST

PNM 1 - Combined Agronomic Biofortification of Iron and Zinc in Radish and Sunflower Microgreens
Tuesday September 24, 2024 11:30am - 11:45am HST
Iron (Fe) and Zinc (Zn) are two micronutrients which are crucial for human health and proper functioning of the circulatory, endocrine, immune, nervous, and reproductive systems. Deficiencies in dietary Fe and Zn can result in numerous illnesses and disorders and are among the most prevalent micronutrient deficiencies worldwide. There is an urgent need for improving the dietary intake of these micronutrients and a promising, quick, and effective improvement strategy is agronomic biofortification. Microgreens are an ideal and versatile choice for meeting nutritional needs. They are nutrient-dense, have low phytic acid content, can be produced for a range of species, and have a relatively short growth cycle – making them a convenient biofortification target crop. Previous studies’ attempts towards the simultaneous biofortification of Fe and Zn have indicated their antagonistic interactions during uptake, where the increase of one mineral led to a decreased uptake of the other. However, limited information is available about the opportunity of enriching microgreens with both nutrients using fertigation. Therefore, in this study we aimed to assess the optimal combination of Fe and Zn fertilizer concentrations, provided via fertigation, to maximize their simultaneous accumulation in radish and sunflower microgreens without impairing yield and quality. Using a completely randomized block design setup, a factorial combination of FeSO4 (0, 20, and 40 mg/L of Fe) and ZnSO4 (0, 10, and 20 mg/L of Zn) was tested. Across both species, it was observed that fertigation using the treatment combination of 40 mg/L FeSO4 and 20 mg/L ZnSO4, (Fe40-Zn20), resulted in a substantial increase of both micronutrient levels. Compared to the untreated control, the Fe40-Zn20 treatment increased Fe and Zn accumulation by about 200% and 900%, respectively, in radish microgreens, and about 180% and 600% in sunflower microgreens. Additionally, this treatment resulted in minimal yield reduction. Fresh and dry biomass decreased by approximately 23% and 9%, respectively, in radish microgreens, and 38% and less than 1% in sunflower microgreens. Although increasing both Fe and Zn content proves to be a challenging endeavor, this study revealed evidence of an optimal combination of selected Fe and Zn sources and application rates that, via fertigation, was effective in their simultaneous enrichment in two microgreen species.
Speakers
RR

Rishi Ravichandran

Student, Pennsylvania State University
Co-authors
EC

Erin Connolly

Pennsylvania State University
NA
FD

Francesco Di Gioia

Pennsylvania State University
PP

Pradip Poudel

The Penn State University
Tuesday September 24, 2024 11:30am - 11:45am HST
Kahili

11:30am HST

POM 1 - Impacts of Rootstock and Crop Load Adjustment on Fruit Quality and Mineral Nutrients in ‘Honeycrisp’ Apple
Tuesday September 24, 2024 11:30am - 11:45am HST
The influence of rootstock and time of crop load adjustment on ‘Honeycrisp’ apple fruit quality at harvest and after storage was studied over four seasons. Yield per trees varied from year to year because of biennial bearing. Trees on V.1 and G.30 were higher while those on G.969 often had lower yield per tree. Fruit from trees on M.26EMLA and G.30 were larger, while those on G.202 and G.969 were smaller than those on other rootstocks in two of three years. Fruit firmness at harvest and after storge was often inversely proportional to their size, so that fruits from trees on G. 202 often had higher but those on G.30 often had lower firmness at harvest and after storage. Percentages of fruit bitter pit among rootstocks at harvest was different than those after storage. However, fruit from trees on M.26EMLA, V.1, and G.30 generally had higher bitter pit than those on G.969 and G.202 rootstocks. Fruit fresh weight continually grew during growing season. However, the increase in percentage fruit dry weight reached a plateau on August 9, after which it leveled off. Trees receiving an “Early Heavy Thinning” and “Thinned Early to 1 Fruit/bunch” had lower yield but larger fruit with more bitter pit than Un-thinned-Control trees. Trees receiving a thinning on June 11 and June 25 had similar fruit size in the same season. However, bitter pit was increased, while fruit size decreased, as the hand thinning was delayed until July 8. Late hand thinning resulted in smaller fruit size with less bitter pit. Fruit potassium/ calcium (K/Ca) ratio did not change significantly between June 20 and August 8 within the same year. This research unveils importance of rootstock, time, and level of and thinning in the fruit quality of ‘Honeycrisp’ apple.
Speakers
avatar for Esmaeil Fallahi

Esmaeil Fallahi

ASHS Board of Directors Chairman; ASHS President 2022-2023, University of Idaho
ASHS Board of Directors Chairman; ASHS President 2022-2023;Professor of Pomology and Viticulture
Co-authors
BF

Bahar Fallahi

University of Idaho
NA
MK

Michael Kiester

University of Idaho
NA
Tuesday September 24, 2024 11:30am - 11:45am HST
Nautilus

11:30am HST

TCHG 1/ADMIN - Service-learning Horticulture Students Growing Food for Themselves and Others
Tuesday September 24, 2024 11:30am - 11:45am HST
Organic gardening (Horticulture 2525) is a mandatory class for students in the LSU medicinal plants and sustainable crop production concentrations, where the focus of the lab is for students to intensively grow their own garden plot of vegetables and herbs in the fall semester. Students are mandated to grow at least 10 different crops and to use both direct seeding and using their own transplants to establish, maintain throughout the semester, and then harvest their plot. The course is a service-learning course and over the years the class have worked in establishing and maintaining community and school gardens, harvesting/gleaning vegetables from garden plots, and assisting with a local farmers market. The most recent classes focused on growing food in community plots for the LSU Food Pantry, a local food bank that is used by many students. Each week students are required to work in the community rows from the beginning of working and shaping the beds, applying and incorporating fertilizer, planting seeds directly into the beds, transplanting crops, and setting up trickle and overhead irrigation systems. Students maintain their own plots as well as the community rows by fertilizing, and applying organic pest management measures as needed. The harvest from the individual plots and the produce is left up to the students and all the students harvest, wash, pack and prepare the product from the community rows for donation each week to the campus food pantry. Students are encouraged to participate my transporting the produce at least once, from the field or the cooler at the teaching facility to the food pantry. Many of the students have indicated that the class is the first time they had grown any plants in a garden and they used the garden harvest in their own kitchens. Students also indicated that they learned about the needs of the community and students and several also became aware of the food pantry and its services. In the fall of 2023 over 1,800 pounds of fresh vegetables were donated to the campus food pantry. Data from the students’ perceptions and comments from the semester will be presented.
Speakers
CM

Carl Motsenbocker

Professor, Executive Director Louisiana Farm to School Program, Louisiana State University
Dr. Carl Motsenbocker is a professor of horticulture and sustainable agriculture at Louisiana State University. Motsenbocker is Executive Director of the Louisiana Farm to School Program and teaches Organic Gardening, Sustainable Agriculture and Vegetable Crops at LSU. Motsenbocker... Read More →
Co-authors
IF

Isabella Frank

Louisiana State University
NA
JT

Jacob Tullos

Louisiana State University
NA
Tuesday September 24, 2024 11:30am - 11:45am HST
South Pacific 4

11:45am HST

POM 1 - Rapid Fruit Growth Rates of Honeycrisp Apples Cause Premature Dysfunction of Xylem, Reduced Peel Calcium, and Increased Susceptibility to Bitter Pit
Tuesday September 24, 2024 11:45am - 12:00pm HST
Insufficient transport of calcium to and throughout the cortex of apple is a primary factor contributing to bitter pit, a disorder characterized by dark lesions on the fruit surface. Calcium transport, in-planta, occurs solely in the xylem. Progressive transport dysfunction of xylem limits calcium concentration in the peel and subtending tissue. Rapid fruit growth may accelerate xylem dysfunction due to the stretching, shearing, or compressing of xylem elements. The relative time course of these events and subsequent effect on calcium concentration of peel tissues is not well understood. Growth rate of fruit was manipulated by manually adjusting the crop load of 6th leaf ‘Honeycrisp' trees to either 4 (low), 8 (moderate), or 16 (high) fruit per cm2 of trunk cross-sectional area via bud extinction. Fruit mass, xylem functionality, and peel calcium content were assessed weekly throughout the season. Fruit tissues were frozen weekly to evaluate the expression of genes related to xylogenesis and calcium transport and for quantification of hormones. At maturity, 25 trees were harvested from each crop load treatment. Fruit were assessed for bitter pit, stored for three months in regular air (3⁰C), then reassessed. Crop load influenced both xylem functionality and bitter pit incidence of fruit. Low crop load fruit lost 80% of xylem functionality by 8 weeks after bloom, which was two weeks earlier than moderate crop. By seven and five weeks before harvest, total xylem dysfunction was observed in fruit of low and moderate crop load, respectively; xylem in high crop load fruit never became fully dysfunctional. Final fruit mass from low crop load trees was only 20 grams larger than fruit from moderate crop load trees, yet, these fruit had a roughly 100% increase in bitter pit incidence at harvest (27.3% vs. 12.6%). Only 4.1% of high crop load fruit were affected by bitter pit. Many previous studies have ascribed the positive relationship between fruit mass and bitter pit incidence to calcium dilution. Our data suggest, however, that the issue is one of transport limits that appear to begin very early in fruit development, exacerbated by the growth rate of fruit, resulting in less peel calcium and higher bitter pit incidence at harvest than fruit of relatively lower growth rates. Future analysis of endogenous hormone concentrations and expression of genes relating to xylogenesis and calcium allocation will facilitate a better understanding of the processes governing xylem dysfunction and its association to bitter pit disorder.
Speakers
CG

Chayce Griffith

Michigan State University
Co-authors
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 →
TE

Todd Einhorn

Michigan State University
NA
Tuesday September 24, 2024 11:45am - 12:00pm HST
Nautilus

11:45am HST

TCHG 1/ADMIN - Assessing “Teaching Effort” to Ensure Fairness and Equity Across Diverse Course Types
Tuesday September 24, 2024 11:45am - 12:00pm HST
An ongoing and challenging issue for all administrators who have to assign teaching responsibilities is assessing “effort” associated with different types of courses. While it is abundantly clear that different amounts of effort go into lecture classes versus lab classes, we still frequently talk about teaching responsibilities as the “number of classes taught per semester.” In the department of Horticulture and Landscape Architecture at Purdue University, we faced this challenge across lecture courses, lab courses and Landscape Architecture studio classes. We undertook a year-long effort to assign “effort” values to each of our classes. In this presentation we will discuss our philosophy and approach to this undertaking, including how we engaged the entire department in the process. We ultimately developed a complex spreadsheet (currently being converted to an interactive database) that assigns points to classes based on number of contact hours, preparation work, service learning or experiential experience, grading/management workload, and class size. We then used this information to determine where additional support, in the form of graduate or undergraduate student TAs or staff, was most needed to create equity across teaching loads. This work is ongoing and needs to be updated annually based on changes in course structures and sizes and teaching assignments. In this presentation, we will share the database we created to make annual updates easy and transparent to everyone in the department.
Speakers
LP

Linda Prokopy

Purdue University
Co-authors
KO

Kathryn Orvis

Purdue Univ
SR

Sean Rotar

Purdue University
NA
Tuesday September 24, 2024 11:45am - 12:00pm HST
South Pacific 4

1:45pm HST

VCM 1 - Nutsedge Management Through Soil Steaming
Tuesday September 24, 2024 1:45pm - 2:00pm HST
Soils host weeds, pathogens, and insects that can cause crop damage and reduce yield. Many methods have been developed to reduce these pressures within the soil, including soil solarization, chemigation, anaerobic soil disinfestation, and soil steaming. We have utilized soil steaming to reduce weed seeds and soil infestation in high tunnel and field tomato (Solanum lycopersicum) production. While it successfully reduces most weed species and southern blight (caused by Athelia rolfsii) in tomatoes, the emergence of nutsedge (Cyperus spp.) in soils with established populations can increase after steaming. Our research goal was to evaluate the efficacy of various soil preparation methods prior to steaming to allow the steam to penetrate the soil and target nutsedge directly. Except where noted, the field was first chisel plowed, disced, and then shaped into 2-foot-wide by 6-inch-tall beds. We compared 8 preparation methods for controlling nutsedge: a no-till control, herbicide control using S-metolachlor and halosulfuron-methyl, 6-inch-tall bed size, 12-inch-tall bed size, chisel plowed row, black plastic mulch, 4-inch-deep trenches on no-till, and 6-inch-deep trenches on no-till. Four trenches were cut into the soil with a soil trencher for each plot. Four replicates were included in a completely randomized design. Half of each bed was steamed until temperatures reached 160 °F, 4 inches deep, except for the herbicide beds and mulched beds, which were left unsteamed. Four sets of temperature probes were placed 12, 8, 6, and 4 inches deep in the soil and temperatures and used to monitor temperature changes in steam soils over time. Nutsedge coverage was visually estimated by placing a 1 by 6-foot rectangular PVC frame in each row over a representative section. 12-inch-tall beds had nearly 100% nutsedge coverage, while 6-inch-tall beds had nearly 50%. Herbicides reduced nutsedge coverage to 29%, and the plastic mulch reduced coverage to 8%. The steamed no-till, 4-inch trench, 6-inch trench, and chisel-plowed beds had no nutsedge emergence through the trial. The 6-inch-tall beds had lower temperatures at 6 and 8 inches deep than the other methods, which could account for the observed increases in nutsedge emergence post steaming. The time-consuming nature of soil trenching would make it impractical for most horticultural production settings; however, the chisel plow and no-till could be readily adopted. Determining effective methods to prepare the fields for soil steaming to reduce or eliminate nutsedge will make soil steaming a more viable method for organic farmers facing nutsedge pressures.
Speakers
SB

Shaun Broderick

Associate Research & Extension Professor, Mississippi State University
Co-authors
CC

Christine Coker

Mississippi State University
TM

Te Ming Tseng

Mississippi State University
Tuesday September 24, 2024 1:45pm - 2:00pm HST
Kahili

2:00pm HST

CITR 1 - Comparing Scion and Rootstock Trunk Injection of Oxytetracycline for HLB Management Across Diverse Rootstocks in Florida
Tuesday September 24, 2024 2:00pm - 2:15pm HST
The huanglongbing (HLB) associated pathogen Candidatus Liberibacter asiaticus (CLas) inhabits the phloem of infected citrus trees, which impedes the efficacy of foliar-applied chemicals for management of the disease. Trunk injection is an alternate method that allows the targeted delivery of agrochemicals into the vasculature, resulting in their systematic distribution throughout the tree. This study aims to determine the large-scale efficacy of trunk injection of oxytetracycline (OTC) on citrus tree health, fruit quality, and yield in existing rootstock trials in a commercial production site in Florida. The study compares 9-year-old Valencia sweet orange (Citrus sinensis) trees grafted on six different rootstocks in a large field trial in Polk County, Florida. The experimental design is a complete randomized block design, with three injection treatments: 1) no injection (control), 2) injection into the scion trunk, and 3) injection into the rootstock trunk. The injections were performed in May 2023, and injected trees received a commercial formulation of OTC at a rate of 1.1 g per tree using FlexInject injectors. Data collection included HLB status, tree size, yield, fruit/juice quality, fibrous root density, and leaf macro- and micronutrient content once a year, wound phenotype every six months, and bacterial titers before injection and 3 days, 1 week, and 1 month after injection. OTC injections into the scion or the rootstock trunk improved tree health, yield, fruit/juice quality, and the leaf Ca content. Overall, injections increased fruit yield by 24% and juice brix by 9%, increasing the revenue by 36% on a per acre basis. Injection into the scion trunk was slightly superior in terms of tree growth and fibrous root density, while injection into the rootstock trunk reduced the wound size, bark cracking, and HLB symptoms. CLas titers were reduced regardless of the injection site one month after injections. In conclusion, our results suggest that OTC injections have the potential for short-term management of HLB to help with the recovery of the Florida citrus industry in the face of endemic disease conditions. The trial will continue to assess longer-term effects.
Speakers
avatar for Larissa Nunes da Silva

Larissa Nunes da Silva

UF/IFAS - Southwest Florida Research
Co-authors
BP

Brandon Page

Citrus Research and Development Foundation
NA
UA

Ute Albrecth

UF/IFAS - Southwest Florida Research
NA
Tuesday September 24, 2024 2:00pm - 2:15pm HST
South Pacific 4

2:00pm HST

VCM 1 - Using the Feekes Growth Stage Scale to Predict the Carbon to Nitrogen Ratio of Cereal Cover Crops
Tuesday September 24, 2024 2:00pm - 2:15pm HST
Cereals and other non-legume cover crops can help vegetable farms to reduce nitrogen leaching to ground water during rainy winter periods. A cover crop’s carbon to nitrogen ratio is an important metric that can help farmers better understand the nitrogen release dynamics from soil-incorporated cover crops. Cover crops with a lower C:N ratio (15:1) typically mineralize nitrogen when they are incorporated into the soil, whereas those with a higher C:N (25:1) usually immobilize nitrogen. But farmers need simple, reliable, field-based methods to predict a cover crop’s C:N ratio. Therefore, we evaluated the relationship between the Feekes growth stage scale and the C:N ratio of rye (Secale cereale L., ‘cv. Merced’) and triticale (X Triticosecale Wittmack, cv. ‘Pacheco’) cover crops in the Central Coast region of California. Over a hundred field samples of rye and triticale shoots were collected at various developmental growth stages from organic and conventional vegetable farms and planting date trials, across multiple soil types, planting times, row spacings, and plant densities. The Feekes scale was correlated with the C:N ratio of cover crop shoots of rye (r2=0.63) and triticale (r2=0.76). The transition from Feekes 9 (when the ligule of the flag leaf is visible) to Feekes 10 (‘boot’ stage) is roughly when the C:N ratio went from below to above 20:1. Regression plots were developed that illustrate the relationship between the Feekes scale and the C:N ratio. These results have practical implications for a new ground water protection regulation (Ag. Order 4.0) in California’s central coast region that incentivizes winter cover crops that are grown until the C:N ratio is 20:1 or more.
Speakers Co-authors
RS

Richard Smith

University of California Cooperative Extension
NA
Tuesday September 24, 2024 2:00pm - 2:15pm HST
Kahili

2:15pm HST

CITR 1 - Evaluation of Different Oxytetracycline Rates Delivery by Trunk Injections on Mature Valencia Sweet Orange Trees
Tuesday September 24, 2024 2:15pm - 2:30pm HST
In Florida, Huanglongbing (HLB), also known as citrus greening, has severely impacted citrus production, prompting research into alternative treatment methods such as trunk injection of oxytetracycline (OTC) to manage Candidatus Liberibacter asiaticus (CLas) colonization. This study aims to 1) determine the optimal OTC rate administered by injection to improve the health and productivity of HLB-affected mature sweet orange trees and 2) determine the impact of spring versus late summer injections to maximize benefits and the potential for extending the harvest window. The study was initiated in 2023 in a commercial citrus production setting in Polk County, Florida. The trees were 18 years old and composed of ‘Valencia’ (Citrus sinensis) scion on Swingle (C. paradisi × Poncirus trifoliata) rootstock. Four different OTC rates (0.55 g, 0.852 g, 1.1 g, and 1.65 g active ingredient per tree) and two injection times (June and September) were compared against a control receiving no injections. The experimental design was a randomized block design with eight replications, and each replication consisted of four linear trees. A commercial formulation of OTC registered in Florida was used and administered through FlexInject injectors. A volume of 100 ml per tree was used for the 0.55-1.1 g rates and administered with one injector. The highest rate (1.65) was administered using two injectors on opposite sides of the tree in a volume of 75 ml per injector. Tree health was assessed by visual ratings of foliar HLB symptoms and canopy densities, while CLas titers were quantified using real-time PCR. Fruit quality and yield measurements included total soluble solids, titratable acidity, fruit weight, and juice characteristics. Trees were harvested, and fruit/juice quality was determined in March 2024. Overall, injected trees produced significantly more and larger fruit with better juice color, a higher percentage of juice, and more total soluble solids than control trees. The highest rate of OTC produced the highest yield and highest-quality fruits compared to the other rates. We did not observe any difference between spring (June) and summer (September) injections on any measured variables. Bacterial titers were reduced in the injected trees compared to the non-injected trees, and injected trees had fewer HLB symptoms and denser canopies than control trees. This research provides important insights into the best practices for managing HLB using trunk injection of OTC.
Speakers
avatar for Gabriel Pugina

Gabriel Pugina

PhD candidate, University of Florida
Co-authors
CT

Caroline Tardivo

University of Florida
UA

Ute Albrecht

University of Florida
NA
Tuesday September 24, 2024 2:15pm - 2:30pm HST
South Pacific 4

2:15pm HST

HEMP 1 - Quantitative and Qualitative Characteristics of High Quality Cannabis Sativa
Tuesday September 24, 2024 2:15pm - 2:30pm HST
Scientific research activities focused on production of high-quality Cannabis sativa continue to grow in both the industry and academic sectors. At the university level in the United States, the majority of the research uses hemp-type or low tetrahydrocannabinolic acid (THCa) cannabis cultivars due to federal restrictions. Only at the industry level and in states with some level of medical or recreational legalization can production research be carried out on high THCa or drug-type Cannabis. Dried female flower inflorescences are the harvested and saleable portion of the Cannabis plant. The quantitative traits of flowers are relatively clear and easily enumerated. To be considered superior quality, THCa concentration should be 25% or greater and the total terpene concentration should be 2% or greater on a dry weight basis (moisture content of 10-12%). While the average cannabis consumer values these characteristics, they also greatly appreciate many of the qualitative characteristics of cannabis flower, which include visual appearance or sometimes referred to as bag appeal, olfactory characteristics when opening the container of cannabis and while breaking apart the flowers, texture, and taste when smoking. These characteristics are more difficult to define and quantify. When conducting research, both quantitative and qualitative characteristics need to be of great consideration when the goal is to produce high quality Cannabis flower.
Speakers
MT

Matthew Taylor

Curio Wellness
Tuesday September 24, 2024 2:15pm - 2:30pm HST
South Pacific 1

2:15pm HST

PH 1 - Ethylene Degreening: A Technique to Enhance Peel Color of Georgia-Grown Satsuma (Citrus reticulata) Citrus Fruit
Tuesday September 24, 2024 2:15pm - 2:30pm HST
In recent years, the production of Satsuma oranges (Citrus reticulata) has significantly increased in the state of Georgia. Satsumas are known to develop a deep orange peel color naturally when the temperature drops below 12°C at night. However, due to the subtropical climate of South Georgia, the fruit often fails to turn orange naturally even after attaining physiological maturity standards. Consumers tend to choose fruits based on appearance, with brightly colored oranges being more likely to attract buyers. Degreening is a postharvest technique that utilizes gaseous ethylene (C2H4) to accelerate and promote the development of orange/yellow color pigments in fresh-market citrus fruit. The study was conducted using four Satsuma cultivars ('Brown Select', 'Owari', 'Miho', and 'Xie Shan') harvested at physiological maturity yet with green peel coloration. The fruit samples were subjected to a degreening treatment which involved exposure to a continuous flow of
Speakers
TO

Taiwo Owolanke

Graduate Research Assistant, University of Georgia
Co-authors
AD

Angelos Deltsidis

University of Georgia
AB

Anthony Bateman

University of Georgia
NA
JP

Jake Price

University of Georgia, Extension
NA
OG

Orestis Giannopoulos

University of Georgia
RC

Ramsey Corn

University of Georgia
Tuesday September 24, 2024 2:15pm - 2:30pm HST
South Pacific 2

2:15pm HST

VCM 1 - Associations Among Crop/Weed Management Practices and Environmental Factors Highlight Challenges Facing U.S. Snap Bean Production
Tuesday September 24, 2024 2:15pm - 2:30pm HST
Snap bean production has decreased by ~30% recently due to an increase in imports and changing consumer preferences towards more fresh and frozen products. A major production concern is weed species that escape control, since they cause yield losses and can contaminate harvest loads. Coupled with changing weather patterns, snap bean processors and growers will have to adjust to these and future challenges. Field surveys were conducted to identify associations among crop/weed management practices and environmental factors on snap bean yield and weed density. From 2019-2023, snap bean fields throughout the major U.S. production regions were surveyed for weeds at harvest. Management records for each field were obtained from growers. Information on soil and weather conditions of each surveyed field also was obtained. In total 358 production fields were surveyed in the Midwest (Illinois, Iowa, Minnesota, Wisconsin), Northeast (Delaware, Maryland, New York. Pennsylvania), and Northwest (Oregon, Washington) regions. To determine associations among management and environmental variables on crop yield and weed density, the machine learning algorithm random forest was utilized. The models had 24 and 22 predictor variables for crop yield and weed density, respectively, and both were trained on 80% of the data with the remainder used as a test set to determine model accuracy. Partial dependence plots were used to visualize the change in response variables based on the most important predictors. The crop yield model had pseudo-R2 values of 0.56 and an accuracy of 74%. Higher average temperatures during early season growth, higher soil organic matter content, and planting midseason (June-July) predicted an increase in average crop yield. Meanwhile, excessive precipitation early in the season, high sand content of the soil, high temperatures at crop flowering and row cultivation predicted a decrease in crop yield. The weed density model had pseudo-R2 values of 0.55 and an accuracy of 81%. While row cultivation was associated with lower snap bean yield, it corresponded to a decrease in weed density, suggesting row cultivation had less-than-ideal selectivity between the crop and weed. Moreover, multiple spring tillage operations prior to planting predicted an increase in average weed density, implying that excessive tillage may favor emergence of weeds in snap bean. Over the coming decades, climate change-driven weather variability is likely to influence snap bean production, both directly through crop growth and indirectly through weeds that escape control practices that also are influenced by the weather.
Speakers Co-authors
BS

Barbara Scott

University of Delaware
NA
CL

Carolyn Lowry

Penn State University
NA
EP

Edward Peachey

Oregon State University
NA
JC

Jed Colquhoun

University of Wisconsin
LS

Lynn Sosnoskie

Cornell University
NA
MV

Mark VanGessel

University of Delaware
NA
NK

Nicholas Korres

University of Ioannina
NA
PP

Pavle Pavlovic

University of Illinois Urbana-Champaign
NA
RL

Rui Liu

Washington State University
Tuesday September 24, 2024 2:15pm - 2:30pm HST
Kahili

2:15pm HST

VSF 1 - Prospects for Grapes in High Tunnels
Tuesday September 24, 2024 2:15pm - 2:30pm HST
High tunnels have proven to be a suitable alternative for a number of small fruits and vegetables, but potential applications for grapes need to be further explored. We have conducted seven years of research with table grapes in high tunnels and demonstrated that profitable production can be achieved with the concomitant reduction of environmental challenges, including vertebrate pests, hail and extremes of weather. This approach has also resulted in less pesticides required to maintain a quality robust canopy. Furthermore, our research has shown that cold storage retains marketable quality, thus enabling extending the marketing season for the cultivars tested (Thomcord, Everest, Marquis, Mars, Canadice and Somerset). In addition, we have explored the potential of growing Vitis vinifera grapes in a high tunnel in the Midwest with the goals of enabling our commercial wineries to have a local source of grapes that are not adapted to field production in Nebraska but are desired by consumers. Vinifera grapes can thus be produced as a local wine varietal or can be employed to enrich wines made from locally adapted cultivars. Data on survival and productivity of specific cultivars such as Cabernet Sauvignon, Tannat, Petit Verdot, Riesling and other vinifera cultivars will be presented while discussing the productivity of closely related new cultivars.
Speakers
PR

Paul Read

University of Nebraska
Tuesday September 24, 2024 2:15pm - 2:30pm HST
Nautilus

2:30pm HST

CITR 1 - Field Performance of Novel Citrus Rootstocks Grafted with Valencia and Their Response to Systemic Delivery of Oxytetracycline
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Worldwide citrus production faces significant challenges from the devastating disease Huanglongbing (HLB), necessitating innovative management strategies. This study aimed to assess the performance of novel rootstocks under natural HLB-endemic conditions using regular management practices and the recently registered practice of delivering oxytetracycline (OTC) through trunk injection to reduce pathogen load. Nine novel rootstocks, US-1673, US-1676, US-1680, US-1672, US-1687, US-1688, US-2111, US-2132, and US-2137 with different genetic backgrounds, including Citrus maxima, C. tachibana, C. reticulata, and Poncirus trifoliata were included in the study. Also included were two commercial rootstock standards, sour orange (C. aurantium) and Swingle (C. paradisi × P. trifoliata). The rootstocks were grafted with ‘Valencia’ sweet orange (C. sinensis) scion and planted in 2014 in a randomized complete block design and 12 single-tree replications in an open field in St. Lucie County, Florida. In July 2023, half of the trees were injected with ReMedium TI® (95.0% oxytetracycline hydrochloride) dissolved in reverse osmosis water acidified with muriatic acid to a pH of 2.0. Each tree received 0.75 g OTC dissolved in a volume of 75 ml (10,000 ppm) administered using FlexInject injectors. Injections were performed in the scion, approximately 5 cm above the graft union. Tree measurements included tree size, canopy health, pathogen titers, fruit yield, and juice quality. Significant differences among rootstocks were observed in the years before injection. In the 2022-2023 production season, US-1688 induced the highest yield, and US-2132 induced the best juice quality. Preliminary results indicate an overall positive response to the OTC treatment across all rootstocks. Injected trees had a 36% increase in yield, an 11% increase in juice brix, and a significant reduction in leaf and root pathogen titers. As in the previous years, growth and productivity varied significantly among the rootstock cultivars. US-1688, a new release by USDA under the name SuperSour 4, continued to be among the largest, healthiest, and most productive trees. The results from this research demonstrate the importance of rootstock selection for sustainable citrus cultivation. It also highlights the benefits of integrating the systemic delivery of antibacterial therapies to maximize the resilience of citrus trees to HLB.
Speakers
avatar for Caroline de Favari Tardivo

Caroline de Favari Tardivo

PhD Candidate, University of Florida
Co-authors
KD

Kim D Bowman

USDA ARS
NA
UA

Ute Albrecht

University of Florida
NA
Tuesday September 24, 2024 2:30pm - 2:45pm HST
South Pacific 4

2:30pm HST

HEMP 1 - A Three-state Summary on the Critical Weed Free Period for Transplanted Floral Hemp.
Tuesday September 24, 2024 2:30pm - 2:45pm HST
There is a growing demand for hemp-derived products but because of the crop's criminalization history, there is limited University-produced information describing best production practices. The research objective was to define the critical weed-free period (CWFP) for transplanted floral hemp. Field trials were conducted in 2022 and 2023 at an outlying NDSU Agriculture Experiment Station near Prosper, ND (46.57° N, 97.01° W), the Cornell AgriTech campus in Geneva (42.88°N, 77.01°W), and the Clemson University Coastal Research and Education Center (33.46°N, 79.55°W). Four cultivars were transplanted at NY with three cultivars (Bubbatonic, Sour Space Candy, and Quick Spectrum) in common with ND. Three cultivars were transplanted in SC with two cultivars (Cherry Wine and Bubbatonic) in common with NY. The CWFP treatments were weeded for 0, 1, 2, 4 and 6 weeks, and weed-free. Weeding was accomplished by manually hoeing and hand-weeding. Weed species varied at each location but were mainly annual weed species (both broadleaf and grasses). Plants were harvested after at least a 16-week period in the field and air-dried before removing leaf and floral biomass from stems. At SC, when averaged across cultivars and trial years, a significant increase in mean floral yield with 2, 4, 6, and season long weed-free intervals when compared to 0 weeks weed-free. In addition, a significant decrease in dry weed biomass existed when comparing the same weed-free intervals to the 0 weeks weed-free treatment. At NY, hemp biomass averaged across all cultivars was significantly affected by the duration of weed competition. Per plant yields were reduced >80% when weeds were allowed to compete almost season-long. Biomass production was maximized when weeds were suppressed for at least 6 weeks after transplanting. At ND, results were quite different due to timely rainfall and lack of rain. Under adequate to excellent moisture conditions, the stem diameter, stem number, plant weight:height ratio, and dry biomass yield responses were significantly different only when weed control was provided for one week. However, under extreme season long drought conditions, stem diameter increased 53%, weight:stem ratio increased 172% and dry biomass increased 201% when weeds were controlled the entire season. Results indicate that transplanted hemp is sensitive to competition and preventing weed establishment for several weeks was necessary to reduce competitive interactions. Results also suggested that the need for a weed-free period was exacerbated and most important when rainfall during the growing season was limited.
Speakers Co-authors
LS

Lynn Sosnoskie

Cornell University
NA
MC

Matthew Cutulle

Clemson University
Tuesday September 24, 2024 2:30pm - 2:45pm HST
South Pacific 1

2:30pm HST

PB 1 - Revolutionizing Grapevine Breeding: Overcoming Perennial Challenges with Genome Editing
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Climate change poses a significant threat to perennial crops like grapevine in the USA, with projections indicating that 50-81% of acreage may become unproductive by 2040. To address this, breeding resilient varieties is imperative. However, traditional breeding for perennials is time-consuming (25-30 years) due to extended evaluation periods. Genome Editing, specifically CRISPR/Cas9, offers targeted modification potential but faces hurdles in perennial crops such as grapevine. These include somaclonal variation, inefficient transformation, transgene removal needs, and industry hesitance. We propose an efficient Genome Editing method for grapevine leveraging the systemic mobility of methylated dicistronic mRNA:tRNA molecules. This approach aims to: 1. Enable genome editing without transgene integration, negating the need for backcrossing and preventing unintended genetic changes. 2. Circumvent in-vitro culture, reducing somaclonal variation risk and preserving existing chimerism. Our method addresses key challenges in Genome Editing adoption for grapevine and could accelerate the development of climate-resilient varieties, crucial for sustainable agriculture in a changing climate.
Speakers
avatar for Bridget Bolt

Bridget Bolt

Graduate Research Assistant, University of Kentucky
NA
Tuesday September 24, 2024 2:30pm - 2:45pm HST
South Pacific 3

2:30pm HST

PH 1 - Postharvest Storage Temperatures to Promote Anthocyanin Accumulation and Antioxidant Activity in Blood Orange cv. Moro
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Blood oranges (Citrus sinensis L. Osbeck) fruit contain valuable compounds for human health, including anthocyanins, flavonoids, polyphenols, hydroxycinnamic acids, and ascorbic acid. Anthocyanin is considered an important internal quality index of blood oranges due to its red color and antioxidant activity. Blood orange pigmentation under similar growing conditions depends on some factors including cultivar, cultural practices, soil characteristics, climate conditions, maturity, and harvest maturity. Blood orange fruit require cold temperatures between 8 °C to 15 °C during the last ripening stages to develop high levels of anthocyanin in their flesh. However, commercial production of blood oranges in subtropical or tropical regions is limited due to very low or lack of cold temperatures to enhance anthocyanin concentration in fruit. We evaluated the effect of different storage temperatures (10, 15, and 20 °C) on anthocyanin enhancement and the antioxidant activity of ‘Moro’ blood orange for 42 days. Fruit were harvested from a commercial citrus orchard in south Georgia and transported to the postharvest lab in Gainesville, Florida. Fruit were checked for absence of defects andr rind injuries, sanitized with 100 ppm sodium hypochlorite solution, and superficial water removed from the fruit surface. The fruit were then divided into sets of four replicates of 10 fruit per treatment and placed in mesh bags for storage at 10, 15, or 20 °C with 90 % relative humidity. Anthocyanin accumulation and antioxidant activity in the flesh were evaluated every 14 days for 42 days. There were significant differences among the applied storage temperatures for anthocyanin content and antioxidant activity. The highest anthocyanin concentration and antioxidant activity were observed at 10 °C, while the lowest anthocyanin level was at 20 °C for all sampling times. The efficiency of these temperatures in enhancing flesh anthocyanin and antioxidant activity was in the following order: 10 °C > 15 °C > 20 °C at all sampling times. Overall, it can be concluded that cold storage can be used as a simple technology for enhancing bioactive compounds and antioxidant activity in blood oranges that are poorly pigmented at harvest in subtropical or tropical climates like Florida.
Speakers
FH

Fariborz Habibi

University of Florida
Co-authors
AS

Ali Sarkhosh

University of Florida
NA
JB

Jeffrey Brecht

University of Florida
NA
Tuesday September 24, 2024 2:30pm - 2:45pm HST
South Pacific 2

2:30pm HST

VCM 1 - Impact of Early Season Tarping on Soil Conditions and Weed Populations in North Central United States Vegetable Production Systems
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Weed management is one of the biggest challenges vegetable growers face. Plastic mulch, herbicides, tillage, and hand-weeding are common ways vegetable growers manage weeds. These methods can be labor intensive, require specialized equipment, and cause environmental harm. Tarping is an alternative weed management method. Silage tarps or high-tunnel plastics are commonly used tarping materials; these are multi-functional tools that can be used for several years. Tarping facilitates stale seedbed weed management techniques by modifying the soil microclimate and promoting weed germination. After weed germination, opaque tarps can terminate weeds via occultation (lack of sunlight), whereas clear tarps terminate weeds by creating extreme temperatures. More information is needed for the type and timing of early-season tarp application for optimal weed control. The research was conducted at the Iowa State University Horticulture Research Stations in Ames, IA. This study examined three types of tarps: black, white, and clear, at three different durations: two, four, and six weeks prior to planting compared to a non-tarped control. Clear tarp and control treatments were cultivated at the time of tarp removal prior to planting. Soil temperature was recorded at 5 centimeters depth for 6-week tarp treatments. Early-season clear tarping did not elevate temperatures enough to terminate the majority of weeds. However, black and white tarps created a weed-free planting bed. Average soil temperatures underneath the clear tarp were the warmest (21.8ºC), followed by black tarp (15.1ºC). White tarp treatments (11.7ºC) had a lower average soil temperature than treatments with no tarp (14.8ºC). Two weeks following tarp removal, six-week clear tarp treatments had a higher percent weed cover than black and white tarp treatments measured using Turf Analyzer, a digital photo analysis software. Differing soil temperatures did not significantly impact soil microbial biomass carbon. The two-week white tarp had significantly higher soil microbial biomass nitrogen than all other treatments except four-week clear tarp. There was no effect of tarp type or duration on onion crop yield. These results indicate that the use of white and black tarps can be a feasible alternative weed management method in North Central vegetable production systems.
Speakers
avatar for Carly Strauser

Carly Strauser

Iowa State University
Graduate Research Assistant, Department of Horticulture at Iowa State University
Co-authors
AN

Ajay Nair

Iowa State University
NA
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Kahili

2:30pm HST

VSF 1 - Growing Grapes on the Texas High Plains: A Review of Grower Concerns and Recent Research
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Within the State of Texas the grape (Vitis vinifera) and wine industry has an economic impact of over $20 billion. Currently there are more than 3,700 ha of vineyards within the state, and greater than 80% of Texas vineyards are within the Texas High Plains American Viticultural Area (AVA). High Plains AVA grape growers are blessed with beneficial soil conditions, low biotic stress factors, and a generally favorable climate. However, geophysical challenges within the AVA include dangerous winter temperature extremes, late spring frosts, high wind speed events, thunderstorms, damaging hail, drought, and herbicide volatility and drift concerns. Despite these challenges, the Texas High Plains AVA has gained a reputation for producing high yields and fruit with exceptional quality. This presentation will focus on recent (past three years) research efforts performed by Texas A&M AgriLife Research and Extension and Texas Tech University personnel: investigating grape grower concerns associated with vine water requirements, avoiding grapevine hail damage, estimating vine cultivar bud dormancy traits, and quantifying herbicide drift and volatilization into vineyards. Presented research results benefit Texas High Plains grape growers and give growers additional insight into production practices and management methods suited for grape production within the unique Texas High Plains AVA environment.
Speakers
avatar for Thayne Montague

Thayne Montague

Professor, Texas Tech University / Texas A&M AgriLife Research
Dr. Montague's teaching responsibilities include Plant Propagation, Woody Landscape Plant Identification, and Introduction to Viticulture. Dr. Montague's research responsibilities focus on physiology and plant/microclimate interactions of grapevines and other fruit crops. 
Co-authors
Tuesday September 24, 2024 2:30pm - 2:45pm HST
Nautilus

2:45pm HST

CITR 1 - Florida-grown 'Hamlin' Sweet Orange Failed to Produce Adequate Pounds-solids Despite Budline, Environment, and Antibiotic Treatment
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Huanglongbing (HLB) is a devastating bacterial disease in Florida and has been spreading in citrus-growing regions in Texas, Georgia, and California. HLB threatens the entire US fresh and processed citrus industries. To date, all commercial sweet orange (Citrus sinensis L. Osbeck) cultivars are susceptible, though some are more tolerant than others. The citrus industry has an estimated economic impact nationwide of over $13 billion. The currently applied strategies for mitigating this disease are costly and unsustainable. The development and commercialization of HLB tolerant sweet orange scions is needed for sustainable and profitable citriculture in the US. Citrus Under Protected Screen (CUPS) is a method used in Florida to exclude the Asian Citrus Psyllid (Diaphorina citri Kuwayama, or ACP), which is a phloem-feeding hemipteran insect that is the vector for Candidatus Liberibacter asiaticus CLas the causal agent believed to be responsible for HLB disease in citrus. ‘Hamlin’ sweet orange is the most important early sweet orange for processing in modern history. ‘Hamlin’ has a budline called ‘Hamlin 1-4-1’, which is the predominant budline in the State of Florida. ‘Hamlin 1-4-1’ has high susceptibility to HLB, which causes symptoms such as blotchy mottle, small fruit size, high titratable acidity (TA), low total soluble solids (TSS), and severe fruit drop. ‘Hamlin N13-32’ is a new budline of ‘Hamlin’ sweet orange that appears to have enhanced tolerance to HLB in terms of tree health. ‘Hamlin 1-4-1’ and ‘Hamlin N13-32’ trees were followed for two years in multiple environments with and without treatments of oxytetracycline. Tree size, rootstock, fruit number, fruit size, TSS, TA, TSS:TA ratio, and pounds-solids data were collected to determine the effects of environment (CUPS versus outside grove), antibiotic treatment effects, and budline effects on production. There were some significant differences among groups for fruit quality, but more research is needed to determine effects of oxytetracycline, budline, rootstock and environment on ‘Hamlin’ sweet orange production.
Speakers
JC

John Chater

University of Florida
Tuesday September 24, 2024 2:45pm - 3:00pm HST
South Pacific 4

2:45pm HST

HEMP 1 - Impact of Cover Crops on Weed Pressure and Soil Health in No-till Fiber Hemp Production
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Current fiber hemp (Cannabis sativa <0.30% total THC) production systems rely on pre-emergent herbicides to manage weeds prior to canopy closure. Due to the rapid growth of fiber hemp, paired with the plastic nature of the crop, the need for weed suppression is most critical in the first month after planting. No-till systems with a rolled cover crop residue may be able to provide weed suppression without the use of herbicides, which can lower the cost of inputs, reduce the risk of negative environmental impacts associated with herbicide use, and improve soil health. Four cover crops - crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), cereal rye (Secale cereale), and triticale (xTriticale)- were roller-crimped into a mulch, and fiber hemp was no-till drilled into the residue. Each cover crop plot was paired with two bare ground plots, one of which was weeded weekly, while the other remained weedy. This design was repeated in three locations in the coastal-plain region of North Carolina (Kinston, Clinton, and Goldsboro). Crop emergence, weed counts and biomass, and fiber hemp biomass and yield were measured in each plot. Cover crop biomass was measured before planting and after retting to determine whether this residue may be a potential contaminant during baling. Soil health parameters were compared among cover and bare plots. Hairy vetch resulted in greater hemp emergence in Kinston, but emergence was not affected by the mulches otherwise. Hairy vetch plots had less weeds than others in Clinton and Goldsboro. Soil respiration and potentially oxidizable carbon did not differ by treatment, with the exception of higher soil respiration in grass covers in Goldsboro. Cover crop biomass remaining after retting was higher in grass plots than legume plots, indicating a potential for bail contamination. These preliminary results indicate that fiber hemp can be grown in a no-till system.
Speakers
AG

Ashlee George

Graduate Student, North Carolina State University
Co-authors
AW

Alex Woodley

North Carolina State University
NA
DS

David Suchoff

North Carolina State University
NA
SH

Shannon Henriquez Inoa

North Carolina State University
NA
Tuesday September 24, 2024 2:45pm - 3:00pm HST
South Pacific 1

2:45pm HST

PB 1 - CRISPR/Cas9-Mediated Development of Low Mowing Frequency Perennial Ryegrass and Tall Fescue Varieties
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Tall fescue (Lolium arundinacea Schreb.) and perennial ryegrass (Lolium perenne) are common cool-season turfgrass species. They are widely utilized in home lawns, athletic fields, golf courses, and roadsides. However, these grasses require frequent mowing to maintain lawn quality. Developing low-mowing frequency varieties is highly desirable because it can significantly reduce maintenance costs and fuel consumption. Gibberellin 20-oxidases (GA20ox) are key genes in the gibberellic acid (GA) biosynthesis pathway, mutations in which can induce a dwarf phenotype in plants and, therefore, reduce mowing frequency, as demonstrated by our dwarf turf varieties developed using conventional mutagenesis techniques. We have recently employed CRISPR/Cas9 technology to create knockout or knockdown mutations in the GA20oxidase1 gene to develop dwarf tall fescue and perennial ryegrass lines. The CRISPR/Cas9 construct used for editing LaGA20ox1 and LpGA20ox1 has ZmUbi and OsU6a promoters controlling the expression of Cas9 and sgRNA, respectively. We have delivered the CRISPR/Cas9 construct into tall fescue and perennial ryegrass via Agrobacterium-mediated transformation. We have observed a 35-50% reduction in plant height compared to the parental wild-type plants. Furthermore, the leaf widths in these mutants are reduced by 30-60%. Some mutants display a smoother leaf texture compared to the wild type. The T2 homozygous mutant progenies will undergo field evaluation for mowing frequency and fertilizer requirements. We anticipate that some of these gene-edited lines should exhibit a significant reduction in mowing frequency and fertilizer input.
Speakers
RB

Roshani Budhathoki

University of Connecticut
Tuesday September 24, 2024 2:45pm - 3:00pm HST
South Pacific 3

2:45pm HST

PH 1 - Preserving Flavor in Grapefruit Juice: Continuous Flow High-Pressure Homogenization Versus Conventional Treatment
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Grapefruit is known for its citrus aroma and tangy flavor. Processors use post-harvest preservation methods for juice production to maintain quality during storage for market distribution. These processes aim to preserve quality and safety while reducing unwanted compounds such as furanocoumarins. However, traditional methods like thermal pasteurization alter sensory quality and nutrient contents. With consumers demanding fresh-like taste without safety issues, researchers have aimed to develop new processing technologies. Here, we tested continuous flow high-pressure homogenization (CFHPH) for grapefruit juice processing. This method may extend shelf-life while maintaining fresh-like flavor. In this study, CFHPH was applied at various pressure levels (200, 250, 300 MPa), inlet temperatures (4 or 22 °C), and a flow rate of 1.125 L/min, and compared with conventional high-temperature short time (HTST) processing for preserving flavor compounds in Ruby Red grapefruit juice during storage at 4 °C for 45 days. Gas chromatography–mass spectrometry analysis identified key volatile compounds such as limonene, myrcene, α-pinene, β-pinene, and linalool. CFHPH preserved flavor compounds better than HTST, while HTST treatments led to flavor loss and off-notes. CFHPH maintained major volatiles like limonene, suggesting its potential as a consumer-preferred preservation method. This research underscores the significance of innovative techniques for maintaining grapefruit juice sensory quality, which is essential for customer satisfaction and market success.
Speakers Co-authors
KA

Koushik Adhikari

University of Georgia
NA
RS

Rakesh Singh

University of Georgia
NA
Tuesday September 24, 2024 2:45pm - 3:00pm HST
South Pacific 2

2:45pm HST

VCM 1 - Applying Advanced Lighting Practices for Vegetable Propagation
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Propagation greenhouses produce a wide range of crops, each presenting unique responses to light quality and quantity. With dynamic LED lighting solutions now available and proven to be viable over large acreages, propagators can tailor their lighting protocols to each crop with regards to zone management, photoperiod, spectrum and intensity. The effects of light quality and quantity on plant morphology and growth are well documented and while the exact impact is not generalizable across all crops and varieties, certain themes hold true. For example, high levels of blue light are generally associated with compact plants and thick, waxy leaves. In contrast, high levels of far-red light can cause etiolation in multiple species through the shade avoidance response but enhances photosynthesis and growth when combined with red light. Given the high importance of crop morphology in propagation, dynamic Dynamic LED lighting has been used to develop advanced lighting protocols in the propagation of fruit, vegetable and ornamental crops. In the production of cucumber transplants, applying high levels of blue light and a long photoperiod effectively slows the growth of cucumber transplants at the end of the propagation cycle, a strategy which proved useful to a propagator looking to delay transplant delivery per the client’s request. Concretely, the combination of high blue levels and a long photoperiod slowed crop growth, prevented tendril development and restricted plant stretching. Further, the use of high-blue treatments over young leafy greens effectively reduced plant height by 2-3 cm and produced stronger plants. Another trial focused on the production of strawberry tray plants found that a balanced light spectrum produced more stolons (i.e., daughter plants) while a blue-enriched spectrum produced significantly more leaves. In the production of ornamentals, dynamic lighting can be used to reduce the greenhouse’s reliance on plant growth regulators (PGRs), enhance leaf or petal coloration and trigger bud formation. In red-leafed varieties, controlled light-induced plant stress through spectral and/intensity adjustments have proven effective at stimulating the production of red pigments and enriching the leaves’ hue. Results from various commercial and research trials demonstrate benefits of dynamic LED lighting in the propagation of horticultural and ornamental crops alike. This presentation presents data from the aforementioned case studies among others.
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 →
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Kahili

2:45pm HST

VSF 1 - Improving the Climate Resilience of Wine Grape Vineyards via Trellis Selection and Applied Water Amounts in Warm/Hot Viticultural Regions
Tuesday September 24, 2024 2:45pm - 3:00pm HST
In grape vineyards, trellis systems are used to provide specific canopy microclimate to optimize grapevine production, physiological performance, and berry composition. However, many major wine producing regions are being challenged by the constantly increasing air temperature and decreasing available water allocated for agricultural use. The objective of this study was to understand the impact of trellis system and applied water amount on grapevine productivity and grape quality. This study was conducted to evaluate six trellis systems, including a vertical shoot positioned (VSP), two modified VSP systems (VSP60 and VSP80), a single high wire (SH), a high quadrilateral (HQ), and a cane-pruned VSP-Guyot (GY) and three applied water amounts based on various crop evapotranspiration (ETc), including 25%, 50%, and 100%, in 2020 and 2021. The results showed that SH and HQ systems, once fully established, could have higher efficiency in accumulating total soluble solids (TSS) and total yield. Also, these two systems showed greater flavonol and anthocyanin accumulation in grape berry skins compared to the VSPs, possibly resulted from reduced chemical degradation from the hotter environment Being strongly correlated with canopy architecture, the flavonols and molar percentage of quercetin in berry skins, indicated that the VSP systems were more likely to be prone to overexposure and potential photooxidative stress. The three applied water amounts showed that with less water, grapevines would have lowered yield but increased berry flavonoid accumulation. Overall, this experiment provides information about selecting trellis systems and applied water amounts to optimize vineyard productivity and berry quality in warm/hot viticultural regions.
Speakers
RY

Runze Yu

Assistant Professor, California State University, Fresno
Co-authors
NT

Nazareth Torres

Universidad Pública de Navarra
NA
SK

Sahap Kaan Kurtural

Kurtural Vineyard Consulting
NA
Tuesday September 24, 2024 2:45pm - 3:00pm HST
Nautilus

3:00pm HST

CITR 1 - Hedging, Thinning, Controlled Release Fertilizer, and Oxytetracycline Trunk Injections to Mitigate Fruit Disorder Incidence in HLB-Affected 'Sugar Belle' Mandarin
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Global citrus production has been severely impacted by huanglongbing (HLB), a disease presumably caused by the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas). While there are not any commercial citrus cultivars currently available that have total resistance to this pathogen, several varieties show some degree of tolerance, including the LB8-9 ‘Sugar Belle’ mandarin. This cultivar was released by the UF/IFAS CREC Plant Improvement Team in 2009 and is known to be one of the most HLB tolerant varieties in HLB-endemic conditions when considering tree health. Fruit from this cultivar can be used for juicing or in the fresh market and with proper cultural care the trees consistently produce relatively high yields with typically an acceptable ratio of total soluble solids (TSS) to titratable acidity and value in pounds-solids per acre. Despite the improved tolerance to HLB in ‘Sugar Belle,’ many growers in Central and South Florida have had increased incidences of fruit disorders with this variety in the past several seasons. Fruit that are misshapen, have a poor peel color, or go soft on the tree are more common making this cultivar often undesirable for packing houses. The objective of this study is to determine if hedging the trees at different times (early summer, middle summer, or late summer), manually removing ~50% of the developing fruit in July (thinning), controlled release fertilizer applications, or oxytetracycline trunk injections will help mitigate some of the incidences of fruit disorders and increase overall fruit and juice quality at harvest. There were two sites used for this experiment (The Citrus Research and Education Center in Lake Alfred, FL, and Tamiami Citrus “Bee Branch Grove” in Avon Park, FL) and it was conducted over two seasons 2022-2024. Significant differences (p-value < 0.05) were discovered among the treatment groups in terms of TSS, titratable acidity, sugar:-acid ratio, pounds-solids per box, fruit size, yield, percent asymptomatic fruit, and peel rupture force. Despite evidence that some treatments may provide benefits to the grower, more research is needed to mitigate the soft fruit problem in ‘Sugar Belle’ mandarin.
Speakers
JV

Joe Volpe

University of Florida
Tuesday September 24, 2024 3:00pm - 3:15pm HST
South Pacific 4

3:00pm HST

HEMP 1 - Heavy Metal Application Timing Impacts Plant Growth in Cannabis sativa
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Cannabis sativa is a known hyperaccumulator of heavy metals (HM), and testing of hemp medicinal products is required for HM contaminants including arsenic (As), cadmium (Cd), and lead (Pb). The objective was to evaluate how the timing of HM applications impacts hemp growth. A plant experiment was conducted where 40 Cannabis sativa ‘Wife’ hemp plants were grown in deep water culture systems in a growth chamber. Aqueous nutrient solutions including combined As, Cd, and Pb were applied directly into the hydroponic solution on a weekly basis, with HM concentrations of 0.0, 0.5, and 1.0 mg HM/L. During the first six weeks, plants were grown under long days to promote vegetative growth, and 15 plants were harvested at the end of this vegetative growth phase. The remaining 25 plants were grown under short days to initiate flowering, with harvest 6 weeks later. Total dry mass (P < 0.05), shoot dry mass (P < 0.05), and root dry mass (P < 0.01) were significantly affected by HM application timing. The total and shoot dry mass was the highest for the control group, followed by the plants that received HM at 0.5 or 1.0 mg/L during the reproductive phase, and the least growth occurred in plants that received HM at 0.5 or 1.0 mg/L during the vegetative phase. Root dry mass decreased as HM concentration increased (P < 0.05). Flower dry mass was not significantly affected by HM application timing or concentration. Results highlight how exposure to HM at 0.5 to 1.0 mg/L markedly reduce biomass accumulation, especially when exposure occurs early in the production cycle.
Speakers
HM

Harrison Meekins

University of Florida
Co-authors
PF

Paul Fisher

University of Florida
NA
Tuesday September 24, 2024 3:00pm - 3:15pm HST
South Pacific 1

3:00pm HST

PB 1 - Precision Breeding Using CRISPR to Improve Production Traits in Blackberry
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Pairwise is a technology-focused food and agriculture company that makes tiny alterations to plant genetics to solve big problems. Powered by our best-in-class technology, Pairwise is harnessing new genomics technologies to create innovative new products. With our FulcrumTM platform, we accelerate innovation in plants and plant-based production systems, delivering value to people and our planet. Partnering with Plant Sciences, Inc. to access their elite germplasm, we created a platform to transform and edit tetraploid blackberry (Rubus sub. Rubus). We used the power of genetics and genomic tools to identify the candidate gene for thornless in blackberries and used CRISPR based gene editing to validate the trait. The identification of this gene will enable faster deployment of a thornless trait, an essential production trait, into blackberries. The gene may be broadly applicable to other Rubus species and horticultural crops such as roses.
Speakers
avatar for Pradeep Marri

Pradeep Marri

Associate Director, Controlled Environments and Trait Testing, Pairwise Plants
Co-authors
Tuesday September 24, 2024 3:00pm - 3:15pm HST
South Pacific 3

3:00pm HST

PH 1 - Effects of Alternative Atmosphere Storage on the Postharvest Quality of Georgia-grown Blackberries
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Blackberries have several susceptibilities that contribute to the fruit’s high perishability resulting in a short shelf-life. The industry-standard technique for maintaining the postharvest quality is to store berries in a room with low temperature and high relative humidity to slow senescence. Despite the use of cold storage, the shelf-life of fresh-market blackberries can be short, limiting their marketing potential. The application of innovative technologies such as controlled atmospheres (CA), or the addition of gaseous ozone (O3) to the cold storage rooms could aid in maintaining the postharvest quality. During the 2023 blackberry season, three harvests were conducted paired with a sensory survey one day after. Four blackberry cultivars (Caddo, Ouachita, Ponca, Osage) were hand-picked, field-packed, and hand-sorted before being placed into cold storage. The storage conditions included a control of cold storage (1 °C, 95% RH), cold storage with additional controlled atmosphere (10% CO2 10% O2), and cold storage with gaseous ozone (0.5 ppm). The blackberries were kept under the above storage conditions for up to 21 days, with quality assessments occurring every seventh day. Quality assessments included sensory attributes of visual quality, weight loss, color, firmness, respiration rates, red drupelet reversion (RDR) presence, anthocyanin content, titratable acidity, and total soluble solids. Significant differences between treatments were recorded in fruit firmness of Caddo and Ouachita berries after seven days of storage. The CA and ozone treatments resulted in higher firmness of Caddo berries compared to the control. The CA and ozone treatments resulting in lower firmness of Ouachita berries compared to the control. RDR was separated by presence of RDR with the parameters none, low, and high. In each harvest, Ouachita had the highest presence of RDR after harvest compared to the other cultivars. Caddo exhibited low to no RDR in each harvest initially and after storage. Caddo was favored by panelists in the sensory survey related to the overall flavor and overall appearance. The experiment will be repeated during the 2024 blackberry season to evaluate the above cultivars’ aroma volatile compound levels using a GC/MS system.
Speakers
RC

Ramsey Corn

University of Georgia
Co-authors
AD

Angelos Deltsidis

University of Georgia
OG

Orestis Giannopoulos

University of Georgia
ZR

Zilfina Rubio

University of Georgia
Tuesday September 24, 2024 3:00pm - 3:15pm HST
South Pacific 2

3:00pm HST

VCM 1 - Evaluating the Effect of Three Algae Extracts Application on Three Crops Growth and Yield in Hawaii
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Food- and nutritional-security are among the highest concerns for Hawaii residents. The state imports about 85% of the consumed food and there’s roughly two-week worth of food locally at any given time. Local food production is costly due to high inputs cost. Algae extracts are known to supports plants' flowering and fruiting, increasing plant nutrient uptake, enhancing resistance and recovery from plant stress events, and increasing nutrient use efficiency and fertilizer assimilation. Three different algae extracts (Afrikelp, Acadian, and Kelpak) were evaluated for their effect on growth and yield of bush bean, bell pepper, and tomato in a randomized complete block design (RCBD) with 5 blocks. The algae extracts were applied 5 times during each growing season. The algae extracts were applied at dilution rate of 1:100 with a week between applications for the bush bean crop and two-week intervals for bell pepper and tomato crops. The results showed a highly significant (p < 0.01) increase in the three crops yield under all algae extracts compared to control (water only) treatment. The results also showed there was a significant (p < 0.05) difference between the algae extracts with highest yield recorded under Afrikelp extract compared to Acadian and Kelpak. The yield increase reached between 150-300% compared to control treatment.
Speakers Co-authors
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Kahili

3:00pm HST

VSF 1 - Heat Stress Effects on South Mississippi Grown Bunch Grapes
Tuesday September 24, 2024 3:00pm - 3:15pm HST
In the challenging climate of Mississippi, where high heat, rainfall, and humidity pose significant challenges to bunch grape (Vitis spp.) production, identifying resilient cultivars is essential for determining stress adaptation and sustainable agricultural practices. This study assessed the heat tolerance of nine interspecific hybrid bunch grape cultivars/selections (‘Ambulo Blanc’, ‘Black Spanish’, ‘Blanc du Bois’, ‘Lomanto’, ‘MidSouth’, ‘Miss Blanc’, ‘Muench’, OK392, ‘Victoria Red’) grown at the Mississippi Agricultural and Forestry Experiment Station South Mississippi Branch in Poplarville, Mississippi, in 2023. Stomatal density, stomatal conductance, transpiration, vapor pressure deficit, and chlorophyll fluorescence were evaluated both in the field and through leaf disks subjected to a 4-hour heat simulation. ‘Miss Blanc’ and OK392 exhibited the highest stomatal density, while ‘Black Spanish’ had the lowest. Monthly in-field measurements showed no significant differences in physiological measurements. Regarding specific cultivars undergoing the heat simulation, ‘Lomanto’ displayed elevated stomatal conductance and transpiration, contrasting with OK392 with lower values. ‘MidSouth’ showcased high chlorophyll fluorescence, whereas ‘Ambulo Blanc’ consistently displayed lower levels. ‘Miss Blanc’ and OK392 exhibited high vapor pressure deficit, while ‘MidSouth’ showed low values. Further analysis unveiled several correlations: a strong positive correlation between stomatal conductance and transpiration (r=0.9, P
Speakers
HW

Haley Williams

Mississippi State University
Co-authors
ES

Eric Stafne

Mississippi State University
NA
JR

Jenny Ryals

Mississippi State University
Tuesday September 24, 2024 3:00pm - 3:15pm HST
Nautilus

3:15pm HST

CITR 1 - Grove First: A Framework to Find Citrus Greening Treatments that are Safe, Affordable, and Available.
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Citrus greening (Huanglongbing, HLB) is considered one of the most devastating diseases affecting the global citrus industry. There is an urgent need to provide relief from HLB and restore profitable citrus production. Since 2005, over a billion dollars has been spent on research to find a solution to HLB. Trunk injection with the antibiotic oxytetracycline is the current treatment that Florida growers are using to manage the disease. To broaden the number of molecules available to growers to treat HLB a framework was developed to efficiently screen molecules in citrus groves, selecting those that enhance tree health over a season. The framework is based on the principles of the design-of-experiments (DOE). Utilizing the injection system developed by TJ Biotech (LLC), 88 molecules were injected into 8-year-old ‘Valencia’ sweet orange (Citrus × sinensis) trees grafted on ‘US-812’ (Citrus reticulata × Poncirus trifoliata) rootstock over a six-week period. The injections were divided into nine sets, with varying numbers of molecules injected in each set (12, 10, or 6). The injections were administered into the scion, approximately 5 cm above the graft union. Visual assessments of tree health index and canopy density were collected to evaluate changes in restoring tree horticultural traits. Ratings were recorded before injections and at 90 and180 days post-injections. In addition to health index and canopy density, a series of seven pictures were taken per tree on the injection day and subsequently at 30, 60, 90, and 180 days after injections. Pre-harvest fruit drops were measured by counting and removing any fruits on the ground beneath each tree. The total number of fruits on each tree was tallied at harvest to calculate the percentage of fruit drops for each tree. Yield, fruit, and juice quality were assessed at harvest. In this screening trial, trees injected with oxytetracycline have been used as a positive control to indicate enhancement in tree health. Results from the tree health index obtained at 90 and 180 days after injection showed that 17 molecules performed similarly or better than the oxytetracycline-treated positive control. We are partnering with regulatory consultants to identify those that are safe and affordable. New molecules for injection will require regulatory labeling.
Speakers
GL

Guilherme Locatelli

University of Florida
Co-authors
EC

Ellen Cochrane

University of Florida/USDA
NA
LR

Lorenzo Rossi

University of Florida
ML

Michelle L Heck

Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service/ Plant Pathology and Plant Microbe Interactions Section, School of Integrative Plant Science, Cornell University
NA
RN

Randall Niedz

U.S. Horticultural Research Laboratory, U.S. Department of Agriculture, Agricultural Research Service
NA
Tuesday September 24, 2024 3:15pm - 3:30pm HST
South Pacific 4

3:15pm HST

HEMP 1 - Photoperiod Sensitive CBD Hemp Response to Fertigation Nitrogen Inputs in a Raised-bed Plasticulture Growing System
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Nitrogen (N) fertilization plays a key role in determining the productivity and quality of horticultural crops and limited information is available on the N requirements of photoperiod-sensitive CBD hemp (Cannabis sativa L.). With the objective of providing recommendations on N fertilization to CBD hemp growers a field study was conducted in Pennsylvania to evaluate the response to N inputs of two photoperiod sensitive CBD hemp genetic resources: a clone named ‘FunDip’ (The Hemp Mine) propagated using rooted cuttings and ‘Sour Kush’ (Kayagene) propagated using feminized seeds. Both selections were planted mid-June on raised beds mulched with black polyethylene film and served by drip irrigation. Plants were established at 1.5-m in-row and 2.4-m between rows. After planting both CBD hemp selections were fertigated weekly with urea (46-0-0) using seasonal application rates equivalent of 84, 168, 252, and 336 kg/ha of N. An unfertilized control was used to account for the N available through the soil and to estimate the crop N use efficiency. Treatments were arranged according to a split plot experimental design with four replications. Nitrogen treatments were randomized within the main plots while hemp selections were randomized within subplots. Each experimental unit had a minimum of 12 plants, unfertilized border rows and in-row areas were used as buffer zones to avoid fertilizer cross-contamination between different N applications rates. Plant response to N inputs was evaluated conducting biometric assessments during the growing season and at final harvest. Representative plants were sampled to measure leaf and inflorescence, stem, and total plant fresh and dry biomass. Oven-dried plant tissue samples were analyzed for their total N content to estimate the plant N accumulation during the growing season. At every biometric assessment, soil samples were collected and analyzed for pH, EC, and nitrate (NO3-) content. A quadratic response to N inputs was observed in both selections. At final harvest, the total fresh plant biomass of both genotypes was maximized with the application of 252 kg/ha of N and declined at higher N rate. However, no increase in plant dry biomass were observed in plants fertigated with over 168 kg/ha of N in both genotypes. An accumulation of NO3-N and associated increase in EC was observed with the progression of the growing seasons especially in plots fertigated with over 84-168 kg/ha of N, in Sour Kush and FunDip, respectively, which suggest an excess of N was applied with N rates exceeding 84-168 kg/ha.
Speakers
FD

Francesco Di Gioia

Pennsylvania State University
Co-authors
AC

Alyssa Collins

Pennsylvania State University
NA
BM

Ben Morrison

Pennsylvania State University
NA
MK

Misha Kwasniewski

Pennsylvania State University
NA
TJ

Trevor Johnson

Pennsylvania State University
NA
Tuesday September 24, 2024 3:15pm - 3:30pm HST
South Pacific 1

3:15pm HST

PB 1 - Double CRISPR Knockout of Pectin Degrading Enzymes Improves Tomato Shelf-life While Ensuring Fruit Quality
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Tomato fruit is an important and popular commodity worldwide. One of the main challenges for the fresh market tomato industry is postharvest deterioration, which is mainly determined by the rate of softening. This rate can affect tomato shelf-life, pathogen susceptibility, and fruit waste. The softening rate is regulated by multiple factors, but mainly by the pectin composition of the cell wall, which is remodeled, disassembled, and solubilized by enzymes during fruit ripening; a process that induces and determines the fruit softening in fleshy fruits. The main pectin-degrading enzymes that act on the pectin backbone are Polygalacturonases (PG) and pectate lyases (PL). In this study, we generated a double CRISPR knockout PGPL. We investigated the combined functions of SlPG2a and SlPL on fruit quality traits in postharvest, including shelf-life attributes like firmness and water loss, fruit marketability, and disease incidence. We also assessed additional attributes impacting consumer acceptance, such as taste and aroma. Our findings revealed that the tomato ripening enzymes SlPG2a and SlPL act additively, significantly affecting fruit firmness and shelf-life. Additionally, aspects of fruit quality, such as external color, sugar: acid ratio, and aroma volatiles, were improved or not affected in the double CRISPR knockout PGPL when compared to control. The discoveries of this research provide new insights into the influence of pectin backbone degradation on fruit physiology and postharvest quality, which can be used in crop improvement programs to make fruit more resilient in the supply chain without compromising consumer-based quality traits.
Speakers
avatar for Isabel Ortega Salazar

Isabel Ortega Salazar

University of California, Davis
Tuesday September 24, 2024 3:15pm - 3:30pm HST
South Pacific 3

3:15pm HST

PH 1 - Examining the Effect of Storage Temperatures on Chilling Injury Incidence of Georgia-Grown Peaches
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Peaches are climacteric fruit that can continue ripening after harvest. When stored at elevated temperatures, peaches exhibit higher respiration rates and increased ethylene production, which makes low-temperature storage key for quality preservation. Cold storage slows down metabolic activities responsible for senescence. However, temperatures between 36 and 46°F (2.2-7.7°C) might induce a disorder commonly known as chilling injury, hence, this range has been named by many scientists as the “killing zone”. The disorder is detrimental to peach quality as it affects the flesh texture, appearance, and fruit juiciness overall. Depending on the severity, peaches might not show external symptoms of the disorder which usually appears after transfer to ambient conditions. Factors such as varietal differences, storage durations, and growing conditions may influence the severity of chilling injury symptoms. Very little research has been done in the Southeast regarding chilling injury incidence, while many of the newer cultivars have never been investigated. This project aimed to investigate the appearance of chilling injury symptoms in important peach cultivars grown in the Southeastern United States. Peaches were stored at five different temperatures of 33, 36, 41, 46, and 50°F (0.5, 2.2, 5, 7.7, and 10°C) and 95% relative humidity for up to four weeks. Quality evaluations occurred on days 0, 7, 14, 21, and 28 after harvest, which were followed by three days of ambient storage to allow for the development of chilling injury. Quality measurements included weight loss, decay incidence, total soluble solids, titratable acidity, firmness, as well as visual appearance. Results show that 33°F storage temperatures had lower respiration. Higher storage temperatures of 41, 46, and 50°F resulted in increased weight loss and lower firmness readings. Peaches stored at 33 and 36°F were juicier until the 21st day of storage. All tested temperatures were tolerated for a storage period of 7 days, with no visible symptoms. On the other hand, storage durations longer than 14 days at temperatures of 36, 41, and 46°F showed the highest chilling injury incidence. More research is currently underway in order to create a map of chilling injury tolerance across different cultivars that are important for the Southeastern region.
Speakers
avatar for Orestis Giannopoulos

Orestis Giannopoulos

Graduate Research Assistant, University of Georgia
Co-authors
AD

Angelos Deltsidis

University of Georgia
DC

Dario Chavez

University of Georgia
NA
RC

Ramsey Corn

University of Georgia
Tuesday September 24, 2024 3:15pm - 3:30pm HST
South Pacific 2

3:15pm HST

VCM 1 - Early Season Soil Tarping Impacts on Weed Pressure and Onion Production in Eastern South Dakota
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Onions are a globally popular kitchen staple, not only for their flavor, but also their nutritional value. According to the Agricultural Marketing Research Center, onions are the fourth most consumed fresh vegetable in the United States. To bring this valued crop to our kitchen tables, quality onions must be produced in high quantities to meet consumer demands. Since they are especially susceptible to weed competition due to their minimal canopy cover, weed management is an important consideration for onion production. One weed management tool is soil tarping. This study evaluated the impact of two types of tarping (solarization and occultation) and duration of tarping (6-, 4- and 2-weeks) on weed control in Patterson and Candy onion production. Field experiments were conducted during the 2023 growing season in Brookings, South Dakota. Solarization was conducted using clear tarps secured with sandbags and buried edges. Tarps were placed in April and May at respective weeks before removal on May 30. Immediately following tarp removal, each plot was tilled, and rows of onion transplants were planted. Occultation was evaluated using white side up and black side up silage tarps, both applied at respective weeks before removal and onion planting. Each treatment plot filled a twenty-four by ten-foot area. A randomized complete block design with four blocks and ten treatment plots per block including a control with no tarp was established. Response variables for data collection included weed type, height, and biomass as well as onion yield. All tarping treatment plots resulted in less weed pressure than the control at tarp removal. Broadleaf weed count collected during the growing season was different among tarp treatments (p=0.03). Data collected June 12 showed 6-week clear tarp to have 67% less broadleaf weed count per acre than the control, and 74% less than the 4-week black tarp. There was no difference in onion yield due to tarping treatment. This may have been due to biweekly weeding events that evened out treatment effect on weeds over the growing season. There was, however, a difference in yield between Candy and Patterson onion cultivars (p=0.02). Candy averaged a marketable count of 19 of 48 planted onions while Patterson averaged a marketable count of 36 of 48 onions planted. Soil tarping may be an effective option for farmers to reduce early season weeds in onion production, however, it should be used alongside other management strategies to obtain a viable yield.
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
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Kahili

3:15pm HST

VSF 1 - Rethinking Chill Models: The Role of Cold Hardiness, Freezing Temperatures and Daily Fluctuation on Promoting Dormancy Progression and Release
Tuesday September 24, 2024 3:15pm - 3:30pm HST
This study addresses fundamental questions in bud dormancy, specifically the impact of temperature on chill accumulation and cold hardiness on dormancy release. We evaluated bud cold hardiness (CH) and time to budbreak responses of grapevines throughout chill accumulation under three treatments: constant (5°C), fluctuating (-3.5 to 6.5 °C daily), and field conditions (Madison, WI, USA), during three dormant seasons. Findings reveal that lower temperatures in chill treatments result in greater cold hardiness gains (CHfield>CHfluctuating>CHconstant). All treatments reduce time to budbreak with increased chill accumulation. However, when time to budbreak was adjusted to remove cold acclimation effects, treatment effectiveness changed. Notably, existing chill models (North Carolina, Utah, and Dynamic) fail to accurately describe adjusted budbreak responses. Our results demonstrate how chill treatment effectiveness changes when adjustments for uneven acclimation are considered. We propose a new model that includes freezing temperatures and enhances chill accumulation under fluctuating conditions.
Speakers
AA

Amaya Atucha

University of Wisconsin Madison
Co-authors
AK

Al Kovaleski

University of Wisconsin-Madison
NA
BA

Beth Ann Workmaster

University of Wisconsin Madison
NA
MG

Michael G North

University of Wisconsin Madison
NA
Tuesday September 24, 2024 3:15pm - 3:30pm HST
Nautilus

3:30pm HST

CITR 1 - Can We Improve Growth and Production in HLB- Affected Citrus Trees Using Plant Growth Regulators?
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Huanglongbing (HLB) disease is arguably the biggest concern for citrus growers in Florida causing a drastic more than 75% decline in citrus-bearing acreage since 2005. HLB symptoms include sparse canopy, poor leaf growth and development, ultimately resulting in yield losses. Standalone applications of plant growth regulators (PGRs) and certain antibiotics have been reported to reduce the impact of HLB on tree growth and promote new flush growth. However, very little research has been done on synergistic effect of PGRs and antibiotics on tree growth and yield. The goal of HLB mitigation strategies is to promote a denser canopy, enhancing source to sink ratio as trees with dense canopies are known to produce high fruit yield. Thus, we initiated a field study to evaluate foliar applications of PGRs (auxins, cytokinins, and gibberellins) and trunk injections of Oxytetracycline (OTC) in 9-year-old orchards of Valencia on ‘Swingle’ rootstock in central Florida. This is the first research in citrus where PGRs are being applied according to tree phenology. The experimental design is a split-plot with a completely randomized block design with 8 replications. The antibiotic programs (with and without OTC injections) are assigned to the main plots, while the PGR treatments assigned to the subplots consist of an no PGR control, PGR applications with varying concentrations, and PGR applications with constant concentrations throughout the year. Parameters such as leaf area, fresh weight, dry weight, water content, chlorophyll content, starch content and carbohydrate content from leaf samples are recorded every three months starting from July 2023. Over 9 months no consistent pattern of PGR or OTC treatment was observed for vegetative traits. Nonetheless, Non-OTC trees showed higher leaf water content compared to OTC during the dry season months of October and January. Regarding yield, the study suggests that both PGR treatments, when applied with or without OTC lead to significant improvement in yield. PGR variable treatment showed 30% improvement in yield efficiency compared to both the control and PGR Constant treatments. No difference is observed between OTC and Non-OTC programs in terms of yield efficiency. These findings suggest that use of PGR treatments regardless of use of antibiotics can be beneficial for growers.
Speakers
PV

Prudhvi Vulchi

University of Florida, CREC
Co-authors
AL

Amit Levy

University of Florida
NA
TV

Tripti Vashisth

University of Florida
Tuesday September 24, 2024 3:30pm - 3:45pm HST
South Pacific 4

3:30pm HST

HEMP 1 - Field Evaluation of Controlled Release Fertilizer in Support of Best Management Practices for Industrial Hemp in Florida
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Successful field cultivation of hemp (Cannabis sativa L.) in Florida is restricted to summer months when rainfall is highest, as hemp is exceptionally sensitive to daylength. Given the prevalence of soils in Florida with poor nutrient and water holding capacities, controlled release fertilizer (CRF) could be ideally suited for outdoor cultivation due to its slow-release profile. To assess the effectiveness of CRF to support plant growth while minimizing water quality risks, the plant growth and biomass production of four hemp cultivars (‘Wife’, ‘Sunset Improved’, ‘FunDip’, and ‘Belle’) were evaluated in response to nitrogen and phosphorous availability from ten CRF formulations in Apopka, Florida during the summer of 2023. Plant growth was assessed post-transplant and monthly thereafter until harvest by measuring the height, widest width, and width perpendicular to the widest width of each hemp plant. At harvest, plants were severed at the soil surface and dried at 70 degrees Celsius for three days. For each plant, the total plant biomass and total flower biomass was measured. Significant differences in plant growth and biomass production were found among varieties; however, minimal differences were found in plant growth and biomass production within variety in response to varying CRF formulations. These results suggest that CRF can provide adequate levels of fertility for the growth and development of hemp cultivated outdoors in Florida, and that selection of hemp cultivar affects plant growth and yield.
Speakers
avatar for Shea Keene

Shea Keene

Postdoctoral Associate, University of Florida
Co-authors
AW

Ajit Williams

University of Florida
NA
BP

Brian Pearson

Oregon State University
NA
HS

Hardeep Singh

University of Florida
NA
JB

Jehangir Bhadha

University of Florida
NA
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 →
TS

Tamara Serrano

University of Florida IFAS-TREC
NA
WD

Winniefred D Sharma

University of Florida
NA
ZB

Zachary Brym

University of Florida
NA
Tuesday September 24, 2024 3:30pm - 3:45pm HST
South Pacific 1

3:30pm HST

PB 1 - Functional Characterization of a Candidate Bacterial Wilt Resistance Gene in Tomato
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Bacterial wilt, caused by Ralstonia solanacearum (Rs), is an economically devastating plant pathogen that causes rapid death and has been widely distributed worldwide. Rs is a soil-borne bacterium that plugs plant xylem vessels, causing wilt and ultimately death in tomatoes (Solanum lycopersicum L.) and many other economically important crops. The most cost-effective and efficient means of managing Rs is planting resistant cultivars. However, acceptable Rs resistance in these genotypes is tightly linked to small fruit size, preventing development of BW-resistant large fruited tomato cultivars. Previous research has shown that a highly resistant cultivar's candidate resistance gene (Sl-BWR) is linked to qualitative resistance of Rs. Our preliminary data indicates that overexpression of the resistant allele in a susceptible cultivar background confers resistance comparable to the wild-type resistant allele. There is ongoing work to generate susceptible allele overexpression lines and knockout lines from the susceptible and resistant cultivars. We hypothesize the resistant allele knockouts will be susceptible to Rs, indicating that the candidate gene is the primary resistance factor. The gene could be functionally characterized to elucidate the Rs resistance mechanism in tomatoes to be deployed in a breeding program to develop resistant cultivars against bacterial wilt.
Speakers
JD

James Duduit

North Carolina State University
Co-authors
TA

Tika Adhikari

North Carolina State University
NA
WL

Wusheng Liu

North Carolina State University
Tuesday September 24, 2024 3:30pm - 3:45pm HST
South Pacific 3

3:30pm HST

PH 1 - Postharvest melatonin application maintains quality of jackfruit bulbs by alleviating enzymatic browning and oxidative stress under low temperature storage
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Jackfruit bulbs are susceptible to postharvest browning which is a major factor limiting shelf life and marketability. In this investigation, the impact of postharvest melatonin (MLT) application on enzymatic browning and antioxidant metabolism in jackfruit bulbs was evaluated. Jackfruit bulbs were dipped in different concentrations of MLT (0, 0.05, 0.1 and 0.2 mmol L-1) prior to cold storage at 4 ± 1 °C temperature and 85-90% relative humidity over the duration of 20d. MLT application considerably delayed the process of senescence as demonstrated by a reduction in browning index and softening of bulbs with 0.1 and 0.2 mmol L-1 MLT application, respectively. At the end of the storage period, 0.2 mmol L-1 MLT treatment significantly maintained higher ascorbic acid (46.9 %), total phenolics (22.3%) and total carotenoids (26.3%) compared to control. Whilst 0.1 mmol L-1 MLT application curtailed fruit weight loss (46.0%) and improved total flavonoid content (16.7 %) and DPPH radical scavenging activity (12.5%) as compared to the control. The levels of polyphenol oxidase and guaiacol peroxidase were significantly lower in 0.1 mmol L-1 and 0.2 mmol L-1 MLT treated bulbs, respectively. The activity of antioxidant enzymes including catalase, superoxide dismutase, and ascorbate peroxidase was improved with the application of 0.2 mmol L-1 MLT. In addition, all MLT treatments effectively reduced malondialdehyde, lipoxygenase and hydrogen peroxide radicals. These findings suggest that dip treatment of MLT (0.1 and 0.2 mmol L-1) effectively lessen flesh browning along with maintenance of antioxidant potential and postharvest quality of jackfruit bulbs.
Speakers
JK

Jashanpreet Kaur

PhD Scholar, Edith Cowan University
Co-authors
AW

Andrew Woodward

Edith Cowan University, Joondalup, Western Australia, Australia
NA
EA

Eben Afrifa-Yamoah

Edith Cowan University, Joondalup, Western Australia, Australia
NA
HM

Hafiz Muhammad Shoaib Shah

Edith Cowan University, Joondalup, Western Australia, Australia
NA
MS

Muhammad Sohail Mazhar

Department of Industry, Tourism and Trade Northern Territory
NA
ZS

Zora Singh

Edith Cowan University
Tuesday September 24, 2024 3:30pm - 3:45pm HST
South Pacific 2

3:30pm HST

VCM 1 - Evaluating the effect of fertilization and controlled-water deficit on growth and yield of compact vegetable plants
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Sales of compact vegetable bedding plants for the home-gardening market segment are increasing. However, production guidelines for these new crops are limited. Our objective was to assess the effect of fertilizer use and controlled-water deficit (CWD) on plant growth during production, and after-production effects on fruit yield. ‘Siam’ tomato and ‘Basket of Fire’ pepper plants were grown in a greenhouse for 4 and 6 weeks, respectively, using 10-cm containers. Half of the plants received a water-soluble fertilizer once a week, and the other half were irrigated with tap water only, relying on the starter fertilizer charge in the substrate (EC = 0.9 mS·cm−1). Plants were irrigated when the substrate volumetric water content (VWC) reached 0.15, 0.30, 0.45, or 0.60 m3·m–3. After the experiment, plants were transplanted into 20-cm containers, top-dressed with controlled-release fertilizer (CRF), and grown for another 10 weeks to evaluate carryover treatment effects. Plants that did not receive fertilizer were shorter and had a lower shoot dry mass (SDM) than those that were fertilized, regardless of species. Shoot height of tomato followed a quadratic trend in response to CWD, which peaked at 0.45 m3·m–3, whereas SDM linearly increased with increasing VWC. No growth responses to CWD were measured for pepper. However, plants of both species that did not receive fertilizer looked chlorotic and had a lower chlorophyll concentration than those that were fertilized (15 and 32 µmol·m–2 for tomato and 15 and 27 µmol·m–2 for pepper, respectively). Plant greenness increased after applying CRF, suggesting that applying fertilizer right before shipping could increase quality of these plants when grown with limited or no fertilizer to control growth. After the carryover phase, differences in plant growth were maintained, and differences in yield was measured between fertilized and non-fertilized plants (56 and 48 fruits for tomato and 153 and 112 fruits for pepper, respectively). Our results show that growth and yield of compact tomato and pepper plants are affected to a larger extent by fertilizer use than by substrate VWC.
Speakers
MF

Michael Fidler

Purdue University
Co-authors
CG

Celina Gomez

Purdue University
Tuesday September 24, 2024 3:30pm - 3:45pm HST
Kahili

3:45pm HST

CITR 1 - Methyl Salicylate and Gibberellic Acid For The Rehabilitation Of HLB- Affected Sweet Oranges.
Tuesday September 24, 2024 3:45pm - 4:00pm HST
Huanglongbing (HLB), is a serious bacterial disease affecting citrus trees. HLB, poses a significant threat to Florida
Speakers
GK

Gurleen Kaur

CREC, University of Florida
Co-authors
SP

Shalini Pareek

University of Florida-Citrus Research and Education Center
NA
TL

Taylor Livingston

University of Florida- Citrus Research and Education Center
NA
TV

Tripti Vashisth

University of Florida
Tuesday September 24, 2024 3:45pm - 4:00pm HST
South Pacific 4

3:45pm HST

PB 1 - Novel Short Synthetic Promoters for Constitutive Expression in Dicot Species
Tuesday September 24, 2024 3:45pm - 4:00pm HST
Determining the promoter motifs involved in regulating transcription, the first process of gene expression, is critical for synthetic promoter engineering. A gene’s promoter contains cis-regulatory elements, or motifs, which are binding sites for transcription factors (TFs) to initiate and drive transcription. Many bioinformatic tools have been developed for determining statistically overrepresented regions, representing sites of potential cis-regulatory elements, that are shared across groups of promoters. Combining the results produced by multiple bioinformatic tools can lead to improved detection accuracy of motifs conferring biological activity. In the present study, we compiled a set of 11 known soybean constitutive gene promoters under the assumption that some of the promoters are regulated by the same transcription factor(s). Seven bioinformatic tools capable of de novo motif discovery were used to determine potentially shared motifs within the promoters, which were then mapped back to the original promoter sequences. A total of 64 overlapping motif regions (OMRs) were commonly detected amongst the 11 constitutive promoters, and each OMR was cloned individually in front of the minimal CaMV 35S promoter driving GUSPlus reporter gene expression. Transient tobacco leaf agroinfiltration and subsequent quantitative GUS activity assays were used to determine each OMR’s ability to drive reporter gene expression. We found that 20 of the 64 bioinformatically-determined OMRs drove functional gene expression significantly higher than the basal levels conferred by the minimal 35S promoter. Of the 20 functional OMRs, 11 drove GUSPlus expression at levels from just twice that of the minimal 35S promoter up to nearly half of the full-length 35S promoter. We also transformed these 20 functional OMRs individually into Arabidopsis. While GUS staining is still ongoing, we identified a few OMRs which showed strong promoter strength in single-copied homozygous Arabidopsis seedlings. These functional OMRs are strong candidates for further characterization and can be used for crop improvement.
Speakers Co-authors
EB

Emily Brooks

North Carolina State University
NA
NM

Nathan Maren

North Carolina State University
NA
WL

Wusheng Liu

North Carolina State University
Tuesday September 24, 2024 3:45pm - 4:00pm HST
South Pacific 3

3:45pm HST

PH 1 - Catalysis of 1-Methylcyclopropene Degradation By Non-Target Materials: Metals and Metal Salts
Tuesday September 24, 2024 3:45pm - 4:00pm HST
1-Methylcyclopropene is a cyclic olefin that inhibits ethylene action and is released as a gas from a formulated cyclodextrin. Different concentrations of 1-MCP are used globally in the fruit industry to enhance the preservation of quality attributes. The concentrations applied cannot be considered stable due to losses to target and non-target sites within the storage or treatment room environment. Copper is used in cooling systems because it transfers heat more efficiently than many other materials, but it is also used as a catalyst for chemical modification. So, we investigated the absorption or degradation of 1-MCP by various metals, including copper. These forms included metal bars (hot and cold-rolled steel, aluminum, galvanized metal, silver, gold, stainless steel, and brass), copper pipes (polished, oxidized, and with patina) and copper salts [covellite (CuS, copper II sulfide); eriochalcite (CuCl22H2O, copper II chloride); chalcopyrite (CuFeS2, copper iron sulfide); cupric carbonate (CuCO3, copper II carbonate); chalcocite (Cu2S, copper I sulfide), cuprite (Cu2O, copper I oxide); chalcanthite (CuSO45H2O, copper sulfate); tenorite (CuO, copper II oxide), and cupric acetate (Cu(CH3CO2)2, copper II acetate)], which possessed copper atoms at different levels of oxidation. The metal pieces had a surface area of 435 cm2, and the powders weighed 1 g. We put the materials in 480-mL glass jars and added 50 μL L−1 of 1-MCP gas to the headspace. Gas concentrations were measured at 0, 2, 4, 6, and 24 h in both humid and dry conditions at room temperature. The loss of 1-MCP was more pronounced in humid condition than in dry condition except when exposed to cupric carbonate. While covellite, eriochalcite, and chalcopyrite caused a 1-MCP loss of over 90% within 24 h in both conditions, stainless steel, aluminum, galvanized iron mesh, silver and galvanized iron yielded a 1-MCP loss below 10%. On the other hand, the impact of copper pipes on reducing 1-MCP is evident, and the reduction of 1-MCP also increases as the oxidation level of the copper increases. Based on mass spectral analysis of the headspace in the treatment chambers, the decrease of 1-MCP appears to occur by adsorption by the materials, polymerization, and disintegration into break-down products. The implications for 1-MCP reductions in commercial treatment rooms will be discussed.
Speakers
OH

Ozge Horzum

Ankara University
NA
Co-authors
NS

Nobuko Sugimoto

Michigan State University
NA
PE

Philip Engelgau

Michigan State University
NA
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 →
Tuesday September 24, 2024 3:45pm - 4:00pm HST
South Pacific 2

4:00pm HST

WUM 2 - Irrigation Management With Spreadsheets in Small Farms
Tuesday September 24, 2024 4:00pm - 4:15pm HST
In the Central Serrana region, Espírito Santo state, Brazil, there is a predominance of small farms and the technological level used is still low, especially in terms of water use. Irrigation management can provide greater water use efficiency and promote optimization of crop productivity and conservation of water resources. Thus, this study aimed to implement an irrigation management program, using simplified electronic spreadsheets, for drip irrigation, based on the climatological water balance, for family-based farmers. We selected four spots located in the towns of Barra de Bom Destino; Barra de Jatibocas; Baixo Sossego and headquarters of the Itarana County, state of Espírito Santo, Brazil, with drip irrigation systems, irrigating banana, arabica coffee, guava and conilon coffee crops. Irrigation management was carried out for seven months, using daily temperature and precipitation data, obtained from maximum and minimum thermometers and rain gauges, respectively. The values were collected by farmers, noted in tables and registered in electronic spreadsheets, which provided recommendations for irrigation times. In adjacent areas, irrigation was carried out according to its local traditional rule, in the way that farmers did before the implementation of management, with the purpose of comparing the volume of water used in the two forms of irrigation. The banana irrigator followed the irrigation management guidelines using the spreadsheet and, comparing the two areas, achieved a 7.5% increase in productivity and a 9.34% increase in water use efficiency. Farmers in areas with arabica coffee and guava managed irrigation, but were not organized to collect crop productivity data. For guava cultivation, an increase in fruit load was visible in the area with irrigation management. The Conilon coffee farmer did not follow the irrigation management recommendations, considering the task laborious and complicated. Irrigation management continues to be carried out on farms with banana, guava and arabica coffee. New neighboring producers expressed interest in using electronic spreadsheets. Work has been done on the development of new tools for irrigation management, using smartphones, to facilitate the task of calculating irrigation management. Therefore, it is expected that with the continuity of the work, the practice of irrigation management will be more widespread among farmers and they will decide to use it.
Speakers
avatar for Gustavo Haddad Souza Vieira

Gustavo Haddad Souza Vieira

Full Professor, IFES campus Santa Teresa
Agronomist,Ph. D. in Agricultural Engineering. Full Professor. Irrigation, Agrometeorology, Horticulture, Coffee Crop.
Co-authors
Tuesday September 24, 2024 4:00pm - 4:15pm HST
Nautilus

4:15pm HST

EcoPhys 1 - Evaluating Plasticity and Acclimation of Linked Hydraulic Traits of Different Taxa Across a Climatic Gradient in the Western U.S.
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Increasing drought conditions and variable water availability under climate change impact plant productivity, ecosystem function and the global carbon cycle, with many species-level responses remaining unknown. Variation in response and ability to acclimate to decreased water availability differs among plant species and across biomes. This project utilized a preexisting water deficit trial of horticultural taxa across sites in the Western U.S. to assess the interactions between acclimation to climate and water availability across a growing season. Four focal taxa, Physocarpus ‘Diabolo’, P. ‘Little Devil’, Cercis canadensis and C. occidentalis shared across three locations in Washington, Oregon and Utah were measured for physiological and hydraulic traits on the leaf and stem scale in response to irrigation treatment. The cultivars of Physocarpus are popular landscape shrubs known for their distinctive purple foliage yet understudied physiologically. C. occidentalis and C. canadensis have distinct native ranges, with the former originating west of the Rocky Mountains while the latter is east coast in origin, thus their performance was compared across these western U.S. sites. Full gas exchange, specific leaf area, 13C isotope discrimination, hydraulic conductivity, stomatal conductance, ΦPSII, were analyzed and water use efficiency was calculated each taxon at each location. Impacts of site, treatment, taxa and change across the growing season were analyzed on this suite of traits. Results show distinctions in water use strategy by climatic location (p: 1e-05) and between closely related species and cultivars. Additionally, physiological measurements indicate measurable physiological plasticity across the growing season. These findings indicate the importance of setting on the ability of different plant cultivars to acclimate to water stress, taxa-level differences among horticulturally important species, and overall knowledge of plant drought response, knowledge gaps that are crucial to address in the face of anthropogenic climate change.
Speakers
AK

Amelia Keyser-Gibson

University of Washington
Co-authors
DH

Darren Haver

South Coast Research and Extension Center
NA
JS

Jared Sisneroz

University of California, Davis
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, Davis
MS

Miro Stuke

University of Washington
SH

Soo Hyung Kim

University of Washington
US

Ursula Schuch

University of Arizona
YS

Youping Sun

Utah State University
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Coral 1

4:15pm HST

RHIZ - Investigating the Effect of Pecan Rootstock on Rhizosphere Soil and Root Microbial Communities
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Pecans (Carya illinoinensis), the most valuable native North American nut crop, are commonly propagated through grafting to maintain desired traits from parent trees. Successful pecan cultivation relies on scion varieties, rootstocks, and soil conditions. This study investigated the microbial abundance and diversity in soils and roots of a southern rootstock (87MX5-1.7) and a northern provenance ('Peruque') in a rootstock test orchard, both grafted with a 'Pawnee' scion cultivar in the USDA ARS Pecan Breeding program. The 16S ribosomal RNA of bacteria and ITS of fungi were sequenced and annotated into trophic and nutrient-related groups to characterize the rhizosphere microbiota. The results showed fungal dominance over bacteria, with Peruque roots having a higher relative abundance of saprotroph fungi compared to 87MX5-1.7, while 87MX5-1.7 exhibited higher levels of nitrogen fixation-related bacteria. Despite no significant difference in diversity index, the presence of symbiotrophs, especially the ectomycorrhizal fungi, exhibited distinct ectomycorrhizal fungi, which may lead to a divergent pathway of nutrient translocation between these two rootstocks. The study suggests rootstocks from different origins shape rhizosphere microbiota differently, affecting nutrient uptake and potentially nut yield. Exploring rootstock-fungi combinations could enhance grafting success and ultimately increase nut yield.
Speakers
avatar for Xinwang Wang

Xinwang Wang

Plant Geneticist, USDA ARS
Co-authors
BT

Braden Tondre

USDA ARS Southern Plains Agricultural Research Center
NA
LZ

Lu Zhang

Oklahoma State University
TX

Tingying Xu

Oklahoma State University
NA
WR

Wei Ren

Oklahoma State University
NA
Tuesday September 24, 2024 4:15pm - 4:30pm HST
South Pacific 4

4:15pm HST

VGBR 1 - Genome-wide Association Study and Genome Prediction of Verticillium Wilt Resistance in Spinach
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Verticillium wilt, caused by Verticillium dahliae Kleb., poses a significant threat to spinach (Spinacia oleracea L.) production, necessitating genetic resistance as the primary defense against this disease. This study conducted a comprehensive genome-wide association study (GWAS) to identify single nucleotide polymorphism (SNP) markers linked to Verticillium wilt resistance in spinach and to evaluate genomic prediction for disease resistance. GWAS utilized a panel of 98 spinach germplasm accessions and 20,742 SNPs obtained from whole-genome resequencing. Various statistical models, including GLM, MLM, FarmCPU, and BLINK, were employed using the GAPIT 3 tool for analysis. Two quantitative trait loci (QTL) regions on chromosome 6 were found to be significantly associated with Verticillium wilt resistance. Specifically, SNP SOVchr6_29382746 at 29,382,746 bp and three SNPs (SOVchr6_86904401, SOVchr6_86906249, and SOVchr6_86906255) at 86,904,401 bp and 86,906,249 bp, respectively, demonstrated notable associations with disease resistance. Genomic prediction exhibited high accuracy, with a prediction ability (GA) represented by an r value of 0.95 for the panel. The identified SNP markers, along with the high prediction ability, offer valuable tools for breeders to select Verticillium wilt-resistant spinach plants and lines through molecular breeding, incorporating marker-assisted selection (MAS) and genomic selection (GS) strategies.
Speakers
KC

Kenani Chiwina

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
HX

Haizheng Xiong

University of Arkansas
Tuesday September 24, 2024 4:15pm - 4:30pm HST
South Pacific 3

4:15pm HST

WUM 2 - Assessing Micro-Irrigation Clogging Risk Through Water Quality Classification Systems
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Clogging poses significant economic risks in greenhouse micro-irrigation systems. While water quality classification systems aim to assess the overall risk of clogging in micro-irrigation systems, they haven’t been evaluated for their ability to predict potential clogging based on water quality characteristics, particularly in controlled environment agriculture. Understanding these causes can inform robust thresholds and effective water management strategies to mitigate economic risks associated with clogging. This project aimed to evaluate if the existing classification systems could be used to identify the cause of clogging in micro-irrigation systems in greenhouses. Water from eight commercial greenhouses with reported clogging was analyzed for physical, chemical, and biological properties to rate the risk of clogging according to the classification systems. In general, iron and manganese from the fertilizers and high microbial load resulted in high ratings. However, the ratings lacked insight into the specific causes of clogging, disregarding interactions among chemical and microbial factors and qualitative characteristics of specific microbial phenotypes (e.g., production of polysaccharides or iron oxidation) that lead to clogging. Furthermore, the systems overemphasize nutrient levels typically used in greenhouse fertigation as the cause of clogging—which is not commonly observed in practice. Enhancing these systems requires parameters that reflect interactions among water quality parameters and the influence of microbial traits on clogging. Further research needs to develop these parameters in new systems with robust and precise thresholds in which emitter performance, profitability, and sustainability are affected.
Speakers
avatar for Juan Cabrera-Garcia

Juan Cabrera-Garcia

Research Assistant Professor & State Extension Specialist, University of Missouri
My extension program focuses on providing research-based resources, trainings, and tools to beginning and established specialty crop growers. Check our programs focused on controlled environment agriculture (Veteran Farmers (umkc.edu)) and commercial horticulture (Commercial Hort... Read More →
Co-authors
MT

Mayra Toro Herrera

University of Connecticut
RR

Rosa Raudales

University of Connecticut
Tuesday September 24, 2024 4:15pm - 4:30pm HST
Nautilus

4:30pm HST

EcoPhys 1 - Climate Ready Stomata: Stomata Morphology and Physiology Varies Across Western US Sites and Irrigation Deficit Treatment
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Stomatal morphology dictates the maximum stomatal conductance and relates to plant water use efficiency and carbon assimilation rate. Aspects of stomatal morphology, including size characteristics and density, are plastic in some taxa, can respond to environmental stressors, and are thought to be relevant in drought acclimation within an individual. The Climate Ready Landscape Plants (CRLP) trial consists of 6 sites across the Western U.S. that have installed common garden drought experiments that utilized daily ETo to implement three water deficit treatments. Stomatal conductance and stomatal images were collected from 3 cultivars of Hibiscus syriacus and 3 cultivars of Rosa spp. from 4 of these sites: Seattle, WA; Aurora, OR; Davis, CA; and Irvine, CA. Stomatal images were measured to determine stomatal density and size, which was used to calculate gsmax. Differences between stomatal traits were tested between sites and water deficit treatments using ANOVA. Correlation between gsw and gsmax were determined with regression analysis. PCA was used to determine which site characteristics and treatments primarily explain observed differences. Here we aim to test 1) Are stomatal morphological traits plastic across water deficit treatments and sites in multiple Rosa and Hibiscus syriacus varieties? 2) Does measured stomatal conductance (gsw) correlate with morphologically derived anatomical maximums (gsmax)? 3) Do site characteristics across the maritime Western US predict physiological and morphological stomatal traits? Findings reveal important ecological and horticultural considerations in plant stress response to drought and acclimation potential across an environmental and latitudinal gradient. The results can help in plant selection and categorization of species vulnerability, based on ability to manipulate stomatal characteristics in response to water deficit.
Speakers
MS

Miro Stuke

University of Washington
Co-authors
JS

Jared Sisneroz

University of California Davis
LN

Lloyd Nackley

Oregon State University
NA
LO

Lorence Oki

University of California Davis
NL

Natalie Levy

University of California South Coast Research and Extension Center
NA
RC

Ryan Contreras

Oregon State University
SH

Soo Hyung Kim

University of Washington
YS

Youping Sun

Utah State University
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Coral 1

4:30pm HST

ORGH 1 - Assessing Producers’ Interest and Barriers in the Transition to Organic Principles
Tuesday September 24, 2024 4:30pm - 4:45pm HST
In the changing landscape of horticulture, sustainability and organic practices have taken center stage. As of the 2021 USDA Organic Certified Survey, 17,445 certified organic farms representing 4,895,279 acres operated in the United States. Our research aims to understand the motivations and barriers that producers encounter when transitioning from conventional to organic production. Mississippi State University partnered with the University of Nebraska – Lincoln as part of the USDA AMS Transition to Organic Partnership Program (TOPP) whose focus is on supporting mentorships, helping overcome barriers, and educating producers. Following a TOPP-sponsored workshop in November 2023, it was noted that both beginning and experienced farmers were very interested in the process of transitioning to organic production. Participants noted their decision to transition was “very much influenced” by economics, market demand, environmental concern, health, and ethics. A review of literature revealed that, while there is a significant body of research on sustainable practices, there remains a gap in understanding the challenges that producers face. To bridge this gap and address the key findings from our workshop, a 43-question national survey was developed. It addressed motivations and barriers while also gathering demographic data to contextualize responses. Producers were questioned about cover crops, crop rotation, no-till farming, and composting among other practices. Social, environmental, and technical concerns were also addressed. Responses included motivations driven by environmental consciousness as it relates to soil health, reduced synthetic chemical inputs, and the goal of improving and maintaining biodiversity on their farms reiterating our previous findings. Producers indicated that they are encouraged by the amount of information available concerning organic production practices; however, they noted a knowledge-implementation gap. Financial constraints and space limitations were also concerns. The survey functions as the inception point for a case study following a beginning farmer in Calhoun City, Mississippi as they adopt organic principles in a region where the use of these growing practices is less than common. The insights gathered from the workshop, national survey, and case study will guide the understanding of producers’ motivations and will serve to inform policymakers, extension services, and the horticulture community at large. This ongoing project and its explorations are not only timely but also critical in shaping a future where horticulture aligns with the ethos of conservation and social equity.
Speakers
BB

Brenton Breland

Mississippi State University
Co-authors
CC

Christine Coker

Mississippi State University
RS

Ronald Stephenson

University of Nebraska-Lincoln
NA
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Lehua Suite

4:30pm HST

RHIZ - Enhancing Urban Food Production: A Multi-Omics Investigation of Microbe-Mediated Soil Improvement and Plant Nutrition in New York City Farms
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Urban agriculture (UA) is an emerging food production system in which farmers grow crops within cities. However, many urban farmers face challenges with their compost soils, including poor soil structure and low nutrient availability. This study aimed to utilize beneficial microbes, such as arbuscular mycorrhizal fungi (AMF) and phosphorus solubilizing bacteria (PSB), to address soil aggregation and biological phosphorus (P) cycling in UA soils while also assisting urban farmers in generating higher economic returns. We cultivated Bush Champion II Hybrid Tomatoes (an indeterminate tomato cultivar) in three organic urban farms in New York City in 2022 under four different treatments: 1) Control tomatoes, which were not treated with PSB or AMF; 2) Tomatoes treated with PSB; 3) Tomatoes treated with AMF; and 4) tomatoes treated with PSB and AMF. Our hypothesis posited that the positive interactions of PSB and AMF would synergistically enhance soil phosphorus cycling and carbon accumulation and, thereby, promote plant growth and nutrition. Our findings indicate that the combined application of AMF and PSB increased the overall abundance of soil microbiomes, as measured by flow cytometry. There was also an increase in the production of soil-aggregating proteins and soil acid phosphatase activity. Additionally, the nutrient uptake by tomatoes, including calcium (Ca), potassium (K), and phosphorus (P), was enhanced. We also employed omics approaches using deep sequencing metagenomics and metaproteomics to generate meaningful insights into how AMF and PSB interacted with soil native microbial populations and defined soil microbiome functions. Our findings offer novel insights into the characteristics and functions of soil microbiomes in UA soils. This knowledge will contribute to advancing the potential of beneficial microbes in enhancing food production within urban agriculture systems.
Speakers
avatar for Yejin Son

Yejin Son

PhD Candidate, Cornell University
Tuesday September 24, 2024 4:30pm - 4:45pm HST
South Pacific 4

4:30pm HST

VGBR 1 - Spinach Seed for Grain Consumption: Feasibility and Potential for Genetic Improvement
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Spinach production is constantly challenged by endemic diseases that significantly reduce producers’ income. Even when resistant cultivars and cultural practices are used, mild disease damage can happen, negatively affecting quality and therefore reducing its commercial value. In contrast, under those conditions, spinach could still produce seed for grain with valuable nutritional content that can fetch premium prices for the gluten-free niche markets. This project evaluated grain production as an additional source of income by assessing yield potential, nutritional quality, and economic feasibility and potential for improvement. A total of ~200 USDA-NPGS accessions were evaluated for GWAS. For all nineteen amino acids evaluated, a wide range in content was observed. E.g. aspartic acid population mean was 106.5 nmol/g with a minimum of 36.2 nmol/g and a maximum of 353.9 nmol/g. Similar results were observed for all eight minerals evaluated. E.g. K population mean was 9,998.1 mg/kg with a minimum of 3,227 mg/kg and a maximum of 24,770 mg/Kg. High diversity can be used to improve nutritional content in spinach seed. Several SNP markers associated with amino acid and mineral content were identified in more than one nutrient, indicating pleiotropic genetic control. Furthermore, protein digestibility tests indicate that spinach provides ~50% of all amino acids required in the diet as compared with Amaranth and Quinoa protein in grain that provided ~20% of all amino acid required. Therefore, indicating spinach grain has a higher nutritional content as compared with highly demanded Amaranth and Quinoa grains. Finally, a partial budgeting approach was used to assess the economic feasibility of producing spinach seeds for grain. The added costs totaled US$ 218.71/ac, including custom harvesting (US$ 24/ac), an additional application of fertilizers (US$ 17.36/ac) and fungicide (US$ 62.54/ac), extra irrigation costs (US$ 60.63), and US$ 54.18/ac in associated interest on production expenses. The break-even price of seeds was estimated to be equal to US$ 0.20/lb when the average experimental yield was considered (i.e., 1,089lbs/ac). Producing seed for grain could expand the farmer portfolio, increase farmed acreage, and fringe products.
Speakers Co-authors
Tuesday September 24, 2024 4:30pm - 4:45pm HST
South Pacific 3

4:30pm HST

WUM 2 - Development of an Open-source, Autonomous Irrigation Controller for Horticultural Applications
Tuesday September 24, 2024 4:30pm - 4:45pm HST
An open-source data-driven irrigation controller, "Open_Irr", was developed by USDA-ARS as a low-cost (≤ $250 USD) entry point to autonomous irrigation installations in horticultural production and research applications. The device is reliant on granular-matrix type Watermark soil tension sensors (n≤16) from which it acts as a datalogger; sensors can be partitioned into 4 groups for water management in which readings can be used to output a logic-level signal for opening valving to initiate irrigation events. Here, we demonstrate the use of the device in research applications for imposing drought stress in containerized plantings of apple (Malus domestica). Our primary objectives were to (i) determine the utility of using granular matrix type soil tension sensors for predicting plant physiologic responses, measured by growth habit, infrared gas exchange, and chlorophyll fluorescence, for improvement of decision support systems; and (ii) determine potential differences in cultivar performance under water deficit conditions. A trial examined performance of ‘B.9’ rootstock grafted to ‘Autumn Gala’, ‘CrimsonCrisp’, and ‘Golden Delicious’ scions at set soil matric potential thresholds for irrigation events (-25, -40, -60, and -80 kPa). A second trial examined five rootstock cultivars (‘B.10’, ‘B.9’, ‘G.11’, ‘G.935’, and ‘G.969’) grafted to a common ‘Honeycrisp’ scion as plant available water contents of the soil were theoretically progressively decreased by 5% each week. Correlation matrices between aspects of physiology and soil matric potential revealed Pearson’s r ≤ |0.43| yet further regression analysis offered potentially useful data shapes warranting further exploration. A piecewise regression suggested soil matric potential could predict, to an extent (r2 = 0.29), the rate of change in leaf water potential upon exposure to water deficit. The break-point of the piecewise regression in leaf and edaphic potentials was respectively -30.6 kPa and -0.73MPa, which may prove useful for incorporation in developing irrigation decision support systems. The pattern of stomatal response to deficit suggested enhanced stomatal regulation capacity of ‘Gala’ relative to other scions in which nonstomatal factors likely contributed to short term maintenance of photosynthetic C assimilation rates. Similarly, the ‘G.935’ rootstock demonstrated superior sensitivity to water deficit through rapid stomatal closure relative to other cultivars. Refinement of the relationships between arduous measures of physiologic function with correlated easy-to-automate proxy measures is advised for potential advancement of irrigation decision support systems.
Speakers
AB

Andrew Bierer

USDA-ARS, AFRS
Co-authors
LT

Lisa Tang

USDA-ARS Appalachian Fruit Research Station
Tuesday September 24, 2024 4:30pm - 4:45pm HST
Nautilus

4:45pm HST

EcoPhys 1 - Ice Formation and Progression in Rhododendron, and a Mechanistic Hypothesis for Winter Thermonasty of Leaves
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Evergreen leaves of Rhododendron species inhabiting temperate/montane climates are typically exposed to both high radiation and freezing temperatures during winter when photosynthetic biochemistry is severely inhibited. This could lead to accumulation of excess energy (radiation) in photosynthetic reaction centers causing photoinhibition or photooxidative damage. Cold-induced ‘thermonasty’, i. e. lamina rolling and petiole curling/drooping, can reduce the amount of leaf area exposed to solar radiation and has been associated with photoprotection in overwintering rhododendrons. The present study was conducted on natural, mature plantings of a cold-hardy and large-leaved thermonastic North American species (R. maximum) during winter freezes. Infrared thermography was used to determine initial sites of ice formation, patterns of ice propagation, and dynamics of the freezing process in leaves to understand the temporal and mechanistic relationship between freezing and thermonasty. Results indicated extracellular freezing in leaves always preceded the initiation or intensification of thermonasty. Ice initially formed in the vascular tissue of the midrib and then propagated into other portions of the vascular system/venation. Ice was never observed to initiate or propagate into palisade, spongy mesophyll, or epidermal tissues. These observations, together with the leaf- and petiole-histology, and a simulation of the rolling effect of dehydrated leaves using a cellulose-based, paper-bilayer system, suggest that thermonasty occurs due to anisotropic contraction of cell wall cellulose fibers of adaxial versus abaxial surface as the cells lose water to ice present in vascular tissues.
Speakers
RA

Rajeev Arora

Iowa State University
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Coral 1

4:45pm HST

ORGH 1 - Merging Traditional Ecological Knowledge with Modern Organic Practices: A Case Study in Participatory Research
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Research in plant ecology and sustainable farming advocate for increasing crop diversity on farms over monocultures. Crop diversity provides many ecosystem services, but mainstream farming relies heavily on mechanical and chemical solutions known to degrade land quality to ensure optimal yields. For centuries, Indigenous peoples in North America maintained sustainable cropping systems characterized by crop diversity and minimal inputs, such as the Three Sisters system. To integrate this knowledge into current research, we collaborated with Indigenous corn growers in Wisconsin interested in growing their traditional corn varieties with cover crops seeded between the rows. Growers are interested in knowing which cover crop mixtures synergize well with their corns while suppressing aggressive weeds. Single and mixed plantings of winter wheat, clover, and chicory/plantain were sown after corn planting while establishing a hand-weeded and weedy control. From 2021 to 2023, we found the triple mixture to lower weed biomass at the end of the season while also having the highest total relative yield, indicating cover crops in this mixture accumulated more biomass than their single plantings. No corn yield was collected in 2022, but low nutrients impacted corn yield in 2021, which was lower overall compared to the 2023 corn yield. Within 2021, weed pressure played a significant role in reducing corn yield, but the single planting of clover and winter wheat had higher yields than the control left weedy and comparable to the control with no cover crops or weeds. In 2023 all cover crop treatments and controls did not differ significantly indicating these corn varieties have a potential higher tolerance from weed or cover crop competition. Indigenous growers now have data relevant to their corn varieties and their goals to preserve their traditional food systems. The trial and error from these experiments was integral to the relationship building between UW-Madison and our Indigenous partners, creating a shared learning environment to better understand sustainable farming practices. From this project, we have developed a framework to guide agricultural research with Indigenous communities centered on the principles of traditional Indigenous farming.
Speakers
ES

Erin Silva

UW-Madison
Co-authors
DH

Daniel Hayden

UW-Madison
NA
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Lehua Suite

4:45pm HST

RHIZ - Root Characterization Analysis of Navajo Peach Seedlings
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Southwest Native American Tribes, such as the Navajo, Hopi, and Pueblo, have grown peaches at least since the early 1600’s, making them a nutritionally and culturally important food source. Historic management practices consisted of reduced irregular irrigation of sandy to sandy loam soils with no fertilizer additions, no pruning, and no fruit thinning. Recent research indicates germinated peach seedlings from seed sourced from a Navajo orchard in Utah are more drought resistant when compared to direct seeded ‘Lovell’ seedlings, and container transplanted ‘Lovell’ seedlings. The purpose of this study was to characterize the Navajo seedlings’ root distribution after direct seeding to better understand their rooting dynamics with regular irrigation and no pruning. All trees were direct seeded in May 2018 and destructively sampled in May 2022. Three trees from each Navajo and ‘Lovell’ treatment were destructively harvested to determine above ground biomass. Root distribution (location relative to the trunk and depth in the soil profile) was determined using a soil core sampling technique. Soil cores were taken in a radial array around the tree, and tree roots (small, medium, large) were separated from the soil cores in the field, before drying and weighing. After the cores were extracted, the remaining root system was excavated, air dried for 10 days, then weighed and photographed. The main effect and interactions of tree type, sampling location, and depth were tested by analysis of variance. The Navajo seedlings had a more extensive root system, including more roots in the grass alleyways, than Lovell seedlings indicating a more competitive root system. There were also qualitative differences in root types between Navajo and ‘Lovell’ in the occurrence of lateral primary roots, sinker roots or fibrous roots. The results of this research will be utilized to determine the Navajo seedlings’ potential for becoming a viable rootstock for the fruit industry.
Speakers
RW

Reagan Wytsalucy

Utah State University
Native American food crops of the Southwest.
Co-authors
BB

Brent Black

Utah State University
NA
DD

Daniel Drost

Retired
NA
GC

Grant Cardon

Utah State University
NA
Tuesday September 24, 2024 4:45pm - 5:00pm HST
South Pacific 4

4:45pm HST

VGBR 1 - Progress and Insights Into Downy Mildew Resistance Mapping Efforts in Spinach
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Spinach (Spinacia oleracea) is a popular leafy vegetable crop in the US, particularly for the fresh market baby leaf spinach. However, downy mildew (DM), caused by the obligate oomycete Peronospora effusa, poses a significant challenge to spinach cultivation in California and Arizona as it reduces the quality and yield of spinach. This is particularly concerning given that the two production areas contribute over 85% of the total fresh market spinach in the US. The emergence of new races of P. effusa, with nineteen races reported and fourteen identified in the last two decades, presents a persistent threat as new races and variant isolates can overcome the existing resistance in commercially deployed cultivars. Furthermore, over 50% of the spinach market is organic production, so utilizing host genetic resistance is a crucial disease management strategy. To combat this challenge, we conducted screenings of germplasm, cultivars, and multi-parent progeny populations in greenhouse conditions to identify resistant sources and genomic regions associated with resistance to multiple races of P. effusa (specifically race 5, 13, and 16). The spinach population panel was sequenced utilizing genotyping by sequencing (GBS), low coverage resequencing, and 10x coverage whole genome resequencing (WGR) to generate single nucleotide polymorphisms (SNP) markers. Subsequently, genetic analysis was performed using disease phenotype response data obtained and SNP markers for the identification of resistance-associated SNP markers and candidate resistance genes. The molecular analysis and mapping efforts have yielded valuable insights into the basis of downy mildew resistance in spinach, providing essential molecular tools to facilitate breeding for disease resistance. This work will summarize the updated findings from these efforts. This work will enhance our understanding of resistance mechanisms, which will contribute to developing more effective breeding strategies, increasing selection gains and breeding efficiency in spinach.
Speakers
GB

Gehendra Bhattarai

University of Arkansas
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, Crop Improvement and Protection Research Unit, Salinas, CA, 93905, USA
NA
JC

James C Correll

University of Arkansas
NA
Tuesday September 24, 2024 4:45pm - 5:00pm HST
South Pacific 3

4:45pm HST

WUM 2 - Microbial Community Composition and Accumulation Of Biofilms In Irrigation Pipes Using Nutrient Solutions with Different
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Biofilms clog irrigation systems, thus affecting water use efficiency, crop yields, and production costs. Microbial attachment and subsequent biofilm accumulation is influenced by the irrigation water quality and materials used in the design of water distribution systems. Therefore, the goal of this research was to evaluate if the pipe material and the load of organic matter in nutrient solutions affected biofilm accumulation, microbial community composition, and emitter performance. Nutrient solutions had 0, 30, 60, and 120 mg·L-1 peat particles under 150 µm in diameter and flowed through pipe loops made of polyvinyl chloride (PVC) and polyethylene (PE). The emitters were pressure compensated drippers with anti-drain mechanism and a nominal discharge of 2 L·h-1. Heterotrophic plate counts and biofilm dry mass were used as indicators of biofilm accumulation. DNA was extracted from the biofilm then sequenced for bacterial community composition analysis. The surface of new and post-biofilm pipes was characterized by measuring hydrophobicity and roughness to evaluate the effects of biofilm on the pipe’s surface. None of the emitters clogged, but there was an increase in discharge with 60 and 120 mg·L-1 peat. This observation suggests that the particles and biofilm accumulation affected the operation of the emitters’ anti-drain mechanism. The pipe material had more influence on the accumulation and bacterial community composition of biofilms than the organic load of the nutrient solution. Overall, biofilm accumulated more on PVC pipes than on PE pipes. The hydrophobicity of PVC pipes decreased, and roughness of PVC and PE pipes increased after biofilm colonization. These results suggest that the characteristics of the pipes can influence and be influenced by biofilms and therefore affect the risk of clogging. Our results also suggest that biofilms establish better on materials that biodegrade easy and that biofilm changes the roughness of PVC pipes which may further affect pipe longevity.
Speakers
avatar for Juan Cabrera-Garcia

Juan Cabrera-Garcia

Research Assistant Professor & State Extension Specialist, University of Missouri
My extension program focuses on providing research-based resources, trainings, and tools to beginning and established specialty crop growers. Check our programs focused on controlled environment agriculture (Veteran Farmers (umkc.edu)) and commercial horticulture (Commercial Hort... Read More →
Co-authors
RR

Rosa Raudales

University of Connecticut
Tuesday September 24, 2024 4:45pm - 5:00pm HST
Nautilus

5:00pm HST

EcoPhys 1 - Trade-Offs in Reproductive Traits and Buds' Freezing Survival Strategies Among Prunus Species
Tuesday September 24, 2024 5:00pm - 5:15pm HST
The adaptation of perennial species to winter freezing temperatures is crucial for their reproductive success and has led to the evolution of diverse survival strategies to mitigate freezing damage. Bud survival is essential for species reproduction and fruit production, as buds carry the dormant flower primordia that will bloom in the next growing season. We studied two freezing survival mechanisms: deep supercooling (DS) and extraorgan freezing (EOF). Deep supercooling involves physical or structural changes that prevent ice nucleation in florets and meristems by sequestering small amounts of water. When the critical nucleating temperature for this sequestered water is reached, ice propagation is rapid, and cellular damage is lethal. Extraorgan freezing causes a gradual dehydration of inner bud tissues, driven by the vapor pressure deficit from extracellular ice formed in bud scales. Despite existing knowledge, the survival benefits of species undergoing deep supercooling, considered a limited strategy compared to extraorgan or extracellular freezing, remain unclear. Similarly, how adaptation to freezing impacts reproductive traits in woody species is not well understood. We focused on the Prunus genus for its dual survival strategies and productive and ornamental value. This study, conducted on six Prunus species at the Arnold Arboretum in Boston, MA, spanned three developmental stages: leaf drop in fall, dormancy in winter, and pre-bud swell in spring. Data encompassed phenology, vascular tissue development, flower primordia size, differential thermal analysis, controlled freezing tests, and characteristics of flowers, fruits, and seeds. Results indicated that DS Prunus species delay vascular tissue development and grow larger flower primordia from fall compared to EOF species. Conversely, EOF species bloom later, producing more and smaller flowers and fruits in a shorter time than DS species. In summary, in the Prunus genus, DS species appear to trade a lower temperature threshold for pre-forming fewer, larger flower primordia per bud, enabling earlier blooming and more efficient use of the growing season to develop larger fruits in contrast to EOF species.
Speakers
avatar for Camilo Villouta

Camilo Villouta

Assistant Professor, University of Rhode Island
Tuesday September 24, 2024 5:00pm - 5:15pm HST
Coral 1

5:00pm HST

ORGH 1 - Bridging the Gap: Culinary Breeding Network Facilitates Collaboration in Variety Development
Tuesday September 24, 2024 5:00pm - 5:15pm HST
In the past decade, there has been a significant rise in initiatives by public sector programs, independent seed companies, and farmer-breeders aimed at developing organic varieties in the United States, particularly targeting farmers engaged in direct-to-consumer sales. Flavor has emerged as a paramount trait for these farmers, driving collaborative breeding efforts involving a diverse array of stakeholders, including farmers selling to restaurants, farmers markets, and CSAs, as well as chefs at farm-to-table establishments, and plant breeders focusing on organic systems. Since seed regulations in the US allow seed to be sold without a registration process, varieties identified as well-suited and high-quality by collaborating farmers and chefs can quickly become available commercially. While diversified organic vegetable farmers often prefer not to produce their own seed, they wish to be actively engaged in the selection processes and support plant breeders focusing on organic systems (Hubbard and Zystro, 2016). The Culinary Breeding Network (CBN) strives to bridge the gap between plant breeders and consumers by facilitating unique opportunities for stakeholders to assess in-development vegetable and grain cultivars, share insights, and actively contribute to variety development. CBN's outreach events span across various regions, including Oregon, Washington, Hawaii, Wisconsin, New York, and Italy, focusing on identifying desirable traits, discerning consumer preferences, tailoring varieties to organic farms and palates, and celebrating local foods. These participatory public gatherings provide breeders with invaluable input rarely accessible otherwise. By integrating culinary professionals, farmers, and consumers into the breeding process, breeders gain deeper insights into preferred traits while also fostering broader awareness and understanding of organic plant breeding. CBN impact is evaluated through post-event surveys completed by attending farmers, chefs, distributors, retailers, and consumers. In 2020, 144 Variety Showcase surveys were collected, with 96% expressing intentions to disseminate gained knowledge, reaching an estimated >2,075 individuals in person and >258,000 through social media. Furthermore, 81% indicated that newfound knowledge would influence their work through expanded networks (34%), revised buying practices (25%), and informed decision-making (41%), among other outcomes such as forging new collaborations and partnerships. Participating breeders, seed companies, and farmers report moderate to significant positive effects to CBN, with 75% reporting impact on their business operations. Notably, CBN's most valued impact lies in "creating buzz in the community around specific vegetables and varieties" (48%) and "facilitating collaboration among breeders, growers, chefs, and consumers" (35%). Remarkably, 80% of respondents stated they had commenced growing a variety following a CBN event.
Speakers
avatar for Lane Selman

Lane Selman

Professor of Practice, Oregon State University
Lane Selman grew up on the citrus farm her Sicilian great-grandparents planted in 1919 on Florida's space coast. She studied Agronomy (BS) and Entomology (MS) at University of Florida before moving to Oregon in 2000. As a Professor of Practice at Oregon State University, Lane has... Read More →
Tuesday September 24, 2024 5:00pm - 5:15pm HST
Lehua Suite

5:00pm HST

RHIZ - Characterizing Root Dynamics and Phenology of Hops in a Subtropical Climate Using an In-situ Root Imaging System
Tuesday September 24, 2024 5:00pm - 5:15pm HST
In Florida's subtropical climate, photoperiod manipulation facilitates a unique production system for hops (Humulus lupulus L.), an important crop for the brewing industry, with two growth cycles per year. The spring season spans from mid-February to early June, immediately followed by the fall season, which concludes in late November. With contrasting climatic conditions, plant phenology, yield, and cone quality differ dramatically between the two growing seasons. To gain insights into the roles of roots in the seasonal differences in plant phenology and performance, we characterized root dynamics and phenology of 'Cascade' hops grown in West Central Florida using an in-situ root imaging system. The soil at the study site was Myakka fine sand with 97% sand. Plants were grown on a 4.5 m V-trellis system, and data were collected over 2 years upon transplanting. Minirhizotron tubes were installed at varying distances (0, 30, and 60 cm) from the planting hill perpendicularly to the row to capture biweekly root images up to a depth of 84 cm. These images were processed using WinRhizo Tron software to measure various root morphological parameters, including total root length, projected area, surface area, volume, and the longest root. Notably, hop roots showed rapid elongation, reaching a depth of 84 cm, and expanding up to 60 cm from the hill center within one month after establishment under subtropical conditions. However, the primary, larger in diameter tap roots exhibited signs of decay after 5 months, culminating in complete mortality within 15 months following their establishment. Interestingly, the phenological stage of cone development induces a proliferation of new root growth, although temporary, with these ephemeral roots having a lifespan limited to approximately 3 months. These results can provide insights into the shoot-root interactions and help improve fertilizer, water, and ground cover recommendations, ultimately optimizing hop production in Florida's unique subtropical system.
Speakers
AJ

Alvaro J. Bautista

University of Florida
Co-authors
SA

Shinsuke Agehara

University of Florida
Tuesday September 24, 2024 5:00pm - 5:15pm HST
South Pacific 4

5:00pm HST

VGBR 1 - Screening Baby Leaf Salad Greens for Downy Mildew Resistance
Tuesday September 24, 2024 5:00pm - 5:15pm HST
Downy mildew presents major challenges to baby leaf salad greens production in California. Baby kale (Brassica oleracea) particularly holds substantial economic value in the region with a crop value of over $12 million in 2022. Downy mildew, caused by the oomycete pathogen Hyaloperonospora brassicae, infects baby kale resulting in leaf chlorosis, necrosis, and sporulation, rendering affected leaves unmarketable. Resistant varieties offer an effective solution, reducing the need for pesticides and promoting sustainable disease management in baby kale production. This research aims to screen baby kale plant materials (accessions) for resistance to downy mildew isolates from across California. Initially, 212 baby kale accessions were evaluated for resistance using a downy mildew isolate from Gilroy, CA. Plants were inoculated with downy mildew spores and incubated in high-humidity conditions before being evaluated for disease symptoms. The initial screening indicated an average disease severity of 31%. From this screening, 50 accessions showing the lowest disease severity were further screened against seven additional downy mildew isolates. Among the subset of 50 accessions, disease severities ranged from 0.1% to 7.6%. Notably, nine accessions consistently exhibited a disease severity of 0%, and 17 accessions maintained disease severities of 0.1% or 0.2% across all seven isolates, making an elite secondary subset of accessions. Ongoing research includes replication trials with a secondary subset of accessions and the two most virulent and weak downy mildew isolates. This research will identify resistant baby kale varieties, providing valuable insights for breeders and improving downy mildew management practices in kale production systems.
Speakers
SD

Shunping Ding

Associate Professor, California Polytechnic State University
Co-authors
EL

Emily Locke-Paddon

California Polytechnic State University
NA
LT

Lauren Taylor

California Polytechnic State University
NA
MF

Marco Fernandez

California Polytechnic State University
NA
Tuesday September 24, 2024 5:00pm - 5:15pm HST
South Pacific 3

5:00pm HST

WUM 2 - ATP vs Petrifilm: Techniques to Quantify Microbial Communities for Water Quality Analysis
Tuesday September 24, 2024 5:00pm - 5:15pm HST
Traditional methods of microbial quantification for irrigation water using colony counts from agar culture require dedicated laboratory space and trained personnel, making them less suitable for on-site application by horticulture growers. Dehydrated Petrifilm™ culture plates are a simpler method than agar, but are still time-consuming and require 2-3 days to culture. Adenosine Triphosphate (ATP) tests may provide an easy and reliable method for quantifying microbes in water that is more rapid than culturing microbes. The objective was to compare ATP measurements against colony counts cultured using Petrifilm™ for assessing microbial water quality. Lake water was recirculated through an ozone system until a target oxidation reduction potential (ORP) of 700 mV was reached. Samples were collected at the following ORP intervals: control, 300 mV, 400 mV, 500 mV, 600 mV, and 700 mV. Samples were plated for aerobic bacterial counts and yeast and mold counts using Petrifilm™ culture plates. Samples were also analyzed for free and total ATP concentration using the Hygiena EnSURE luminometer and its accompanying free and total ATP swabs. Microbial ATP was calculated by subtracting free ATP from total ATP. Results showed a consistent decrease in bacterial and fungal counts with increasing ORP using Petrifilm™ culture plates. At 700 mV ORP, there was 99.5% reduction of bacterial colony counts and 92.8% reduction of fungal colony counts from the initial. Similarly, a decreasing trend was observed for free, total, and microbial ATP concentration with increased ORP levels. There was a 97.5 % reduction of microbial ATP from the initial concentration at 700 mV ORP. A positive correlation was observed between microbial ATP measured with the luminometer and bacterial counts obtained from Petrifilm™. Integrating ATP quantification into routine monitoring practices could provide easy and rapid results and enhance the efficacy of microbial assessments in irrigation water.
Speakers
DT

Dharti Thakulla

University of Florida
Tuesday September 24, 2024 5:00pm - 5:15pm HST
Nautilus

5:15pm HST

EcoPhys 1 - Potential Genes Involved in the Adaptation of Potato to Long Term Heat Stress
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Heat stress is one of the most significant uncontrollable abiotic factors that affect potato plant growth, development, and tuber yield. While short-term acute heat stress experiments have produced considerable insights into the effects of heat stress on potato, there is a lack of information on the mechanisms involved in heat stress adaptation. Our recent studies demonstrate that under prolonged heat stress (35/25°C, day/night, for 3 weeks), newly developed leaves can maintain health and adapt to heat stress by modifying anatomy and physiology. Whereas, the leaves developed prior to heat stress (20/15 °C, day/night) on the same plant suffer (chloroses, senescence) from heat stress. We compared the gene expression in the youngest, fully expanded terminal leaflets developed under control and heat stress in two genotypes, Solanum tuberosum L. ‘Atlantic’ (ATL) and Solanum microdontum Bitter (MCD). As expected, several heat shock proteins (HSP) genes were upregulated in both genotypes. In addition, several desaturase genes were downregulated suggesting an increase in the saturation of membrane lipids may provide membrane integrity under heat stress. Our parallel physiological and anatomical studies have shown that adaptation to heat stress involves increase in stomatal density, lowering of leaf temperature via increased transpiration and maintenance of photosynthesis. Consistent with these results we found significantly regulated genes involved in ABA biosynthesis, photosynthesis, cell growth, expansion and patterning. These data offer insight into potential genes involved in heat tolerance in potato that may be useful in breeding for heat-tolerant potato varieties.
Speakers
JP

Jiwan Palta

UW Madison
Co-authors
AD

Alfonso DelRio

University of Wisconsin Madison
NA
JB

John Bamberg

University of Wisconsin Madison
NA
JS

Justin Schabow

University of Florida
NA
JM

Jyostna Mura

University of Wisconsin
NA
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Coral 1

5:15pm HST

ORGH 1 - Growing Urban Organic Farms in Iowa: New Initiatives and Support
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Urban agriculture, which encompasses both home use and commercial sales, has shown positive impacts on enhancing sustainable agriculture and food security, especially for disadvantaged and underrepresented citizens. The benefits of community gardens/farms have been found to be extensive, including improved quality of life and nutrition, enhanced economic security and environmental sustainability, entrepreneurship and employment, and community commitment. In a new Iowa State University (ISU) Extension and Outreach project, the ISU Organic Ag program (OAP) will be working with urban farms in Iowa to create a Community of Practice network that will promulgate best management practices and sharing of results among farmers and agency staff supporting this clientele group. Because the majority of urban farms use organic practices, these farms will be surveyed for critical pest issues; suitability of organic treatments for specific pests; and economic viability of these strategies. In addition, farmers will be queried on the potential for organic certification, including group certification. A statewide Urban Ag group, created in 2023, identified the following needs, based on urban farmers’ interests: Land access and utilization; Education and program access; Production needs, including managing soil health and irrigation; Food safety and food insecurity; and Business development. A Directory of Expertise in Urban Ag was developed to highlight six specialists focused on urban ag in Iowa at Iowa State University; four at federal agencies (NRCS, RMA, FSA), three in state and municipal government (IDALS, City of Des Moines); two at government-associated programs (SWCD), and eight at non-profit, non-governmental institutions (NGOs). Working with county Extension staff, Master Gardeners, 4-H, NRCS, SWCD, and urban ag NGOs and farmers, this project seeks to advance Urban Ag through: 1) Demonstration sites showcasing innovative nutrient and pest management techniques, bee keeping, food safety practices, and marketing; 2) Field Days held at key urban farm partners with adjoining Farmers’ Market tours; and 3) A series of webinars, videos and pamphlets covering these topics, and translated for Spanish, Burmese and Congolese audiences–the most prominent groups of immigrant urban farmers in Iowa. Evaluation will assess knowledge and behavioral change related to addressing key food security concerns in urban spaces, community well-being, and sustainability indicators, including soil and water quality.
Speakers
KD

Kathleen Delate

Iowa State University
Co-authors
JP

Josiah Pollock

Iowa State University
NA
KP

Karenna Petersen

Iowa State University
NA
RT

Robert Turnbull

Iowa State University
NA
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Lehua Suite

5:15pm HST

RHIZ - Effects of Reclaimed Water on Blueberry Seedling Growth and Root Morphology
Tuesday September 24, 2024 5:15pm - 5:30pm HST
A high percentage of agricultural production depends highly on groundwater irrigation. Groundwater depletion has been putting significant pressure on global water resources and food production. Using reclaimed water (RW) as an alternative source of irrigation water for crop production can mitigate the huge demand on groundwater resources. Blueberry plants are characterized by their preference for acidic soil conditions with a shallow, salt-sensitive root system. The alkaline and saline nature of RW necessitates an understanding of its suitability as irrigation water for blueberry production. We conducted a greenhouse rhizotron experiment to characterize root morphological responses of ‘Arcadia’ blueberry seedlings to RW. Four irrigation water treatments were implemented: 100% well water (WW), 100% deionized water (DW), a blend of 50% DW/50% RW, and 100% RW. These treatments were applied to rhizotron boxes filled with 50% sand and 50% pine bark mixed uniformly by volume. Root morphological variables, stem diameter, plant height, canopy projected area, and plant physiological variables were examined biweekly. Soil and plant tissue nutrient contents and plant biomass were examined at the end of the experiment. Water quality was slightly alkaline with pH values of 7.8 for 100% WW and 100% DW, and 7.7 for 100% RW. Electrical Conductivity (EC) values varied among the treatments, with 0.428 dS/m for 100% WW, 0.338 dS/m for 100% DW, and 0.769 dS/m for 100% RW. Initial soil mix pH at the beginning of the experiment was 6.8. Our preliminary findings indicate no significant difference in root elongation, plant above-ground biomass and leaf chlorophyll index among the four irrigation treatments (p > 0.05). A significant difference was observed between DW and WW for plant stem diameter and height (p > 0.05), possibly attributed to blueberry plants’ sensitivity to salt. The soil mix pH had risen to 7.8 for all the treatments at the end of the experiment. Our preliminary interpretation suggests that 100% RW does not adversely affect young blueberry plants growth parameter over the short-time period of the experiment. That indicates that RW can be a promising alternative of irrigation. Existing literature indicates that blueberry plants have the ability to adopt to irrigation water EC level of up to 2 dS/m, while the measured EC of 100% RW was 0.77 dS/m, it appears that the blueberry plants didn’t reach to the stress level that could significantly affect their growth parameters. We believe the experiment duration was insufficient to observe the high pH symptoms.
Speakers
YS

Yasmeen Saleem

University of Florida
PhD student
Co-authors
DK

Davie Kadyampakeni

University of Florida
NA
SA

Shinsuke Agehara

University of Florida
Tuesday September 24, 2024 5:15pm - 5:30pm HST
South Pacific 4

5:15pm HST

VGBR 1 - Detection of Novel Lettuce Fusarium Wilt Pathogenic Variants in California
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Fusarium wilt (FW), caused by the soilborne fungus Fusarium oxysporum f.sp. lactucae (FOL), is an economically important disease of lettuce (Lactuca sativa L.). Four pathogenic races of FOL have been reported, though only race 1 is known to exist in the United States. Recently, California coastal lettuce growers have experienced changes in the severity and incidence of FW. Some race 1-resistant cultivars have exhibited susceptibility, whereas some susceptible cultivars have displayed a reduction in disease severity. In order to determine whether such changes in disease patterns are responses to potentially novel variants, we collected FW symptomatic plant samples from commercial fields in Salinas Valley and Santa Maria, recovered the fungus, and conducted a series of pathogenicity tests in controlled conditions over two years (2022 and 2023) using a standard set of FOL race differentials. Pathogenicity tests revealed two new FOL variants, Fol621s and 916, that elicited novel disease reaction patterns on the standard differentials which have never been reported in the United States or other parts of the world. Isolate 916 incited severe FW on race 1-resistant ‘Costa Rica No. 4’, whereas Fol621s was less virulent on race 1-suceptible ‘Banchu Red Fire’. This study provides valuable information critical for the development of FW management strategies, including broad-spectrum resistance breeding efforts against multiple FOL races and novel variants.
Speakers Co-authors
AP

Alexander Putman

U.C. Riverside
NA
FM

Frank Martin

USDA-ARS
NA
NL

Ningxiao Li

USDA-ARS
NA
Tuesday September 24, 2024 5:15pm - 5:30pm HST
South Pacific 3

5:15pm HST

WUM 2 - Water use and crop coefficients for outdoor nursery ornamentals in 15-gal containers
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Nurseries and greenhouses in California face challenges of limited water supply and increased scrutiny from water quality regulators. Improving irrigation efficiency thus minimizing irrigation runoff are the main strategies to save water and comply with regulations. Evapotranspiration-based (ET) methods that make use of weather station data has the potential to substantially improve efficiency. In California, a statewide network maintained by DWR CIMIS project is widely used. However, crop-specific coefficients to calculate irrigation needs from weather data are not widely available in the nursery industry, particularly for large (15-gal and up) containers. In this project we measured water use and developed crop coefficient for 15-gal trees, one low water user (Olive, Olea europaea) and two high water users (Sycamore, Platanus acerifolia and Ficus microcarpa) with different canopy architectures. Container weight was measured with load cells (Omega LC103B, a weighing device similar to a scale), with values logged every minute by a Campbell Scientific data logger (CR1000X). Daily water use was calculated as the difference in weight from after each irrigation to before the following one. Local CIMIS reference ET was used to calculate crop coefficients. Tree water use yielded crop coefficients averaged 1.19 for Ficus; 0.57 for Olive and 1.21 in Sycamore during fall 2023 before defoliation started to occur for Sycamore in mid-October. Olive and Ficus defoliated through winter reaching the lowest crop coefficient in March 2024 when the coefficient was 0.42 for Ficus; 0.22 in Olive and 0.12 in Sycamore. Crop coefficients were substantially lower than those presented by Burger et al., 1987. for similar woody ornamentals grown in 1-gal containers. The difference is that Burger’s crop coefficients were calculated using the container surface area, while we used the (larger) block area divided by the number of containers. While less meaningful from a plant physiology point of view, a block-based crop coefficient is more useful for irrigation management and more similar to the crop coefficient calculation in field crops, grape vines and fruit trees. Results from our method can be converted to Burger et al. method by dividing by interception efficiency (i.e. cumulative container surface area divided by irrigation block area).
Speakers
avatar for Gerry Spinelli

Gerry Spinelli

University of California Cooperative Extension
Irrigation management in nurseries and greenhouses
Co-authors
CS

Chris Shogren

University of California Cooperative Extension Los Angeles
Tuesday September 24, 2024 5:15pm - 5:30pm HST
Nautilus

5:30pm HST

EcoPhys 1 - Species-specific Differences in Leaf Photosynthetic Rate when Substituting Far-red Light for PAR Photons
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Phosynthetically active radiation (PAR; 400 – 700 nm) is widely acknowledged as essential for photosynthesis in plants. However, recent research has revealed the significant contribution of far-red photons (FR; 700 – 750 nm) to photosynthetic processes, particularly when present alongside PAR. While previous studies have primarily focused on whole-plant gas exchange, limited research exists on leaf-level replication of these findings. In this preliminary study, we investigated leaf gas exchange in five field-grown crop species using A/Ci curves. We exposed the leaves to equal proportions of blue, green, and red light at a photon flux density of 1000 µmol·m-2·s-1 and replaced varying percentages (0%, 15%, or 30%) of these photons with FR. Our hypothesis, based on previous whole-plant studies, was that all species would exhibit similar photosynthetic rates (Pn) across different FR treatments. Contrary to our hypothesis, we observed species- and cultivar-specific variations in leaf-level Pn with FR treatments. For instance, strawberry and green leaf lettuce exhibited decreased Pn with increasing FR, while apple and Swiss chard showed increased Pn. Red leaf lettuce maintained consistent Pn levels. Despite these differences, the overall trends across CO2 concentrations remained consistent regardless of FR levels. Considering that direct sunlight naturally contains FR equivalent to approximately 18% of PAR, and our crops were grown in open-field conditions, our findings suggest a species-specific capacity to utilize FR in photosynthesis. These findings are preliminary, but data is being collected to examine species responses throughout a full growing season.
Speakers
JE

John Ertle

PP Systems
NA
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Coral 1

5:30pm HST

ORGH 1 - Metabolomic Analysis Provides Novel Insight Into the Evaluation of Organic Tomato Fruits
Tuesday September 24, 2024 5:30pm - 5:45pm HST
A gradual shift in the evaluation of crop quality has taken place, led by analytical scientists with the advancement of instrumentation and system-based technology (system biology). Metabolomics, one of the emerging omics techniques, provides a complete and unbiased chemical analysis within an organism. Information obtained through metabolomic analysis may range from identifying beneficial compounds for human health to toxicants, can help solve challenges faced by the agricultural industry. Current phytochemical studies focusing on organically-grown crops have typically focused on individual compounds or classes of compounds that may be affected by production practices. This study compared metabolomic profiles between organic and conventionally-grown tomato (Solanum lycopersicon) fruit to systemically access the quality and nutritional value of tomatoes under different growing conditions. Two tomato cultivars (‘Estiva’ and ‘Tomimaru Muchoo’) were grown with three different treatments (organic field, organic high-tunnel, and conventional field) and were assessed for metabolomic analysis using gas chromatography‒mass spectrometry (GC‒MS) and liquid chromatography‒mass spectrometry (LC‒MS). Target metabolites included various primary and secondary metabolites covering a wide range of metabolic pathways, involving citrate cycle, pyruvate metabolism, amino acid biosynthesis, alkaloids biosynthesis, shikimate pathway, salicylic acid pathway, plant hormone biosynthesis, phenylpropanoid biosynthesis, flavone, flavonol, and flavonoid biosynthesis, anthocyanin biosynthesis, and so on. Differentially expressed metabolites (potential biomarkers) between organic and conventional tomatoes were selected, and a core metabolic network was identified by pathway enrichment analysis. Major variations between groups were observed in the network related to plant secondary metabolisms (e.g., plant defense signaling). This is likely due to varying amounts of external stresses between organic and conventional tomatoes by the difference in pesticide input. The organic high-tunnel group also showed some distinct metabolic responses within the secondary metabolisms, probably because of its unique growing conditions. The selected biomarkers and identified metabolic network provided insights into biochemical processes influenced by different cultivation methods. This work will contribute to the evaluation of organic farming practices in the US.
Speakers
avatar for Jashanpreet Kaur

Jashanpreet Kaur

Graduate Research Assistant, The University of Georgia
Hello! I am a 2nd-year master's student in the Food Science and Technology Department at the University of Georgia. My current research focuses on utilizing liquid chromatography-mass spectrometry (LC−MS) and gas chromatography-mass spectrometry (GC−MS) based metabolomics to identify... Read More →
Co-authors
JH

Joon Hyuk Suh

The University of Georgia
NA
KC

Kate Cassity Duffey

The University of Georgia
NA
TC

Timothy Coolong

The University of Georgia
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Lehua Suite

5:30pm HST

VGBR 1 - Unraveling Gene Regulation on the Interaction of Lettuce (Lactuca sativa L.) and Xanthomonas hortorum pv. vitians Causal Agent of Bacterial Leaf Spot.
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Bacterial leaf spot (BLS) of lettuce is a sporadic and destructive foliar disease that poses an economic threat to farmers, particularly those within Florida due to the subtropical environmental conditions. The disease is caused by the bacteria Xanthomonas hortorum pv. vitians (Xhv), which has three races. There are no chemical interventions that can effectively control this pathogen, creating a significant challenge for farmers to manage BLS. Additionally, most commercial lettuce cultivars are susceptible to BLS, emphasizing the need to improve host resistance. Resistance to Xhv race-1 has been identified in heirloom lettuce PI 358001-1 and ‘La Brillante’, and PI 667690. To facilitate and accelerate modern plant breeding techniques and the introgression of resistance into new cultivars, the identification of resistance genes is crucial. However, a detailed description on how these genes is regulated in the lettuce genome remains unknown. To aid in the understanding of the interaction between lettuce and Xhv, a gene expression study was conducted. A total of 180 plants each of La Brillante (R), PI 358001-1 (R), PI 667690 (R), and Okeechobee (S) were grown in laboratory conditions for 21 days. Half of the plants were mock inoculated with buffer, and the remaining plants were inoculated with Xhv race-1 isolate L7. Leaf samples were collected at 24-, 72-, and 144-hours post-inoculation, and RNA was extracted for sequencing using the Illumina NovaSeq 6000 platform. The analysis of differentially expressed genes and their associated pathways revealed distinct reactions upon interaction with Xhv. Additionally, similar reactions were observed in other crops and their respective Xanthomonas pathovars, such as the upregulation of peroxidases, chitinases, and proteases, were observed between inoculated and mock-inoculated plants, such response was time point dependent. Primers will be designed and validated for these candidate genes using qPCR with additional time points to confirm their expression across key plant development stages. These findings provide valuable insights into the molecular resistance of lettuce to BLS, unlocking new opportunities for molecular breeding techniques, identification of chemical compounds within the plant that control BLS, and the development of new resistant cultivars. This knowledge will benefit not only the UF/IFAS lettuce breeding program, but also be disseminated to other research groups working to breed BLS-resistant lettuce cultivars.
Speakers
BM

Byron Manzanero

Horticultural Sciences Department, University of Florida
My name is Byron Manzanero a Ph.D. Candidate in plant breeding.
Co-authors
GS

German Sandoya

University of Florida
JM

Jesse Murray

University of Florida
NA
Tuesday September 24, 2024 5:30pm - 5:45pm HST
South Pacific 3

5:30pm HST

WUM 2 - Quantification of irrigation and stormwater runoff volume, sediment load, and nutrient load when producing nursery crops
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Container nurseries produce a high volume of operational water (OW) during irrigation and storm events. OW is irrigation return flow (IRF) and storm runoff that has traveled through crop production areas and could carry sediment and agrichemicals, making nurseries a potential contributor to nonpoint source pollution. OW is collected in retention reservoirs for treatment and reuse or allowed to leave the site. A monitoring program was conducted on five production areas (study catchments) with two different irrigation systems (i.e., overhead and spray stake) in two container nurseries located in the Midwestern USA (Central Lowland physiographic region). Total suspended solid (TSS), dissolved inorganic nitrogen (DIN) and phosphate (PO4-P) in OW during storm and irrigation events. We found median event mean concentrations (EMCs) during irrigation events for TSS, DIN, and PO4-P were 131 mg∙L-1, 2.9 mg∙ L-1, and 1.2 mg∙ L-1, respectively. During storm events, DIN and PO4-P EMCs were similar to irrigation events; however, TSS EMCs were almost 8 times greater than those of irrigation events. The median daily TSS, DIN and PO4-P load per ha during storm events were 13.3 kg·ha−1·day−1, 82.3 g·ha−1·day−1 and 43.5 g·ha−1·day−1, respectively, which were 20, 3, and 4 times greater than those of irrigation events. The results indicated that the portion contribution of storm and irrigation for producing TSS was 86% and 14%, respectively. The results of this study can facilitate improved irrigation scheduling and help assess potential treatment options.
Speakers
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 →
Co-authors
MN

Mohammad Nayeb Yazdi

Arlington County Virginia
NA
SL

Steve Lyon

The Ohio State University
NA
Tuesday September 24, 2024 5:30pm - 5:45pm HST
Nautilus

5:45pm HST

EcoPhys 1 - Investigating Dormancy ​ and Germination Characteristics​ to Promote Restoration Success​ in the Northern Great Plains​
Tuesday September 24, 2024 5:45pm - 6:00pm HST
In wildlands, such as the prairies of the Northern Great Plains, environmental degradation has created the need for ecological restoration of native plants on the landscape. These ecological restorations require native seed. However, many seed-based restoration efforts fail in that they do not produce the desired vegetation. Lack of species-specific information on germination characteristics and dormancy of native seed could be contributing to these failures. Therefore, restoration practitioners and other users of native seed need germination and dormancy information for native species to improve outcomes. Our objectives in this study were to examine germination characteristics and seed treatments that best promote germination in plant species native to the Northern Great Plains and define dormancy classes for each of our study species. To meet these objectives and promote success in seed-based restoration, we conducted a germination experiment for 15 high-priority native forbs. Seeds were treated with four pretreatments (scarification, smoke, fertilizer, and a control), three stratification lengths (2, 4, and 8 weeks), and different temperature regimes. We examined the influence of each factor to determine the means of breaking dormancy and best planting practices. Our data indicated that a scarification treatment before planting Gaillardia aristata increased germination by over 19%. This data suggests that while the majority of our G. aristata seeds are non-dormant, a percentage are physiologically dormant. Our data also shows that Penstemon albidus is strongly influenced by temperature conditions, and the species requires a period of cold stratification to increase overall germination. This information will be used to develop best planting practices for government agencies and aid seed producers and distributors by offering seed storage and planting instructions matching the phenology of native plant species. This rigorous germination experiment can also be used as a model for other priority species and can be adapted to different ecoregions.
Speakers
BL

Bret Lang

Student, South Dakota State University
Co-authors
GC

Gregory Cooper

South Dakota State University
NA
LP

Lora Perkins

South Dakota State University
NA
Tuesday September 24, 2024 5:45pm - 6:00pm HST
Coral 1

5:45pm HST

VGBR 1 - Exploring Physiological Traits as Predictors of Heat Content in Chile Peppers (Capsicum annuum L.)
Tuesday September 24, 2024 5:45pm - 6:00pm HST
Chile peppers (C. annuum L.) are valued for their capsaicinoid content, which contributes to their pungency (heat) and has various health benefits, including anti-inflammatory and anti-cancer properties. Assessing photosynthetic efficiency through the LICOR-600 porometer/fluorometer (https://www.licor.com/env/products/LI-600/) provides insights into the physiological vigor of the plants. This study employs a comprehensive suite of machine learning models to investigate the correlation between photosynthetic efficiency (stomatal conductance and chlorophyll a fluorescence) and Scoville Heat Units (SHU) to predict the capsaicinoid content within 20 chile pepper varieties. Photosynthetic data were collected at two sites, Fabian Garcia Science Center and Leyendecker Plant Science Research Center, Las Cruces, NM, with readings taken from three different leaves of each of five plants per genotype. Capsaicinoid levels were quantified using High-Performance Liquid Chromatography (HPLC) for each variety. Correlation and principal component analyses (PCA) were implemented to discern the primary influencers on capsaicinoid production. Five predictive models were explored: Decision trees, Random forests, Ridge regression, LASSO Regression, and Support Vector Regression. Each model was applied to predict both total SHU values and categorical SHU labels (mild, hot, very hot). Among these, the decision tree model was the most superior, achieving an R² of 0.77. Initial findings indicate notable variability in photosynthetic activity and capsaicinoid concentrations across the varieties, suggesting a significant but complex relationship that may guide future genetic improvements. The challenges in modeling can be attributed to data collection constraints. Additionally, uniform growing conditions across all test plants might have limited the variability necessary for more definitive model differentiation. This analysis not only advances our understanding of the physiological and genetic factors affecting capsaicinoid content but also underscores the complexities of modeling agricultural traits under consistent environmental conditions. Future research should consider more frequent data collection and the introduction of environmental stressors to better capture the dynamics influencing capsaicinoid production in chile peppers. Key word: High-Performance Liquid Chromatography, Scoville heat unit, photosynthetic efficiency
Speakers
MI

Muhammad Ibrar Khan

New Mexico State University
Co-authors
DN

Dennis Nicuh Lozada

New Mexico State University
EK

Ehtisham Khokhar

New Mexico State University (NMSU)
Tuesday September 24, 2024 5:45pm - 6:00pm HST
South Pacific 3

5:45pm HST

WUM 2 - Water Supply Resilience Through Florida-Friendly Landscaping
Tuesday September 24, 2024 5:45pm - 6:00pm HST
Traditional irrigated landscapes and in particular turfgrass dominated landscapes are being challenged across the U.S. due in part to the demand on potable water supplies. So called “ornamental” turfgrass will be outlawed in Nevada by 2027 and efforts are underway in other areas of the desert southwestern states to do the same. Meanwhile, in these areas, aggressive turfgrass removal programs utilizing financial incentives are occurring. This dramatic change is due to water supply associated with the Colorado River and western water supply in general. In the eastern U.S. changes are occurring in new development in North Carolina warm season grasses are displacing cool season grasses in new landscapes. Accordingly the new trend is to install bermudagrass without irrigation. In Florida, numerous municipalities have or are adopting codes mandating a maximum of the landscaped area as 60% sprinkler irrigation, which means turfgrass, and in some municipalities as low as 20% of the landscaped area. The remainder of the landscaped area is filled with a mixture of microirrigated ornamentals, mulched area, or unirrigated turfgrass. Some newer developments are eliminating irrigated turfgrass altogether. The Florida-Friendly Landscaping (FFL) program is uniquely positioned to deliver education relevant to the radical change that is occurring in designed and built landscapes. Many local governments are adopting landscape codes that include or mandate FFL principles. This talk will discuss these trends along with the factors driving this cultural change of landscapes and in particular the use of turfgrass in landscapes. Additionally, the talk will focus on the challenges ahead for landscapes under water supply constraints and how they may impact nonpoint source pollution from urban areas.
Speakers
MD

Michael Dukes

Professor & Director, University of Florida
Tuesday September 24, 2024 5:45pm - 6:00pm HST
Nautilus
 


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