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Wednesday, September 25
 

8:00am HST

CE 2 - Will Increasing the Potassium to Nitrogen Ratio Benefit Hydroponic Strawberry Production?
Wednesday September 25, 2024 8:00am - 8:15am HST
Strawberries (Fragaria × ananassa) are increasingly being grown in hydroponic systems, where effective nutrient management is critical for optimizing crop production and yield. Among essential mineral nutrients, potassium is a key nutrient that affect fruit quality in many fruiting crops. This study investigated how potassium to nitrogen (K:N) ratios regulate strawberry growth and development in a deep-water culture hydroponic system. We hypothesized that increasing the K:N ratios would enhance vegetative growth, fruit yield, and fruit quality. Bare-root plants of strawberry ‘Monterey’ and ‘San Andreas’ were grown indoor under a 23 °C air temperature and an 18-h photoperiod with an extended photosynthetic photon flux density of 350 µmol∙m–2∙s–1. The N level was kept constant at 77 ppm, while the study tested K:N ratios ranging from 1.5:1 to 4:5:1. Three weeks after nutrient treatments, strawberry plants showed similar crown number, crown diameter, leaf number, leaf area, and shoot dry mass regardless of K:N ratios in both cultivars. Increasing K:N from 1.5:1 to 4.5:1 linearly increased the root dry mass of Monterey’ but not in ‘San Andreas’. During the fruit production, K:N ratios did not affect the total number of fruits or total fresh mass of fruits. However, there was a linear decrease in the diameter, length, and fresh mass of individual fruits with increasing K:N ratio from 1.5:1 to 4.5:1 in both 'Monterey' and 'San Andreas'. Additionally, increasing K:N ratio from 1.5:1 to 4.5:1 slightly increased total soluble solids in ‘San Andreas’, but led to a greater increase in titratable acidity compared to the increase in total soluble solids in both ‘Monterey’ and ‘San Andreas’. These results suggest that increasing K:N ratios from 1.5:1 to 4.5:1 has little beneficial effect on overall plant growth, fruit yield and fruit quality for hydroponic strawberry production in deep-water culture systems.
Speakers
JR

Jonathan Ries

Arizona State University
Co-authors
YP

Yujin Park

Arizona State University
Wednesday September 25, 2024 8:00am - 8:15am HST
Coral 2

8:00am HST

CITR 2/HIST - Precision Nutrition Management: Finding Optimal Methods for Leaf Nutrient Analysis in HLB-affected Citrus Trees
Wednesday September 25, 2024 8:00am - 8:15am HST
Effective fertilizer management and accurate nutritional analysis are critical for healthy tree growth and maximum yield. Citrus trees perform best in the optimum range of each nutrient, and a deficiency or excess can result in poor tree growth and yield. Accurate fertilizer management decisions for citrus trees begin with proper leaf sampling. To accurately assess tree nutrition status, the appropriate time and procedure for collecting leaves for nutrient analysis must be followed. Historically, nutrient management for healthy citrus trees involved annual leaf sampling from July to August, with subsequent year fertilization plans based on single nutrient analysis. Currently, nearly all commercial Florida citrus orchards are affected by Huanglongbing (HLB), a systemic bacterial disease that affects all citrus varieties and rootstocks, causing extensive tree health decline. Studies suggest that a good nutrition program can improve the tree health and production of HLB-affected trees. However, the key is to supply the nutrients that are deficient or low. This widespread prevalence of HLB needs new approaches for managing fertilizer programs by regular leaf sampling to identify tree nutrient status and requirements. Thus, this study focuses to improve and revise the leaf nutrient sampling guideline for HLB-affected trees by determining the optimal time for leaf sampling and adjusting fertilization for increased production and tree health. Key objectives include assessing the frequency of leaf sampling required per year to capture the tree's nutritional status effectively and adjust fertilizer accordingly to establish the correlation of leaf nutrient concentration with the yield, fruit drop, and canopy density. For this study, spring and summer emerging flushes were tagged on HLB-affected ‘Hamlin’ and ‘Valencia’ mild and severe sweet orange trees in a central Florida orchard over two years. The leaves from tagged branches were collected every 3 months for leaf nutrient analysis and the results of both spring and summer leaves were used to adjust the fertilization plan accordingly. It was found that the spring emerging flush was optimal in adjusting the fertilizer for the highest yield compared to the summer emerging flush. With the use of precision fertilization, the improvement in tree canopy density and fruit yield was more obvious in mildly HLB-symptomatic trees compared to severely symptomatic trees. Our results demonstrate the growers should be performing nutrient sampling quarterly and use this information to precisely manage fertilization and improve tree productivity.
Speakers
MM

Meryam Manzoor

University of Florida
Co-authors
JB

Jamie Burrow

University of Florida
NA
TL

Taylor Livingston

University of Florida
NA
TV

Tripti Vashisth

University of Florida
Wednesday September 25, 2024 8:00am - 8:15am HST
South Pacific 1

8:00am HST

FLOR 1 - Phosphate Solubilizing Bacteria: Leveraging The Soilless Substrate For Improved Phosphorus Nutrition In Controlled Environment Agriculture.
Wednesday September 25, 2024 8:00am - 8:15am HST
Phosphorus (P) is an essential macronutrient with low availability for plant uptake. The availability of P is reduced by the formation of insoluble complexes with calcium (Ca) and iron (Fe). Phosphorus solubilizing bacteria (PSB) can enhance P uptake by producing organic acids that acidify the rhizosphere and breakdown the insoluble P compounds. The goal of this research is to identify PSB that can increase P uptake efficiency in soilless production systems. A collection of bacteria isolated from the rhizosphere of greenhouse grown ornamentals was used to identify PSB using both in vitro and in planta evaluations. A malachite green assay optimized for 96-well plates was used to screen 1,056 bacterial isolates for the ability to solubilize phosphorus from both calcium phosphate and iron phosphate. This in vitro assay identified 14 and 24 PSB that solubilized 25% or more of the P from Ca2(PO4)3 and FePO4·2H20, respectively. There was no overlap between the PSB that solubilized Ca2(PO4)3 and those that solubilized FePO4. In planta evaluations were conducted in Marigold ‘Durango Yellow’ (Tagetes patula) and Tomato ‘Bush Beefsteak’ (Solanum lycopersicum) grown in a peat-based substrate (pH=7) and inoculated with individual PSB as a media drench (20 mL; OD595=0.1). Digital phenotyping with the TraitFinder (Phenospex) was used to quantify growth promotion (digital biomass and bloom area), and the severity of P deficiency symptoms [Green Leaf Index (GLI), normalized difference vegetation index (NDVI), Normalized Pigment Chlorophyll Ratio Index (NPCI), and Plant Senescence Reflectance Index (PSRI)]. Only seven FePO4·2H20 solubilizers (Fe-PSB) and six Ca2(PO4)3 solubilizers (Ca-PSB) performed better than the control in at least one of the evaluated parameters. A validation experiment was conducted to confirm the beneficial activity of the seven Fe-PSB (C2F9, C3A8, C11G1, C8D10, C6E7, C3G9, and C3F10) and the six Ca-PSB (C4A1, C2G6, B3A7, C11A5, C4B6, C12F4, and C6H6). The validation experiments were conducted with Marigold ‘Durango Yellow’ and Tomato ‘Early girl’ grown in a peat-based substrate (pH=7) and inoculated with individual PSB as a media drench (20 mL; OD595=0.1). Bacillus megaterium (C3F10), Pseudomonas sp. (C6E7), and two strains of Pantoea rwandensis (C3A8 and C8D10) showed a beneficial response when applied to plants fertilized with FePO4·2H20. Only, Enterobacter soli C4A1 showed a beneficial response when applied to plants fertilized with Ca2(PO4)3. The malachite-green assay and digital phenotyping are suitable tools for high-throughput identification of PSB that can be used to improve phosphorus nutrition in soilless culture systems.
Speakers
MJ

Michelle Jones

Professor, The Ohio State University
Co-authors
JQ

Juan Quijia Pillajo

The Ohio State University
LC

Laura Chapin

The Ohio State University
NA
SN

Sachin Naik

The Ohio State University
NA
Wednesday September 25, 2024 8:00am - 8:15am HST
Nautilus

8:00am HST

GG 1 - Assembling a Reference Panel of DNA Profiles for U.S. Heirloom Apple Cultivars
Wednesday September 25, 2024 8:00am - 8:15am HST
Heirloom apple cultivars represent an important specialty crop for producers and a genetic resource for the dessert apple industry. These cultivars are plagued with misidentifications, which hinders utilization and long-term preservation. Phenotypic identification, used for centuries, is unable to distinguish among the thousands of existing U.S. heirlooms. DNA profiling provides an objective basis for cultivar identification. Washington State University’s “MyFruitTree” (myfruittree.org), built upon the RosBREED project and with international collaborations, has accumulated a DNA profile dataset of thousands of apple individuals focused on the U.S. genepool. Users submit leaf samples for trees of interest, and MyFruitTree’s cost-recovery research opportunity determines the cultivar identity (or reveals their uniqueness and pedigree position). However, a common and valid question is, “How do you know that is the correct identity?” The core panel of robustly identified cultivars was based on public breeding germplasm, modern cultivars, and their ancestors, which were DNA profiled in the RosBREED project last decade. Since then, examined trees from collections in the U.S. and abroad have greatly expanded the number of DNA profiles with cultivar labels. But those labels are not always correct, especially when a tree is derived from only a single source. Therefore, a system was derived for assigning confidence to the cultivar labels associated with DNA profiles. Cultivar name evidence is assembled in the categories of provenance, phenotype, and genotype for both the DNA-profiled tree and the historically named cultivar, and congruence is examined. This system is applied at two levels: streamlined and comprehensive. The streamlined approach for the current DNA profile dataset efficiently determined whether each individual belongs confidently in the “Reference Panel” or is relegated to “Accessory Profiles” pending further evidence. A Reference Panel was assembled of hundreds of U.S. heirlooms (and more than a thousand close relatives from other regions). The comprehensive approach involves attention from a transdisciplinary tribunal of experts who carefully weigh evidence that an apple individual – often a proposed new discovery of an otherwise lost heirloom – is indeed a historically named cultivar. As MyFruitTree accumulates more DNA profiles submitted by cultivar collection managers and apple enthusiasts nationwide, the cultivar name assignment system is being applied to unidentified trees with strong provenance evidence of cultivar status. Establishing accurate cultivar identities of valued trees via DNA profiling is providing the critical foundation for a coordinated national effort to sustain preservation and utilization of apple crop diversity.
Speakers
CP

Cameron Peace

Washington State University
Co-authors
DL

Dongyun Lee

Washington State University
Wednesday September 25, 2024 8:00am - 8:15am HST
Coral 1

8:00am HST

PGR 1 - Evaluation of Plant Growth Regulators on Sweetpotato Slip Propagation
Wednesday September 25, 2024 8:00am - 8:15am HST
Producing sweetpotatoes involve several phases presenting unique challenges, most notably during transplanting. Sweetpotato slips, used for asexual reproduction, have non-uniform characteristics, making transplanting difficult. Additionally, the transition from a greenhouse to a field condition poses environmental risks and challenges, resulting in low transplant survival rates. A high slip mortality rate creates economic and logistical problems for producers. Plant growth regulators (PGRs) have been found to induce lignification or thickening of cell walls, which can alleviate environmental stresses in other crops; however, their impact remains unexplored in sweetpotato slips. Therefore, a study at Mississippi State University was conducted with the primary goal to enhance sweetpotato slip quality and improve transplant establishment rates. The study involves two greenhouse trials to identify the most effective PGR types and concentrations, and two histology trials to illustrate the effects of PGRs on sweetpotato slip lignin and cell wall. The greenhouse trials utilize a randomized complete block design to assess four different PGR types and thirteen concentrations on three replications of sweetpotato slips with 38 subsamples per treatment per replication. Data on plant height, stem diameter, number of nodes, SPAD, leaf area, and dry weight and fresh weight of the slips and roots were collected to determine the effects of PGRs on the plants. The histology trials included the same PGR treatments and concentrations to the slips. The slips were then collected, cross-sectioned, stained, and evaluated and measured under a microscope. The study proved that PGRs do have an effect on sweetpotato slips, by altering plant height, dry weight, and fresh weight, while not impacting the number of nodes. Thickening of the cell wall was also observed in slips treated with certain PGRs and it is hypothesized that this thickening of cell walls can contribute to reduced slip mortality when transplanting greenhouse produced slips to the field.
Speakers
avatar for Kerington Bass

Kerington Bass

Graduate Student, Mississippi State University
Originally from Louisiana Nontraditional ag background Interested in horticulture of specialty crops or ornamentals Highly interested in Controlled Environment Agriculture Looking for job opportunities Looking for opportunities to learn a second language 
Co-authors
BG

Bi Guihong

Mississippi State University
LH

Lorin Harvey

Mississippi State University
NA
avatar for Richard Harkess

Richard Harkess

Mississippi State University
NA
TB

Taylor Blaise

Mississippi State University
NA
Wednesday September 25, 2024 8:00am - 8:15am HST
South Pacific 3

8:00am HST

PLAST - Cover Crop Windbreaks for Slowing Biodegradable Mulch Deterioration and Improving Bell Pepper Productivity.
Wednesday September 25, 2024 8:00am - 8:15am HST
Polyethylene mulch films have become a dominant production practice to increase the yield potential of high value crops, but they are a significant source of environmental contamination. Alternatively, biodegradable mulches are a potentially sustainable alternative , but are less popular among growers as they vary in durability and performance in the field environment. Cover crops when sufficiently tall may be able to improve biodegradable mulch durability by reducing wind intensity within a mulched bed. To quantify the utility of a cover crop windbreak, we tested the effect of a fall-planted, 6ft wide strip of cereal rye planted parallel to the southern side of mulched bell pepper beds. Whole plot treatments included presence or absence of rye and split plot treatments included a comparison of polyethylene mulch, biodegradable mulch, and a bare ground control. Day windspeeds were reduced in peppers protected by a south-facing cereal rye strip by 60% relative to unprotected peppers. Large hole occurrences in biodegradable mulch were reduced by 50% and small holes by 15% in peppers protected by a cereal rye strip relative to unprotected peppers. Peppers grown behind the cover of cereal rye had a 42% reduction in leaning plants compared to peppers without cereal rye. Stomatal conductance was increased by 27% in peppers protected by cereal rye relative to unprotected peppers as a result of reduced windspeeds, though there were no differences in fruit yields. Results suggest cover crops can extend the useful life of biodegradable mulch films, which may help address a common barrier to adoption. Ongoing research aims to better understand the effects of the cover crop on crop health, yield, and quality.
Speakers
CW

Caleb Wehrbein

University of Nebraska - Lincoln
Co-authors
SW

Samuel Wortman

University of Nebraska - Lincoln
Wednesday September 25, 2024 8:00am - 8:15am HST
Lehua Suite

8:00am HST

QUAL - The Effect of Fruit Tree Virus and Viroid Infections on Tree Growth and Fruit Quality
Wednesday September 25, 2024 8:00am - 8:15am HST
This study aimed to investigate the impact of virus and viroid infections on tree growth and fruit quality attributes in apple, pear, peach, and grape. Trials were conducted in 2019 at the National Institute of Horticultural and Herbal Science in Korea, utilizing virus-infected, viroid-infected, combined virus/viroid-infected, and uninfected trees in an experimental fruit-tree orchard. Additionally, the experimental orchard served as an exhibition package for farmers and agricultural workers. Annual measurements of tree growth were compared between virus-free and virus/viroid-infected trees. Fruit quality attributes, including yield, weight, firmness, titratable acidity, and anthocyanin content, were assessed during 2021-2023. The results revealed significant differences between virus-free trees and those infected with virus, viroid, or both. Viral and viroid infections led to reduced tree height, trunk area, fruit yield, fruit weight, and anthocyanin content, while increasing fruit firmness and titratable acidity, respectively. These findings are expected to contribute to fruit tree virus and viroid disease control and fruit cultivation management. Furthermore, we anticipate that this research will enhance the understanding of agricultural stakeholders through scientific and comprehensive evidence on the damages caused by fruit tree viruses and viroid infections, thereby stimulating the adoption of virus-free stocks and promoting their widespread distribution.
Speakers
SY

Sang Yun Cho

agricultural researcher, National Institute of Horticultural and Herbal Science
Co-authors
BY

Byeonghyeon Yun

National Institute of Horticultural and Herbal Science
NA
HR

Hyun Ran Kim

National Institute of Horticultural and Herbal Science
NA
KH

Kang Hee Cho

Rural Development Administration
NA
SH

Se Hee Kim

National Institute of Horticultural and Herbal Science
NA
SO

Sewon Oh

National Institute of Horticultural and Herbal Science
NA
Wednesday September 25, 2024 8:00am - 8:15am HST
Kahili

8:00am HST

TECH 1 - Advanced 3D Imaging for High Throughput Phenotyping of Horticultural Crops
Wednesday September 25, 2024 8:00am - 8:15am HST
Understanding plant growth and development is crucial for insights into plant structure and function, and recent advancements in AI-driven 3D imaging technologies have revolutionized the acquisition and analysis of high-fidelity plant models. These technologies enable accurate and rapid measurement of phenotypic traits, aiding breeders in developing new varieties and helping horticulturists optimize production management. The overarching goal of this study was to establish an AI-based 3D imaging and analysis pipeline specifically designed for detailed examination of horticultural crops at the organ level within controlled environments. We developed a robotic platform equipped with a rotating base and a high-resolution camera mounted on a robotic arm, allowing comprehensive imaging from any angle around the plant. Utilizing this robot, we generated 3D models of 30 hemp plants from two growth-rate categories in controlled environments, on a weekly basis. An AI model was developed to segment these 3D models into stems, branches, and leaves. Morphological traits were extracted from each category of the segmented organs, including stem length (i.e., plant height), stem diameter, branch length, branch diameter, leaf number, leaf area, and leaf aspect ratio. These measurements contributed to a classification model capable of distinguishing between fast and regular growth rates. Experimental results showed that the 3D imaging-derived measurements were highly correlated with human-derived measurements. In addition, the extracted traits were used as quantitative descriptors to classify hemp cultivars with different growth rates in CEA. Therefore, the developed pipeline can be used as an effective and efficient tool for breeding programs and CEA production management in the future.
Speakers
YJ

Yu Jiang

Cornell University
Co-authors
JM

Jonathan Moon

Cornell University
NA
LS

Larry Smart

Cornell University
NA
NM

Neil Mattson

Cornell University
RD

Ruiming Du

Cornell University
NA
Wednesday September 25, 2024 8:00am - 8:15am HST
South Pacific 2

8:00am HST

VCM 2 - Optimizing Tomato Crop Production: Fertility Management in Soilless Media
Wednesday September 25, 2024 8:00am - 8:15am HST
Tomatoes are one of the most important greenhouse produced crops and the number of producers using greenhouse to grow them has risen in recent years. Sustainable development and effective resource management are becoming more and more important to the agricultural industries as well. Applying fertilizer precisely is becoming more and more important in different agricultural systems. Different physical and chemical characteristics of soilless growing substrate result in varying capacities for retaining nutrients. As a result, precise fertilizer rates are essential. This study investigated 14 fertilizer blends with varying proportions of nitrogen (0-400ppm), phosphorus (0-100ppm), and potassium (0-425). Six-cell seedling starter trays were filled with Berger BM6, and 'Big Beef' tomato seeds were planted. After four weeks, the seedlings were transplanted into five-gallon aeration fabric grow bags. Plants were hand-watered once a week with each treatment fertilizer rate to maintain a 10% leaching fraction. End measurements included the number of leaves, dry shoot weight, fresh root weight, dried root weight, and SPAD readings. The study revealed that a higher rate of nitrogen increased fresh shoot weight and lower rates of phosphorous increased number of non-harvestable fruits, increasing the need for further investigation to determine optimal fertilizer rates for various specialty crops grown in soilless greenhouse environments. Such endeavors are crucial for maximizing agricultural productivity while minimizing resource wastage and environmental impact.
Speakers
BW

Bryce Waugh

Grad Student, Oklahoma State University
Co-authors
BD

Bruce Dunn

Oklahoma State University
Wednesday September 25, 2024 8:00am - 8:15am HST
South Pacific 4

8:15am HST

CE 2- Impact of Diurnal Chilling on Vegetative and Floral Development of Strawberry (Fragaria x annanassa) cvs. ‘Albion’, ‘Chandler’, ‘Monterey’, ‘Sensation’ Tray Plants in a Controlled Environment
Wednesday September 25, 2024 8:15am - 8:30am HST
In US open field nurseries, strawberry transplants for fruit production accumulate diurnal chilling hours (hours between -2 and 7°C) in the field prior to harvest and receive supplemental chilling as bare root plants in a cooler before being transplanted into a fruit production system. In nurseries in Northwestern Europe, tray plants are placed outside after rooting to accumulate diurnal chill hours and are moved into the cooler with leaves and substrate for supplemental chilling before being transplanted. The optimal amount of chilling varies among cultivars but is thought to contribute to a proper balance of vegetative vigor and floral development leading to best fruiting after transplanting into the production system. Climate change, labor cost and related issues cause problems in both nurseries and production. Therefore more and more growers and start-up companies venture into controlled environment production systems. Due to high cost, these systems require transplants that are optimally conditioned for early flowering. We evaluated the impact of diurnal chilling on vegetative and floral development of 250 cc strawberry tray plants in a controlled environment. 28 day old ‘Albion’, ‘Chandler’, ‘Monterey’, and ‘Sensation’ rooted daughter plants were moved into growth chambers where they received 0 (15°C 24 hours), 100 (4°C, 16°C), 250 (4°C, 19°C), or 450 (4°C, 24°C) chill hours over a six week period. Within each treatment, the same amount of chill hours were applied each day for the six week period. Among treatments, the non-chill temperature increased as the number of chill hours increased to ensure the same daily average temperature of 15°C. Chambers were fixed at 50% RH, 450 ppm CO2, 130-40 µmol m-2 s-1 for all treatments and a 12 hour photoperiod for ‘Chandler’ and ‘Sensation’ and a 16 hour photoperiod for ‘Albion’ and ‘Monterey’. After the treatment, all plants were dissected under the microscope to determine the number and development of floral meristems (flower mapping). Our results show that the plants in the 100 and 250 hour treatments produced more floral meristems and branch crowns than the 0 and 450 hour treatments across all cultivars. Additionally, in ‘Albion’ and ‘Monterey’, the plants of the 100 and 250 hour treatments had greater fresh mass and higher crown diameter than the plants in the 0 and 450 hour treatments. Finally, all cultivars except ‘Sensation’ had more flowers on plants in the 100 and 250 hour treatments than those of the 0 and 450 hour treatments.
Speakers
MP

Michael Palmer

North Carolina State University
Co-authors
MH

Mark Hoffmann

North Carolina State University
NA
Wednesday September 25, 2024 8:15am - 8:30am HST
Coral 2

8:15am HST

CITR 2/HIST - Cover Crop Effects on HLB-affected Citrus Tree Growth and Soil Characteristics: Results From a 3-year Field Trial
Wednesday September 25, 2024 8:15am - 8:30am HST
Citrus greening, or Huanglongbing (HLB), poses a severe threat to Florida’s citrus industry, impacting tree health and yield. Due to the lack of a known cure, growers employ various strategies to manage its effects, including increased nutrient application. However, in regions like the Indian River District (IRD), characterized by poor soil fertility and organic matter content, nutrient retention is challenging. Consequently, there is growing interest in using cover crops to enhance soil fertility. Despite this, there is limited published data on their effectiveness in the IRD. To address this gap, a collaborative study was initiated in Ft. Pierce, Florida, involving a commercial grower and the University of Florida. A three-year field trial, employing a randomized complete block design with four blocks, included ‘Star Ruby’ grapefruit trees grafted on ‘US-942’ rootstock, ‘Bearss’ lemon trees on ‘Sour Orange’ rootstock, and ‘OLL’ sweet orange trees on 'US-942' rootstock. Two treatments were applied: conventional (without cover crops) and experimental (with cover crops). Cover crops were planted bi-annually (winter and summer), grown, and terminated at each season’s end. Soil nutrient content, organic matter, microbiome diversity, moisture, and temperature, as well tree and root growth parameters were measured seasonally. After three years of cover cropping, significant differences in soil nutrient content, organic matter, and microbiome diversity were observed between the conventional and experimental treatments, suggesting potential impacts of cover crops on soil characteristics. However, there were no noticeable effects on tree growth or physiology. This study is ongoing and aims to provide a comprehensive understanding of the long-term effects of cover cropping on soil parameters in HLB-affected citrus groves, informing sustainable management practices in citrus cultivation.
Speakers
avatar for Lorenzo Rossi

Lorenzo Rossi

Associate Professor, University of Florida
Dr. Rossi’s research program focuses on improving root health and growth on cultivated crops, leading to the development of environmentally sound and effective management methods. He is a horticulturist with specific expertise related to plant stress physiology, root dynamics and... Read More →
Co-authors
AW

Alan Wright

University of Florida
NA
JF

John-Paul Fox

University of Florida
LH

Lukas Hallman

University of Florida
Wednesday September 25, 2024 8:15am - 8:30am HST
South Pacific 1

8:15am HST

FLOR 1 - Phosphate Solubilizing Bacteria Isolated From Greenhouse Ornamentals Solubilize Phosphate In Vitro And Ameliorate P Deficiency Symptoms In Marigold ‘Durango Yellow’ Fertilized With Calcium Phosphate.
Wednesday September 25, 2024 8:15am - 8:30am HST
Phosphorus (P) is an essential macronutrient absorbed by plants as orthophosphate (PO4). P availability depends on the pH of the substrate. At high pH, P forms insoluble compounds like Ca3(PO4)2 which is unavailable for plant uptake. Phosphate solubilizing bacteria (PSB) are plant-associated microorganisms that can break down Ca3(PO4)2 by secreting organic acids. PSB have been primarily evaluated as inoculum for crops grown in soil to improve P availability. However, less is known about the application of PSB in ornamentals grown in soilless substrates. Our goal was to identify PSB from a collection of bacteria isolated from the rhizosphere of greenhouse ornamentals. First, the collection was screened in vitro for the bacterial capacity to reduce pH of the media using the bromophenol-blue color assay. Thirty-five isolates were identified to reduce media pH, and their P solubilization capacity was quantified using ion chromatography. Fourteen isolates with the highest P solubilization were selected for whole-genome sequencing, but only two bacterial isolates (C2B11 and C8D10) were advanced to the in-planta evaluation using Marigold (Tagetes patula) 'Durango Yellow' grown in a peat-based substrate (pH = 7). Plants were irrigated with 100 mg·L-1 N from a 15N-0P-15K fertilizer, and P was supplemented weekly as Ca3(PO4)2 via substrate drench applications. Lalrise Vita (Lallemand Plant Care) and Bacillus velezensis (the active ingredient in Lalrise Vita) were included as positive controls. Plant phenotyping was conducted using the TraitFinder automatic system (Phenospex). TraitFinder assessment parameters included digital biomass, bloom area, Green Leaf Index (GLI), Normalized Pigment Chlorophyll Ratio Index (NPCI), and Plant Senescence Reflectance Index (PSRI). Lalrise Vita performed better than the control in all the parameters evaluated. B. velezensis increased bloom area and showed higher GLI and lower NPCI than the control. Pantoea sp. C2B11 significantly increased digital biomass, bloom area, and GLI. Pantoea sp. C8D10 only showed an increase in GLI values. Both C2B11 and C8D10 possess various genes involved in gluconic acid production. We identified two PSB that solubilize P in vitro, promote growth and bloom area, and improve canopy health (high GLI or low NPCI) in marigold plants fertilized with Ca3(PO4)2. Our next step is to validate the growth-promoting capacity of the identified PSB in other ornamentals. PSB can contribute to improving phosphorus nutrition and fertilizer use efficiency in greenhouse ornamental production.
Speakers
JQ

Juan Quijia Pillajo

The Ohio State University
Co-authors
MJ

Michelle Jones

The Ohio State University
NN

Nathan Nordstedt

FMC Corporation
NA
Wednesday September 25, 2024 8:15am - 8:30am HST
Nautilus

8:15am HST

GG 1 - Rediscovering Lost Heirloom Apple Cultivars with DNA Fingerprinting
Wednesday September 25, 2024 8:15am - 8:30am HST
U.S. heirloom apple cultivars are an underutilized and threatened resource, that DNA fingerprinting can help save and remobilize. These heirlooms are old cultivars that were named, clonally propagated, and distributed more than a century ago. Many heirloom cultivars have great historical value, some are still grown commercially, and others could be reintroduced to enhance rural prosperity and diversify options for consumers. While some heirloom cultivars are ancestors of modern cultivars, many others could be valuable for future breeding. However, most heirlooms have been long neglected, and thousands once documented are already extinct. Before more heirlooms disappear forever, mystery trees need to be distinguished from known cultivars, identified, and adequately preserved. Leaf samples for more than 2000 apple trees in collections, national heritage sites, old orchards, and backyards across the U.S. were crowdsourced from about 150 “MyFruitTree” submitters and DNA fingerprinted using KASP genotyping with 48 SNPs. The cultivar identity or uniqueness of each tree was determined by comparing obtained DNA profiles to a previously developed dataset of several thousand apple cultivars and individuals. Trees with replicates were prioritized into five categories according to several criteria for likelihood of representing heirloom cultivars. After removing duplicate samples, poor genotypic data, and non-apple samples, about 60% (1202) of samples were identified as cultivars and most were heirlooms. Of the unidentified samples, 85% (665) were unique, and 15% (118) of the samples represented replicated trees. We found five “Priority 1” trees (filled cultivar pedigree gaps or from three U.S. regions) and four “Priority 2” trees (detected in two regions). Hundreds more trees likely representing unknown heirlooms were also identified in single regions. Collaborators across the country, including historians and citizen scientists, can now closely examine the highest priority trees to uncover their historic cultivar names, while ensuring they are propagated so that they are preserved and valued once again. As more old apple trees are DNA fingerprinted, it is expected that current “unique” DNA profiles will be replicated in the same or other regions. Replicated trees must represent propagated, valued, and likely named cultivars, increasing the opportunities to rediscover lost heirlooms.
Speakers
DL

Dongyun Lee

Washington State University
Co-authors
AD

Amy Dunbar-Wallis

University of Colorado
NA
CP

Cameron Peace

Washington State University
JB

John Bunker

Maine Heritage Orchard
NA
RM

Rebecca McGee

USDA-ARS Pullman
NA
TL

Todd Little-Siebold

College of the Atlantic
NA
Wednesday September 25, 2024 8:15am - 8:30am HST
Coral 1

8:15am HST

PGR 1 - Effects of a Cytokinin-Containing Biostimulant Applied at Different Phenological Timings on Almond (Prunus dulcis) Yield
Wednesday September 25, 2024 8:15am - 8:30am HST
Almond (Prunus dulcis) is one of the most important crops in California. This commodity represented an economic impact of over 3.5 billion dollars for the state in 2022. During that year, 1,630,000 million planted acres were reported. In 2023, this number dropped by 74,000 acres, continuing the trend of decline due to numerous challenges that the industry has been facing. These include volatile prices, high input costs, reduced water allocations, climate unpredictability, and high temperatures during key phenological timings. The almond crop is highly sensitive to environmental factors, and photosynthetic rates can significantly decrease when temperatures reach 94F, heat levels are easily reached during the hot summer months in California’s production areas. To this matter, significant contributions are needed to support the industry. There are over 700 peer-reviewed scientific publications that evidence the benefits of using biologicals, which include plant biostimulants (PBS), in agriculture. It has been shown that season-long exogenous applications of cytokinin-containing PBS can support higher marketable yields. It is important to understand the physiological timings in which these applications have the most impact, in terms of maximizing the yield and quality potential. In 2023, a randomized complete-block design (RCBD) study was conducted on 5th leaf Var. Nonpareil in California’s Central Valley. The objective was to evaluate the yield and quality effects of an application of X-CyteTM, a 0.04% cytokinin-containing biostimulant registered for use on almonds in California, at different standalone phenological timings. These included early bloom, full bloom, petal fall, may spray, and hull-split. The trial consisted of six four-tree replications per treatment. Yield and quality data were subjected to a one-way ANOVA using IBM® SPSS® Statistics, and means were separated using Tukey’s HSD. The standard grower practice (SGP) produced 1801.5 marketable pounds of kernel meat per acre. X-Cyte™ treatment yields of 1845.16, 2140.16, 2215.66, 2137.67, and 2318.33, were observed for early bloom, full bloom, petal fall, may spray, and hull-split timings, respectively. Statistically significant differences were observed (p-value: 0.003). The hull-split and petal fall timing applications represented the higher yield increases (516.8 and 414.2 lbs/A, respectively) overall, compared to the SGP. It has been documented that taking place at these timings are key phenological stages deemed as major contributors to the components of yield: fruit set and nut fill. Significant differences in kernel size were not observed (p-value: 0.549). These findings further support and help fine-tune the use of biologicals and PBS in agricultural production systems.
Speakers
OT

Orlando Tapia

California State University Fresno / Corteva Agriscience
Co-authors
DG

Dave Goorahoo

California State University, Fresno
RM

Ryan Miller

Corteva Agriscience
NA
Wednesday September 25, 2024 8:15am - 8:30am HST
South Pacific 3

8:15am HST

PLAST - Influence of Plastic Mulch Color on Yield and Quality of Day-neutral Strawberries
Wednesday September 25, 2024 8:15am - 8:30am HST
High tunnel production of day-neutral strawberries is a promising production system in the central U.S. The use of different colored plastic mulches in a high tunnel production system can vary the microclimate around plants and alter yield and fruit quality. This study was conducted to identify the most appropriate color plastic mulch in a high tunnel production system as it relates to yield and fruit quality. The experiment was conducted at the Kansas State University, Olathe Horticulture Research and Extension Center in 2020 and 2021 using a split-plot, randomized complete block design. We evaluated six plastic mulches (black, white, striped silver, silver, red, and green) and two day-neutral cultivars, ‘Albion’ and ‘Portola’. Soil temperature and UV light reflected from the mulch were measured to monitor microclimate modifications. Fruit quality was assessed by overall visual quality, color, soluble solids content, titratable acidity, sugar/acid ratio, total phenolics, and anthocyanin content of strawberries. 'Portola’ produced greater yields than ‘Albion’, but ‘Albion’ had better fruit quality. The plastic mulches altered the reflected UV light and soil temperatures. During the mid and late season, the silver mulch had higher fruit yields than the red and green mulches, likely due to its ability to limit solar warming during warm production months. The mulches had inconsistent impacts on fruit quality. Overall, the silver mulch maintained the best microclimate for day-neutral strawberry production in high tunnels.
Speakers
avatar for Tricia Jenkins

Tricia Jenkins

Kansas State University
Co-authors
AM

Amrita Mukherjee

University of California, Davis
Amrita Mukherjee, Urban Agriculture/Small Farm Advisor at the University of California Agriculture and Natural Resources in Southern California, focuses on research and education in organic farming, urban agriculture, and sustainable practices for small-scale growers in both field... Read More →
CR

Cary Rivard

Kansas State University
EP

Eleni Pliakoni

Kansas State University
Wednesday September 25, 2024 8:15am - 8:30am HST
Lehua Suite

8:15am HST

QUAL - Bacteriophage as an Alternative Method to Control Salmonella enterica in Water-Recirculated Systems for Lettuce Production
Wednesday September 25, 2024 8:15am - 8:30am HST
In recent years, controlled environment agriculture (CEA) has gained popularity as a sustainable and efficient method of cultivation, offering solutions to challenges posed by traditional farming practices and meeting the growing demand for high-quality produce. However, advancements in CEA have raised concerns about food safety, requiring new approaches to minimize the risk of produce contamination. This research explores the effectiveness of a bacteriophage cocktail as a biocontrol agent against Salmonella contamination in lettuce grown in water-recirculating systems. Salmonella Newport and Salmonella Typhimurium (103 CFU/mL) were inoculated into aquaponic and hydroponic nutrient solutions into a water-recirculating system to mimic sporadic contamination, followed by treatment with a bacteriophage cocktail (S7, S10, and S13) at different multiplicities of infection (MOI 0.01 and MOI 1). The results demonstrated a significant reduction in Salmonella Newport and Salmonella Typhimurium populations at both MOI 0.01 and MOI 1 in aquaponic and hydroponic nutrient solutions, with levels reaching below the limit of detection (LOD) after 3 to 4 days of bacteriophage cocktail inoculation. From the plant parts, there was a significant reduction in the microbial population of Salmonella serovars in media plugs and roots from the hydroponic nutrient solution, reaching levels below the LOD in both phage cocktail treatments after a 2-day inoculation period. Contrarily, significant reductions were not observed in Salmonella serovar levels in plant roots and media plugs from the aquaponic nutrient solution treatment. These findings highlight the potential of utilizing bacteriophages to improve food safety in indoor-grown lettuce by controlling Salmonella populations while also indicating the necessity for further research to understand the microbial dynamics within each type of system.
Speakers
CR

Camila Rodrigues

Auburn University
Co-authors
CB

Caroline Blanchard

Auburn University
DW

Daniel Wells

Auburn University
NA
VM

Vania Mickos

Auburn University
NA
Wednesday September 25, 2024 8:15am - 8:30am HST
Kahili

8:15am HST

TECH 1 - Integrating UAV Imagery and AI to Forecast Vidalia Onion Yield and Quality
Wednesday September 25, 2024 8:15am - 8:30am HST
Forecasting yield and quality of Vidalia onions allows the stakeholders to make decisions on the best time and place to harvest. While yield defines an important quantitative parameter, conversely, sweetness emerges as timely factor of quality. Traditionally, measuring these parameters requires a field team and routine laboratory for the assessments, making it a subjective, time-consuming, labor-intensive, costly, and not-scalable approach. However, image technology and artificial intelligence (AI)-based methods could improve decision-making strategies. In this study, we collected unmanned aerial vehicle (UAV) multispectral images of two Vidalia onions fields from crop establishment until the harvest date, totaling six sets of images for each field. Each flight was performed with approximately 15 days apart. At the harvest date, 50 samples were collected in each field to determine yield, while 10 samples were used for sweetness. To ensure the robustness of the dataset, both fields were combined into a single dataset. Consequently, we used machine learning (ML) algorithms to perform predictive models, namely multiple linear regression (MLR), random forest (RF), and support vector machine (SVM). The dataset was split into 70% and 30% for training and testing, respectively, and the predictions were performed using the test dataset. Regarding the assessment of the models, we used the metrics namely coefficient of determination (R2), mean absolute error (MAE), and root mean squared error (RMSE). The models with higher R2 and lower MAE and RMSE were the bests. Notably, the considerable correlation between yield and spectral data made the MLR model perform well as more complex models such as RF. Conversely, when there was a weak correlation between the sweetness and spectral data, RF model could perform much better. In short, both models (MLR, RF, and SVM) could perform well into a predictive model, which highlights the strength of spectral data for representing Vidalia onions either quantitative or qualitative parameters. Therefore, our study not only represents an innovation in the field of specialty crop production, but also brings ready-to-use solutions to improve the production process and introduce Vidalia onions into the concept of field technology.
Speakers
avatar for Marcelo Barbosa

Marcelo Barbosa

University of Georgia
Co-authors
LO

Luan Oliveira

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 →
RD

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 →
Wednesday September 25, 2024 8:15am - 8:30am HST
South Pacific 2

8:15am HST

VCM 2 - Improving the Growth and Yield of Tomato through new Integrated Pest Management Strategies
Wednesday September 25, 2024 8:15am - 8:30am HST
Tomato (Solanum lycopersicum L.) is the number one vegetable crop in Hawaii in terms of popularity and market value. Of the total tomatoes consumed in Hawaii only 23% is produced locally. Local production has decreased substantially over the past few years due to crop losses caused primarily by the Tomato Yellow Leaf Curl Virus (TYLCV), which is vectored by whiteflies Bemisia tabaci and Bemisia argentifolii. Crop losses by TYLCV in tomato crops on Maui range between 60 to 100%. Efforts to keep plants from becoming infected, manage the rate of infection, timing, or severity of the infection are needed to protect crop health. Therefore, a new integrated pest management approach was conducted integrating the use of reflective ground cover, companion plants, insecticides, and tomato varieties resistant to TYLCV. The highest total weight (4.4 lb/pl per harvest time) was observed in the variety PS01522935 in the treatment combining reflective ground cover and companion plants and the highest marketable weight was observed in the same treatment in the varieties PS01522935 and Mesquite (3.5 lb/pl per harvest time), and the highest TYLCV infection was observed in the conventional treatment in the varieties Paisano followed by Healani, Celebrity Plus and Kewalo, and the varieties with no TYLCV infection were PS01522935, SVTD8601 and Mesquite. The use of reflective ground cover and companion plants may reduce TYLCV infections in tomato crops by reducing whitefly populations.
Speakers
RG

Rosemary Gutierrez Coarite

University of Hawaii at Manoa
Wednesday September 25, 2024 8:15am - 8:30am HST
South Pacific 4

8:30am HST

CE 2 - Utilizing Controlled Environment Agriculture to Enhance the Yield and Flavor of Strawberries
Wednesday September 25, 2024 8:30am - 8:45am HST
Presentation: Oral ASHS 2024 Keywords: CEA, greenhouse, Fragaria ×ananassa, temperature Utilizing Controlled Environment Agriculture to Enhance the Yield and Flavor of Strawberries Nicholas Cooley, Joshua Vanderweide, and Roberto Lopez In the U.S., strawberries (Fragaria ×ananassa) are the most popular berry fruit with a value of $2.8B. In 2022, strawberries experienced 12% growth in annual sales, with the majority of field production occurring in California and Florida. To meet consumer demand for flavorful, fresh, local, and year-round fresh strawberries, the industry is expanding controlled environment (CE) production of day-neutral (everbearing) cultivars in greenhouses and indoor farms. Within CEs, growers can potentially meet these demands through the manipulation of environmental parameters such as temperature, light, vapor pressure deficit, and carbon dioxide concentration. Despite the recent growth, CE growers are reporting low profitability. This imbalance of production and profitability stems from high energy costs, supra-optimal greenhouse temperatures during parts of the year, and low yield from the industry standard cultivar ‘Albion’. For producers to be considered profitable, they must reach an approximate annual yield of 15 kg∙m–2, which equates to a weekly yield of around 0.3 kg∙m–2. The objectives of our research are to 1) quantify the yield of other day-neutral cultivars in greenhouses; 2) determine how day and night temperature influence yield and fruit quality parameters; and 3) develop a model to predict the cardinal temperatures of each cultivar. Three cultivars, ‘Albion’, ‘Cabrillo’, and ‘Monterey’ were grown at day/ night temperatures (12 h/ 12 h) of 15/7, 18/10, 21/13, 24/16 or 27/19 °C, under a 16-h photoperiod, and a target DLI of 15 mol·m–2·d–1. Fruits were harvested three times weekly and at harvest, berry weight, diameter, color, shape, distortion, brix content, and flavor-related volatile organic concentrations were recorded. After 12 weeks of harvest, the highest average weekly yield was 0.17, 0.19, and 0.24 kg∙m–2 for ‘Albion’, ‘Cabrillo’ ‘Monterey’ at 18/10, 24/16, and 24/16 C, respectively. While the highest combined overall yield for all three cultivars was at 24/16 °C, the highest average berry weight differed. At day and night temperatures of 18/10, 18/10, and 15/7 °C, ‘Albion’, ‘Cabrillo’, and ‘Monterey had the highest average berry weights, respectively. Our results collectively indicate there are higher yielding day-neutral cultivars than the industry standard ‘Albion’.
Speakers
NC

Nicholas Cooley

Michigan State University
Wednesday September 25, 2024 8:30am - 8:45am HST
Coral 2

8:30am HST

CITR 2/HIST - More Frequent Irrigation Increases Yield in HLB-Affected Sweet Orange
Wednesday September 25, 2024 8:30am - 8:45am HST
Huanglongbing (HLB) causes a steady decline in tree health. Part of this decline includes root dieback which limits their capacity to take up water. For this reason, affected trees tend to be more susceptible to drought stress. This raises a significant concern during the dry season (Oct-May) when trees are largely dependent on supplemental irrigation for water. Unfortunately, most growers continue using irrigation schedules that were optimized for healthy trees. We hypothesized that irrigating more frequently, but in smaller doses would provide more opportunities for uptake and improve water relations in HLB-affected trees. The control treatment received the standard practice of irrigating every other day for 2 hours (12 gal/hr). The experimental treatment received water every day, 3 times a day, for 20 minutes (12 gal/hr). The two treatments received the same amount of water over the course of a week, but the experimental treatment received water more often. Treatments were initiated prior to flowering in January 2022 and were continued for two years. Tree water status improved in the experimental trees as reflected in higher mid-day leaf water potentials than in the control. This suggests the experimental regime was better able to maintain tree water status than the conventional method. In the second year, flowering was more synchronized in the experimental treatment. The control treatment saw two peaks in bud production with the latter one being consistent with a drought stress-induced flowering event. The experimental trees also saw an increase in fruit set in both years. Trees receiving the experimental and control treatments dropped a similar proportion of their crop load during June Drop and preharvest fruit drop in year 1 and 2. Finally, the experimental treatment resulted in significantly higher yields on average than the control in both year 1 and year 2 (72% and 200%, respectively). Altogether, more frequent irrigation improved tree productivity.
Speakers
TV

Tripti Vashisth

University of Florida
Co-authors
MS

Mary Sutton

University of Florida
NA
Wednesday September 25, 2024 8:30am - 8:45am HST
South Pacific 1

8:30am HST

FLOR 1 - Activated Aluminum Amended Substrates Reduce Phosphorus Leaching in Floriculture Production
Wednesday September 25, 2024 8:30am - 8:45am HST
The use of water-soluble fertilizers in floricultural production provides readily available nutrients to sustain short-term crop production; however, nutrients such as phosphorus are poorly retained in typical peat substrates. Activated aluminum is an amendment that has demonstrated success in binding phosphorus within substrates, reducing the amount of phosphorus that is leached from the container. This research investigated the production of Tagetes in peat-based substrates amended with or without activated aluminum and provided four different phosphorus fertilizer regimens. The fertilizer regimens encompassed a nitrogen, phosphorus, and potassium liquid blend applied weekly; however, phosphorus was only included for 0, 2, 4, or 6 weeks in total over the duration of the study. Growth of Tagetes was effectively similar, and leachate analysis provided insights that can be applied towards more efficient production methods. In this research, utilizing activated aluminum resulted in less phosphorus loss in container leachate than unamended substrates. The potential to decrease applied phosphorus during floricultural production can similarly be achieved when using substrates amended with activated aluminum. This presentation will decipher the dynamics of the movement of phosphorus and other anions of interest that may be relevant to sustainable floriculture production.
Speakers
DA

Damon Abdi

Louisiana State University Agricultural Center
Co-authors
JF

Jeb Fields

LSU AgCenter Hammond Research Station
JB

Jeffrey Beasley

University of North Carolina - Pembroke
NA
Wednesday September 25, 2024 8:30am - 8:45am HST
Nautilus

8:30am HST

GG 1 - Air or Soil Temperature: Understanding the Cues for Dormancy Transition in Peach
Wednesday September 25, 2024 8:30am - 8:45am HST
Peach trees require quantitative exposure to winter chilling (chilling requirement, CR) for spring bloom. The chill accumulation time points are determined using weather data of air temperatures between 32 and 45 ºF, using various calculation methods such as the simple chill hour (CH) method or more sophisticated methods like Utah and Chill portions (CP) that account for negations of chilling due to warm weather during the dormancy. All these methods rely on air temperature and do not consider the soil temperature during the dormancy and its effect on the tree’s perception and account for chill accumulation. Peach flowers and developing fruit are highly sensitive to freezing temperatures and are killed following even a limited exposure. In the past decade, mild winters and early spring frosts have significantly reduced or eliminated the annual peach production in the southeast U.S. Low-chill winters have become increasingly common in the southeastern peach-producing regions, and when followed by warm springs, result in early bud break and early flowering, increasing the risk of crop loss to frost. Due to a replant issue caused by Armillaria root rot, almost all acreage under the new peach orchards in the southeast, including South Carolina, are planted on berms adopting root collar excavation as a method to extend the life of orchards on infested soil. We observed significant differences between the air temperature and temperature of undisrupted soil and soil within berms at various depths (3, 6, 12 and 18 in) during dormancy. The effect of observed temperature differences on ‘Cresthaven’ tree chill accumulation calculation and transition between endo- and eco-dormancy stages was investigated by collecting vegetative bud and root tissue from all four depths at six chill hour time points (400, 500, 600, 700, 800 and 900). Preliminary data show significant gene expression differences between bud and root tissue and different gene expression profiles related to the chill accumulation in each tissue. Detailed analyses of the gene expression profiles between the tissues at the different chill accumulation stages and their effect on chilling and heat accumulation, bloom time, and the transition between the dormancy stages in peaches will be discussed.
Speakers
avatar for Ksenija Gasic

Ksenija Gasic

Clemson University
Co-authors
CS

Christopher Saski

Clemson University
NA
JL

John Lawton

Clemson University
NA
SP

Stephen Parris

Clemson University
ZL

Zhigang Li

Clemson University
NA
Wednesday September 25, 2024 8:30am - 8:45am HST
Coral 1

8:30am HST

PGR 1 - The Application of a Cytokinin B-Mo-based Product Influences the Source-to-Sink Dynamics and Non-Structural Carbohydrate
Wednesday September 25, 2024 8:30am - 8:45am HST
Understanding the sink-to-source relationship on leafy crops offers valuable insights into optimizing resource allocation for enhanced plant growth and quality. Variations in growth rates and carbon pools across individual leaves or groups of leaves at similar developmental stages allow us to understand the plant strategies of carbon allocation and partitioning. We hypothesized that products that enhance the carbon source-to-sink relationship during leaf development can lead to increased growth and dry matter accumulation. This project aimed to determine if the exogenous application of a cytokinin and B-Mo-based product during leaf development would impact carbon source-to-sink relationship and, hence, influence plant growth and quality. The experiment was a complete randomized design with two treatments consisting of a negative control and the application of the product twice during the growing cycle. The experimental unit consisted of a deep-water culture reservoir with three lettuce plants. Destructive sampling was conducted at five sampling points. At each sampling point (n=4 per experimental run), the phenological stage was determined, and root and shoot length and dry matter, leaf length, width, area, and non-structural carbon and chlorophyll contents were measured. This data was used to estimate growth rates. Results indicate that the cytokinin and B-Mo-based product increased the number of true unfolded leaves by 1 ± 0.4 and the overall size of the lettuce head by 9%. The treated lettuce reached a marketable size four days earlier than the control treatment. Statistically significant differences were observed in the shoot and root dry matter accumulation and foliar length and width at some sampling points. Some of the growth indices indicate an increase in leaf surface area investment and enhanced conversion efficiency of assimilates into biomass in plants treated with the product. Plants exhibiting these alterations had higher sucrose and total soluble sugar content. There was a noticeable pattern of higher concentrations of non-structural carbohydrates, proteins, and amino acids in the leaves compared with the roots across all plants and treatments. Overall, our study on using a cytokinin and B-Mo-based product to strengthen the source-to-sink relationship during the development of a leafy crop provides new insights into non-structural carbohydrate metabolism and the role of CKs, B, and Mo in generating a high-quality plant in a shorter timeframe.
Speakers
avatar for Mayra Toro Herrera

Mayra Toro Herrera

Postdoctoral Research Associate, University of Connecticut
Co-authors
RR

Rosa Raudales

University of Connecticut
Wednesday September 25, 2024 8:30am - 8:45am HST
South Pacific 3

8:30am HST

PLAST - Exploring sustainable mulch solutions: a comparative study in strawberry production systems in northwestern Washington
Wednesday September 25, 2024 8:30am - 8:45am HST
Agricultural plastic mulch made from non-biodegradable polyethylene (i.e., “PE mulch”) provides many horticultural benefits. However, PE mulch requires annual removal and disposal, which generates large volumes of plastic waste that is rarely recycled and can become a pollutant. Incomplete removal of PE mulch also can leave behind plastic fragments that threaten soil and ecosystem health. To address these challenges, soil-biodegradable mulches (BDMs) have emerged as a potentially more eco-friendly alternative. BDMs are designed to provide the same advantages for specialty crop production as PE mulch and naturally biodegrade when incorporated into the soil. In addition, non-biodegradable reflective mulch has emerged as a promising mulch technology that may reduce key insect pests. The objective of this research was to evaluate the impacts of different mulch technologies, including soil-biodegradable and reflective mulches, on horticultural and pest dynamics in day-neutral strawberry (Fragaria×ananassa cv. Albion) in northwest Washington. Seven mulch treatments were established in a randomized complete block design with four replications in 2023. Treatments included green and black BDM made with ecovio and Mater-Bi feedstocks, non-biodegradable metalized mulch, and controls of black PE mulch and unmulched plots. Yield from all mulch treatments did not differ significantly from black PE control except for the green BDM made with ecovio feedstock. The green BDM made with ecovio resulted in significantly lower (32%) yield, similar to unmulched control. Lower yield may be attributed to the rapid deterioration of the green BDM treatments, which lacks carbon black and deteriorated more rapidly compared to other mulch treatments. However, black BDM made from MaterBi feedstock and metalized mulch were 37% and 11% less deteriorated than PE control respectively. Additionally, all mulch treatments suppressed weeds better than the unmulched control and were not different from black PE mulch. Aphid and thrips populations were highest in unmulched plots, whereas metalized mulch had fewer thrips (on sticky cards) and fewer aphids (on leaves) than all other treatments. Overall, the study highlighted that black BDM performs similarly to PE mulch with regards to potential weed suppression and maintenance of yield, whereas the rapid deterioration of green BDM could effect the soil microclimate and subsequent plant growth. Despite rapid mulch deterioration, the study did not observe compromised weed management. Metalized mulch may contribute to reducing pest populations but impacts on pollination and biological control remains unknown. Additional research on soil health effects is required given the fate of BDMs is in-soil incorporation.
Speakers
NG

Nayab Gull

Graduate Research Assistant, Washington State University
Wednesday September 25, 2024 8:30am - 8:45am HST
Lehua Suite

8:30am HST

QUAL - Transfer of Escherichia coli from Plastic Mulch to Tomato and Pepper Fruit by Ground Contact in a Field Environment
Wednesday September 25, 2024 8:30am - 8:45am HST
In the southeast US, tomatoes (Solanum lycopersicum) and bell pepper (Capsicum annuum) are typically staked and trellised and grown using plastic mulch for weed control. The Produce Safety Rule that is part of the Food Safety Modernization Act requires that fruit from tomato and pepper be declared non-harvestable if they fall to the ground or contact the ground through drooping while attached to the plant before harvest. The objective of this study was to quantify percent transfer from plastic mulch inoculated with Escherichia coli with green fluorescent protein (GFP) to pepper and tomato fruit making ground contact in spring and fall growing seasons. E. coli GFP was spot inoculated on plastic mulch in the field using ten - 10 µL drops (100 uL total) at approximately 7 log CFU/mL and allowed to dry for at least 1 h before fruit contact. In the spring season, white and black colored plastic mulch were compared and in the fall season, reused (second crop) plastic mulch and new white plastic mulch were compared. Fruit contacted the ground by drooping (remained attached to the plant) with a contact time of 1 h or 24 h as well as contact through dropping fruit at heights of 30 cm, 60 cm, and 120 cm (n=9 per treatment). After inoculum was allowed to dry on the plastic mulch, the E. coli population was reduced an average of 2.8 and 4.8 log CFU/mL, in the spring and fall seasons, respectively. In both seasons all dropped peppers had significantly different percent transfer than dropped tomatoes, while drooping fruit were not significantly different between the two commodities. In the fall, dropped fruit on new plastic had significantly greater bacterial transfer than fruit which was dropped on reused plastic for both tomato and pepper. No significant differences were obtained between drooping duration treatments or between the different height of dropping in either season. There was relatively low transfer overall from both drooping and dropping of fruit on inoculated plastic mulch, regardless of crop or season. Further, in this inoculated study, results suggest that there was a significant reduction in E. coli populations in a field setting after a short period of exposure to the natural environment.
Speakers
AB

Autumn Burnett

University of Georgia
Co-authors
BR

Blanca Ruiz Llacsuanga

University of Georgia
NA
FC

Faith Critzer

University of Georgia
NA
HG

Halle Greenbaum

University of Georgia
NA
RR

Rawane Raad

University of Georgia
NA
TC

Timothy Coolong

University of Georgia
Wednesday September 25, 2024 8:30am - 8:45am HST
Kahili

8:30am HST

TECH 1 - Deep Learning Application for Field Phenotyping of Shoot Structure in Grapevine
Wednesday September 25, 2024 8:30am - 8:45am HST
In the cultivation of fruit trees and vines, plant architecture is a critical determinant of productivity. While there are considerable diversities in plant architecture, which can be modified through pruning in fruit production, a method for high-throughput measurement and recording of architecture has not yet been established, posing a limitation to research and development in this area. Here we evaluated Transformer-based architecture for detecting above-ground shoot network of grapevine in an outdoor vineyard condition. The problem here was defined as the detection of nodes (buds or branching points) and their physical relationships (internodes or edges) within plant images. We also developed an evaluation metric inspired by the inherent structure of plant shoots to efficiently smooth detected structures to more closely resemble realistic systems in plants. The proposed framework has been successfully applied to the detection task in outdoor condition with complex background. Through the application of this method, we have demonstrated that our proposed framework is capable of extracting topological parameters of dormant shoot architecture of grapevine that effectively models the shoot biomass in a large-scale vineyard.
Speakers
SN

Soichiro Nishiyama

Kyoto University
Co-authors
DG

Dario Guevara

Department of Viticulture
NA
GG

Guillermo Garcia Zamora

Department of Viticulture
NA
ME

Mason Earles

Department of Viticulture
NA
Wednesday September 25, 2024 8:30am - 8:45am HST
South Pacific 2

8:30am HST

VCM 2 - Assessment of Novel, Interspecific Hybrid Tomato Rootstocks for Production under Environmental Stress
Wednesday September 25, 2024 8:30am - 8:45am HST
A growing global population and worsening global environmental change necessitate the development of improved crop varieties and cultivation techniques. In tomatoes, the world’s most popular vegetable crop, grafting has emerged as a cultivation technique for addressing these challenges through improving tomato crop vigor and stress resistance, especially to abiotic stresses that are becoming more widespread including heat, salinity, and drought stress. In order to expand the offerings of tomato rootstocks, we have conducted multiple trials to assess the beneficial impact of 10 novel tomato rootstocks on ‘Celebrity’ scion vigor and stress resistance. The rootstocks, developed by colleagues at the King Abdullah University of Science and Technology (KAUST) consist of interspecific Solanum spp. hybrids including two tetraploid hybrids. We conducted three trials to assess the impact of grafting with the novel rootstocks, including a greenhouse pot trial to quantify growth and vigor and two controlled environment trials to assess stress resistance. In each trial, ‘Celebrity ’ scions were grafted with either the novel rootstocks, ‘Maxifort’, ‘Multifort’, or left ungrafted. In the greenhouse trial, measurements of stem diameter, shoot height, shoot canopy projection area, and fresh and dry weights at harvest were used to determine overall vigor. We identified five and eight of the novel rootstock grafting combinations that outperformed the ungrafted and ‘Maxifort’-grafted plants, respectively. Additionally, measurements of SPAD and observations of foliage coloration provided initial evidence of differential nutritive requirements between the novel rootstocks. In our controlled environment trials, chlorophyll fluorescence, SPAD, and porometer data demonstrated differential susceptibility to salinity, heat, and drought stress between the rootstocks. This presentation will highlight key differences in morphological and physiological traits that assisted us in selecting a narrow set of rootstocks for a forthcoming evaluation in a passive high tunnel to demonstrate the utility of these new rootstocks.
Speakers Co-authors
NR

Nathaly Rodriguez Ortiz

King Abdullah University of Science and Technology
NA
Wednesday September 25, 2024 8:30am - 8:45am HST
South Pacific 4

8:45am HST

CE 2 - Impact Of Elevated CO2 And Two Daily Light Integrals on the Production Efficiency of Strawberry (Fragaria × ananassa ‘Monterey’) Daughter Plants
Wednesday September 25, 2024 8:45am - 9:00am HST
Abstract: Strawberry nurseries face many challenges, and are considering controlled environment propagation as an alternative to conventional open-field propagation. Limiting factors to economic feasibility include stock plant yield (number of daughters produced per stock plant). From published research we know that increasing CO2 concentration and light intensity increases strawberry photosynthetic rate, however there has been no research on the effects of these treatments on the total stock plant yield of daughters. Our hypothesis is that higher light intensity and CO2 concentrations will improve plant growth and lead to greater total daughter plant production. The objective of this experiment is to increase stock plant yield by increasing CO2 concentration (500, 850, and 1200 μmol mol-1) and light intensity (DLI 14.4 and 28.8 mol m-2 d-1). Strawberry (Fragaria × ananassa Duch., ‘Monterey’) stock plants were transplanted into three controlled environment growth chambers, under combinations of CO2 and DLI treatments in a split plot design under 26°C, 65% relative humidity, and a 16-hour photoperiod. The stock plants were grown under treatment conditions for 70 days, and newly-formed daughters were logged every day. At the end of the experiment the stock plants and their daughter plants were harvested, and each daughter plant was evaluated based on its size (number of leaves, leaf area, and fresh/dry mass). Increasing CO2 concentration linearly increased stock plant yield, leading to 23.96% more daughter plants per mother plant from the 500 to the 1200 μmol mol-1 treatment. Plants under higher light intensity (500 μmol m-2 s-1) had 38% higher stock plant yield than those under 250 μmol m-2 s-1. These data support our hypothesis that increasing CO2 concentration and light intensity increase the total yield of daughter plants produced per stock plant. By optimizing CO2 concentration and light intensity, strawberry nurseries may be able to grow more daughter plants more efficiently in controlled environment nurseries than in the conventional open-field system.
Speakers
SH

Samson Humphrey

Univ. of Tennessee
N/A
Co-authors
RH

Ricardo Hernandez

North Carolina State University
NA
Wednesday September 25, 2024 8:45am - 9:00am HST
Coral 2

8:45am HST

CITR 2/HIST - Impact of Different Organic Matter Contents on ‘US-942’ Citrus Rootstock Physiology, Nutrient Uptake, and Root Morpholog
Wednesday September 25, 2024 8:45am - 9:00am HST
The disease citrus greening (HLB, Huanglongbing) continues to decimate Florida’s citrus industry, resulting in the lowest yields since the 1940s. With no cure or tolerant rootstock/scion combinations available, growers must manage the disease. Although increased fertilizer applications have been shown to improve tree health, the additional inputs are expensive and decrease operational profitability. As a result, interest has grown in improving soil fertility parameters such as organic matter, with the goal of reducing inputs and increasing horticultural sustainability. Despite the recognized potential of organic matter, little research has been undertaken to establish the optimal contents required to improve citrus root characteristics. The objective of this study was to answer two specific questions: what are the amounts of organic matter needed to significantly affect citrus root growth and physiology? And how does the incorporation of organic matter influence nutrient availability? To answer these questions, a six-month completely randomized greenhouse experiment was conducted to measure the impact of different soil organic matter contents on potted citrus trees. Six different treatments consisting of different organic matter contents (0% - control, 1%, 2%, 3%, 5%, and >10%) were created by mixing different amounts of locally sourced compost with sand. One-year-old ‘US-942’ (Citrus reticulata x Poncirus trifoliata) rootstock plants (n = 6 per treatment) were grown in the different mixtures for six months under controlled greenhouse conditions. During the study, soil moisture, plant height, and stem diameters were assessed every other month. At the conclusion of the study, total plant and root biomass, root nutrients, average root length, and average root diameter were measured. Results from the study indicated that higher organic matter contents (>2%) led to significantly increased plant biomass and stem diameter, and increased root growth. Significant results were also found at the soil level, where increased organic matter contents led to increased nutrient retention and increased root uptake of nutrients. Additional investigation is needed to better understand the advantages of increasing organic matter content, even by marginal percentages, utilizing grafted citrus trees of various cultivars in field trials. Such trials would provide insights into the practical implications of these findings within the industry.
Speakers
LH

Lukas Hallman

University of Florida
Co-authors
AW

Alan Wright

University of Florida
NA
JF

John-Paul Fox

University of Florida
LR

Lorenzo Rossi

University of Florida
Wednesday September 25, 2024 8:45am - 9:00am HST
South Pacific 1

8:45am HST

FLOR 1 - Iron-coated Sand as a Sustainable Substrate Amendment for Nutrient Management of Containerized Floriculture Crops
Wednesday September 25, 2024 8:45am - 9:00am HST
As natural resources dwindle, sustainable alternatives to current fertilization methods are essential for environmental and economic progress. Acid mine drainage (AMD) and phosphorus from fertilizer runoff are significant sources of water pollution in the Appalachian region of the United States. Horticultural producers are faced with rising prices of phosphate fertilizers, putting the industry in a tenuous position: reducing these costly inputs to minimize water pollution but, in turn, diminishing product quality. AMD-based iron-coated sand is a novel phosphate sorbent that can potentially ameliorate AMD and prevent further phosphate pollution. This technology can cut growers’ input costs and slow the consumption of finite phosphate resources. This study aimed to determine the viability of iron-coated sand as a substrate amendment for reducing phosphate leaching and enhancing growth, flowering, and phosphorus uptake of floriculture crops during and after production. The ideal sand-to-potting mix ratio was determined based on pansies, petunias, and chrysanthemums' growth, flowering, and leachate content. The rate of applied phosphate and P-saturation of sand were determined from growth, flowering, and leachate data of chrysanthemum during production. Finally, the effects of the coated sand were examined on petunia and chrysanthemum growth, flowering, mineral content, and leachate composition over time in production and post-production environments. Twenty percent P-saturated iron-coated sand with low to moderate rates of applied phosphorus reduces leached phosphate with no deleterious, and usually positive, effects on the performance of floriculture crops during and after production. Iron-coated sand as a substrate amendment in container production of ornamentals has tremendous potential for advancing environmental and economic sustainability in the horticultural industry.
Speakers
SM

Savannah Mead

West Virginia University
Co-authors
EP

Eugenia Pena Yewtukhiw

West Virginia University
NA
KB

Karen Buzby

West Virginia University
NA
LL

Lance Lin

West Virginia University
NA
NW

Nicole Waterland

West Virginia University
NA
Wednesday September 25, 2024 8:45am - 9:00am HST
Nautilus

8:45am HST

GG 1 - Selection and Evaluation of Citrus Resistobiome for HLB Resistance/Tolerance
Wednesday September 25, 2024 8:45am - 9:00am HST
Since no Huanglongbing (HLB)-resistant citrus cultivar is available in the world, selection of elite natural mutants of commercial citrus for HLB-resistance/tolerance becomes a much more appealing breeding approach, especially in HLB-epidemic regions. In this study, we have selected and evaluated more than 30 citrus mutants from commercial citrus varieties in the past eight years in Florida. After greenhouse and field trials with high HLB disease pressure, we have identified several citrus lines with improved HLB-resistance/tolerance, which can be released or used for large scale of field trials. Our analyses of these lines have revealed that citrus resistobiome plays a role in the HLB resistance/tolerance, which involves a plant virus that can enhance plant resistance and illustrated the pursuit of breeding for biocontrol and a healthy microbiome. Meanwhile, we revealed that transposons have driven the selection and diversification of sweet orange (SWO). We identified six transposon families with up to 8900-fold activity increases in modern sweet orange cultivars tracing back to a common ancestor ~500 years ago. Notably, these six families of transposons contribute significantly to the formation of major cultivar groups, with frequent independent activations or accelerations observed in the breeding history of SWO. We will discuss the molecular mechanisms underlying the improved HLB-resistance, especially how the resistobiome plays a role in the improved HLB resistance/tolerance, and how to implement this new approach by utilizing and expanding the breeding of citrus resistobiome for the control of citrus HLB.
Speakers
YD

Yongping Duan

USDA ARS
NA
Co-authors
BW

Bo Wu

Clemson University
NA
DZ

Desen Zheng

USDA ARS
NA
FL

Feng Luo

Clemson University
NA
ZD

Zhanao Deng

University of Florida
Wednesday September 25, 2024 8:45am - 9:00am HST
Coral 1

8:45am HST

PGR 1 - PGR applications to reduce HLB-associated preharvest fruit drop in Sweet Orange
Wednesday September 25, 2024 8:45am - 9:00am HST
The Florida citrus industry has seen a steady decline in production since the arrival of Huanglongbing (HLB), or citrus greening disease, in Southern Florida in 2005. Following infection, trees experience a steady decline in health and productivity. HLB has since spread throughout all of Florida’s citrus producing regions resulting in nearly 100% infection rates in traditional field settings. Lamentably, no cure has been found for HLB, so research efforts have focused on mitigating the symptoms associated with this disease. Among the myriad of symptoms associated with HLB, the increased rates of mature fruit (preharvest fruit drop) is a major concern for growers. Not only do more fruit drop in HLB-affected trees, but fruit also begin dropping earlier in affected trees as well. This loss of mature, and potentially marketable, fruit in the months leading up to harvest represents a visual loss of revenue for the growers. The authors have previously reported that the likelihood of a fruit to drop during preharvest fruit drop is related to the size of that fruit; the relatively smaller fruit on the tree are more likely to drop during the preharvest fruit drop window. As plant growth regulators (PGRs) have had promising results in preventing fruit drop in many crop species, the efficacy of PGR applications in reducing preharvest fruit drop was evaluated. Thirty small and thirty large fruit were tagged on four 12-year-old ‘Valencia’ on ‘Swingle’ rootstock trees. Small fruit were those that were a ½ standard deviation below the average fruit size for that tree whereas large fruit were those that were a ½ standard deviation above the average. Ten of the small tagged fruit and ten of the large tagged fruit were then dipped into ProGibb® (33 ppm Gibberellic Acid [GA]), Citrus Fix® (106 ppm 2,4-Dichlorophenoxyacetic Acid [2,4-D]), or left untreated (control). Citrus Fix® improved retention in both small and large fruit whereas ProGibb® only improved retention in the large fruit. As GA prevents drop by delaying the senescence process, the lack of effect in the small fruit may suggest that they have already entered the senescence process. To further explore why the small and large fruit differ in their likelihood to drop and why they respond differently to PGR applications, additional biochemical and molecular analyses are underway.
Speakers
TV

Tripti Vashisth

University of Florida
Co-authors
MP

Maricielo Postillos Flores

University of Florida
NA
MS

Mary Sutton

University of Florida
NA
Wednesday September 25, 2024 8:45am - 9:00am HST
South Pacific 3

8:45am HST

PLAST - Shade level effects on fruit yield of habanero chili (Capsicum chinense Jacq.)
Wednesday September 25, 2024 8:45am - 9:00am HST
Habanero chili fruit is shiny, orange, or red, about 5 cm long, and very pungent (200,000 to 300,000 Scoville heat units). It is popular in Mexico, Central America, and the Caribbean, although it is increasing in demand in the U.S. There is reduced information on chili production under shade nets. The objective was to determine the effects of shade level and cultivar on the fruit yield of habanero chili. The study was conducted in Tifton, Georgia, under field conditions in two seasons. Habanero plants were grown using raised beds, black plastic film mulch, and drip irrigation, following the University of Georgia extension recommendations for bell peppers. The experimental design was a randomized complete block with four replications and 10 treatments (5 shade levels x 2 cultivar combinations). Habanero chili ‘Kabal’ and ‘Kukulkan’ were grown at 0% (unshaded), 30%, 47%, 62%, and 80% shade levels. Marketable fruit number and yield decreased quadratically with shade level, although there were no statistical differences in marketable yield for plants in unshaded conditions and 30% and 47% shade levels. Mean marketable yields were 33.6 t/ha (unshaded) and 5.7 t/ha (80% shade level). Less than 2.5% of total fruit were affected by sunscald and blossom-end rot. Total and marketable fruit numbers and yields and individual fruit size were higher in ‘Kukulkan’ than in ‘Kabal.’ In conclusion, although shading increased fruit size, it did not improve marketable yield compared to unshaded conditions.
Speakers
avatar for Juan Carlos Diaz Perez

Juan Carlos Diaz Perez

Professor of Horticulture, University of Georgia
Co-authors
MB

Mamata Bashyal

University of Massachussets
YK

Yamin Kabir

Khulna University
NA
Wednesday September 25, 2024 8:45am - 9:00am HST
Lehua Suite

8:45am HST

QUAL - Assessing the Impact of Biological Soil Amendments of Animal Origin on Bell Pepper Microbial Safety, Soil Properties, and Quality
Wednesday September 25, 2024 8:45am - 9:00am HST
The shift towards sustainable food production has forced farmers to explore alternative practices, such as the use of Biological Soil Amendments of Animal Origin (BSAAOs). However, concerns due to food safety regulations restrict the use of BSAAOs on crops consumed raw. This study assessed the microbial safety of bell peppers, the impact of BSAAOs on soil properties, and on quality. The field experiment was established with 36 plots (88 ft2) planted with bell pepper seedlings on 12-inch centers for a total of 20 plants/plot. BSAAO treatments consisted of either raw CM, PL, or non-BSAAO (NB) application, with each treatment being either tilled or top dressed. E. coli/Total Coliforms were determined from soil samples collected during weeks 1, 3, 6, and 12 and from harvested bell peppers during weeks 13 and 14. Nalidixic acid resistant E. coli was inoculated on bell peppers for a 5-day die-off determination (40 inoculated on the upper portion and 40 on the side). Ammonium and nitrate content in soil was determined before and after the establishment of the experiment, while SOM content was determined from soil samples collected after the experiment. Higher levels of E. coli (1.1–2.6 log CFU/g) and total coliforms (4.1–4.7 log CFU/g) were reported in plots with BSAAO application as compared to NB plots (1.00–1.17 log CFU/g; 3.89–4.14 respectively), although levels decreased significantly after one week. E. coli levels on bell peppers previously inoculated declined by over 2 logs within four days, with a die-off rate of 0.57 and 0.51 log CFU/cm2/day for bell peppers inoculated on top and on the side, respectively. CM tilled plots had slightly higher E. coli levels (0.02 log CFU/ cm2). The quality of bell peppers was unaffected by BSAAOs. NB top dressed and CM tilled plots had higher soil organic matter (SOM) content (2.18 and 2.08%, respectively) while both CM and PL increased soil nitrate and ammonium content significantly by the end of the experiment. CM and PL can enrich soil with inorganic nitrogen without compromising produce quality. However, the use of untreated BSAAOs poses a risk of cross-contamination, which highlights the importance of minimizing potential contamination events. Overall, this study highlighted the potential of CM and PL as BSAAOs to enhance soil fertility while maintaining food safety. It emphasized the need for appropriate management practices to mitigate risks associated with microbial contamination, ensuring the safety and sustainability of food production systems.
Speakers
DL

Daniel Leiva

Research Assistant, Louisiana State University
Co-authors
AA

Achyut Adhikari

Louisiana State University AgCenter
NA
JM

Juan Moreira

University of Arkansas
NA
KF

Kathryn Fontenot

LSU AgCenter
Wednesday September 25, 2024 8:45am - 9:00am HST
Kahili

8:45am HST

TECH 1 - Investigation of Using Hyperspectral Vegetation Indices to Assess Brassica Downy Mildew
Wednesday September 25, 2024 8:45am - 9:00am HST
Downy mildew, caused by Hyaloperonospora parasitica, poses a significant threat to Brassica oleracea crops, leading to substantial reductions in yield and marketability. This study seeks to assess various vegetation indices for detecting different levels of downy mildew infection in a Brassica variety, Mildis, using hyperspectral data. Through artificial inoculation with H. parasitica sporangia suspension, distinct levels of downy mildew disease were induced. Spectral measurements, ranging from 350 nm to 1050 nm, were performed on the leaves under controlled environmental conditions, and reflectance data were collected and processed. The Successive Projections Algorithm (SPA) and signal sensitivity calculations were employed to identify the most informative wavelengths, which were then used to develop Downy Mildew Indices (DMI). A total of 37 existing vegetation indices and three proposed DMIs were evaluated to assess downy mildew infection levels. The results revealed that a support vector machine achieved accuracies of 71.3%, 80.7%, and 85.3% in distinguishing healthy leaves from those with early (DM1), progressed (DM2), and severe (DM3) infections, respectively, using the proposed downy mildew index. The development of this novel downy mildew index has the potential to facilitate the creation of an automated monitoring system for downy mildew and aid in resistance profiling in Brassica breeding lines.
Speakers
BL

Bo Liu

Professor, California Polytechnic State University
NA
Co-authors
MF

Marco Fernandez

California Polytechnic State University
NA
SD

Shunping Ding

California Polytechnic State University
TL

Taryn Liu

California Polytechnic State University
NA
Wednesday September 25, 2024 8:45am - 9:00am HST
South Pacific 2

8:45am HST

VCM 2 - Evaluation of Biostimulant on Nutrient Use Efficiency in Tomato
Wednesday September 25, 2024 8:45am - 9:00am HST
To evaluate the efficacy of a commercial available biostimulant (a product containing friendly microorganisms like N2 fixing bacteria) on the improvement of nitrogen (N) and phosphorus (P) use efficiency in tomato, two independent field experiments were conducted in West Central Florida in the fall production season of year 2023. For both experiments, treatments included a factorial combination of two biostimulant rates (0 or 0.247 kg/ha) and four fertilizer rates (N or P2O5) (0, 67, 135, 202 or 269 kg/ha) that were arranged in a split-plot design. Biostimulant was applied as a solution drenched in soil following transplanting, and fertilizer treatments were applied as pre-plant application in soil and/or through drip injection during the season. Commercial tomato cultivar ‘HM1823’ was chosen as plant material. Analysis of variance (ANOVA) revealed that biostimulant did not have statistically significant influence on fruit marketable yield, fruit quality (Brix) and plant biomass, regardless of application rates of P2O5. By contrast, however, application of N had statistically (P
Speakers
WW

Weining Wang

University of Florida
Co-authors
LS

Lakesh Sharma

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

Shinsuke Agehara

University of Florida
Wednesday September 25, 2024 8:45am - 9:00am HST
South Pacific 4

9:00am HST

CE 2 - Unraveling Strawberry Stock Plant Architecture, Morphology, and Tips’ Spatial Distribution under Three Photoperiods to Facilitate Future Propagation System Design: A Comparative Study on Monterey as a Long-day Cultivar
Wednesday September 25, 2024 9:00am - 9:15am HST
The US strawberry industry needs healthy, high-quality transplants every year for fruit production. Following the challenges in open-field nurseries, research is focused on controlled-environment agriculture as a potential alternative to not only increase strawberry tip yield but also to produce healthier, virus-free transplants (rooted tips). Growing stock plants indoors where the runners grow vertically downward increases the yield and quality of tips, however, there is a lack of information on the general architecture of plants especially the spatial distribution of daughter plants and also the leaf area index (LAI) distribution of the daughter plants’ canopy in the growing space. This information is vital for future system design as it determines the distance between the shelves and the potential need for intracanopy lighting. Furthermore, besides temperature, photoperiod strongly affects the trade-off between runner Vs. flower production. Yet, there is also a lack of information on how photoperiod will change the yield, quality, and architecture of stock plants in CEA, specifically on long-day cultivars. Here, we examined 12, 16, and 20 h photoperiods with the same DLI of 26 mol m-2 d-1 on ‘Monterey’ as a long-day cultivar with two replications in time. The chamber environment was maintained at a high temperature of 26 °C, ambient CO2, and 65% relative humidity. The plant density was 9 plant m-2. Following 64 days of growth, parameters related to yield, architecture, and quality were recorded. Results showed that even under relatively high temperatures, with shortening the photoperiod, a linear increase in the number of tips was observed, increasing from ~36.3 to ~44.3 (18%) with the same DLI. Regardless of the photoperiod, the highest proportion of tips (30.8%) were harvested on the runners from 40 – 80 cm distance from the mother plant, though the highest LAI (53.2%) was recorded on the tips from 0 – 40 cm, causing a sudden drop (92.8%) in the light intensity after 40 cm where most of the tips are growing. This information shows the need for intracanopy lighting under 40 cm depth from the mother plants. Around 98% of the tips were harvested from 0 – 160 cm, showing the needed space for the growth of runners (i.e., the distance between the shelves). Several morphology and photosynthetic parameters were also recorded. The information from this study will be used as a base for a follow-up experiment comparing top versus intracanopy lighting.
Speakers
avatar for Moein Moosavi

Moein Moosavi

PhD student, NC State University
Moein Moosavi-Nezhad is a Ph.D. student in the Horticultural Sciences department at NC State University, working in the Controlled-Environment Agriculture Lab under Ricardo Hernandez. He started working in CEA in 2016 at the University of Tehran focusing on plant-light interactions... Read More →
Co-authors
RH

Ricardo Hernandez

NC State University
NA
Wednesday September 25, 2024 9:00am - 9:15am HST
Coral 2

9:00am HST

CITR 2/HIST - Soil Amendment Strategies to Rehabilitate Freeze Damaged Citrus Trees for Sustainable Crop Management
Wednesday September 25, 2024 9:00am - 9:15am HST
Citrus in key citrus production states in the U.S. have been heavy hit from insect borne and disease pressures. The bacterial disease Huanglongbing (HLB) has had devastating impacts on the citrus industry in Florida. Despite having this threat to the Texas industry as well, the most recent negative impact to decrease citrus acreage has been due to harsh climatic events. In February 2021, citrus groves in south Texas were hit with icy weather that exposed orchards to prolonged freezing temperatures for several hours. The impacts of this one event reduced citrus orchards in south Texas by approximately 25% (over 2,800 ha or 7,000 acres). Climate variability has increased grower awareness to the potential for more frequent extensive drought and freezing winter periods. To better evaluate how to rehabilitate freeze damaged citrus trees, a two-year field study was created aimed at improving tree root health and soil conditions. Compost amendment (CA) was broadcast applied as well as application underneath the tree canopy of grapefruit trees in combination with varying nitrogen fertilizer rate application. Three fertilizer treatments: T1 (base rate = 112 kg N ha-1), T2=1.5x and T3=2x the T1 base rate were evaluated in a randomized complete block design with (11.2 Mg CA ha-1) and without CA in Rio Red grapefruits. Results indicated that root abundance significantly increased under composted trees compared to non-composted trees. Composted trees led to higher yields within 18 months following the freeze event compared to non-composted trees. The impacts of this research may aid Texas citrus growers and other producers looking to improve in-field management strategies that may assist in preparation for post-freeze weather events and extended seasons of water scarcity.
Speakers
SN

Shad Nelson

Dean and Professor, Texas A&M University Kingsville
Dr. Shad Nelson has serves as the Dean of the Dick & Mary Lewis Kleberg College of Agriculture & Natural Resource since 2016.  Prior to this he served as a Professor teaching Horticulture Science courses and research in alternative irrigation strategies for South Texas Citrus industry... Read More →
Co-authors
Wednesday September 25, 2024 9:00am - 9:15am HST
South Pacific 1

9:00am HST

FLOR 1 - Phosphorous Restriction Suppresses Growth of Containerized Coneflower
Wednesday September 25, 2024 9:00am - 9:15am HST
Containerized coneflower (Echinacea sp.) production in greenhouses and nurseries often relies on commercial fertilizers, such as 20 nitrogen (N)–4.4 phosphorous (P)–16.6 potassium (K), applied at 100 to 200 mg·L−1 N; however, increasing N concentrations proportionately increase phosphorous pentoxide (P2O5) and thus, elemental P concentrations. As such, the recommended N fertilization supplies P concentrations of 21.8 to 43.6 mg·L−1 P, exceeding plant requirements and potentially leading to excessive stem elongation and P runoff, posing ecological risks. Therefore, the objective of this study was to evaluate the effects of P concentrations on the growth, ornamental value, and tissue mineral nutrient concentrations of coneflower (E. × hybrida Sombrero® Granada Gold ‘Balsomold’). A custom soilless substrate was formulated with (by vol.) 55% aged pine bark, 35% sphagnum peatmoss, and 10% perlite, and amended with 0.6 kg·m−3 wetting agent and 3.9 kg·m−3 dolomitic limestone to achieve a final pH of ≈5.6 to 5.8. Young plants of coneflower were individually transplanted into 16.5-cm-diameter (1.7 L) containers filled with the custom soilless substrate. Upon transplanting and throughout the experiment, plants were irrigated with nutrition solutions formulated from technical grade salts providing 0, 2.5, 5, 7.5, 10, 15, 20, or 30 mg·L–1 P. Plants were grown in a glass-glazed greenhouse at 20 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈120 µmol·m–2·s–1 delivered from light-emitting diode lamps from 0600 to 2200 hr (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At anthesis (≈69 d after transplant), data were collected. In general, plant height, plant diameter, and shoot and root dry weights were significantly influenced by P concentrations, although to different magnitudes. Quadratic plateau models demonstrated plant height, plant diameter, and shoot dry weight were maximized at 52.7 cm, 36.5 cm, and 27.2 g, respectively, with P concentrations of 18.3, 15.9, and 23.4 mg·L−1 P, respectively. Root dry weight demonstrated a positive linear correlation with increasing P concentration where roots were 74% (3.3 g) larger at a P concentration of 30 than 0 mg·L−1 P. Concentrations of ≤ 7.5 mg·L−1 P resulted low (≤ 0.2% P) leaf tissue P concentrations and ≤ 2.5 mg·L−1 P resulted in low-quality plants with incipient symptoms of P deficiency. Collectively, these results indicate that a narrow range of P concentrations may be used to control coneflower growth and mitigate P pollution.
Speakers
avatar for Garrett Owen

Garrett Owen

Extension Specialist and Assistant Professor of Sustainable Greenhouse & Nursery Systems, The Ohio State University
Dr. W. Garrett Owen is Assistant Professor and Extension Specialist of Sustainable Greenhouse and Nursery Production Systems with primary responsibilities in teaching (20%), research (30%), and Extension (50%) in the Department of Horticulture and Crop Science at The Ohio State University... Read More →
Wednesday September 25, 2024 9:00am - 9:15am HST
Nautilus

9:00am HST

GG 1 - Population Genetics and Genome-wide Association Studies Provide Insights into the Genetic Basis of Persea Fruit Quality Traits
Wednesday September 25, 2024 9:00am - 9:15am HST
Avocado (Persea americana) is renowned for its high nutritional value and its global consumption is steadily increasing. Currently, only a few cultivars with limited genetic variability are cultivated, and there is a need for developing new avocado cultivars with enhanced horticultural, fruit quality and nutritional traits as well as resistance to diseases and pests. Application of marker assisted selection can significantly accelerate breeding new avocado varieties, which can take 15 - 20 years using traditional breeding methods. Towards the application of molecular markers in avocado breeding, in this report, genome-wide association studies (GWAS) of nine fruit quality traits of a diversity panel of 110 avocado accessions were explored using 4,706 high-quality single nucleotide polymorphisms (SNPs) using multiple models. In addition, genetic diversity and population structure were also investigated, which unveiled three main populations corresponding to the three major avocado botanical races representing Mexican, West Indian, and Guatemalan ecotypes. Phylogenetic study and quantitative genetic analyses suggested a closer relationship between the Guatemalan and West Indian races compared to the Mexican race. Genome-wide association study revealed twelve markers distributed over eleven genomic regions strongly associated with fruit quality traits including fruit color, shape, taste, and skin texture. Annotation analyses of these genomic regions revealed candidate genes affecting these traits. These findings contribute to a comprehensive understanding of the genetic composition of avocado germplasm, which will be useful for identifying genes governing fruit quality traits as well as for accelerating breeding and parent selection efforts in the avocado breeding pipeline.
Speakers
GA

Gul Ali

Geneticist/Lead Scientist, USDA ARS Subtropical Horticulture Research Station
Co-authors
BF

Barbie Freeman

USDA ARS Subtropical Horticulture Research Station
NA
JL

Jin Li

USDA ARS Subtropical Horticulture Research Station
NA
SE

Shamseldeen Eltaher

USDA ARS Subtropical Horticulture Research Station
NA
Wednesday September 25, 2024 9:00am - 9:15am HST
Coral 1

9:00am HST

PGR 1 - Ethephon Effect on Blooming of Three Southern Highbush Cultivars
Wednesday September 25, 2024 9:00am - 9:15am HST
Spring frost is the primary cause of yield reduction in southern highbush, representing a significant challenge to blueberry production in the southeastern United States. Plant growth regulators are used as aids in different agricultural industries to either advance or delay growth and development process. Ethephon influences fruit set, size, and yield and has also been used as a tool to delay bloom in order to avoid freeze damage. This study examined the efficacy of ethephon to delay flower bud growth stages in three Southern Highbush Blueberry cultivars (‘Farthing’, ‘Georgia Dawn’, and ‘Kee Crisp’). Ethephon was applied at different concentrations of 200, 400, and 800 ppm, and a control treatment water/surfactant was also included. Flower buds were visually assessed from January until March. No relevant results were found for ‘Farthing’; however, for ‘Georgia Dawn’ and ‘Kee Crisp', ethephon at 800 ppm had the highest effect on delaying blooming development compared to the control. These results suggest that ethephon might delay flower bud growth stages in Georgia Dawn and Kee Crisp, offering potential advantages in reducing susceptibility to spring chill injury.
Speakers
LC

Lilian Carcamo

University of Georgia
Co-authors
MC

Mark Czarnota

University of Georgia
NA
MB

Melissa Brannon

University of Georgia
NA
ZR

Zilfina Rubio Ames

University of Georgia
Wednesday September 25, 2024 9:00am - 9:15am HST
South Pacific 3

9:00am HST

QUAL - Inhibiting Foodborne Pathogens and Biofilms on Fresh Produce by Nano-emulsions Developed from Lactobacillus-Derived Exopolysaccharide and Eugenol
Wednesday September 25, 2024 9:00am - 9:15am HST
The proliferation of foodborne pathogens and the formation of biofilms poses a major threat to the food industry, particularly in fresh produce. Raw and minimally processed fruits and vegetables are often sold to consumers in ready-to-use or ready-to-eat forms and are at the forefront of this risk. These products lack preservatives and rarely undergo any heat processing prior to consumption, making them more susceptible to contamination. To address this, we synthesized an oil/water emulsion encapsulating eugenol, using exopolysaccharide extracted from Lactobacillus as a natural emulsifier, and investigated its effectiveness against pathogenic cell populations within biofilm matrices. Different strains of Listeria monocytogenes, Salmonella, and E. coli were studied; results reveal substantial variations in biofilm-forming abilities among different E. coli, Salmonella, and L. monocytogenes strains. Specifically, L. monocytogenes V7 and Scott A strains displayed resistance to the emulsion, resulting in a minimal reduction of 2.8 log CFU/cm2 on the stainless-steel surface within the biofilm. Conversely, other strains exhibited reductions ranging from 3 to 4.5 log CFU/cm2. Most strains’ biofilm inhibition was 85% on plastic surfaces, whereas L. monocytogenes V7, Scott A, and Salmonella enterica ATCC 35664 showed less inhibition. The emulsion was applied to fresh produce (tomatoes, blueberries, and lettuce), where the reduction in E. coli and Salmonella biofilms, along with planktonic cells, varied from 0.53 to 5.1 log CFU/cm2, indicating that the emulsion significantly inhibited the growth of the tested pathogens. In conclusion, the results indicate that biofilm inhibition depends on the microbial species due to the observed individual variation in strains. However, combining eugenol and exopolysaccharide as emulsions is a promising natural alternative and sustainable technology for removing pathogenic biofilms. This research has the potential to advance food safety and hygiene standards, with practical applications in preserving fresh produce and disinfecting surfaces. This work was supported by USDA-NIFA- SCRI- 2017-51181-26834 through the National Center of Excellence for Melon at the Vegetable and Fruit Improvement Center of Texas A
Speakers
SB

SANGEETA BALYAN

Graduate Student, Texas A & M
Co-authors
Wednesday September 25, 2024 9:00am - 9:15am HST
Kahili

9:00am HST

TECH 1 - Effect of Innovative Laser Labeling Technology on Fresh Produce Quality and Safety
Wednesday September 25, 2024 9:00am - 9:15am HST
Introduction: Fresh produce is commonly associated with foodborne disease outbreaks and food recalls. To prevent the lethal impact of outbreaks, effective traceability is crucial. Produce items are traditionally labeled with price lookup (PLU) stickers. However, those stickers are environmental hazards, and frequent detachment of PLU stickers losses the information for traceability. Purpose: To investigate the effect of postharvest quality and microbial safety of laser labeling on fresh produce. Methods: Three horticultural crops, apple ‘Red Delicious ‘apple, cucumber, and green bell pepper, were procured from a local grocery store. Each produce was printed with a Quick Response (QR) code or text code using the laser engraver machine, followed by the application of edible wax. All produce was stored at 4° C temperature and 90% relative humidity during the study period. The postharvest quality was measured through fresh weight loss, QR code readability, and visual quality for 16 days. In another study, the laser-labeled produce was assessed for microbial contamination by quantifying artificially inoculated rifampicin-resistant E.coli (ATCC 25922) at an initial concentration of 106 CFU/mL. The experiment had five treatments: QR-coded labels followed by waxing or no wax, text-coded labels followed by waxing or no wax, and nontreated control. Results: Fresh weight loss for laser-printed produce was slightly higher than the nontreated control, but no difference in visual quality ratings was observed compared to the control. The population of rifampicin-resistant E.coli was statistically higher in all three produce labeled with text code compared to the nontreated control. However, QR-coded treatments were similar in the control. The application of wax did not facilitate microbial attachment. Significance: Laser labeling technology did not deteriorate the postharvest quality and susceptibility to microbial contamination. Hence this technology has the potential in commercial application as a better alternative to the PLU sticker to improve traceability.
Speakers
avatar for Manreet Bhullar

Manreet Bhullar

Kansas State University
Co-authors
DK

Durga Khadka

Kansas State University
NA
EP

Eleni Pliakoni

Kansas State University
MJ

Majid Jaberi Douraki

Kansas State University
NA
PA

Patrick Abeli

Kansas State University
NA
XX

Xuan Xu

Kansas State University
NA
Wednesday September 25, 2024 9:00am - 9:15am HST
South Pacific 2

9:00am HST

VCM 2 - Alternative Carbon Sources Effects on the Soil-plant Nutrient Dynamics During and Post ASD in a High Tunnel Tomato Crop System
Wednesday September 25, 2024 9:00am - 9:15am HST
Anaerobic soil disinfestation (ASD) is a microbial-driven soil disinfestation approach for the management of soilborne pests and pathogens of horticultural crops including protected vegetable production systems increasingly affected by emerging soilborne issues. ASD is implemented by incorporating in the soil an easily labile carbon (C) source, mulching the soil with an impermeable film, and irrigating the soil to field capacity. Organic amendments used as C source also provide N and other nutrients, and research is needed to assess if and how crop fertilization should be adjusted accounting for such nutrients. A study was conducted to evaluate the effect of alternative C sources on soil nutrient availability during and post-ASD in a high tunnel tomato production system. Carbon sources tested included sugarcane molasses, wheat middlings, and soybean meal mixed with wheat middlings. Each C source was applied at the standard rate of 6 Mg/ha of total C. The same C sources were also applied at half rate (3 Mg/ha of total C) balancing the total nitrogen (N) applied to 350 kg/ha of N using composted chicken manure as a source of N. The selected C source treatments were compared with untreated soil amended only with composted chicken manure and an untreated control to estimate the amount of nutrients provided by the untreated soil or by the composted chicken manure. Post ASD, fresh-market tomato cv Red Deuce was planted and used as a test crop evaluating plant growth, nutrient uptake, and yield and quality performance in response to soil treatments. Post-ASD, soil redox potential (Eh) was monitored revealing that all C sources tested determined a significant decrease of soil Eh, suggesting a good efficacy of the ASD treatment. During and post-ASD soil pH, EC, nitrate-N and ammonium-N levels were monitored using soil-water extracts (obtained with the 1:2 v:v method). Significant variation of soil pH, EC and mineral-N content were observed during and post-ASD, which influenced tomato marketable yield. Among the treatment tested WM applied at half rate and balanced for the N which had an intermediate C:N ratio (11.65) provided the highest seasonal marketable yield (10.4 kg/plant), while the untreated control amended with chicken manure provided the lowest yield. Overall, this study suggests that C application rate and the C:N ratio of the organic amendments used to apply ASD have significant effects on the efficacy of the ASD treatment as well as on the availability of nutrients and the crop performance post-ASD.
Speakers
FD

Francesco Di Gioia

Pennsylvania State University
Co-authors
FP

Fritzner Pierre

Pennsylvania State University
NA
Wednesday September 25, 2024 9:00am - 9:15am HST
South Pacific 4

9:15am HST

CE 2 - Stratified Wood Substrates for Optimizing Growth of Greenhouse-Grown Strawberries and Blueberries
Wednesday September 25, 2024 9:15am - 9:30am HST
As the demand for locally grown produce, particularly fresh fruits like blueberries and strawberries, continues to surge, the imperative for year-round production becomes increasingly evident. While these fruits are globally recognized for their extended-season production potential in controlled environments, the intricate environmental factors crucial for improved production and profitability remain partially understood, including the impact of soilless substrates. Amid growing concerns about the availability of internationally sourced substrates, such as coconut coir, this study explores an alternative approach to reduce reliance on such components, particularly in the cultivation of two small fruits rapidly integrated into controlled environments. Substrate stratification, involving the vertical layering of substrates within a single container, has shown promise in nursery and greenhouse settings, enhancing resource efficiency in terms of water and fertilizer inputs. However, no research has assessed the application of stratified substrates for fruit crops with the specific aim of reducing coir inputs in greenhouse production. Thus, the objective of this study was to investigate whether stratifying coir over low-cost, hammer-milled processed tree fiber could effectively decrease coir usage, dependency, and associated costs within the controlled environment fruit production industry. 'Albion' strawberries and 'Star' blueberries were cultivated in five substrate treatments, ranging from 100% coir to various stratified layers beneath coir, including 25%, 50%, and 75% coir compositions, as well as a 100% processed tree fiber treatment. Results suggest that employing substrate stratification enhanced plant growth for both fruit crops, indicating its potential utility in optimizing controlled environment fruit production while reducing reliance on costly substrate materials like coir. Further analysis will elucidate the full implications of this innovative approach on production efficiency and profitability.
Speakers
BS

Brandan Shur

PhD Student, Virginia Tech
Co-authors
BJ

Brian Jackson

NC State
NA
Wednesday September 25, 2024 9:15am - 9:30am HST
Coral 2

9:15am HST

CITR 2/HIST - Physiological and Metabolomic Changes in Young Citrus Trees Under Elevated CO₂ and High Temperatures: A longitudinal st
Wednesday September 25, 2024 9:15am - 9:30am HST
As the atmospheric levels of CO₂ continue to rise, the concentration of carbon sources available for the plants also increases photosynthesis. The rise in atmospheric CO₂ is associated with global temperatures, resulting in an array of plant responses. Studies evaluating plant response to CO₂ treatments of 350 plant species show that plant responses are highly variable and species dependent, with the majority of studies being conducted on vegetable and grain crops, leaving a gap in understanding how tree crops respond. Mandarin (C. reticulata) trees are an economically important crop produced in California subject to climate change. This study used nursery trees of cv. Tango budded on C35 rootstock to determine the effect of elevated CO₂ exposure (400 ppm ambient vs. 800 ppm elevated) at elevated temperature (28°C ambient vs. 45°C elevated) to identify the physiological and metabolomic plant responses associated with each treatment. A longitudinal investigation was conducted over eight weeks in growth chambers (Conviron A1000, Winnipeg, CA) utilizing four treatment groups: ambCO2/Tamb (Control: CO2 400 ppm/Temperature 28°C); eCO2/Tamb (elevated CO2 at 800 ppm/Temperature 28°C); ambCO2/eTemp (CO2 at 400 ppm/Temperature 45°C); and eCO2/eTemp (CO2 at 800 ppm/ Temperature 45°C). Every two weeks, four replicates were collected from each treatment group. physiological measurements, photosynthesis response surveys, and metabolomic analysis were performed. Phenotypic measurements such as plant height, branches, leaf area, and leaf count showed that plant growth was impacted by treatment. Plant height, dry weight, and leaf count were significantly lower in the ambCO2/eTemp treatment as compared to the control (ambCO2/Tamb) as well as the other two treatments, indicating heat stress. Under elevated CO2 levels, trees were able to exhibit similar growth behaviors as the control treatment even under heat stress, signaling that the trees under eCO2 could compensate for a higher burden on carbon balance under heat stress. eCO2/Tamb trees accumulated significantly higher starch than all other treatments, whereas trees under both eTemp treatments showed significantly higher soluble sugars while significantly lower starch levels. This indicates that the trees under supplemental CO2 accumulate higher photoassimilates when they are free from heat stress, and the trees under heat stress exhibit starch conversion to soluble sugars as a stress response. Metabolomics analysis using Nuclear Magnetic Resonance (NMR) will provide valuable insight into the impact of treatment groups of eCO₂ and eTemp impact on Mandarin trees.
Speakers
avatar for Taylor Hornburg

Taylor Hornburg

Graduate Student, california state university
Co-authors
DG

Dave Goorahoo

California State University, Fresno
GB

GURREET BRAR

california state university
VK

Vishvanathan Krishnan

California State University
NA
Wednesday September 25, 2024 9:15am - 9:30am HST
South Pacific 1

9:15am HST

FLOR 1 - Investigating Synergistic Effects of Biostimulants and Biochar on Water Use Efficiency for Containerized Celosia (Argentea cristata) and Gomphrena (Gomphrena globose) Production
Wednesday September 25, 2024 9:15am - 9:30am HST
Given the escalating demands for water and the accompanying scarcity, enhancing water use efficiency (WUE) in horticultural practices has become imperative. Research has revealed that both biochar (BC) and seaweed extract biostimulants (BS) significantly enhanced WUE in plant growth, presenting promising avenues for sustainable agricultural advancement. This study aimed to investigate the synergistic effect of BC and BS on WUE for celosia (Argentea cristata) and gomphrena (Gomphrena globose) production. Three factors were included in this experiment including 1) mixed hardwood biochar blended with commerical substrate mixes (CS) at 0%, 10%, 15%, and 25% 2) 60% or 80% irrigation and 3) 0 or 5 mL BS(seaweed extract). The physical properties of substrate, including container capacity (CC), total porosity (TP), air space (AS), bulk density (BD), and water holding capacity (WHC), and chemical properties including leachate pH and electrical conductivity (EC) were measured. Plant growth parameters including growth index (GI) and leave greenness (indicated with SPAD value), biomass, and numbers of flowers were measured biweekly. Photosynthesis rate, transpiration rate, and stomatal conductance rate were measured at 6, 7, 8 WAT. The results showed that BC rates had significant effects on CC, and BD, but no effects on either TP, AS or WHC. Celosia plants grown in the 25% BC mix treated with 5mL BS at 80% irrigation had significantly higher biomass and WUE, and both plants in the same mix (25
Speakers
avatar for Lilin Chen

Lilin Chen

Graduate Research Assistant, University of Georgia
I'm interested in biochar effect on containerized plants, especially the effect under abiotic stresses such as drought and salinity.
Co-authors
PY

Ping Yu

University of Georgia
YC

Yulong Chen

The University of Georgia
Wednesday September 25, 2024 9:15am - 9:30am HST
Nautilus

9:15am HST

GG 1 - Genome Assembly of Persia Americana cv. Simmonds Provides Insights on Genetic Relationships Among Avocado Hybrids Exhibiting Tolerance To Laurel Wilt
Wednesday September 25, 2024 9:15am - 9:30am HST
Avocado (Persea americana) is the major fruit cultivated in southern Florida counties with a value exceeding 20 million dollars annually. While production in other regions is dominated by the Hass cultivar, south Florida is unique in production of the increasingly popular, green-skinned varieties. Recently, the avocado industry in South Florida has been devastated by laurel wilt (LW), an insect-disease complex spread by Raffaelea lauricola (Rf), a fungal symbiont of redbay ambrosia beetle (Xyleborus glabratus Eichhoff). Current management practices including prophylactic fungicide injections, tree rejuvenation and ambrosia beetle population reduction are costly and onerous . Unfortunately, no mature avocado trees tolerant to LW are available to growers and genetic mechanism of LW tolerance observed in some avocado seedlings is unknown. In this study, a chromosomal genome of avocado cv. ‘Simmonds’, a ‘West Indian’ (Lowland) ecotype was assembled from Pacific Biosciences HiFi reads. The genome assembly contained 451 scaffolds spanning 98.89% of the avocado genome, a N50 of 82.34MB and a BUSCO score of 95%. This assembly served as a reference genome to generate 9198 genome wide single nucleotide polymorphisms (SNPs) using genotyping by sequencing (GBS) reads of a germplasm collection comprising 80 accessions of three avocado ecotypes (Mexican, Guatemalan and West Indian) and 18 novel hybrids exhibiting seedling tolerance to LW. Phylogentic analyses revealed three major clusters with majority of LW tolerant seedlings clustering amongst Hass derived hybrids as well as cultivars belonging to Mexican and Guatemalan ecotypes such as 'Winter Mexican', and 'Ettinger'. This work provides genomic resources for characterization of genetic tolerance of LW in avocado germplasm collections and is a significant step in developing LW tolerant hybrids to support local avocado industry.
Speakers
VN

Vincent Njung'e Michael

University of Florida
Co-authors
JH

Jonathan H Crane

University of Florida, TREC
RG

Romina Gazis

University of Florida
NA
XW

Xingbo Wu

Chair 2023-2024, University of Florida
NA
Wednesday September 25, 2024 9:15am - 9:30am HST
Coral 1

9:15am HST

PGR 1 - Development of a Tissue Culture Approach for Doubling the Ploidy Level of Southern Highbush Blueberry Varieties
Wednesday September 25, 2024 9:15am - 9:30am HST
Increased consumption of blueberries has led to a prominent rise in demand. However, Georgia blueberry production is limited by challenges including short orchard life of southern highbush (SHB; tetraploid) and fruit quality issues associated with rabbiteye (RE; hexaploid) varieties. Interspecific hybridization can bring in beneficial alleles to improve the local adaptability and fruit quality of commercial varieties. Many of the wild blueberry germplasm with valuable soil adaptability and fruit quality traits such as V. fuscatum are diploids. Heteroploid crossings between SHB and diploid wild blueberry were shown to have a very low level of success. Ploidy induction through tissue culture is promising to circumvent the ploidy barrier and improve the efficiency of wide-hybridization. The objective of this research focuses on developing a ploidy induction protocol using two SHB varieties ‘Emerald’ and ‘Rebel’. SHBs previously initiated in tissue culture, were treated with 0%, 0.02% and 0.2% colchicine. SHBs were segmented into single and double node segments and put into woody plant medium (WPM) culture media containing either 6-(γ,γ-Dimethylallylamino)Purine (2iP) or trans-Zeatin. The treatments, along with non-treated control, were grown in a growth chamber of 26°C with 16/8 day and night cycles. The number and length of new shoots were recorded 35 and 50 days after treatment (DAT). Significant longer axillary stem growth was observed in the non-treated control compared to that of colchicine-treated segments for both SHBs indicating the suppressive effect of stem growth from colchicine treatments. Several Octo- and mix ploidy-shoots of ‘Emerald’ and ‘Rebel’ were identified among colchicine-treated SHB explants after ~ 21 weeks using a flow cytometer. Both levels of colchicine treatments generated octoploids. These new synthetic octoploid blueberries will be useful to cross with SHB and RE blueberries. The established ploidy induction protocol will be utilized to double the chromosomal levels of diploid V. fuscatum species and make them cross-compatible with SHB varieties.
Speakers
EW

Emily Walter

University of Georgia
Co-authors
YC

Ye Chu

University of Georgia
NA
Wednesday September 25, 2024 9:15am - 9:30am HST
South Pacific 3

9:15am HST

QUAL - Evaluating Nutritional Quality and Consumer Acceptability of Lettuce (Lactuca sativa L.) Grown with a Movable High Tunnel
Wednesday September 25, 2024 9:15am - 9:30am HST
Light quality is known to affect the growth and phytochemical content of numerous crops, including lettuce (Lactuca sativa L.). High tunnel production of lettuce provides many benefits to growers including increased yield due to higher soil temperatures and protection from abiotic stressors, such as strong wind and heavy rains. However, the use of UV-blocking polyethylene films can also result in lower antioxidant capacity and phenolic content, leading to a decrease in nutritional quality compared to lettuce grown in the open-field. Movable tunnels provide the ability to expose the crop to full-spectrum light once the crop has grown to full size. Our objective was to identify management strategies to optimize yield, phytochemical production, color, safety, and consumer acceptability of red-leaf cultivar (‘New Red Fire’). Lettuce was planted in a movable high tunnel April 2022 and exposed to 0, 2, 7, or 14 days of full sun prior to harvest. Total marketable yield, leaf color (L*a*b* color space), total phenolic content (TPC) and anthocyanin content were measured at harvest. Lettuce consumers (N=100) were asked to rate overall liking and various sensory attributes using continuous intensity scales, CATA, and open-ended comments. Total marketable yield and TPC were not affected. Leaf redness (a*) and anthocyanin content were significantly higher after 14, 7, and 2 days of full-sun exposure compared to 0 days. Significant differences were found in consumer liking for overall liking, color intensity, and ruffleness. The crop that was exposed to 14 days of full-spectrum light had a higher liking and more red color intensity. Using a movable tunnel system provides lettuce growers the ability to affect the color, phytochemical content, and consumer liking of their crop to varying degrees. This level of flexibility provides local, small-scale growers a crucial advantage in marketing their produce.
Speakers
CR

Cary Rivard

Kansas State University
Co-authors
EP

Eleni Pliakoni

Kansas State University
MB

Manreet Bhullar

Kansas State University
MT

Martin Talavera

Kansas State University
NA
OH

Olivia Haley

Kansas State University
NA
PA

Patrick Abeli

Kansas State University
NA
TJ

Tricia Jenkins

Kansas State University
Wednesday September 25, 2024 9:15am - 9:30am HST
Kahili

9:15am HST

TECH 1 - Cover Crop Decision Support Tools: Exploring the new suite of online cover crop tools
Wednesday September 25, 2024 9:15am - 9:30am HST
Cover crop recommendations can be complex based on regional factors and different growing conditions. In order to combat these challenges, the Precision Sustainable Agriculture team (PSA) developed online tools that are readily available for producers to help them optimize cover crops on their operation. Tools include a species and variety selector tool, seeding rate calculator, nitrogen calculator, and economic decisions tool. These platforms look to help producers find success with cover crops that fit their operation’s needs.
Speakers
avatar for Esleyther Henriquez Inoa

Esleyther Henriquez Inoa

Research Assist., North Carolina State University
Technologies in agriculture and Cover Crop breeding.
Co-authors
SM

Steven Mirsky

USDA ARS BARC
NA
Wednesday September 25, 2024 9:15am - 9:30am HST
South Pacific 2

9:15am HST

VCM 2 - Advancing Pepper Production Beyond Seasonal Limits: Findings from a High Tunnel System Integrated with Biostimulant Applications
Wednesday September 25, 2024 9:15am - 9:30am HST
Pepper is an important specialty crop in the Southwest U.S., cherished for its economic importance, cultural history, and high nutritional values. Despite being a leading pepper producer in the U.S., challenges such as high temperatures, erratic weather patterns, and imports from Mexico have hindered both production and profitability of growers in this region. In response, alternative systems like high tunnels have emerged as viable solutions. The mild winter climate in Southwest Texas offers an ideal setting for winter pepper cultivation in high tunnels, potentially boosting growers' profitability with off-season market opportunities. Application of biostimulants, such as seaweed extracts, holds promise in enhancing cold tolerance and transplant success within high tunnel systems. This study investigates the feasibility of winter pepper production in high tunnels established in the Wintergarden region, assessing various cultivars based on yield and quality. The high tunnel maintained a range of 8-10°C higher temperatures than the open-field on chilly days without additional heating. Seven pepper cultivars were evaluated, with and without seaweed extracts. Seaweed-treated plants exhibited an overall higher stomatal conductance and leaf transpiration rates along with reduced leaf electrolyte leakage. Rio de Oro; a Santa Fe type pepper had the highest PSII efficiency and total fruit yield. Seaweed application also increased total yield and individual fruit weight in cultivar-specific manner. The total phenolic content of fruits was increased by seaweed application at the early maturity stage whereas total flavonoid content varied by cultivar and maturity stage. Despite facing freeze challenges at the early transplant stage, this first-year experiment demonstrated promising potential for off-season pepper production in high tunnels in our region.
Speakers
AN

ASMITA NAGILA

Graduate Research Assistant, Texas A&M university
Co-authors
Wednesday September 25, 2024 9:15am - 9:30am HST
South Pacific 4

9:30am HST

CE 2 - Effect of Light Intensity on Strawberry Runner Tips Propagated Indoors
Wednesday September 25, 2024 9:30am - 9:45am HST
Indoor propagation systems that use sole-source lighting in controlled environments can facilitate year-round production of disease-free, uniform strawberry liners. However, optimal conditions to propagate strawberry runner tips indoors are unknown. Runner tips of ‘Albion’ and ‘Fronteras’ strawberries were propagated indoors for 28 d under four photosynthetic photon flux density (PPFD) treatments: 75, 150, 225, or 300 ± 5 μmol·m–2·s–1 provided for 24 h·d–1 by white light-emitting diode fixtures. Runner tips were also propagated in a shaded greenhouse under mist. After propagation, plants were moved to a common greenhouse compartment and grown for 7 weeks to evaluate carryover effects on fruit yield (‘Albion’) or daughter-plant production (‘Fronteras’). Treatment responses were similar for both cultivars, except that shoot dry mass (DM) of ‘Fronteras’ followed a quadratic response with increasing PPFD, which peaked at 225 μmol·m–2·s–1. In contrast, shoot DM of ‘Albion’ linearly increased with increasing PPFD. Root DM of both cultivars also followed an increasing response with PPFD. However, there were no treatment differences in the number of shoots produced per plant or the length of the longest root. Interestingly, plants propagated under ≥150 μmol·m–2·s–1 had several dead shoots (up to 20%), likely attributed to plant stress. After the carryover phase, ‘Albion’ propagated under 225 or 300 μmol·m–2·s–1 were statistically different and produced the lowest fruit fresh mass compared to those grown in the greenhouse, whereas values were similar among plants propagated in the greenhouse or indoors under 75 or 150 μmol·m–2·s–1. No treatment differences were measured in the number of daughter plants produced by ‘Fronteras’. These findings suggest that although higher PPFD indoors promoted rooting and growth, plants propagated in the greenhouse were likely better adjusted to the dynamic greenhouse environment, which enabled them to reach the same growth and development of indoor-propagated plants at the end of the carryover phase.
Speakers
LD

Lian Duron

Purdue University
Wednesday September 25, 2024 9:30am - 9:45am HST
Coral 2

9:30am HST

CITR 2/HIST - Reports and research on incorporating cover crops in Florida citriculture, 1896 – 2024
Wednesday September 25, 2024 9:30am - 9:45am HST
Florida is perhaps the state in the U.S. most identified with citrus cultivation. The warm winters, abundant sunshine and significant rainfall are qualities which promote this industry, although other factors make producing these fruits on larger groves more arduous. These include limited nutrient concentrations, problematic drainage dynamics, and low organic matter and cation exchange capacity. Such issues combine to make citrus production in Florida highly dependent on external inputs of labor and material, both of which can be financially burdensome and demonstrate high volatility in price or availability from year to year. Cover crops have the potential to cost-effectively amend many soil issues in Florida citrus groves if they are established and maintained according to certain management practices. This principle was first presented at the Florida State Horticultural Society meeting in the late 1890s, and then clarified by Harold Hume in Citrus Fruits and their Culture in 1904. Later, the non-native legumes Crotolaria pallida and Crotolaria juncea were identified in multiple publications as soil-building cover crops which could be implemented into Floridian citrus production. Florida’s citrus production in the wake of World War II saw a decline in its incorporation of legume cover crops in favor of synthetic fertilizers. More modern research initiatives in Florida focused primarily on the mitigation of transmissible disease like Phytophthora root rot and citrus canker, a trend which has become more apparent following the discovery of citrus greening in 2005 and the stark decreases in yields this bacterial illness has been the primary cause of. In response, a number of Florida citrus growers have adopted cover crop mixes featuring legumes to supply disease-afflicted citrus roots with a sustainable and regular source of nitrogen. This presentation will review past literature and will also discuss current research on legume cover crops that have the potential to bolster citrus operations which is being conducted by individuals in the state of Florida.
Speakers
avatar for Lorenzo Rossi

Lorenzo Rossi

Associate Professor, University of Florida
Dr. Rossi’s research program focuses on improving root health and growth on cultivated crops, leading to the development of environmentally sound and effective management methods. He is a horticulturist with specific expertise related to plant stress physiology, root dynamics and... Read More →
Co-authors
JP

Joseph Paoli

University of Florida
I am a Master's student at the University of Florida based at the Indian River Research and Education Center (IRREC). I am a long-time Florida resident, having gone to Middle and High School in Central Florida before enrolling at the University of Florida. During my four years of... Read More →
LH

Lukas Hallman

University of Florida
Wednesday September 25, 2024 9:30am - 9:45am HST
South Pacific 1

9:30am HST

FLOR 1 - Effects of Reduced Water Usage During Production on Economic Value, Growth, And Quality of Flowering Indoor Plants
Wednesday September 25, 2024 9:30am - 9:45am HST
The objective of this study was to investigate the effects of soil moisture content during greenhouse production of selected floriculture crops. Over the course of several seasons, multiple flowering species were investigated, including Euphorbia milii, Cyclamen persicum, and Begonia x tuberhybrida. Plant quality characteristics were evaluated both during the production timeframe, and after a simulated shipping and retail setting. Treatments included two soil moisture content levels (20% and 40%), which was monitored by soil moisture probes. Production timelines varied, due to the differences in species. Once the predetermined production weeks were concluded the plant went into simulated shipping and retail environment. Qualities such as growth index (GI), leaf greenness (SPAD), Leaf thickness, petiole thickness, irrigation events, and irrigation amount were measured weekly. Flower number and foliage fresh /dry weights were gathered after the two week simulated retail period. Results varied depending on the species. In all species the 20% group had less watering events, which equates to producer savings in fertigation inputs as well as labor. All species had reduced canopy size in the 20% treatment, which could equate to bench space conservation. Some of the plant quality characteristics depending on the species had similar results after simulated retail. This equates to the idea that producers could reduce water application events and volumes and generate an equal quality plant compared to the traditional watering methods, while also saving on input and labor costs.
Speakers
KH

Kaitlin Hopkins

Sam Houston State University
Wednesday September 25, 2024 9:30am - 9:45am HST
Nautilus

9:30am HST

GG 1 - Utilizing Haploid Pollen Grains and Diploid Leaf Tissue Genomic Sequence Data to Phase the ‘Wonderful’ Pomegranate Genome
Wednesday September 25, 2024 9:30am - 9:45am HST
The scientific and commercial interest in pomegranate (Punica granatum L.) cultivation has increased noticeably during the last two decades. Because of the high concentration of bioactive compounds and its nutraceutical properties, pomegranate has been defined as a super food. The consumption of pomegranate juice or arils has been related to several possible benefits on human health. Recent studies have highlighted an antioxidant and anti-inflammatory activity of this fruit which seem to prevent cardiovascular, neoplastic, neurological, metabolic, and intestinal disease. The areas of cultivation of this crop are exposed to current and future challenges like long term-drought conditions and invasive pests and diseases. Increasing the biodiversity of pomegranate has been proposed has the main strategy to reduce the risk of food system vulnerability related to monoculture and the valorization of marginal land. In order to develop advanced genetic tools to improve pomegranate breeding program efficiency we present the de novo sequencing of the ‘Wonderful’ pomegranate genome. DNA isolated from diploid leaf tissues was sequenced using long read sequencing technology (PacBio), while DNA extracted from haploid pollen grains was sequenced using short reads (Illumina). Genomic data from single haploid gamete cells were analyzed using the R package called ‘Hapi’. This allowed to infer chromosomal haplotypes obtaining a higher resolution for DNA variants detection and investigating recombination events in single gametes. Although ‘Wonderful’ represents the industry standard in the United States, several cultivars with desirable traits, such as low acidity and soft seednesses, have been identified in the national germplasm. The results of this study will provide the genomic data required to investigate differences among cultivars and create trait-gene associations. This will allow breeders to facilitate the integration of desired quality traits into new germplasm resources.
Speakers
GL

Giuseppe Lana

University of Florida
Co-authors
DS

Danelle Seymour

UC-Riverside
NA
DM

Donald Merhaut

UC-Riverside
NA
HQ

Han Qu

UC-Riverside
NA
JC

John Chater

University of Florida
MR

Mikeal Roose

UC-Riverside
NA
RT

Ryan Traband

UC- Riverside
NA
TB

Taylor Beaullieau

UC-Riverside
NA
ZJ

Zhenyu Jia

UC-Riverside
NA
Wednesday September 25, 2024 9:30am - 9:45am HST
Coral 1

9:30am HST

NUTS 1 - Can Hedge-Pruning Reduce Water Needs In Southeastern United States Pecan Orchards?
Wednesday September 25, 2024 9:30am - 9:45am HST
Pecan (Carya illinoinensis) trees have experienced higher density plantings which enhances the need for better water use efficiency to increase the sustainability of the orchard. The implementation of hedge-pruning allows for better light penetration as well as more efficient water use in the humid climate of the southeastern United States. The objectives of this study were to determine if irrigation rates can be reduced on hedge-pruned pecan trees with no loss in pecan yield or nut quality. The study is a split-plot design with pruning serving as the main plot effect and irrigation serving as the split plot effect. On hedge-pruned trees, all growth beyond 8’ from the trunk on the East side of the tree was pruned in year 1 and on the West side of the tree in year 2. Trees were topped on each side in their respective years at an angle with a peak at 40’. No pruning will be done in year 3. Hedging treatments are arranged in three tree blocks with each irrigation treatment occurring once per block as follows: 1) 100% irrigation; 2) 50 % irrigation; 3) non-irrigated control. Hedged blocks were replicated four times, and the non-hedged blocks were replicated three times. Among the irrigation regimes, there was no statistical difference between treatments indicating that, under the environmental conditions observed, less water is sufficient for pecan production, regardless of pruning treatment. Although, there has been no improvement in yield from the hedge-pruned trees, percent kernel has increased in the hedged trees compared to the non-hedged trees, suggesting an enhancement of pecan nut quality with hedge pruning.
Speakers
BR

Bailey Rayfield

University of Georgia
Co-authors
LW

Lenny Wells

University of Georgia
NA
Wednesday September 25, 2024 9:30am - 9:45am HST
Lehua Suite

9:30am HST

TECH 1 - CFD-based aerodynamic analysis under high wind velocity environment for multiple greenhouses
Wednesday September 25, 2024 9:30am - 9:45am HST
In South Korea, approximately 65% of the land is mountainous or forested, which limits large-scale farming. Over 53,000 ha of land has been reclaimed from the sea and dedicated to the development of large-scale indoor agricultural complexes. Given the coastal climatic conditions and flat nature, these areas present unique challenges including stronger winds and colder temperatures compared to the inland, leading to high air velocities and operation costs in naturally ventilated greenhouses. Aerodynamic analysis is necessary to estimate crop risk factors and identify potential aerodynamic problems before the construction of these structures. Traditional studies have focused on using natural ventilation rates to estimate greenhouse suitability for plant growth. However, under scenarios of high wind velocity, this approach has critical limitations in accounting for crop damage resulting from high air velocity induced inside naturally ventilated facilities. This is tailored to the fact that ventilation efficiency in naturally ventilated structures increases with an increase in air velocity. High wind velocity induced inside greenhouses is associated with rapid CO2 depletion, stomatal dysfunction, leaf abrasion, mechanical stress etc., which critically affect crop yield and biomass development. Under high wind environment, crop damage resulting from high internal air velocities is an important factor that needs to be accounted for during design of indoor agricultural facilities. This study introduces a CFD model for designing greenhouse complex including multiple greenhouses and model analysis approach. We developed the Aerodynamic Crop Damage Index (ACDI), used it to analyze the model, and compared it to the convectional ventilation efficiency approach. The ACDI revealed a 2.2-fold variation in damage potential based on the greenhouse's location within the complex and a 15-fold variation attributable to wind direction, pinpointing significant damage risks in zones with the highest and lowest air velocities. In contrast, the convectional ventilation efficiency method only identified damage risks in low-velocity areas. ACDI has not only the potential to account for high air velocity effects in naturally ventilated greenhouses but also presents an opportunity for specialized greenhouse complex control and management according to greenhouse position and incoming wind direction. Future research should aim at refining the ACDI for better aerodynamic analysis in greenhouse complexes planning and its integration into greenhouse ventilation control systems.

Acknowledgments: This work was supported by “Regional Innovations Strategy (RIS)” through the National Research Foundation of Korea (NRF) funded by Ministry of Education (MOE) (2024RIS-008)
Speakers
AK

Anthony kintu Kibwika

phd student, Jeonbuk National University, Korea
Co-authors
IS

Il-Hwan Seo

Associate Professor
Wednesday September 25, 2024 9:30am - 9:45am HST
South Pacific 2

9:30am HST

VCM 2 - Optimizing Nitrogen Fertilizer Rate and Planting Density of Vidalia Onion Yield and Bulb Size Distributions
Wednesday September 25, 2024 9:30am - 9:45am HST
This study was carried out at the University of Georgia (UGA) Vidalia Research Center during the 2022/2023 winter season and is being repeated in 2023/2024. The objectives of this experiment were to identify the relationship between planting density, nitrogen fertilizer rates, and the effects on yields and bulb size distribution. The variety “Sweet Magnolia” was tested at three planting densities (116,000; 87,000; and 58,000 plants per acre) and three nitrogen rates (120, 100, and 80 lbs. per acre). Results indicated there is no interaction between planting density and nitrogen rates on onion bulb size distribution or total production. However, the effect of planting density was significant. Higher densities (116,000 plants/acre) yielded a total weight of 1788 40 lbs. bags/acre with a significant proportion of jumbo-sized bulbs 62%, while lower densities (58,000 plants/acre) resulted in larger colossal bulbs 290 40 lbs. bags/acre with a reduced total yield 1370 40 lbs. bags/acre. Nitrogen application also had a significant impact on both yield and size of the bulb. The highest nitrogen rate (120 lbs./acre) produced a higher total yield (1670 40 lbs. bag/acre), with a significant portion of jumbo at 50% and colossal bulbs at 15%. There was no significant difference between the nitrogen rates of 100 and 120 lbs./acre, but the lowest nitrogen rate (80 lbs./acre) had the worst yield with 1434 40 lbs. bags/acre resulting in a 15% decreased yield compared with the higher rate. These results suggest that optimal planting density and nitrogen application are decisive for reaching the desired bulb size distribution and maximizing yield.
Speakers
avatar for Elvis Pulici

Elvis Pulici

MS Graduate Research Assistant, University of Georgia
Co-authors
HY

Henry Y Sintim

University of Georgia
NA
JC

Juan Carlos Diaz Perez

University of Georgia
TM

Ted McAvoy

University of Georgia
NA
Wednesday September 25, 2024 9:30am - 9:45am HST
South Pacific 4

9:45am HST

CE 2 - Characterizing the Growth, Morphology, Productivity, and Fruit Quality of Twenty-five Strawberry Cultivars in Vertical Farm Environment
Wednesday September 25, 2024 9:45am - 10:00am HST
As the interest in strawberry production in controlled environment agriculture is ascending, the demand for cultivars that yield premium-quality fruit is rising. To identify strawberry suitable for vertical farm production, 25 strawberry (Fragaria × ananassa) cultivars were selected for premium flavor from USDA National Clonal Germplasm Repository. Fruit productivity and quality traits, plant vegetative phenotypes, and photosynthetic rates were evaluated using strawberries grown in a walk-in growth chamber where photoperiod altered between short day and long day to promote flowering and fruit production. Our results show that strawberry ‘Mara des Bois’ produced the earliest harvest, and ‘Hood’ had the highest maximum productivity coefficient. The largest fruit was produced by ‘Chandler’, and the reddest fruit was produced by ‘Marshall’. Among the 25 cultivars, 11 exhibited fruit Brix levels above 0.9, and 3 had a fruit Brix:TA ratio of 1.0. Ongoing fruit flavor analysis aims to identify unique flavor compounds within these strawberries. Correlations linked time to first harvest and maximum productivity coefficient with canopy area, shoot height, and photosynthetic rate per plant, revealing the intricate sink-source dynamics in strawberry plants. Interestingly, no correlation was found between maximum productivity coefficient and any fruit quality trait, challenging the commonly held belief in the constant competition between crop productivity and quality. The information of strawberry growth and production in vertical farm environment provided in this study can assist indoor growers in cultivar selection and potentially contribute to future strawberry breeding programs.
Speakers
YL

Yiyun Lin

The Ohio State University
Co-authors
CK

Changhyeon Kim

The Ohio State University
NA
CK

Chieri Kubota

The Ohio State University
NA
JO

Jim Oliphant

US Department of Agriculture
NA
MH

Michael Hardigan

US Department of Agriculture
NA
NB

Nahla Bassil

US Department of Agriculture
NA
Wednesday September 25, 2024 9:45am - 10:00am HST
Coral 2

9:45am HST

NUTS 1 - Leaf Anatomical Traits and Water Use Efficiency in Four Pecan Cultivars
Wednesday September 25, 2024 9:45am - 10:00am HST
The leaf surface and interior structure can affect photosynthesis and transpiration rates associated with water use efficiency. Several studies have assessed pecan (𝘊𝘢𝘳𝘺𝘢 𝘪𝘭𝘭𝘪𝘯𝘰𝘪𝘯𝘦𝘯𝘴𝘪𝘴) leaf anatomical traits and established differences between cultivars; however, the effect of these traits on water use efficiency across cultivars has not been established. Understanding the relationship between leaf anatomical structures and water use efficiency across pecan cultivars allows for the identification of those that are well suited for water limited environments. In this study, we examined the leaf mesophyll layer thickness (µm), trichome density (trichome mm⁻²), stomatal density (stomata mm⁻²), and stomatal pore area (µm²) of four pecan cultivars (‘Wichita’, ‘Western’, ‘Pawnee’, and ‘Lakota’; all grafted to clonally propagated rootstocks). Leaves were collected at the NMSU Leyendecker Plant Science Research Center, and their cross-section and abaxial surface were imaged using light and scanning electron microscopy, respectively. ‘Lakota’ leaves had the thinnest palisade mesophyll layer and thickest spongy mesophyll layer relative to total leaf thickness. The stomatal density of ‘Pawnee’ was significantly less than the other cultivars, but no significant differences in stomatal pore area were observed. Intrinsic water use efficiency, calculated as ratio of the carbon assimilation rate to stomatal conductance to water vapor, was obtained using a leaf gas exchange meter on three separate days. A stable carbon isotope composition analysis was also conducted to provide insight into the leaf’s longer-term water use efficiency. The results showed that the intrinsic water use efficiency of ‘Lakota’ was different from ‘Western’ on one of the days; however, differences between cultivars were not significant when averaged across the measurement dates. Furthermore, the relative ¹³C abundance and ¹³C discrimination did not have significant differences across the four pecan cultivars evaluated, suggesting that differences in leaf anatomical traits did not influence the water use efficiency of these samples.
Speakers
SB

Sarahi Bracamontes

New Mexico State University
Co-authors
CV

Ciro Velasco-Cruz

New Mexico State University
NA
JR

Jennifer Randall

New Mexico State University
NA
KG

Kanchan Grover

New Mexico State University
NA
RH

Richard Heerema

New Mexico State University
NA
SB

Samy Belteton

New Mexico State University
NA
Wednesday September 25, 2024 9:45am - 10:00am HST
Lehua Suite

9:45am HST

VCM 2 - Assessing the Efficacy of Plant Biostimulants on Onion Growth and Production in Greenhouse Trials and Field Conditions
Wednesday September 25, 2024 9:45am - 10:00am HST
The escalating impacts of climate change on agriculture necessitate the exploration of sustainable crop enhancement methods. This research integrates greenhouse screening and field application to evaluate the efficacy of biostimulants in promoting the growth of onion (Allium cepa L.) under variable environmental conditions. In the initial greenhouse experiment, seven biostimulants were tested, including three bacterial products (Continuum, Spectrum DS, and Tribus Original), two mycorrhizal products (Mighty Mycorrhizae and Myco Apply), one seaweed extract product (Seaweed), and one product containing humic acid (Huma Pro 16). These were applied to assess their impact on seedling emergence and growth in a peat-based soilless substrate. Huma Pro 16 and Spectrum DS were identified as the most effective in increasing seedling emergence, leaf area, and biomass. Based on these findings, field trials were conducted with four onion cultivars (red, sweet, white, and yellow), subjected to conditions simulating drought and normal watering (75 % and 100 % evapotranspiration) or with nitrogen levels adjusted to low and high (75 % and 100 % of optimal 168 kilograms per hectare). The field trials assessed bulb diameter, weight, and leaf metrics. Results indicated that cultivars responded differently to varying conditions, with red and white onions showing consistent growth patterns, while sweet onions displayed more variability. Yellow onions benefited from the biostimulants, exhibiting improved growth under both drought and low nitrogen conditions. This study demonstrates that the application of certain biostimulants can significantly enhance crop growth and resilience. Huma Pro 16 and Spectrum DS show promise for improving onion yield in the face of climatic challenges. Keywords: biostimulants, drought stress, nitrogen availability, onion, and sustainable agriculture.
Speakers
PN

PRAKRITI NEPAL

Utah State Univeristy
Co-authors
DT

Daniel T Drost

Utah State University
NA
YS

Youping Sun

Utah State University
Wednesday September 25, 2024 9:45am - 10:00am HST
South Pacific 4

9:45am HST

VSF 2 - Evaluation of Pierce's Disease-resistant Grapevine Cultivars in South Carolina
Wednesday September 25, 2024 9:45am - 10:00am HST
Recently, there has been an increased interest in wine grape (Vitis vinifera) production in South Carolina (SC). The warm and humid climate in SC creates a conducive environment for a high risk of disease incidence. Despite the typical climate, SC has droughts periodically. Pierce’s Disease (PD), caused by the xylem-limited bacterium Xylella fastidiosa (Xf), is a major limiting factor to grapevine cultivation throughout the United States and, specifically, in the southeastern U.S. However, PD-resistant grapevine cultivars have been released by UC Davis. Xf-infected grapes can be heavily influenced by water deficit. Preliminary data from a drought-stress experiment in the Summer of 2023 indicated two PD-resistant cultivars perform well under a water deficit. The objective of this study was to evaluate the water dynamics and gas exchange of PD-resistant cultivars during periods of drought. In March 2023, five PD- resistant cultivars and one French-American hybrid were planted in a variety trial at Musser Fruit Research Center in Seneca, SC. The drought-stressed PD-resistant ‘Paseante Noir’ and ‘Errante Noir’ had similar carbon dioxide assimilation to well-watered PD-resistant cultivars. PD-resistant cultivar ‘Ambulo Blanc’ showed the worst leaf water status and lowest carbon dioxide assimilation when stressed. In 2024, physiological measurements, such as sap flow, trunk diameter, gas exchange, and water potential, were taken throughout the growing season. Our results supported previous research that some PD- resistant grapevine cultivars perform well in the field under drought conditions.
Speakers
avatar for Annie Bruno

Annie Bruno

Grad Student, Clemson University
Wednesday September 25, 2024 9:45am - 10:00am HST
Kahili

10:00am HST

CHMG 1 - Fruit Classes Teach Invasive Species Management and IPM Practices to Homeowners, Master Gardener Volunteers, and Pesticide Applicators
Wednesday September 25, 2024 10:00am - 10:15am HST
Florida's diverse climate offers ample opportunities for cultivating various fruit crops, especially as traditional citrus faces disease challenges. However, accessible information on alternative fruit crops is limited. In response, a series of online classes was initiated in 2020 to address this gap, coinciding with the need for Continued Education Units (CEUs) for pesticide license holders during COVID-19 lockdowns. The objectives of the class series were threefold: to enhance knowledge of fruit crop cultivation in Central Florida, promote the adoption of Best Management Practices (BMPs) in crop selection and care, and provide CEUs for pesticide license holders in Florida. In its pilot year, three Extension Agents developed a five-week class, expanding to a six-week series in 2021 involving five Agents across three counties. Each session focused on BMPs for landscapes and the cultivation of at least three different fruit crops, including discussions on potential invasive pests as well as alternatives to invasive fruit trees that shouldn’t be planted. The classes were conducted via Zoom and archived on YouTube for wider accessibility. Evaluation of the program included a post-class survey to assess knowledge gain and a three-month follow-up to measure the adoption of practices. Over the course of 2020-2023, the series covered care techniques for 29 different fruit crops. The impact of the classes has been significant. Since 2020, 23 episodes have been produced, attracting a total of 2,015 live viewers. Participants earned a total of 361 CEUs. Survey results indicated a substantial knowledge gain, with 96% (1,480/1,540) of respondents reporting increased understanding of the material. Moreover, 79% (195/248) of respondents adopted at least one new Integrated Pest Management (IPM) strategy after taking the class. According to that same survey 48% (98/202) have altered turf to fruit trees, planting a total of 37,477 square feet with edible plants. In summary, the online class series successfully addressed the demand for information on alternative fruit crops in Florida while providing valuable CEUs for pesticide license holders. Its impact is evidenced by increased knowledge among participants and tangible changes in cultivation practices towards more sustainable and diverse fruit production.
Speakers
KM

Kaydie McCormick

Extension Agent, University of Florida Institute of Food and Agricultural Sciences
Co-authors
MP

Morgan Pinkerton

UF/IFAS Extension Seminole County
TS

Tiare Silvasy

UF/IFAS Extension Hillsborough County
NA
TM

Tina McIntyre

UF/IFAS Extension Seminole County
NA
WL

William Lester

UF/IFAS Extension Hernando County
Wednesday September 25, 2024 10:00am - 10:15am HST
South Pacific 2

10:00am HST

NUTS 1 - Performance of Five Early-harvest Pecan Cultivars in South Georgia
Wednesday September 25, 2024 10:00am - 10:15am HST
Five pecan (Carya illinoinensis) cultivars were evaluated over 15 years in a trial at Tifton, GA, USA. Trialed cultivars included the standard early cultivar Pawnee, and the more recent releases Byrd, Morrill, Lakota, and Treadwell. Actual yield were measured for each tree each year and a 50-nut sample was taken to determine nut quality. Trees were evaluated for leaf and nut scab infection (Venturia effusa) and black aphid (Melanocallis caryaefoliae) damage. ‘Pawnee’ yielded significantly less than all the newer cultivars which had similar cumulative yields. However, ‘Byrd’, ‘Lakota’, and ‘Treadwell’ had significantly more yield alternation than ‘Pawnee’ and ‘Morrill’, with reduction of nut quality in the “ON” years. ‘Pawnee’ was the earliest cultivar and produced excellent quality nuts, but yields were mediocre. ‘Lakota’ had excellent scab resistance, but overcropped resulting in inferior quality, and should only be grown in orchards were crop loads are controlled by hedging or tree shaking. ‘Byrd’ and ‘Treadwell’ are very scab susceptible and also need crop load control, making them poorly suited for south Georgia. ‘Morrill’ had consistent cropping and excellent nut quality but is also very scab susceptible and should only be grown with excellent disease management practices.
Speakers
PC

Patrick Conner

University of Georgia
Wednesday September 25, 2024 10:00am - 10:15am HST
Lehua Suite

10:00am HST

O/LT 1 - BeeGardens Mobile Application Improves Pollinator Plant Knowledge Gain in Landscaping and Gardening Courses
Wednesday September 25, 2024 10:00am - 10:15am HST
Florida is home to over 300 species of native wild bees, some in critical decline. To encourage gardeners to plant bee friendly species that support bee pollinators year-round, an online application called BeeGardens was built using a shared library of code and a relational database management system. The application, accessible by a mobile device or computer, enables users to quickly access over 85 bee-friendly plants that attract 12 primary bee groups; and provides tips for incorporating these into different landscape designs (https://ffl.ifas.ufl.edu/bees). The functionality and usefulness of the app was evaluated by students enrolled in two courses at the University of Florida: Florida Native Landscaping and Annual and Perennial Gardening, taught in different semesters. Before and after the semester, students were asked to report their abilities to 1) identify bee-friendly plants, 2) identify bee pollinators, and 3) design a bee-friendly garden, using a Likert scale with responses ranging from 1 (strongly disagree) to 5 (strongly agree). Means of pre- and post-test responses showed a significant perceived knowledge gain upon using the BeeGardens online application in both courses. This data was consistent with pre- and post-tested means where students were asked to identify three major pollinator plants and three major pollinators using multiple choice response options. Test scores increased by 26.3% and 37.9% in Annual and Perennial Gardening and Florida Native Landscaping, respectively. The majority of students (95.0%) agreed or strongly agreed this learning tool was organized, easy to navigate, and would use it in the future. Since its inception in March 2021, this web application has been accessed by over 26,554 new users from across Florida and beyond.
Speakers
avatar for Sandra Wilson

Sandra Wilson

Professor, University of Florida
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
Co-authors
HK

Heather Kalaman

UF IFAS Extension Orange County
RM

Rachel Mallinger

University of Florida
NA
Wednesday September 25, 2024 10:00am - 10:15am HST
Coral 1

10:00am HST

PH 2 - Postharvest Performance of Tomato Fruit at Shelf-life Conditions in Relation to Fertilization Rate During Plant Producti
Wednesday September 25, 2024 10:00am - 10:15am HST
This study investigates how the ripening stage at harvest and fertilization rate impact tomato fruit quality. Tomato plants (cv. HM1823) were grown during the Fall 2023 season under four levels of fertilization (75%, 100%, 125%, and 150% of the recommended UF/IFAS rate, which is 200 lb/A nitrogen and potassium). Fruit were harvested at four distinct ripening stages: mature green (MG), turning (T), pink (P), and red (R), as assessed visually and stored at 25°C. Color, firmness, soluble solids content (SSC), pH, and titratable acidity (TA) were measured every 4 days until 12 or 16 days (for MG fruit). According to the analysis of variance, all factors (fertilization rate-FR, ripening stage at harvest- RS and shelf life period- SL), as well as the interaction RSSL significantly (P
Speakers
ST

Sotirios Tasioulas

SWFREC - University of Florida/IFAS
Co-authors
JW

Jessie Watson

SWFREC - University of Florida/IFAS
NA
PT

Pavlos Tsouvaltzis

Southwest Florida Research and Education Center, University of Florida
NA
Wednesday September 25, 2024 10:00am - 10:15am HST
Nautilus

10:00am HST

VSF 2 - Diversity and Abundance of Bees Visiting Grape Flowers in Wisconsin Vineyards
Wednesday September 25, 2024 10:00am - 10:15am HST
Bees play an essential role in plant pollination and the ecosystem services they provide to increase the quantity and quality of many agricultural crops. Many food crops are either dependent on, or benefit from, bee pollination, yet bees have experienced population declines due to a combination of factors including pesticide exposure, susceptibility to pathogens and parasites, habitat loss through land use intensification, and lack of suitable resources. Most studies on pollinator conservation and pollination services focus on pollinator-dependent crops and fail to address the role self- and wind-pollinated plants, such as grapes, play in maintaining or threatening pollinators. In vineyards, bees are often overlooked, as they are not required for the pollination of grape. This study aimed to survey the bees visiting grape flowers of cold climate grapes by recording the abundance and diversity of bees. Observations were conducted at six commercial vineyards in South Central Wisconsin during grape bloom, late May to mid-June in 2022. At each vineyard, vines of mixed cold-climate grape varieties were observed between 10:00 and 17:00 hrs on six separate days. Timed observations (5 min per vine) of bees visiting grape inflorescences were conducted at ten randomly selected grape plants per plot per day. In addition, each day, one 10 min wandering transect was walked along two adjacent rows of grape vines and all bees observed visiting grape inflorescences were recorded. To prevent destructive sampling, bees were identified in the field to species when known or assigned to one of 14 pre-determined morphospecies representing 24 likely genera. Timed plant observations showed a total of 1,059 floral visitations, with an average of 0.31 /- 0.16 bees per minute of sampling. During the wandering transects, a total of 417 floral visitations were observed, with 1.44 /- 0.43 bee visits per minute of sampling. This research underscores the need for reduced pesticide inputs, particularly around bloom time, to protect the diversity and abundance of bees visiting grape inflorescences.
Speakers
CG

Christelle Guedot

University of Wisconsin - Madison
Co-authors
ML

Mitchell Lannan

University of Wisconsin - Madison
NA
Wednesday September 25, 2024 10:00am - 10:15am HST
Kahili

10:15am HST

CHMG 1 - Invasive Potential of Ornamental Landscape Plants in Southern Arizona
Wednesday September 25, 2024 10:15am - 10:30am HST
Plants introduced through ornamental horticulture have contributed to exotic species invasions around the world. Fifteen landscape plants commonly used in horticulture in southern Arizona have been evaluated using the Plant Risk Evaluator (PRE) tool developed by PlantRight and Cal-IPC. The evaluations have recognized eight of these species as presenting high potential risk of escaping cultivation and becoming invasive in Arizona. The process of evaluating ornamentals has fostered communication and collaboration between invasive species managers and Extension horticulture agents, who previously had little interaction. The findings have been communicated through several articles on invasive species in the trade magazine, Southwest Horticulture. This information has contributed to two cultivated species (Searsia lancea and Ulmus pumila) and the entire genus Tamarix being newly added to the Arizona State Noxious Weed List. Arizona Master Gardeners have been educated on invasive plant issues to foster outreach to the public and to aid their planting choices.
Speakers
MC

Michael Chamberland

University of Arizona
Wednesday September 25, 2024 10:15am - 10:30am HST
South Pacific 2

10:15am HST

HSMP 1 - Saffron (Crocus sativus) Production in North Central New Mexico
Wednesday September 25, 2024 10:15am - 10:30am HST
Saffron (Crocus sativus L.) holds a high economic value as the world's most expensive spice. It plays a crucial role in many small farm economies in countries such as Iran, India, Afghanistan, Greece, Morocco, Spain, and Italy. In this project the effects of three different corm size (10 ,9 , and 8 ) on saffron stigma’s yield were studied in hoop house and open field production systems in a randomized complete block design with three replications at Certified Organic Farm of the Sustainable Agriculture Science Center of New Mexico State University in Alcalde located in north central New Mexico. Saffron corms were planted 6 to 8 inches in depth and 6 inches apart on September 19, 2023. The saffron flowers were harvested from October 18th until November 6th, 2023, in different treatments. Flowering started earlier and the flowering period was longer in plots planted with bigger corms. Saffron flowers picked up in the morning and then the stigmas were separated and dehydrated at 100 °C for ten minutes. The first-year results showed that the highest number of flowers were obtained from 10 corm size plots. The highest yield of dehydrated stigmas was also harvested from 10 corm size in high tunnel production system with 3.43 Kg/ha (3.06 lbs./acre). The bigger corms of saffron produced significantly higher stigma yield than smaller ones; 2.84 kg/ha (2.53 lbs./acre) for 10 corms vs 0.89 kg/ha (0.79 lbs./acre) for 8 corms, however, the difference between saffron yield in high tunnel and open field production systems was not significant. In summary the outcome of this research shows that saffron can be produced successfully even in open field production system in northern New Mexico and using bigger corms for planting may produce higher saffron in the first year, although the evaluation of winter hardiness and the following years performance will be necessary.
Speakers
SZ

Saeid Zehtab Salmasi

Associate Professor and Research Director, New Mexico State University
Research Director of the Sustainable Agriculture Science Center of New Mexico State University in Alcalde
Co-authors
RH

Robert Heyduck

New Mexico State University
NA
Wednesday September 25, 2024 10:15am - 10:30am HST
South Pacific 1

10:15am HST

NUTS 1 - Enhancing Pecan Tree Resilience Against Spring Freeze Events: Insights from Secondary Bud Dynamics and Carbohydrate Analysis
Wednesday September 25, 2024 10:15am - 10:30am HST
Pecan growers face significant challenges in protecting their crops from the spring freezes that devastate yields. Conventional freeze protection methods are impractical for the large, tall trees. This study investigated the dynamics of the secondary bud break in pecan trees, a mechanism that ensures yield when primary buds are damaged. In three pecan cultivars ('Pawnee,' 'Kanza,' and 'Maramec') we characterized the sprouting potential of secondary buds after the primary buds were cold damaged. Primary bud shoots were collected at three different bud growth stages: outer bud scale shed stage, inner bud scale shed stage, and early bloom stage. The shoot samples held at 6°C to terminate primary buds’ growth. The cold treated shoots were then held in growth chambers set to mimic spring humidity, temperature, and light conditions. The percentage of branches with secondary bud break was recorded. The carbohydrate levels (sugar and starch) were measured in the apical shoots treated at the outer bud scale shed stage. The results showed variation among cultivars in the number of shoots with secondary buds and the stage at which primary buds were terminated. The ‘Kanza’ and ‘Pawnee’ cultivars produced more secondary buds when the primary buds were cold damaged in the outer bud scale shed stage. The ‘Maramec’ cultivar produced more secondary buds when the primary buds were cold damaged in the inner bud scale shed stage. The A carbohydrate analysis of the three cultivars demonstrated a correlation between successful secondary bud break and elevated carbohydrate levels in the one-year-old shoots. Cultivars with higher secondary bud break rates, 'Kanza' and 'Pawnee', had higher carbohydrate levels than 'Maramec.' These findings suggest that higher carbohydrate levels in one-year-old shoots facilitate successful secondary bud break following spring freeze damage to primary buds. This research suggests developing production practices to improve tree carbohydrate levels in the late summer and fall could potentially protect pecan production from spring freeze damage.
Speakers
LZ

Lu Zhang

Oklahoma State University
Co-authors
AK

Amandeep Kaur

Oklahoma State University
NA
JM

Justin Moss

Oklahoma State University
NA
LF

Louise Ferguson

University of California, Davis
NA
NM

Niels Maness

Oklahoma State University
NA
YS

Yanwei Sun

Oklahoma State University
NA
Wednesday September 25, 2024 10:15am - 10:30am HST
Lehua Suite

10:15am HST

O/LT 1 - Pesticide Management Decisions Affect Contamination of Nectar in Containerized Ornamental Plant Production
Wednesday September 25, 2024 10:15am - 10:30am HST
Declines in pollinator populations have gained much attention over the last decade. Exposures to pesticides are one potential contributor to these declines. Given that the ornamental plant production industry produces crops that are attractive to pollinators and that pesticide use is often integral to ensuring plants are pest-free, attention is needed to assess and possibly reduce contamination of flower nectar and pollen before plants go to market. Three major factors associated with pesticide management practices that may influence contamination of floral resources are: application method, application rate, and application timing relative to flowering. Using the systemic insecticide thiamethoxam as a model pesticide and Salvia x ‘Indigo Spires’ (Salvia longispicata x S. farinacea) as a model species, this study investigated the influence of each of these factors on contamination of nectar. Plants were treated by spray and drench methods, at low and high rates according to the pesticide label, and before flower buds formed or close to the time of floret opening. Nectar samples were collected using microcapillary tubes when all plants were uniformly flowering and thiamethoxam concentrations were analyzed by LC-MS/MS. Concentrations of thiamethoxam in nectar were highest in drench applications, regardless of application timing and rate, and exceeded published LC50s for native bees and/or honeybees. Thiamethoxam concentrations were much lower in the spray-applied treatments, but they still exceeded published LC50s for native bees and/or honeybees except for the spray treatment applied before blooming at the low rate. These results provide insight into how some pesticide management practices influence contamination of floral resources and indicate a need for developing best management practices focused on limiting thiamethoxam exposures once plants go to market. Additional studies are underway to evaluate other plant species and systemic insecticides to address gaps in knowledge.
Speakers
avatar for Patrick Wilson

Patrick Wilson

University of Florida
pesticide fate and toxicology, pollinator protection, pesticide analysis in different matrices
Co-authors
MC

Mia Cabrera

university of florida
NA
SW

sandra wilson

University of Florida
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
VR

Vanesa Rostan

university of florida
NA
Wednesday September 25, 2024 10:15am - 10:30am HST
Coral 1

10:15am HST

PH 2 - Identification of NAC Transcription Factors Involved in the Ripening and Senescence of Pepper (Capsicum annuum L.) Fruit
Wednesday September 25, 2024 10:15am - 10:30am HST
Pepper (Capsicum annuum L.) as a non-climacteric fruit is usually harvested at either mature green or ripe stage, and fruit quality including texture, color, and nutritive values is different according to the fruit developmental stages. Understanding molecular mechanisms of fruit ripening and senescence processes is crucial to control the fruit quality and reduce the postharvest loss. This study was aimed to identify NAC transcription factors (TFs) involved in the ripening and senescence of pepper fruit by analyzing gene expressions and protein-protein interactions. To identify NAC genes related to the ripening, transcript levels of total 104 NAC TFs were investigated using publicly available transcriptome data. Among them, transcript levels of 8 genes significantly increased during the ripening and senescence. Their phylogenetic analysis also showed that they are closely associated with NAC TFs which play a role in ripening or senescence in other crop species. Among them, 4 genes showing abundant transcript levels at the ripening stage were selected, including CaNAC14, 45, 84, and 92, to further investigate their roles. In pepper (C. annuum var. ‘Gyeonggiyangpyeiong’) fruit, their expressions clearly increased during the ripening or induced by exogenous ABA, the major phytohormone regulating non-climacteric fruit ripening. To reveal a relationship between the CaNACs and ABA signaling, protein-protein interactions between the CaNACs and ABA receptors were analyzed through yeast- two-hybrid and bimolecular-fluorescence complementation assays. Among them, CaNAC92 and CaPYL12, the ABA receptor, interacted each other in a nucleus with an ABA-dependent manner. This result indicated that their interaction may affect the ABA signaling or the transcriptional regulation during the ripening. We identified CaNAC TFs involved in the pepper fruit ripening and suggested CaNAC92 as a putative molecule functioning in the ripening. These findings will provide genetic information to control the ripening and to improve pepper fruit quality.
Speakers
KM

Kyeonglim Min

Student, Seoul National University
Co-authors
EJ

Eun Jin Lee

Seoul National University
Wednesday September 25, 2024 10:15am - 10:30am HST
Nautilus

10:15am HST

VSF 2 - The Grape Health Index: Validation of a New Methodology for Quantifying Wine Grape Spoilage by Means of FT-MIR Spectrosc
Wednesday September 25, 2024 10:15am - 10:30am HST
For wineries processing hand harvested grapes, a visual inspection of microbial spoilage is expedient and cost effective. However, due to the increasing adoption of machine harvesters, which frequently rupture berry skins making visual inspection less precise, and the high degree of error of visual inspections between individuals, a quantitative approach to assess spoilage is needed. Fourier Transform Mid-Infrared Spectroscopy (FT-MIR), combined with multivariate analysis, is being investigated as an approach to predict grape health as a sample that can be analyzed in less than one minute. Calibration data was obtained from grape samples of Chardonnay, Riesling, Petite Sirah, and Zinfandel, which were sorted into fractions of 0, 5, 10, 15, and 20% microbially impacted clusters in healthy grape material, and analyzed using the spectrophotometer. The spectral data was analyzed using the Partial Least Squares (PLS) regression. Predicting factors included volatile acidity (VA), gluconic acid, ethanol, lactic acid, glucose-fructose content, Brix, titratable acidity, tartaric acid, malic acid, pH, alpha amino nitrogen, ammonia, and yeast assimilable nitrogen (YAN). A model was selected which optimized for a high coefficient of determination (R2) and a low root mean squared error (RMSE). Additional selection criteria included the extent to which predicting factors have been observed to correlate with microbial spoilage in other studies. The model selected had a R2 of 0.620 and a RMSE of 4.596, making it suitable for identifying grapes marked by spoilage. The output of the model was converted to Grape Health Index (GHI) Scores for better usability by operators at the test stand. The GHI was implemented at the test stands of two large-scale wineries during the 2022 and 2023 seasons. Additional wineries will be added in 2024. The testing of the impact of microbial spoilage on wine aging is currently underway. Wines made in 2018, 2019 and 2020 are evaluated for color degradation and browning, anthocyanins, tannins, pigments, and acetaldehyde. The results will be compared with the original harvest results for comparative analysis concluding the project.
Speakers
SV

Sonet Van Zyl

Fresno State
Co-authors
SS

Stephan Sommer

University of Missouri
NA
SC

Steven Craig Ebersole

Foley Family Wines
NA
Wednesday September 25, 2024 10:15am - 10:30am HST
Kahili

10:15am HST

WUM 1 - Developing Irrigation Tools and Information for Effective Irrigation Management of California’s Avocado Orchards
Wednesday September 25, 2024 10:15am - 10:30am HST
In California, avocado is primarily grown in Southern and Central parts of the state, typically in regions tempered by coastal climates and fine or course sandy loam soils. These regions face uncertain water supplies, mandatory reductions of water use, and the rising cost of water, while efficient use of irrigation water is one of the highest conservation priorities. Moreover, due to increasing salinity in water sources, effective irrigation is more critical to ensure optimal yield and high-quality avocado fruits. A two-year study was conducted in 12 mature avocado sites in California. Extensive field measurements and surveys were conducted to better understand the current water management practices, to acquire and develop relevant information on crop water use (ET) and crop coefficients, and to assess the performance of satellite-based OpenET tool for irrigation management in avocados. Surface renewal and eddy covariance equipment was used to measure actual evapotranspiration (ETa) in each site. The results illustrated considerable variability in avocado crop water consumption both spatially and temporally. The crop coefficients curves were developed for each site. Across the avocado research sites, the average seasonal crop coefficient values varied from 0.6 to 0.76. The findings demonstrated that canopy features, soil types and conditions, pruning practices, soil surface cover, and row orientations need to be considered to perform effective water management in avocado orchards. Ground shading percentage and row orientations provide a good estimation of canopy size/volume and the amount of light that it can intercept are likely the most important drivers influence crop water needs. The RMSE of the measured ETa from eddy covariance equipment and estimated ETa from Ensemble OpenET varied from 0.53 to 1.37 mm d-1. The preliminarily findings indicated that the Ensemble OpenET estimates ETa relatively well in some sites and could be an effective irrigation management tool in the future for avocado orchards, however more evaluations are required.
Speakers
AM

Ali Montazar

University Of California Cooperative Extension
Wednesday September 25, 2024 10:15am - 10:30am HST
South Pacific 4

10:30am HST

CHMG 1 - Education on Water Saving Landscaping Practices Results in Measurable Water Conservation
Wednesday September 25, 2024 10:30am - 10:45am HST
Florida is facing critical water scarcity due to population growth. The home landscape is an opportune setting to make changes in practices to conserve water. Extension programs on water conservation in the landscape can provide residents with the information they need to adopt new practices to conserve water. In 2021-2023, UF/IFAS Extension residential horticulture programs in Central Florida, educated 6,474 residents about sustainable landscape practices. Based on client self-reported follow-up surveys (n=342), the annual water savings due to adoption of best landscaping practices was approximately 11.6 million gallons. It saved homeowners $49,977 in utility bills (based on regional value of $4.30 per 1,000 gallons). The most adopted practices included calibrating sprinkler systems to deliver ½ inch to ¾ inch of water instead of 1 inch, reducing irrigation frequency during summer, and reducing irrigation frequency during winter. Adoption is lower for water conservation practices that require installing soil moisture sensors and converting or installing irrigation spray heads. Participants reported (n=342): 35% eliminated irrigation or converted to low volume irrigation, 46% reduced irrigation from 3 to 2 days per week, 45% reduced irrigation frequency in winter, 46% reduced irrigation frequency in summer, 25% using a working rain shutoff device, 37% calibrated irrigation to ½” or ¾” rather than 1” or more. Impacts of changes in household water use multiply when life cycle assessment of a water supply system is considered. The reduction of 11.6 million gallons of residential water use resulted in saving 40,022 kWh of energy and $30,162 in treating and delivering water to the end users, reducing 28 metric tons of carbon dioxide equivalent of greenhouse gas emissions, deferring the need for $98,734 investment in alternative water supply infrastructure, and potentially reducing stormwater runoff and avoiding water quality deterioration. The impacts of these water conservation efforts are even greater than the values represented here based on total program attendance. This shows the efforts of extension agents educational programs resulted in measurable water savings to help Florida households conserve water.
Speakers
TS

Tia Silvasy

University of Florida
Wednesday September 25, 2024 10:30am - 10:45am HST
South Pacific 2

10:30am HST

HSMP 1 - Experiences Cropping Wasabi in Inland Oregon
Wednesday September 25, 2024 10:30am - 10:45am HST
Wasabi (Eutrema japonicum) is a high-value and notoriously difficult crop traditionally cultivated in East Asia. There has been some limited commercial cultivation of the crop in the Pacific Northwest, including in the coastal mountains of Oregon. This presentation shares insights into the challenges and approaches to inland wasabi farming, focusing on environmental conditions, potential growing systems, and media types. Key points include: 1. Environmental Conditions: Wasabi has a narrow range of light, temperature, and water requirements and is prone to a myriad of fungal and bacterial diseases. Knowing this narrow range is essential to the practicality of commercial wasabi production. Balancing the ideal environmental factors for wasabi without creating disease outbreaks is a primary challenge in wasabi production. 2. Growing System
Speakers
avatar for Clint Taylor

Clint Taylor

Oregon State University - NWREC
Co-authors
CB

Chip Bubl

Oregon State University
NA
CO

Cynthia Ocamb

Oregon State University
NA
DM

Dalyn McCauley

Oregon State University
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 →
Wednesday September 25, 2024 10:30am - 10:45am HST
South Pacific 1

10:30am HST

NUTS 1 - Biochar in Pecan Orchards: Unraveling Water Stress Dynamics for Sustainable Irrigation Management
Wednesday September 25, 2024 10:30am - 10:45am HST
Pecan orchards in the southwestern United States face significant challenges due to persistent drought conditions that adversely affect yield and nut quality. Pecans are recognized as the most water-intensive crop in the region, and therefore require innovative strategies to optimize the available irrigation water. This study explores the use of pecan wood-derived biochar as a soil amendment to enhance the soil water-holding capacity and alleviate water stress in pecan orchards. We conducted field experiments during the summer of 2023 in a flood-irrigated pecan orchard located in the Mesilla Valley, New Mexico, USA. We accounted for the irrigation gradient in a flood-irrigated orchard by using a randomized complete block design with four blocks, each containing three equidistant trees from the irrigation valves. The trees within each block were randomly assigned to one of three biochar application rates: 0 kg/ha (treated area), 6300 kg/ha, and 12600 kg/ha. The treated area was situated within the herbicide strip, spanning 9.14 m in length – centered on the tree – with 1.22 m on either side of the tree. To assess tree water status, two leaf samples from the lower shaded canopy were covered in aluminum foil bags for a minimum of 15 minutes before mid-day stem water potential was measured. Mid-day stem water potential was measured throughout the growing season near the end of each irrigation dry-down cycle. For each tree, we calculated the average mid-day stem water potential and then performed an ANOVA to compare the averages across the treatment groups. In the five months after biochar application, there were no significant differences in tree water status across the treatment groups. This highlights the need for more research to study the interactions among soil moisture content, biochar amendment applications, and pecan tree mid-day stem water potential. This study contributes to the ongoing discourse that calls for enhancing crop water use efficiency in arid regions by providing a foundation for future studies that seek to use biochar as a sustainable agricultural practice in pecan orchards.
Speakers
JM

Jamin Miller

New Mexico State University
Co-authors
AF

Alexander Fernald

New Mexico State University
NA
CV

Ciro Velasco-Cruz

New Mexico State University
NA
DD

David Dubois

New Mexico State University
NA
JI

John Idowu

New Mexico State University
NA
RH

Richard Heerema

New Mexico State University
NA
Wednesday September 25, 2024 10:30am - 10:45am HST
Lehua Suite

10:30am HST

O/LT 1 - Comparing Pollinator Species Richness and Abundance Between Pycnanthemum Species and Accessions
Wednesday September 25, 2024 10:30am - 10:45am HST
Pollinators play a crucial role in the ecosystem, human health, and the economy. However, despite the significance of pollinators, their populations are declining globally. Pycnanthemum is a marketable pollinator-attractive plant that could supplement pollinator resources in the landscape. Breeders would benefit from a comparison of the pollinator attractiveness between Pycnanthemum species and accessions. Cultivating Pycnanthemum should focus on aesthetic traits and maximizing pollinator abundance and species richness. Pollinator visitation was compared among three species and five accessions of Pycnanthemum (P. flexuosum (F), P. virginianum (V), and three accessions of P. tenuifolium (T1-T3)) using observations and capture. Lepidoptera, honey bees (Apis mellifera), Diptera, carpenter bees (Xylocopa spp.), small bees, and bumble bees (Bombus spp.) were observed most abundantly on Plant F. Plant V attracted the highest number of pollinators overall, with Apis mellifera (honey bees) accounting for more than half of the pollinator visitation. Xylocopa spp. (carpenter bees) and honey bees did not have a significant preference between the species. Plants F, T2, T3, and V attracted the greatest abundance of Diptera (flies). Wasps were most attracted to Plants T3 and V, while Bombus spp. (bumble bees) was observed most often on Plants F and V. Plant F attracted the highest number of Lepidoptera (butterflies and moths) and small bees. The species richness of pollinators did not significantly differ across Pycnanthemum species, with at least 24 to 29 different pollinator species visiting each plant. A range of factors, including olfactory cues, the morphology of plants, and accessibility of resources, may have affected pollinator preferences. Determining which Pycnanthemum species attracted an abundance and diversity of pollinators provides breeders a foundation for cultivation and conservation expectations.
Speakers
KS

Kaitlin Swiantek

Ball FloraPlant
Co-authors
JR

John Ruter

University of Georgia
Allan Armitage Endowed Professor of Horticulture and Director, Trial Gardens at UGA
Wednesday September 25, 2024 10:30am - 10:45am HST
Coral 1

10:30am HST

PH 2 - Comparative Analysis of Volatile Organic Compounds of Eight Microgreens in the Brassicaceae Family
Wednesday September 25, 2024 10:30am - 10:45am HST
This study investigates the volatile organic compounds (VOCs) of eight microgreens in the Brassicaceae family, known for their robust flavors and potential health benefits, including detoxification properties and anti-cancer effects. The microgreens analyzed included five Brassica species—B. juncea (mustard), B. napus (kale), B. rapa (mizuna), B. oleracea L. var. capitata (red cabbage), and B. oleracea L. var. italica (broccoli)—as well as Eruca sativa (arugula), Lepidium sativum (cress), and Raphanus sativus (radish). The above-ground plant tissues were homogenized in saturated salt water and the VOCs were examined using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GCMS). A total of 117 VOCs were identified across all tested species, with individual species VOC counts ranging from 42 to 67. Radish showed the highest total ion current at 676 million (mTIC), with other species varying down to 190 mTIC in arugula. Notably, sulfur and/or nitrogen-containing compounds (SCCs and/or NCCs) constituted over 90% of the total VOCs collected from all species, with Brassica species containing more than 96% SCCs and 93% NCCs. Conversely, radish and arugula had less than 88% NCCs, and cress contained only 66% SCCs. Dominant compounds were primarily isothiocyanates, with significant variability in major VOCs across different species. For instance, allyl isothiocyanate was prevalent in mustard, mizuna, and red cabbage; 4-isothiocyanato-1-butene in kale and mizuna; isothiocyanatomethyl-benzene in cress; 1-isothiocyanato-4-(methylthio)-butane in arugula and broccoli; and (E)-4-isothiocyanato-1-(methylthio)-1-butene in radish. The reduced SCCs in cress were attributed to the higher presence of benzyl nitrile and benzyl isocyanate, while the lower NCCs in radish were linked to increased levels of dimethyl disulfide and dimethyl trisulfide. This diversity in SCCs and NCCs contributes to the varied volatile flavors and potential health benefits of these microgreens.
Speakers
avatar for Jinhe Bai

Jinhe Bai

Research Chemist, USDA-ARS
preserve the postharvest flavor and nutrient quality of fruits and vegetables. Specific areas of expertise include controlled-atmosphere storage, modified atmosphere packaging, and edible coating technologies, and the discovery of how internal and environmental factors influence metabolism... Read More →
Co-authors
AP

Anne Plotto

USDA-ARS
NA
ER

Erin Rosskopf

USDA-ARS
NA
FD

Francesco Di Gioia

Pennsylvania State University
JH

Jason Hong

USDA Agricultural Research Service
NA
LW

Libin Wang

Nanjing Agricultural University,
NA
WZ

Wei Zhao

USDA-ARS
NA
Wednesday September 25, 2024 10:30am - 10:45am HST
Nautilus

10:30am HST

VSF 2 - World Grape Rootstocks Pedigree Review
Wednesday September 25, 2024 10:30am - 10:45am HST
Grapes belong to the Vitis genus, which includes about 80 species and is considered as two sub-genera, including Euvitis and Muscadinia. Muscadine grapes are sometimes considered as a separate genus in different classification systems and include three species: Muscadinia rotundifolia, Muscadinia munsoniana, and Muscadinia popenoei. The Euvitis sub-genus includes the most commercially important grape varieties. Euvitis is divided into three groups. 1) The American group consists of about 30 species that are important for rootstock breeding; 2) The Asian group consists of about 50 species, which, up to this point, have been underutilized for grape cultivation; and 3) The Eurasian group consists of a single species, Vitis vinifera L., which includes two sub-species of V. vinifera: V. vinifera subsp. sylvestris, considered to be the wild form of grape; and V. vinifera subsp. vinifera, refers to cultivated forms. Of all species in the genus Vitis, the V. vinifera, is undoubtedly the most important worldwide for commercializing grapes and represents the most cultivated varieties worldwide. Other grape species contributed to breeding programs beyond the traditional efforts of rootstock hybridization from wild species. An aphid-like pest, phylloxera (Daktulosphaira vitifoliae), causes damage by feeding on the structural roots of V. vinifera, eventually leading to vine death. In an effort, American Vitis species that coevolved with phylloxera were eventually used as rootstocks for the widely planted V. vinifera scion cultivars. Later, crosses between these wild species became common, and historical breeding efforts led to the modern grape rootstock breeding programs currently active worldwide. Two-thirds of American species have already been used for rootstock breeding. However, it has been reported that the most commonly available rootstocks are derived from just three American species (Vitis berlandieri, Vitis rupestris, and Vitis riparia). Therefore, the most common grape rootstocks have a narrow genetic base, and efforts to extend the gene pools for breeding programs by using other species are of ongoing importance to the industry and scientific community. There are around 1500 grape rootstocks developed in the world, of which around 50 are commonly used as commercial rootstock and play a fundamental role in resistance to biotic and abiotic stresses and adaptation of grapevine to different environmental conditions, a factor that has opened commercial grape growing to regions that might otherwise be overlooked.
Speakers
AR

Alireza Rahemi

Morehead State University
Co-authors
Wednesday September 25, 2024 10:30am - 10:45am HST
Kahili

10:30am HST

WUM 1 - Comparative Assessment of Satellite-Derived Crop Evapotranspiration and Estimated Evapotranspiration in Almond and Walnu
Wednesday September 25, 2024 10:30am - 10:45am HST
Almond and Walnut are the major irrigated crops in the Northern San Joaquin Valley (NSJV) of California. The recurring droughts and climate change in California will likely increase the uncertainty in water supply to almond, walnut, and other specialty crops. Site-specific irrigation is critical to cope with these challenges. Knowing the water consumption of these water use intensive crops is imperative for optimizing irrigation management since it affects nut quality, productivity, and composition. This requires accurate estimates of crop water use (Evapotranspiration, ET). Traditional methods for estimating crop water use are spatially limited, whereas satellite remote sensing of ET offers the advantage of large-scale coverage and is increasingly adopted in irrigated agriculture. This study compares OpenET models, an open-source database providing ET estimates, against calculated ET from weather stations that are commonly used by growers in their irrigation management. Evaluation of OpenET against estimated ET might provide a good opportunity for growers to improve water use efficiency. Such improvements could lead to the adoption of publicly available irrigation management tools and ensure healthier tree development, better resource utilization, and more resilient orchards in the face of climate change. This presentation delves into the preliminary findings of the OpenET evaluation against calculated ET from weather stations in estimating water use for almonds and walnuts, while also examining the potential and challenges associated with each approach for implementation in growers' fields.
Speakers
AM

Abdelmoneim Mohamed

Irrigation and Soils Advisor, University of California ANR
Wednesday September 25, 2024 10:30am - 10:45am HST
South Pacific 4

10:45am HST

CHMG 1 - Cultivating Connections: Empowering Professionals through NC Farm to School Training Initiative
Wednesday September 25, 2024 10:45am - 11:00am HST
As the Farm to School movement continues to gain momentum, professionals in education, agriculture, and public health are seeking innovative ways to integrate this holistic approach into their practices. In North Carolina, our local, regional, and statewide food system has strengths across various sectors. Local agencies and community organizations now have decades of experience partnering together to maximize opportunities for local farmers and local food businesses. Partnering together, these food system practitioners have clearly begun to see that a systems approach is vital to supporting all sectors and stakeholders, vital to addressing the deep roots of inequity that negatively impacts our communities of color and particularly our children. The central need is in how to facilitate integrated efforts–both across farm to school components and also with multi-sector stakeholders–given that research shows that integration of farm to school programming brings the longest and most significant health and learning impacts on children. Our approach has been to develop the North Carolina Farm to School Training Initiative, a rich space of collaboratively created online content that informs and educates across the farm to school program areas. Through a combination of interactive modules, case studies, and expert-led discussions, our first course, School Gardening, provided participants with the knowledge and skills needed to navigate the complexities of Farm to School programming. The results from surveying pilot participants suggest numerous impacts, both on an individual and community level. Preliminary results found participants increased their knowledge and gained a deeper understanding of farm-to-school initiatives, including building community engagement through school garden teams, integrating gardening into curriculum, and the horticulture knowledge to successfully grow a garden. Participants improved their practical skills such as gardening techniques and the application of educational programming in the garden. Part of the course included interactive discussion boards and a qualitative review showed a number of themes emerged including that the course participants strongly benefitted by connecting with a group of like-minded educators and community organizers by fostering collaboration and support for farm-to-school efforts. Community engagement was another emergent theme with participants and they named that they would like to become more involved in their local food systems, finding connections with community partners like growers and Extension for access to resources and materials. These results suggest that fostering a community of practice that transcends geographic boundaries and provides localized and engaging content has significant potential to support great professional engagement in farm to school.
Speakers
LD

Liz Driscoll

Extension Associate, NC State University/ NC Cooperative Extension
Co-authors
KB

Kirsten Blackburn

NC State University
NA
RH

Remi Ham

NC State University
Wednesday September 25, 2024 10:45am - 11:00am HST
South Pacific 2

10:45am HST

HSMP 1 - Double-season production of hops (Humulus lupulus L.) with photoperiod manipulation in a subtropical climate
Wednesday September 25, 2024 10:45am - 11:00am HST
Hops (Humulus lupulus L.) have an ancient history of cultivation in temperate climates primarily as an ingredient of beer. However, growing hops in subtropical or tropical climates has been challenging because of non-optimal day length conditions. We examined the potential of subtropical hop production with photoperiod manipulation. ‘Cascade’ hops were grown in Florida, United States with extended day length (>16.5 hours) using light-emitting diode (LED) bulbs to inhibit flowering until sufficient vegetative growth was achieved. Phenology, plant growth, yield, and cone quality data were collected during the first two years after planting. With as little as 0.47 μmol/m2/s, photoperiod extension was effective in inhibiting flowering, while promoting vegetative growth. Uniform flowering was induced upon the discontinuation of photoperiod extension. As a result, plants achieved two growing cycles per year, with the spring and fall growing seasons running from February to July and July to December, respectively. Yield increased by 92% from Year 1 to Year 2 but decreased by 37% from the spring to fall growing season. The maximum yield was 465 kg/ha in Year 2 Spring. Cone quality was greatly affected by both year and season, with α acid, β acid, and total oil concentrations ranging from 2.7% to 6.2%, 1.9% to 3.2% and 0.14 to 0.53 mL/100 g, respectively. These results demonstrate that, with an aid of photoperiod manipulation for flowering control, ‘Cascade’ hops exhibit high phenological plasticity and acclimation capacity to subtropical climatic conditions. This study provides a foundation for developing the double-season hop production system in a subtropical climate.
Speakers
SA

Shinsuke Agehara

University of Florida
Co-authors
AA

Aleyda Acosta-Rangel

University of Florida
NA
JR

Jack Rechcigl

University of Florida
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
South Pacific 1

10:45am HST

NUTS 1 - Evaluating Soil Management Impacts on the Pecan Orchard Mycobiome in the Semi-Arid Southwestern United States
Wednesday September 25, 2024 10:45am - 11:00am HST
Pecans hold significant agricultural importance in the water-limited Southwestern United States, underscoring the need for sustainable soil management practices in pecan cultivation. Recognizing the intricate relationship between soil treatments and the soil microbiome is essential to develop effective orchard soil management strategies. Soil fungi, particularly root-associated mycorrhizal fungi, are vital in facilitating water and nutrient uptake, protecting against pathogens, and enhancing overall orchard health and productivity. Soil management may impact the fungal community composition of Southwestern pecan orchard soils. Various soil management strategies are implemented in pecan orchards, including varying soil cover or applying mycorrhizal and bacterial inoculants. These techniques alter the soil environment, which may change the soil fungal biodiversity. This study investigates the impact of diverse soil management techniques on the soil mycobiome within a twelve-year-old ‘Pawnee’ pecan orchard in New Mexico. In a randomized complete block design, eight treatments of various soil cover – bare soil, cover crops, compost, or a combination of cover crops and compost – each either with or without mycorrhizal and bacterial inoculants, were applied to evaluate their effects on soil fungal diversity. Laboratory analyses, including DNA extraction, PCR amplification, and Illumina sequencing, were performed, alongside physiochemical testing for soil pH, electrical conductivity, and mineral nutrient content. The resulting sequence data were analyzed to provide insights into the complex interactions between soil management practices and microbial communities. Sampling conducted during the 2022 Spring and harvest seasons revealed significant differences in alpha and beta diversity between roots and bulk/rhizosphere soil (P < 0.10). Significant differences in alpha and beta diversity of fungi based on treatment were also observed, highlighting the potential influence of soil management practices, including soil cover and inoculant use, on fungal community composition. Our study offers valuable insights into the temporal changes in the community structure of pecan orchard fungi when treated with different soil amendments. Understanding how soil management practices influence the soil mycobiome can inform more sustainable pecan cultivation practices. By optimizing soil management strategies to support beneficial fungal communities, growers may enhance soil health, water and nutrient availability, and plant resilience to environmental stress.
Speakers
avatar for McKenzie Stock

McKenzie Stock

New Mexico State University
Co-authors
CV

Ciro Velasco-Cruz

New Mexico State University
NA
JR

Jennifer Randall

New Mexico State University
NA
NP

Nicole Pietrasiak

University of Nevada Las Vegas
NA
PG

Paul Gabriel

New Mexico State University
NA
RH

Richard Heeremaa

New Mexico State University
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
Lehua Suite

10:45am HST

O/LT 1 - The Art and Technique of Producing Unique Lagerstroemia Plants
Wednesday September 25, 2024 10:45am - 11:00am HST
Crape myrtle (Lagerstroemia L.) stands as a ubiquitous presence in landscapes worldwide. Beyond its captivating smooth and exfoliating bark, a spectrum of flower colors, and impressive variable mature heights, the artistic modeling potential of crape myrtle has found favor in the high-end landscape market. Crafting a crape myrtle tree becomes a gratifying and imaginative endeavor. The preeminent modeled shapes include vases, screenings, letters, columnar forms, dragon-inspired (animalistic), symbolic representations, pavilions, tunnels, tree bonsai, ornamental root architecture, and even cartoon characters. Constructing a foundational armature from steel demands your artistic prowess and creativity, serving as the structural basis for the tree. Opting for fast-growing crape myrtle cultivars with pliable branches becomes imperative for success. Consistent pruning becomes a requisite to mold the growth pattern according to our artistic aspirations. Utilizing modeling wire facilitates the creation of the trunk and branch framework, with strategically tied crossed knots enhancing natural grafting unions. Developing distinctive Lagerstroemia plants requires a more extended timeframe and demands advanced modeling and pruning techniques compared to conventional growth processes. This production journey provides ample creative freedom and the ultimate performance should align with our artistic vision and the preferences of our clientele. Future studies should delve into plant growth dynamics and the development of trunk/branch anatomical structures to further enhance our understanding of this artistic horticultural practice.
Speakers
DZ

Donglin Zhang

University of Georgia
Co-authors
XL

Xi Li

Sichuan Agricultural University
NA
XH

Xiaoling Hou

Chongqing Yuexin Valley Ecological Agriculture Co. Ltd
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
Coral 1

10:45am HST

PH 2 - Nutritional Quality and Shelf-Life of “Living Lettuce” Through 28 Days of Cold Storage
Wednesday September 25, 2024 10:45am - 11:00am HST
Lettuce (Lactuca sativa) is cultivated in controlled environment agriculture via vertical production or hydroponic well systems. To extend shelf-life, growers harvest “living lettuce” by keeping roots intact, but there is limited data supporting this harvesting technique. The objective of this study was to assess the use of clamshell and root treatments on the shelf-life and nutritional quality of lettuce. Treatments included storage either inside or outside of plastic clamshells and with roots removed or intact. Lettuce was stored for 28 days at 4 oC, 85% relative humidity. Percent weight loss (%weight loss), visual ratings (1 to 5 scale, 1 = poor and 5 = excellent), and colorimeter analysis (L*, a*, b*, c*, hue angle) were measured every 3 days. Total assays of chlorophyll, carotenoids, anthocyanins, flavonoids and phenolic activity were analyzed via UV VIS spectrophotometry every 7 days throughout storage. Few differences were seen in root treatment. As days in storage progressed, %weight loss progressed to 16.9%. Closed clamshells decreased %weight loss (5.5%) compared to open (18.1%). Visual ratings of yellowing/nutrient deficiency, relative greenness, wilt/head looseness, and salability decreased through storage. Lettuce stored in closed clamshells decreased %weight loss by 12% and delayed wilt/head looseness by 11 days. Similarly, lettuce stored in closed clamshells with roots were salable until 18 days in storage, while open clamshells were no longer salable after 7 days. Short root length (~4 cm) may be the dominant factor for the lack of significance as previous research suggested harvesting “living lettuce” with 9 cm roots increased storage and quality. Color data differed, and lettuce stored in closed clamshells with roots had more intense red color a* (-3.7 vs. -2.7), blue color b* (12.6 vs 10.1), and were purer in color c* (13.3 vs. 10.5) compared to open clamshells with roots. No differences were seen in total anthocyanin (mg/L), total chlorophyll (g/g) or total carotenoid (g/g) content in clamshell or root treatment (p > 0.05). Through 14 days of storage, total anthocyanins degraded by 7.55 mg/L (Day 0 = 10.78 vs. Day 14 = 3.22), while no loss of total chlorophyll (9204.84 g/g) or total carotenoids (1947.25 g/g) were seen. Anthocyanins are water soluble pigments and with increased weight/water loss, anthocyanins solubilize leading to degradation. Chlorophylls and carotenoids were not lost, potentially due to low enzyme activity of chlorophyllase. This experiment indicates consumers should eat lettuce within 7-10 days of harvest for highest nutritional and postharvest quality.
Speakers
MT

Marlee Trandel-Hayse

Assistant Professor of Postharvest Physiology, Auburn University
High nutritional quality, good texture and long shelf-life are critical for consumer acceptance of fruit and vegetable crops. As the assistant professor of Postharvest Physiology at Auburn University, my research addresses the impact of preharvest systems on postharvest quality. I... Read More →
Co-authors
CR

Camila Rodrigues

Auburn Univeristy
NA
CB

Caroline Blanchard

Auburn University
DW

Daniel Wells

Auburn University
NA
MH

MD Hasibur Rahman

Auburn University
NA
TR

Tanzeel Rehman

Auburn University
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
Nautilus

10:45am HST

VSF 2 - Genome Database for Vaccinium: Genomics Data and Tools to Facilitate Research
Wednesday September 25, 2024 10:45am - 11:00am HST
The Genome Database for Vaccinium (GDV, www.vaccinium.org) is a community database resource for Vaccinium researchers and breeders. The database contains genomics data for blueberry, cranberry, bilberry, and lingonberry that are integrated with other types of data such as genetic maps, markers, and QTL/GWAS. The genomics data is accessible via a plethora of search interfaces and tools. GDV has over 40 genomes and allows users to view the genomes in JBrowse, query sequences against the genomes in BLAST and view genome synteny via the Synteny Viewer tool. Highly utilized genomes in JBrowse contain tracks of aligned markers, GWAS, and QTL. Standard GDV analyses on the genomes include synteny analysis and functional annotation of predicted genes with InterPro protein domains and GO terms as well as homology to known proteins. The genes and mRNAs of each genome, along with the functional annotations and orthologs/paralogs, are searchable on GDV. Representative genomes are available in the PathwayCyc tool which displays metabolic pathways and allows for transcriptomics or metabolomics data overlays. GDV also has the genomes and structural pangenomes from the Vaccinium Pangenome Project, a product of VacCAP. Expression datasets that are mapped to genomes are also available to explore using the Expression Heatmap tool. Also available in GDV is the Breeding Information Management System (BIMS) that allows breeders to manage and analyze the phenotypic and genotypic data and provides public access to GRIN phenotype data. This presentation will showcase how to access these genomics data through various tools.
Speakers
avatar for Jodi Humann

Jodi Humann

Research Associate, Washington State University
Co-authors
CH

Chun Huai Cheng

Washington State University
NA
DM

Dorrie Main

Washington State University
KB

Katheryn Buble

Washington State University
NA
MI

Massimo Iorizzo

North Carolina State University
NA
PZ

Ping Zheng

Washington State University
NA
SJ

Sook Jung

Washington State University
NA
TL

Taein Lee

Washington State University
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
Kahili

10:45am HST

WUM 1 - Physiological Thresholds Provide Targets for Climate-Resilient Irrigation Management in Hazelnut
Wednesday September 25, 2024 10:45am - 11:00am HST
The rapidly changing climate is creating challenges for the selection and management of woody perennial crops. For North American (NA) cultivars of hazelnut (Corylus avellana), there is insufficient information on water stress management to maintain physiological performance and optimize productivity under limited soil water availability. Current plantings of NA hazelnuts are predominantly comprised of cultivars resistant to biotic stress (e.g., Eastern Filbert Blight) such as ‘Jefferson’ and ‘Yamhill’ cultivars, but their responses to abiotic stressors exacerbated by climate change is unknown. Our research objectives were to: 1. identify cultivar-specific physiological thresholds in response to water stress such as negligible leaf gas exchange (i.e., stomatal closure) and onset of leaf wilting (i.e., cell turgor loss) for phenotyping in greenhouse conditions; and 2. relate vapor pressure deficit to plant water status in order to generate a water-potential baseline capable of differentiating between atmospheric and soil moisture impacts on water stress in field conditions. Using the water potential (Ψ) curve (WPC) method, stomatal closure was initiated at less negative Ψ in ‘Jefferson’ (-0.85 MPa) compared to ‘Yamhill’ (-1.1 MPa). Similarly, turgor loss was found to occur at less negative Ψ in ‘Jefferson’ (-1.26 MPa) compared to ‘Yamhill’ (-1.48 MPa). These cultivar-specific differences were confirmed with direct measurements of stomatal conductance using a porometer and an evaluation of turgor loss point using the pressure-volume curve method. In the field, we established a water potential baseline to distinguish between the effects of soil moisture and vapor pressure deficit on Ψ. Our field results found a deviation from baseline of -1.0 MPa resulted in stomatal closure in Yamhill, which was consistent with our prediction from the WPC. ‘Yamhill’ trees that had Ψ on average -0.68 MPa below baseline over the growing season were also observed to have 34% smaller nuts, 46% higher shell-to-kernel ratio, and an estimated 50% of total in-shell yield. Upcoming research will seek to replicate results experimentally with both cultivars. In summary, our results indicate that the WPC is a valid tool for physiological phenotyping and preliminary results suggest that thresholds from the WPC provide viable cultivar-specific targets for improving irrigation management in hazelnuts. These results highlight methods to help determine sustainable irrigation management targets that can help conserve water resources strained by climate change while also maintaining plant productivity.
Speakers
SB

Steven Bristow (He/Him)

University of British Columbia
NA
Co-authors
TK

Thorsten Knipfer

University of British Columbia
NA
Wednesday September 25, 2024 10:45am - 11:00am HST
South Pacific 4

11:00am HST

CHMG 1 - The gARTening Program: Fostering Community Engagement through Innovative Education
Wednesday September 25, 2024 11:00am - 11:15am HST
Orange County, Florida, an urban county with a boasting a population of 1.4 million residents, faces a distinctive demographic trend with a homeowner rate of 56%, notably below the national average of 64%. This indicates a higher proportion of renters and apartment dwellers within our community. In order to expand the reach of our horticultural efforts beyond the limitations of traditional homeownership and include all residents, our Master Gardener Volunteer Program developed the Garden Art (gARTening) program, aimed to appeal to a wider audience. Beyond mere attraction of new attendees, our focus was to increase: office foot traffic, awareness of UF/IFAS Extension Services, and create a unique hands-on program that maintained affordability while generating revenue. We developed "The gARTening Program," featuring unique garden-related art projects, to achieve our objectives. Classes ranged from 1-2 hours and $5-35, with topics such as terrariums, kokedamas, pressed flower art, and more. Collaborating with Master Gardener Volunteers (MGVs), we created educational materials such as PowerPoints, handouts, and economical shopping lists. Our diverse approach attracted a broad audience, including young families, mother-daughter pairs, couples, and individuals, fostering inclusivity and engagement. The outcomes of the gARTening Program exceeded expectations: • Revenue generated in one year: $3200 • 47% of participants were new to UF/IFAS Extension and had never utilized our services before. • 70% joined due to the unique hands-on experience. • 95% indicated they gained knowledge of UF/IFAS Extension services as a result of attending the workshop. • Additionally, participants showed continued engagement, with many signing up for additional classes, volunteering with 4-H or becoming an MGV, and promoting our services to others. The gARTening Program not only met, but surpassed its objectives, illustrating its efficacy in community engagement and revenue generation. By offering unique experiences, we heightened awareness of UF/IFAS Extension Services, attracting new participants and fostering long-term engagement. The program's success underscores the potential for innovative education methods to address funding challenges while advancing community outreach and awareness. This model holds broader implications for enhancing community well-being and supporting sustainable organizational growth.
Speakers
avatar for Clarissa Chairez

Clarissa Chairez

Extension Faculty, UF/IFAS Extension Orange County
Wednesday September 25, 2024 11:00am - 11:15am HST
South Pacific 2

11:00am HST

HSMP 1 - Brewing Conditions and UV treatment affect Shelf Life of Cold-brew US-grown Tea
Wednesday September 25, 2024 11:00am - 11:15am HST
Tea, Camellia sinensis, is grown around the world under diverse geographic and climatic conditions and can be cultivated as a specialty crop in the U.S. U.S. specialty tea growers cater to the high-quality specialty tea niche market, and innovations in mechanization and novel products increase profitability. The objective of this study was to develop a cold brew methodology that would maximize the flavor characteristics and shelf life of cold brew black teas to facilitate the development of new products. 'Black Magnolia' from the Great Mississippi Tea Co. (Brookhaven, MS) was used to determine combinations of cold brew conditions affecting taste and health-promoting compositions (polyphenol and caffeine), including selected combinations of tea-to-water ratio (1, 2, and 3g of tea per cup of water), temperature (40, 45, 50, 55, and 60°F), brewing time (6, 8, 10, 12, and 14 hours), and particle size (whole-leaf, coarse, and fine). Selected conditions were then used in a UV light experiment to compare shelf life (microbial growth at 2, 4, and 6 days after brewing) using hot water-brewed tea as a control. Results indicate that, for this specific black tea, 2g per cup at higher temperatures of 55 to 60°F resulted in comparable polyphenol contents to hot water brew, but lower caffeine concentrations. However, compared to lower temperatures, teas made at this range of temperatures resulted in a higher number of yeast and mold by day 4. Brewing at 45°F for 14 hours resulted in comparable polyphenol contents as hot water brew and was described with more positive words compared to a shorter brewing time during sensory surveys conducted on campus with over 100 students. Initial testing of UV light treatments for 0, 0.5, 1.0, and 2.0 hours of duration before cold brew indicated that UV light is insignificant in reducing microbial growth. Further research is needed to improve the UV treatment or use other methods to extend the shelf life of cold brew tea. The best brewing conditions obtained from this study could be of guidance for future large-scale consumer sensory evaluations that will compare the flavor of four U.S.-grown black teas to imported specialty teas and their health-benefiting compounds. This next study will provide essential and important information for U.S. tea growers and consumers on how U.S.-grown tea performs in comparison with internationally known black teas and potential enhancements to maximize the health benefits and popularity of U.S.-grown specialty tea.
Speakers
YC

Yan Chen

LSU AgCenter
Co-authors
ZX

Zhimin Xu

Louisiana State University School of Nutrition and Food Sciences
NA
Wednesday September 25, 2024 11:00am - 11:15am HST
South Pacific 1

11:00am HST

O/LT 1 - Effects of Different Pruning Regimes on Growth Reallocation and Carbon Storage in Buxus microphylla var. japonica ‘Winter Gem’
Wednesday September 25, 2024 11:00am - 11:15am HST
Hedge shaping and size maintenance is often accomplished with electric or gas-powered shears due to a lower cost compared to hand pruning. Shearing plants arbitrarily removes the apical growing points from external portions of the shrub to achieve a desired shape and size of the plant and often results in poor quality cuts, leaving ragged ends of woody tissues or leaves. Contrarily, hand pruning makes strategic, ‘clean’ cuts often back to lateral branches to achieve these goals. Use of plant growth regulators like paclobutrazol (PBZ) can reduce the frequency of pruning and could be a useful component of a hedge management program. The purpose of this study was to investigate the effects of shearing, hand pruning, and/or PBZ application on regrowth of foliage and non-structural carbohydrates (NSCs) of ‘Winter Gem’ boxwood over time. Fifteen shrubs each per pruning type x frequency combination were pruned with bypass hand pruners (hand pruned) or gas-powered shears (sheared) in 2021, 2022, and 2023 once or twice per growing season. In addition, another 15 shrubs each were sheared once followed by an immediate application of a foliar PBZ (i.e. Trimtect®) in accordance with the label using an electric backpack or left as non-pruned controls. In 2021 and 2022, shrubs were pruned by removing 15 percent of the overall height and 20% of the overall widths in two perpendicular directions of each shrub. In 2023, pruned shrubs were cut back to the previous season’s overall height and width. Regrowth was measured by weighing the fresh biomass removed at each pruning and NSCs were measured from ten woody twigs from the exterior of each shrub using the phenol-sulfuric acid quantification method. Two and three years after pruning, shearing shrubs twice had significantly more biomass produced year over year compared to hand pruning, while PBZ treated shrubs had the least amount of regrowth. NSCs trended to be highest in shrubs that were hand pruned once or in PBZ treated shrubs, while the least in shrubs that were sheared twice. PBZ-treated shrubs had tighter clusters of internodes resulting in approximately 30% reduction in stem elongation compared to controls. The differences in growth dynamics and carbon storage across these different pruning strategies can have different long- and short-term implications in managing boxwood hedges, which will be presented here.
Speakers
AL

Andrew Loyd

Plant Pathologist, Bartlett Tree Research Laboratories
Co-authors
CL

Caitlin Littlejohn

Bartlett Tree Research Laboratories
NA
CR

Chad Rigsby

Bartlett Tree Research Laboratories/Morton Arboretum
NA
Wednesday September 25, 2024 11:00am - 11:15am HST
Coral 1

11:00am HST

PH 2 - Comparing the Postharvest Phytonutrient Content of Red and Green Butterhead Lettuce Cultivars
Wednesday September 25, 2024 11:00am - 11:15am HST
Lettuce is a popular leafy vegetable that can play an important role in human nutrition and diets with regular consumption. Lettuce cultivars can vary considerably in their postharvest nutritional composition. It is critically important to determine which lettuce cultivars have the highest nutritional quality to allow growers to select those that are best for their market. The objectives of this experiment were twofold, to determine differences in the phytonutrient content of two butterhead lettuce cultivars, ‘Nancy’ (green butterhead) and ‘Skyphos’ (red butterhead), and if leaf location within the head (lower or mid leaves) differs in nutritional composition. The experiment was conducted in the spring of 2023 in a high tunnel, and setup as a completely randomized design with 4 replications. At horticultural maturity (40 days after germination), the lower and mid leaves were harvested. Lettuce samples were frozen and shipped to Auburn University where samples were assayed for total chlorophyll, carotenoids, anthocyanins, flavonoids, phenolics and antioxidant activity via UV VIS spectrophotometry. Carotenoids of violaxanthin, neoxanthin, lutein and -carotene were quantitated by UPLC/MS. The interaction of leaf location*cultivar (P < 0.05) indicated that the lower leaves of ‘Skyphos’ lettuce had the highest total anthocyanin content at 2.94 mg/L compared to ‘Nancy’ at 0.05 mg/L, respectively. No other differences (P > 0.05) were detected between the cultivars. Sample location differed in total carotenoids (mg/g) and total chlorophyll (mg/g) with the lower leaves having the highest nutritional composition at 1380.18 and 5973.58 mg/g, respectively compared to the mid leaves (509.02 and 1684.42 mg/g, respectively). Chlorophyll a (4399.67 mg/g) and b (1573.90 mg/g) was also highest in the lower leaves of both cultivars compared to the mid leaves. Our results indicate that both butterhead lettuce cultivar and leaf location strongly impacts human health. ‘Skyphos’, a red butterhead lettuce, had the high highest total anthocyanin content in the lower leaves. Anthocyanins are critical phytochemicals known for many health promoting properties such as free radical scavenging, and anti-cancer and anti-diabetic properties. This experiment also indicated the lower leaves of both cultivars had the highest amount of total chlorophyll and carotenoids. The lower leaves of red butterhead lettuces, such as ‘Skyphos’, should be eaten to obtain the highest nutrition for their diet.
Speakers
MT

Marlee Trandel-Hayse

Assistant Professor of Postharvest Physiology, Auburn University
High nutritional quality, good texture and long shelf-life are critical for consumer acceptance of fruit and vegetable crops. As the assistant professor of Postharvest Physiology at Auburn University, my research addresses the impact of preharvest systems on postharvest quality. I... Read More →
Co-authors
AW

Alan Walters

Southern Illinois University
Wednesday September 25, 2024 11:00am - 11:15am HST
Nautilus

11:00am HST

VSF 2 - Use of glycine betaine and kelp extract mitigates heat stress in red raspberry (Rubus idaeus)
Wednesday September 25, 2024 11:00am - 11:15am HST
Heat stress poses a significant threat to global food production and security by disrupting plant physiological and biochemical processes. Global simulation models predict a 4 to 5°C increase in atmospheric temperatures by the year 2100, as well as increases in the frequency of extreme heat events. This has necessitated preemptive measures to enhance the resiliency of horticultural crop production. Biostimulants, a class of agricultural products, show great promise in mitigating heat stress effects by enhancing physiological and biochemical stress tolerance. However, limited research exists on the efficacy of commercial biostimulant products in improving heat stress tolerance in horticultural crops. This study evaluated the impacts of three exogenously applied commercial biostimulants representing a range of active ingredients and included FRUIT ARMORTM, Optysil®, and KelpXpressTM [active ingredients glycine betaine, silicone, and kelp (Ascophyllum nodosum) extract, respectively], plus a water control, on physiological, biochemical, and growth parameters in different raspberry genotypes exposed to continuous heat stress (Tmax ≥ 35°C/day) in a glasshouse. Over a 28-day period, the biostimulants and the water control were applied weekly to three raspberry genotypes (‘Meeker’, WSU 2188, and ORUS 4715-2). The results indicated that ‘Meeker’ consistently maintained high chlorophyll fluorescence (Fv/Fm) and photosynthesis under control and biostimulant treatments. In contrast, WSU 2188 and ORUS 4715-2 exhibited increased Fv/Fm and photosynthesis when treated with FRUIT ARMORTM. Additionally, KelpXpressTM application improved Fv/Fm in WSU 2188. ‘Meeker’ and WSU 2188 treated with FRUIT ARMORTM and KelpXpressTM accumulated more anthocyanins and had greater shoot and total biomass compared to ORUS 4715-2. These findings underscore genotype-specific and biostimulant-dependent responses to heat stress mitigation. The superior physiological performance by ‘Meeker’ under both control conditions and biostimulant treatments indicates heat tolerance in the genotype. Furthermore, higher anthocyanins accumulation, improved Fv/Fm, enhanced gas exchange, and greater total biomass of WSU 2188, as well as improved Fv/Fm of ORUS 4715-2, suggests that application of the biostimulants contributed to enhanced repair and maintenance of photosystem II (PSII) structural integrity, improved photosynthetic performance, and increased antioxidative capabilities, which may have contributed to higher total biomass of raspberry treated with FRUIT ARMORTM relative to the untreated control. In summary, the positive impacts on physiological, biochemical, and growth parameters support the potential role of biostimulants in enhancing thermotolerance in raspberries and other horticultural crops exposed to heat stress.
Speakers
MG

Makonya Givemore Munashe

Washington State University
Co-authors
Wednesday September 25, 2024 11:00am - 11:15am HST
Kahili

11:00am HST

WUM 1 - Determination of Crop Coefficient and its Inter-annual Variability in Pecan Orchard in Georgia
Wednesday September 25, 2024 11:00am - 11:15am HST
Pecans have high economic importance in the US. Nonetheless, as one of the top pecan producers, there is little research on water use of pecan trees in the Southeast of the US. The water status of the tree impacts the yield, mostly during the kernel filling period (August and September). The knowledge gap of pecan water requirements stems largely from the Southwest. There, pecan tree needs in the hot and arid climate of the Southwest contrast sharply with those of the long, hot and humid Southeastern climate. Furthermore, the Southwest management practices use flood irrigation in contrast with most Georgia orchards which use micro-irrigation. This paper reports on the development of a crop coefficient specifically addressing the pecan tree needs in the Southeastern US. This study uses an eddy-covariance system and micro-lysimeter to determine the actual evapotranspiration of pecans. The potential evapotranspiration is determined using nearest local weather station data. This paper discusses the behavior of the crop coefficient throughout the different physiological stages of the tree from budbreak to harvest. Results of the crop coefficient obtained throughout the season differs from the Southwest, where the actual evapotranspiration during the growing season is significantly higher than the one observed in the Southeast. The daily and monthly crop coefficient throughout the growing period from 2019 through 2023 respectively are discussed. The year-to-year variability is also discussed. These results should support pecan growers and researchers alike to more tailored irrigation schedule in Southeast pecan orchards.
Speakers
KP

Kriti Poudel

University of Georgia
Co-authors
GZ

Gengsheng Zhang

The University of Georgia
NA
LW

Lenny Wells

University of Georgia
NA
ML

Monique Leclerc

University of Georgia
NA
Wednesday September 25, 2024 11:00am - 11:15am HST
South Pacific 4

11:15am HST

CHMG 1 - Welcome Home to Gardening in Tennessee: Reaching New Audiences with New Collaborative Outreach Models
Wednesday September 25, 2024 11:15am - 11:30am HST
New residents in the state along with new gardeners are an increasingly large Extension audience. As our Extension horticulture team discussed the challenges in individually addressing these questions and meeting the needs of these new stakeholders, we realized new models and resources were needed. While Extension has a great array of publications and resources on lawns, landscapes and gardens, there wasn’t a publication that provided a good entry point for those new to the region or gardening. So, we set out to develop a ‘gateway publication’ to provide a general overview and connect folks to further resources without being overwhelming. A magazine format with easy to digest 2-page spreads on the most common areas of gardening was developed titled “Welcome Home: Gardening in Tennessee.” To extend the reach and impact of this new resource and engage Extension agents and stakeholders across the state, our horticulture team developed a new outreach program that paired live, distance teaching with local hands-on labs and activities. In October of 2023, we had a 5-session workshop series where new residents could come to their local office for an hour of teaching from our best horticulture content folks and then take part in a hands-on teaching demonstration with their local agriculture Extension agent. Nearly 300 participants in 32 counties took part in the series. Evaluation data revealed that over 70% of attendees had attended no or very few prior Extension programs. With a fee of only $30-50 locally, attendees reported a value of over $950 received from information delivered in the class. This presentation will focus on the novel delivery model and evaluation data along with perspectives on opportunities and challenges in reaching these new Extension audiences.
Speakers
NB

Natalie Bumgarner

Assistant Professor, University of Tennessee Knoxville
Co-authors
AL

Andrea Ludwig

University of Tennessee
NA
AD

Anna Duncan

University of Tennessee
NA
CS

Celeste Scott

University of Tennessee
NA
GU

Gregg Upchurch

University of Tennessee
NA
HT

Haley Treadway

University of Tennessee
NA
JS

Justin Stefanski

University of Tennessee
NA
LR

Lee Rumble

University of Tennessee
NA
MR

Melody Rose

University of Tennessee
NA
MM

Mitchell Mote

University of Tennessee
NA
SW

Seth Whitehouse

University of Tennessee
NA
TR

Taylor Reeder

University of Tennessee
NA
VS

Virginia Sykes

University of Tennessee
Wednesday September 25, 2024 11:15am - 11:30am HST
South Pacific 2

11:15am HST

HSMP 1 - Withering Duration and Drying Temperature Significantly Affect Postharvest Quality of Kratom (Mitragyna speciosa)
Wednesday September 25, 2024 11:15am - 11:30am HST
Kratom (Mitragyna speciosa) is an ethnobotanical plant with high medicinal value that has been historically utilized in Southeast Asia as a traditional remedy for fatigue mitigation and productivity enhancement. Recently, it has attracted widespread attention, particularly in North America and Europe, for its potential for pain management and alleviating opioid withdrawal symptoms and has become an important source for future drug development. Postharvest processing represents a key step in the kratom farm-to-pharm chain where products undergo chemical modifications before reaching consumers. In this study, we investigated how different withering durations, drying temperatures, and lighting conditions could affect kratom postharvest product qualities. Leaves were harvested from cultivar H and mixed well before randomly assigned to one of four withering durations (0, 12, 24, and 72 h) at 25 ℃ in the dark and subsequently one of five drying temperatures (-40, 25, 40, 60, and 80 ℃). Additionally, leaves were dried at 25 ℃ under either light or dark. Overall, withering at 25 ℃ significantly increased mitragynine concentration. Compared to 0 h withering, a 12 h withering followed by drying at -40, 25, 40, or 60 ℃ increased mitragynine concentrations by 117%, 17-123%, 16-61%, and 43-103%, respectively. The 12 h withering increased the concentration of speciogynine and paynantheine by 27-28% and 35-67%, respectively, when leaves were dried below 40 ℃. In contrast, speciociliatine levels initially decreased during 12 or 24 h withering but subsequently elevated after the withering duration increased to 72 h. Drying temperatures and light exposure generally had little effect on the biosynthesis of most of the alkaloids. However, an alternation in kratom powder color was noticed for those with a short withering duration and subsequently a high drying temperature. Other minor alkaloids including corynoxine A, corynoxine B, speciofoline, isospeciofoline, mitraphylline, and ajmalicine were below the lower limit of quantifications. Taken together, our study shows that withering and subsequent drying temperatures have significant effects on the color and content of bioactive compounds of kratom, and further research on optimizing kratom postharvest processing is needed.
Speakers
MZ

Mengzi Zhang

Biological Scientist, University of Florida
Co-authors
BP

Brian Pearson

Oregon State University
NA
JC

Jianjun Chen

University of Florida
NA
Wednesday September 25, 2024 11:15am - 11:30am HST
South Pacific 1

11:15am HST

O/LT 1 - Establishment, Growth, and Physiology of Container-Grown Trees Following Root Remediation at Planting
Wednesday September 25, 2024 11:15am - 11:30am HST
Root defects, especially circling roots, are a major concern when planting container-grown trees. In this study, we compared survival, crown dieback, and plant water potential of four common landscape tree species (Carpinus caroliniana, Liriodendron tulipifera, Ostrya virginiana, and Platanus × acerifolia) in response to root modifications (control, bare-root washing, shaving, and vertical slicing) prior to planting. P. × acerifolia trees were robust with respect to root correction treatments and had 100% survival except for some mortality following vertical root-ball slicing. In contrast, C. caroliniana, L. tulipifera, and O. virginiana trees had significant mortality and crown dieback in response to bare-root washing. The responses of these species to bare-root washing reflected extreme plant moisture stress immediately after planting. These three species are also considered ‘difficult to transplant’ as bare-root nursery stock. Our results suggest that trees that are generally known to be difficult to transplant as bare-root stock are poor candidates for extreme root disturbance such as bare-rooting when grown as container trees. In contrast, shaving and vertical slicing had little or no adverse effects on tree survival, crown dieback, or plant water potential.
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
Wednesday September 25, 2024 11:15am - 11:30am HST
Coral 1

11:15am HST

PH 2 - Production System Alters Phytonutrient Content of ‘Skyphos’ Butterhead Lettuce
Wednesday September 25, 2024 11:15am - 11:30am HST
Lettuce is one of the most widely consumed vegetables in the world and can provide various health benefits to consumers. The type of production system, such as high tunnel, green roof or open field environments, can influence the nutritional composition of lettuce. To determine the extent of phytonutrient content change, ‘Skyphos’ lettuce was grown in these various production environments to compare phytonutrient content at harvest. The production experiment was conducted at Southern Illinois University-Carbondale and set up with three treatment locations and four replications. Two production systems used organic fertility practices (high tunnel and green roof), while the field production system used conventional fertilizers. At horticultural maturity (40 days after germination), the lower and mid leaves were harvested to determine phytonutrient content. Lettuce samples were frozen and shipped to Auburn University where samples were assayed for total chlorophyll, carotenoids, anthocyanins, flavonoids, phenolics and antioxidant activity via UV VIS spectrophotometry. Carotenoids of violaxanthin, neoxanthin, lutein and b-carotene were quantitated by UPLC/MS. The interaction of production system*leaf sampling location differed (P < 0.05) in total anthocyanins, total carotenoids and total chlorophyll. Total anthocyanins were highest in the lower leaves of ‘Skyphos’ lettuce cultivated on the green roof at 3.57 mg/L. In comparison, total carotenoids, total chlorophyll and chlorophyll a were highest in the lower leaves of lettuce cultivated in the high tunnel at 1316.48, 6093.45 and 4401. 97 mg/g, respectively. Cultivating lettuce in the high tunnel provided the highest Chlorophyll b content (1638.37 mg/g) compared to the field (888.80 mg/g) or green roof (893.43 mg/g). The phytonutrient content of lettuce can be influenced by location, temperature, soil type, humidity and UV radiation. The green roof increased total anthocyanin content which may be due to the higher temperatures and irradiation levels on compared to the field or high tunnel. Total Chlorophyll and carotenoid content was increased in the high tunnel likely due to increases of UV-A and UV-B exposure from the poly film leading to an increase in photosystem response. This experiment suggests the specific phytonutrient content (e.g., anthocyanin or carotenoids) in a red lettuce like ‘Skyphos’ differs based on production system and can be used in market development to increase consumer consumption by highlighting the specific phytonutrients highest in each production system.
Speakers
MT

Marlee Trandel-Hayse

Assistant Professor of Postharvest Physiology, Auburn University
High nutritional quality, good texture and long shelf-life are critical for consumer acceptance of fruit and vegetable crops. As the assistant professor of Postharvest Physiology at Auburn University, my research addresses the impact of preharvest systems on postharvest quality. I... Read More →
Co-authors
AW

Alan Walters

Southern Illinois University
Wednesday September 25, 2024 11:15am - 11:30am HST
Nautilus

11:15am HST

UG - Evaluating the Feasibility of Lettuce Crop Cultivation with Reclaimed Water Utilizing GREENBOX Technology
Wednesday September 25, 2024 11:15am - 11:30am HST
The development of GREENBOX technology addresses the challenges posed by rapid population growth, which intensifies the demand for agricultural resources essential for cultivating and distributing fresh produce, including arable land, water, and nutrients, to both rural and urban areas. Utilizing principles of Controlled Environment Agriculture (CEA), GREENBOX technology optimizes growth conditions for leafy green crops by leveraging existing urban infrastructure and readily available commercial equipment. GREENBOX technology allows for precise control over environmental variables such as temperature, humidity, light intensity/spectrum, and nutrient delivery, thereby enhancing the growth performance of leafy greens. We were interested in assessing the feasibility of utilizing reclaimed water for crop production as preliminary experiments employing GREENBOX technology that employed a standard nutrient solution comprising a blend of 5-12-26 and 15-0-0 Calcium Nitrate for crop production. This study's primary objective was to conduct a comparative analysis of Lactuca sativa Rex Butterhead Lettuce production using the standard nutrient solution as the control (Treatment 1), and Reclaimed water or treated wastewater supplemented with additional nutrients (Treatment 2). The assessment focused on measuring crop biomass and productivity and environmental conditions associated with each nutrient solution to identify any significant differences. Biomass parameters, including wet weight, dry weight, leaf area, leaf count, and chlorophyll concentration, were measured alongside derived data such as Leaf Area Index (LAI), Specific Leaf Area (SLA), and biomass productivity. Statistical analysis of the biomass data was conducted to discern differences in biomass parameters between crop growth using both hydroponic solutions. Both treatments yielded Rex Butterhead lettuce well above the anticipated harvest weight of 180g, indicating their suitability for crop production in urban warehouse settings. The findings of this experiment contribute valuable insights into the feasibility of utilizing various types of wastewater for hydroponic crop growth. Future experiments employing GREENBOX technology may utilize these findings to enhance the efficiency, productivity, and sustainability of GREENBOX units. This study has impactful implications for sustainability, as it offers a potential solution to mitigate water scarcity and promote efficient resource utilization in agricultural practices. Keywords: CEA, Hydroponics, lettuce, Reclaimed Wastewater, urban agriculture
Speakers
MG

Mya Griffith

Florida Gulf Coast University
Co-authors
AS

Ankit Singh

University of Maine
NA
BR

Barry Rosen

Florida Gulf Coast University
NA
GP

Galen Papkov

Florida Gulf Coast University
NA
GB

George Buss

Florida Gulf Coast University
JG

John Griffis

Florida Gulf Coast University
NA
KJ

Kathryn Jackson

Independent Researcher
NA
PC

Paige Carroll

Florida Gulf Coast University
NA
SB

Sarah Bauer

Mercer University
NA
XY

Xiusheng Yang

University of Connecticut
NA
Wednesday September 25, 2024 11:15am - 11:30am HST
Lehua Suite

11:15am HST

WUM 1 - Assessing Water Status in Citrus Plants Using Thermal Imaging in Greenhouses
Wednesday September 25, 2024 11:15am - 11:30am HST
Thermal cameras can easily determine plant canopy temperature, and the resulting data can be used for irrigation scheduling in addition to other water management tools. This study aimed to develop a method to use thermal imaging for canopy temperature measurements in one-year-old citrus plants to assess citrus water status. We evaluated the influence of five water levels (25%, 50%, 75%, 100%, and 125%) based on the crop evapotranspiration replacement of two citrus species [‘Red Ruby’ grapefruit (Citrus paradisi) and ‘Valencia’ sweet orange (Citrus sinensis)] for 48 days in a greenhouse. To determine the irrigation requirements for the treatment 100%, we estimated the water loss from pots by calculating the difference in soil moisture between the day before and the day of the measurement. We irrigated the pots when the soil moisture was close to the maximum allowable water depletion, keeping the soil moisture between the field capacity and the maximum allowable depletion. A portable thermal camera was used to take images that were later analyzed using open-source software. We determined the canopy temperature, leaf photosynthesis and transpiration, and plant biomass. A positive relationship between the amount of water applied and the temperature response of plants exposed to different water levels was observed. Grapefruit and sweet orange plants that received less water presented water restrictions and reached 6 °C higher canopy temperatures than the air. The thermal images easily identified water-stressed plants. This study allowed quick measuring of the canopy temperature using readily available equipment and can be used as a tool to assess water status in citrus plants in greenhouses. An automated routine to process the thermal images in real-time and remove the background weeds to determine the canopy temperature can potentially allow using it for irrigation management.
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
RS

Rhuanito Soranz Ferrarezi

University of Georgia
NA
Wednesday September 25, 2024 11:15am - 11:30am HST
South Pacific 4

11:30am HST

CHMG 1 - Enhancing Backyard Fruiting Cultivation Efficacy Through Florida-Friendly Landscaping™ Techniques for Homeowners
Wednesday September 25, 2024 11:30am - 11:45am HST
Florida's distinctive subtropical climate renders it a haven for the average backyard gardener. Yet, numerous homeowners grapple with challenges in cultivating dooryard fruits, often due to incorrect planting times or a dearth of expertise. Recognizing this, the University of Florida/Institute of Food & Agricultural Sciences (UF/IFAS) has introduced the Florida-Friendly Landscaping TM program, illuminating nine core principles. These guidelines equip homeowners with the necessary methods and techniques to optimize plant growth and development. As we continue to increase resident population daily from various parts of the world, educating homeowners on these principles, can significantly elevate their chances of realizing their cultivation aspirations.
To meet the persistent demand for edible landscapes, a series of enlightening workshops unfolded across Flagler, Putnam, and Volusia counties. These sessions honed in on sustainable management strategies tailored for cultivating delectable fruits like blackberries, mulberries, goji berries, and citrus varieties. Spanning two to three hours, participants delved into a comprehensive curriculum covering optimal planting and harvest timings, varietal nuances, cultivation methodologies, fertilizer selection, integrated pest management protocols, and the significance of hardiness zones. These workshops roamed through the tri-county region, shining a spotlight on local agricultural enterprises engaged in the production or promotion of sought-after backyard fruits.

This collaborative initiative not only bolstered our overarching educational goals but also catalyzed a surge in agrotourism intrigue. As each program reached its conclusion, attendees departed armed with two plants of their preference and a wealth of resources, poised to lay down the groundwork for thriving cultivation endeavors.
22 Program participants indicated the following as measured via post evaluation survey:
Participants indicated a 73% (n=16) implementation plan for Florida-Friendly Landscaping TM (FFL) principle of "Right Plant Right Place” as they continue in their gardening endeavors.
Participants indicated an 82% (n=18) knowledge gain on cultivar selection, soil testing, and importance of fertilization.
64% (n=14) of program participants shared a plan to continue backyard fruit production using the information disseminated during this program.
Speakers
BC

Brittany Council-Morton

UF/IFAS Volusia County Extension
Co-authors
CJ

Claude Judy Jean

University of Florida
Wednesday September 25, 2024 11:30am - 11:45am HST
South Pacific 2
  Oral presentation (Individual talk), Consumer Horticulture and Master Gardeners
  • SUBJECT Consumer Hort and Master Gardeners
  • Agricultural Sciences (UF/IFAS) 16) implementation plan for Florida-Friendly Landscaping TM (FFL) principle of "Right Plant Right Place” as they continue in their gardening endeavors. Participants indicated an 82% (n=18) knowledge gain on cultivar selection, soil testing, and importance of fertilization. 64% (n=14) of program participants shared a plan to continue backyard fruit production using the information disseminated during this program.

11:30am HST

HSMP 1 - Consumer preference of saffron uses in baked goods and dishes
Wednesday September 25, 2024 11:30am - 11:45am HST
Saffron (Crocus sativus L.) is a perennial cormous crop, possibly originated in Iran, cultivated in the Mediterranean climate region, including Iran, Afghanistan, Spain, Greece, and Kashmir. Due to the labor-intensive harvesting and processing involved, saffron is known as the most expensive spice. Its production has seen a revival in certain regions of the U.S., and Kentucky State University has been evaluating its potential as a niche crop for small and limited-resource farmers in Kentucky since 2019. One objective of this portion of the study was to evaluate consumer preferences for saffron used in various recipes. Two sets of sensory evaluation were conducted with saffron containing cheesecakes and baked goods (i.e., pound cake and short bread). There were three types of cheesecakes (vanilla, lemon, and persimmon) with and without saffron flakes. Overall, test subjects preferred cheesecakes without saffron, with the lemon cheesecake without saffron being the most popular combination. In contrast, participants showed preference for saffron containing recipes over the ones without saffron for the sensory evaluation of both baked goods, especially shortbread. A preliminary test for taste testing was conducted with pound cake to determine the optimal content of saffron. There were three levels of saffron, which was first dissolved in water, and then added to mixture, for both pound cake and shortbread (0, 0.5 and 1.0 tbsp/recipe). The current findings suggest that consumers are favorable of baked goods when saffron is compatible and used in the correct amount and possibly in the correct form.
Speakers
HK

Hideka Kobayashi

Kentucky State University
Co-authors
SC

Sheri Crabtree

Kentucky State University
Wednesday September 25, 2024 11:30am - 11:45am HST
South Pacific 1

11:30am HST

O/LT 1 - The Effects of Mulch Color and Depth on Soil Temperature and Light Transmission
Wednesday September 25, 2024 11:30am - 11:45am HST
Mulching is a common task in the landscape industry, with materials selected to provide environmental benefits (i.e. moderating soil conditions, limiting weed growth) and aesthetic value, with colored mulches often employed to add an artistic element to landscapes. Questions arise over possible effects that mulch color may have on soil temperatures, especially when using darker materials. This research investigated the effects of a commercially available shredded mulch (dyed black, brown, or red) on soil temperature and light transmission in model research plots. A plot at the Hammond Research Station was cleared, graded, and prepared with a typical bed mix comprised of pine bark and sand. A total of 21 sub-plots were prepared, where each sub-plot had a remote temperature sensor buried at the base of the bed mix (8 cm below surface), and a temperature and light sensor placed over top of the bed mix. Mulch was applied to depths of 5 cm or 10 cm directly over the top of the temperature and light sensors, with n=3 for our control (no mulch over the bed mix), red mulch (n=3 for depth of 5 cm and n=3 for depth of 10 cm), brown mulch (n=3 for depth of 5 cm and n=3 for depth of 10 cm), and black mulch (n=3 for depth of 5 cm and n=3 for depth of 10 cm). Soil temperature conditions (both within the mulch itself, and at the base of the bed mix) as well as light transmission through the mulch layer was recorded every 30 minutes throughout a spring and summer season at the Hammond Research Station. Blank (unmulched) plots naturally experienced the most light transmission and temperature extremes. Regardless of mulch color or depth, light transmission was substantially reduced (and often eliminated) equivalently between mulch treatments. Temperature was measured both within the surface mulch layer, and 8 cm below into the subsurface bedding mix. While subsurface temperatures were effectively equivalent between all mulched plots, surface temperatures exhibited substantial differences between mulch colors and depths. Thinner mulch layers experienced more extreme surface temperature fluctuations, with mulch color influencing peak temperatures. The results of this work suggest that different mulch colors and depths have a greater influence on temperature at the immediate surface, but far more muted differences in subsurface temperatures.
Speakers
DA

Damon Abdi

Louisiana State University Agricultural Center
Co-authors
AH

Ashley Hickman

Louisiana State University Agricultural Center Hammond Research Station
NA
JF

Jeb Fields

LSU AgCenter Hammond Research Station
Wednesday September 25, 2024 11:30am - 11:45am HST
Coral 1

11:30am HST

PH 2 - Improving Postharvest Storage and Late-Season Production of Caladium Tubers in Florida Through Chemical Treatments
Wednesday September 25, 2024 11:30am - 11:45am HST
Florida is home to the largest caladium production in the world, supplying essentially all the global caladium tuber demand. These plants are famous for their vibrant leaf colors and patterns and are asexually propagated through tubers. Following plant development, tubers are harvested and stored for a few months before being forced from March to September for potted plant production and direct landscape planting. During extended postharvest storage, caladium tubers risk severe weight loss, tissue decay, and Fusarium tuber rot. The current storage practices under ambient conditions with high temperatures and high relative humidity exacerbate weight loss and tuber rot. The challenges of long-term tuber storage make it difficult to produce pot caladium plants for winter holidays, including Thanksgiving, Christmas, and New Year. These challenges also affect the commercialization of tubers in the Southern Hemisphere during the summer. Opening these marketing opportunities can allow growers to extend and increase their production. Additionally, identifying caladium tubers suitable for late-season production will give Florida growers a competitive advantage. To identify caladium varieties with long-term tuber storage potential and late-season production, 12 varieties were evaluated to target Thanksgiving and Valentine’s Day. No.1-sized tubers were potted in 5-inch containers and grown in a greenhouse. For each variety, 10 tubers were monitored for sprouting and leaf expansion and later evaluated for plant quality using a rating scale from 1 to 5. Potted tubers from all cultivars achieved suitable market quality standards when targeting Thanksgiving, with the higher ratings obtained by cultivars ‘Splash of Wine’, ‘Classic Pink’, and ‘Lemon Blush’. The higher number of leaves and height were obtained by cultivars ‘Classic Pink’, ‘Desert Sunset’, and ‘White Wonder’, and ‘Party Punch’, ‘Ballet Slipper’, and ‘Classic Pink’, respectively. For Valentine’s Day, despite sprouting decreasing, cultivars ‘Splash of Wine’, ‘Hot 2 Trot’, ‘Desert Sunset’, ‘Party Punch’, ‘Classic Pink’, ‘White Wonder’, and ‘Lemon Blush’ reached suitable market quality standards. Overall, the number of leaves and height decreased compared to plants targeting Thanksgiving, however, cultivars with a more desirable number of leaves were ‘Classic Pink’ and ‘Lemon Blush’ whereas cultivars with higher height were ‘Party Punch’ and ‘Ballet Slipper’. Identifying cultivars suitable for late-season production will allow growers to expand their commercialization window for major holidays and to supply tuber demand to the Southern Hemisphere.
Speakers
GC

Gasselle Cordova

University of Florida
Co-authors
ZD

Zhanao Deng

University of Florida
Wednesday September 25, 2024 11:30am - 11:45am HST
Nautilus

11:30am HST

UG - The Assessment of Different Growth Mediums for Plug Cultivation in a Controlled Environment
Wednesday September 25, 2024 11:30am - 11:45am HST
Plugs are crucial for starting crop production in greenhouses, soil, and controlled environment agriculture (CEA). Horticultural, vegetable, fruiting, and ornamental crops that utilize plugs for production have demonstrated better plant health, transplant establishment rate, and total yield. Many substances are capable of supporting plug growth, so the APS Laboratory for Sustainable Food at Florida Gulf Coast University investigated the quality of plugs prepared based on different commonly used growth mediums for plug production. We carried out the growth of Rex Butterhead Lettuce Latuca Sativa plugs with six different treatments: 1) Rockwool, 2) Oasis® Horticube, 3) Perlite 4) Coco Coir, 5) Phenolic Foam, and 6) Peat Pellets. The seeds were sowed in their respective growth medium and watered every day. The plugs were then cultivated for 15 days in a controlled environment until two leaves apart from the cotyledon had developed. After 15 days, we collected data which included wet weight (g), dry weight (g), leaf area (cm2), nitrogen content (mg/g), and chlorophyll concentration (mg/cm2). In addition, we derived data including the Leaf Area Index (LAI) and Specific Leaf Area (SLA, cm2/g). Descriptive statistics were used to describe the biomass data. Pairwise permanovas were conducted, followed by pairwise Wilcoxon tests to determine which treatments result in significant differences for each response variable. A permutation MANOVA revealed a significant treatment effect on plug preparation (p=0.001). All subsequent multilevel pairwise comparisons were significant, with the exception of phenolic foam vs perlite (p=0.294). Of all the treatments, we concluded that plugs grown in Peat Pellets produced the most viable plugs with the largest wet weight (g), dry weight (g), and total leaf area (cm2). Results from this study may inform growers about appropriate growth mediums for efficient plug production. Keywords: Controlled Environments, Growth Mediums, Lettuce, Plugs, Urban Agriculture
Speakers
avatar for George Buss

George Buss

Florida Gulf Coast University
Co-authors
AS

Ankit Singh

University of Maine
NA
GP

Galen Papkov

Florida Gulf Coast University
NA
JL

John L Griffis

Florida Gulf Coast University
NA
KJ

Kathryn Jackson

Independent Researcher
NA
MG

Mya Griffith

Florida Gulf Coast University
PC

Paige Carroll

Florida Gulf Coast University
NA
SB

Sarah Bauer

Mercer University
NA
XY

Xiusheng Yang

University of Connecticut
NA
Wednesday September 25, 2024 11:30am - 11:45am HST
Lehua Suite

11:30am HST

WUM 1 - The Impact of Irrigation Rates Based on Crop Water Requirement on Tree Growth and Water Relations in Commercial Citrus Groves
Wednesday September 25, 2024 11:30am - 11:45am HST
The growing demand for affordable and healthy food to feed the growing population necessitates multilayered strategies to meet food demand and supply features: excessive irrigation application to overcome the impact of erratic rainfall, which imposes pressure on groundwater withdrawals, adversely affecting crop failure and sustainability. The objective of the study was to determine the impact of varying irrigation levels on tree growth, leaf nutrient concentrations, and water relations at selected citrus tree densities. The experiment was carried out on Malabar fine sand (sandy, siliceous, hyperthermic Arenic Alaquods) in a commercial citrus grove near Immokalee, FL, USA from 2019 to 2022. Mature thirteen-year-old ‘Valencia’ (Citrus sinensis) citrus trees grafted on Carrizo (a hybrid of Washington Navel orange and Poncirus trifoliata) planted in tree densities of 360, 485, and US-897 (Citrus reticulata Blanco x Poncirus trifoliata (L.) Raf.) citrus rootstock with 920 trees ha-1. Significant water distribution and movement were detected along the soil profile in response to the irrigation rates with higher volumetric water content on the grower standard highest irrigation. As a result, significant fibrous root length densities (FRLD) and median lifespan were observed in the three-row and two-row experiments with the deficit (50%-crop evapotranspiration, ETc) and moderate (78%-ETc) as compared with the grower standard highest (100%-ETc) irrigation regimes, respectively. Stomata conductance and stem water potential ( manifested less tree water stress when trees received moderate irrigation in the low and moderate tree densities than the highest tree density. This significantly impacted the FRLD in the soil and leaf area index (LAI) above the ground tree growth. Moderate irrigation triggered FRLD and improved root survival probability and lifespan. Meanwhile, nutrient uptake from the soil significantly affected leaf nutrient concentration when trees received moderate irrigation than deficit or highest irrigation rates. As a result, irrigation management improved water relations, leaf nutrient concentration, and tree growth across the varying irrigation regimes.
Speakers
AA

Alisheikh Atta

University of Florida
Alisheikh Atta currently works at the Department of Soil, Water, and Ecosystem Science, University of Florida. Alisheikh does research on HLB-affected citrus nutrient and water management. He studies the impact of plant nutrients on the performance of citrus trees, irrigation water... Read More →
Co-authors
DK

Davie Kadyampakeni

University of Florida
NA
KM

Kelly Morgan

University of Florida
NA
SH

Said Hamido

Rodale Institute
Soil Scientist
Wednesday September 25, 2024 11:30am - 11:45am HST
South Pacific 4

11:45am HST

O/LT 1 - Subterranean Termite Landscape Mulch Consumption Challenge
Wednesday September 25, 2024 11:45am - 12:00pm HST
Formosan Sub-terranean Termite Landscape Mulch Consumption Payton Floyed1, Edward Bush*2, and Qian Sun1 (1)LSU Department of Entomology and (2)LSU AgCenter, SPESS, Baton Rouge, LA Many landscapers utilize organic mulch substrates composed primarily of wood and bark, making it an ideal food source for the Formosan subterranean termite (Coptotermes formosanus). Formosan termites are one of the most destructive structural pests and recognized as one of the 100 worst invasive species in the world. While foraging, these termites can find and may be able to fully establish colonies in landscaping that uses mulch. The mulch type that attracts the most termites has not been widely investigated and continues to be an issue that needs to be determined. The objective of this research was to measure the biomass consumption by termites. Three C. formosanus colonies were used, two from New Orleans, Louisiana, and one from Gonzales, Louisiana. All were maintained in the laboratory using three total replications per experiment over a 14 d period. Five-hundred total termites (450 workers and 50 soldiers) were placed in each arena (7.5”x10”x4” plastic bin) which used a sand layered bottom for both worker and soldier termites. Each arena was covered with a dark plastic bag to mimic typical subterranean foraging conditions. Mulch particle size distribution and bulk density resulted in expected differences with crushed pine straw having the finest particle size (>50% particle size
Speakers
EB

Edward Bush

LSU AgCenter
Co-authors
QS

Qian Sun

LSU AgCenter
NA
Wednesday September 25, 2024 11:45am - 12:00pm HST
Coral 1

11:45am HST

PH 2 - Impact of Storage Environment on Dormancy Progression and Microbiome of Potato Tubers
Wednesday September 25, 2024 11:45am - 12:00pm HST
Preservation of nutritional and market qualities of potato tubers during postharvest storage is essential for optimum economic return. Protecting tubers from unintended sprouting during storage is one of the major postharvest challenges that potato growers and stakeholders encounter. Storage environment, particularly storage temperature, significantly impacts dormancy progression and sprouting and effect overall marketability. Potato tubers carry significant amount of microbiome in different tissues of tubers from field to storage, which might contribute to overall storage qualities. However, how storage temperature impacts overall potato tuber microbiome and how changes in microbiome influence tuber dormancy are largely unknown. Therefore, the primary objective of this study was to investigate the impact of different storage temperatures on tuber microbiome and monitor the dormancy progression and sprout growth during long-term storage. Certified seed tubers of Russet Burbank were cured after harvest following industry practices. Then, one subset of tubers was stored at constant 8°C, and a second subset was stored at constant 21°C. Three types of tuber tissues (primary meristem, secondary meristem, and tuber flesh) were collected after 4, 8, 12, 17, and 24 weeks of storage for microbiome profiling and sugar and protein analysis. Additionally, a third subset was generated by moving tubers from 8°C to 21°C three days before sampling time of 8, 12, and 17 weeks. Tuber dormancy progression was monitored using additional subsets for each storage condition. As expected, the subset of tubers stored at 8°C had delayed sprouting compare to 21°C, and rapid sprout growth was observed when tubers were moved from 8°C to 21°C. Increase in reducing sugar content was observed in meristem tissues, while it decreased in tuber flesh with progression of storage duration. Interestingly, higher protein content was determined in secondary meristem tissues compare to primary meristems and tuber flesh. Overall, greater bacterial and fungal diversity and abundance were observed in meristem tissues when compared to tuber flesh. Additionally, storage temperatures, storage time, and tuber tissue types significantly impacted tuber microbial profile. In tuber tissues, Ascomycota and Basidiomycota were predominant fungal phyla, while Actinobacteria, Proteobacteria, and Cyanobacteria were the predominant bacterial phyla. Our results suggested that storage temperature and storage duration significantly impact both dormancy progression and tuber microbiome and subsequently contribute to postharvest qualities of potato tubers.
Speakers
avatar for Munevver Dogramaci

Munevver Dogramaci

United States Department of Agriculture
Co-authors
DS

Dipayan Sarkar

United States Department of Agriculture
NA
EF

Evandro Fortini

United States Department of Agriculture
NA
MB

Malick Bill

United States Department of Agriculture
NA
SK

Shyam Kandel

United States Department of Agriculture
NA
Wednesday September 25, 2024 11:45am - 12:00pm HST
Nautilus

11:45am HST

UG - Comparative Analysis of Lettuce Growth Using Compost Versus Conventional Soil
Wednesday September 25, 2024 11:45am - 12:00pm HST
 Conventional agricultural techniques have been degrading American soils nationwide since the beginnings of modern-day agriculture through practices such as soil tilling, using nitrogen synthetic fertilizers, and monocultural systems. These previously mentioned techniques contribute to degrading soil health, mass emissions of carbon dioxide into the atmosphere, and decreased biodiversity. Regenerative agriculture offers a combination of sustainable practices that will create carbon sinks to sequester atmospheric carbon dioxide, restore national food systems, and prioritize soil health. Regenerative agriculture techniques include the utilization of cover crops, compost, no-tillage, mob grazing, and polyculture. The APS Laboratory for Sustainable Agriculture focused on the effectiveness of compost by comparing the growth of lettuce in four different treatments: 100% compost (100%C), 75% compost 25% Miracle-Gro (75%C-25%MG), 50% compost 50% Miracle-Gro (50%C-50%MG), and finally, 100% Miracle-Gro (100%MG). The lettuce seeds were kept in a growth tent for 15 days during their period of germination before being transferred to four 1x1 meter plots in the Food Forest at Florida Gulf Coast University (FGCU) for the 60-day growth period. The lettuce crops grew to full bloom and ready for harvest. Sampling events took place every six days in which crop growth data including wet weight (g), dry weight (g), chlorophyll concentration (μmol/m^2), and leaf area (cm^2) were collected. Specific Leaf Area (g/cm^2) and Leaf Area Index were derived, and statistical analysis was conducted. Based on the statistical tests conducted at the 5% significance level using R statistical software, soil treatment type was found to be significant (p=0.0002). Soil treatment type was shown to have significantly impacted wet weight (p<0.0001), dry weight (p<0.0001), and leaf area (p=0.0011), but not nitrogen (χ^2 [3]=3.91, p=0.2717). Results demonstrate the effectiveness and feasibility of using compost as a technique for regenerative agriculture.
Speakers
SH

Sofia Huber

Florida Gulf Coast University
Co-authors
AS

Ankit Singh

University of Maine
NA
GP

Galen Papkov

Florida Gulf Coast University
NA
JG

John Griffis

Florida Gulf Coast University
NA
KJ

Kathryn Jackson

Independent Researcher
NA
SB

Sarah Bauer

Mercer University
NA
XY

Xiusheng Yang

University of Connecticut
NA
Wednesday September 25, 2024 11:45am - 12:00pm HST
Lehua Suite

12:00pm HST

PH 2 - Strawberry Anthocyanins, Extraction, Assessments and Storage
Wednesday September 25, 2024 12:00pm - 12:15pm HST
The anthocyanin pigments have antioxidant activities and play critical roles in plant and human health. They are abundant in flowers, vegetables, and fruits and are soluble in water, methanol, and nonpolar solvents such as chloroform. Extracting stable pigments with higher concentrations has been the research community's and industries' goal. Spectrophotometric methods can easily measure the total anthocyanin content. Other complex and more expensive methods, such as high-pressure liquid chromatography and ultrasound-assisted methods, are also available to identify and quantify the anthocyanin pigment. Strawberry color affects the appearance, fruit quality after harvest, and consumers' decision-making process. A large group of factors, such as sample type, temperature, pH, solvent type, and the ratio of its components, affect strawberry anthocyanin yield. We studied the effect of some of these variables on the anthocyanin yield, profile, and color of strawberries. Extraction solvents significantly changed the anthocyanin yield. The results suggest that acidified chloroform-methanol extracted the highest anthocyanin content compared to water-based solvents. Methanol-water-based solvents also performed better than water alone. Processing time (incubation time) was lowest in the pH differential method; however, the haze produced in this method may interfere with the spectrophotometry. Chloroform-methanol solvent with higher pH extracted pelargonidin as the main anthocyanin, and methanol and water-based solvents extracted delphinidin in UHPLC. Chloroform extracts reduced the redness and increased the extracts' brightness mainly due to higher pelargonidin content. Less redness and increased brightness indicated some level of color degradation of the extracts after storage for 48h at 4 °C.
Speakers
Wednesday September 25, 2024 12:00pm - 12:15pm HST
Nautilus

12:00pm HST

UG - Feasibility of Plug Production Utilizing Digestate From Home Water-Energy-Food Systems (H-WEF)
Wednesday September 25, 2024 12:00pm - 12:15pm HST
The integration of sustainable technologies in waste management systems has become imperative in addressing the escalating challenges of agricultural productivity and sustainability. Plugs are essential when starting crop production in controlled environment agriculture (CEA) setups and greenhouses. Horticultural crops such as vegetables, fruiting, and ornamental plants that utilize plugs have demonstrated higher success rates, healthier plants, and higher total yields. The APS Laboratory for Sustainable Agriculture at explored the innovative utilization of digestate from the Home Water-Energy-Food Systems (H-WEF), the H-WEF system converts household food waste into biogas, electricity, and nutrient-rich digestate. The digestate from the H-WEF system was used to produce agricultural plugs, presenting a novel approach to circular resource utilization. We carried out the growth of Rex Butterhead Lettuce Latuca Sativa plugs with eight different treatments, 1) control synthetic fertilizer; 2) 5% Digestate – 95% RO Water (5D–95RO); 3) 10% Digestate – 90% RO Water (10D–90RO); 4) 15% Digestate – 85% RO Water (15D–85RO); 5) 20% Digestate – 80% RO Water (20D–80RO); 6) 25% Digestate – 75% RO Water (25D–75RO); 7) 30% Digestate – 70% RO Water (30D–70RO); 8) 35% Digestate – 65% RO Water (35D–65RO). The seeds were sowed with their fertigation treatment and watered every day. The plugs were cultivated for 15 days in a controlled environment until two leaves had developed after the cotyledon. After 15 days, we collected data on wet weight (g), plug head area (cm2), total leaf area (cm2), total nitrogen content (mg/g), total chlorophyll content (mg/cm2), and dry weight (g). In addition, we collected data on the Leaf Area Index (LAI, cm2/cm2) and Specific Leaf Area (SLA, cm2/g). The synthetic fertigation yielded a higher wet weight than the following treatments: 5D–95RO, 10D–90RO, and 35D–65RO. While the 30D–70RO treatment produced a larger plug head than all other treatments. The digestate-based fertilizers were comparable to the synthetic fertilizer at dilutions of 25D–75RO and 30D–70RO. Results from this study may inform growers about the viability of utilizing digestate for plug production.
Speakers
RD

Rory Dunn

Undergraduate Research Assistant, Florida Gulf Coast University
Co-authors
AS

Ankit Singh

University of Maine
NA
GP

Galen Papkov

Florida Gulf Coast University
NA
JG

John Griffis

Florida Gulf Coast University
NA
PC

Paige Carroll

Florida Gulf Coast University
NA
SB

Sarah Bauer

Mercer University
NA
ST

Seneshaw Tsegaye

Florida Gulf Coast University
NA
XY

Xiusheng Yang

University of Connecticut
NA
Wednesday September 25, 2024 12:00pm - 12:15pm HST
Lehua Suite

12:15pm HST

PB 2 - New insights into the Yellow2 locus and its role in beta-carotene accumulation in carrots (Daucus carota)
Wednesday September 25, 2024 12:15pm - 12:30pm HST
Carrots (Daucus carota) are a unique model for the accumulation of carotenoids. Beta-carotene accumulates in large amounts in the taproot if the proper alleles of the following three loci are present: OR, Y, and Y2. These three loci are not carotenoid biosynthetic genes but rather post-transcriptional regulation of carotenoid accumulation. The genes underlying the OR and Y loci have been characterized, but the gene underlying the Y2 locus is unknown. Through genomic and transcriptomic analyses, a single candidate that may interact with light signaling was found. To determine the function of this gene, the functional transcript from wild carrot was overexpressed in orange carrots and used in a transient infiltration assay with a GFP fusion tag in tobacco. The orange allele of this gene has a large transposon insertion that theoretically inactivates the gene. However, full length transcript can still be detected in orange carrots. This begs the question of whether the transposon is still active in certain accessions. In this study, the proportion properly assembled Y2 transcript was analyzed via qRT-PCR. A KASP marker was also developed to assist plant breeders in selection for the Y2 locus.
Speakers
avatar for Michael Paulsmeyer

Michael Paulsmeyer

Postdoc, USDA-ARS
Co-authors
PS

Philipp Simon

USDA-ARS
NA
Wednesday September 25, 2024 12:15pm - 12:30pm HST
South Pacific 4

12:15pm HST

PH 2 - Isolation of Pathogenic Strain of Trichoderma atroviride from Symptomless, Disease-Free Sweetpotato (Ipomoea batatas L.) Storage Roots.
Wednesday September 25, 2024 12:15pm - 12:30pm HST
Many fungal endophytes have the ability to promote plant growth, as well as increase the host plant’s tolerance to abiotic and biotic stresses. Most endophytic species of Trichoderma are well known biocontrol agents and have been used to control diseases caused by phytopathogens of the genera Rhizoctonia, Fusarium, and Phytophthora. However, our recent research has isolated a strain of Trichoderma from sweetpotato storage roots purchased from a local farm, which was shown to develop root rot symptoms. Therefore, the objective of this project was to evaluate this isolate, especially for its potentially pathogenic nature. In the laboratory, the ITS region of the isolate was amplified, and gene sequencing placed it to T. atroviride with 99% homology. However, T. atroviride has never been identified as a disease-causing agent for sweetpotato in literature so far. Pathogenicity test was carried out accordingly, by inoculating this isolate onto healthy, symptomless sweetpotato storage roots. Two weeks post-inoculation, the storage roots were cut in half to reveal necrotic lesion development between 1.7 and 2.1cm in diameter based on three replications. The necrotic tissue was sampled and cultured on PDA, and the re-isolated fungal specimen was confirmed to be T. atroviride through gene sequencing. This result demonstrated that under environmental conditions conducive for pathogen development, this strain of T. atroviride is capable of causing root rot disease in sweetpotatoes. This finding is particularly significant as farmers typically store sweetpotatoes for an extended time, sometimes up to a year, which increases the possibilities for disease occurrence. Dual-culture assays are still ongoing to determine if this strain of T. atroviride could be a beneficial endophyte under different storage conditions, especially when other fungal endophytes are co-existing in the same storage root.
Speakers
RN

Richard Noel Torres

University of Missouri - Columbia
Co-authors
JS

James Schoelz

University of Missouri - Columbia
NA
PT

Peng Tian

University of Missouri - Columbia
NA
XX

Xi Xiong

University of Missouri - Columbia
NA
Wednesday September 25, 2024 12:15pm - 12:30pm HST
Nautilus

12:15pm HST

UG - From Flower to Fruit: Growing Degree Days and Peach Ripening
Wednesday September 25, 2024 12:15pm - 12:30pm HST
Anticipating crop advancement, particularly fruit maturation, is critical for peach growers' success and marketing. Growing Degree Days (GDD) predict the growth and development stages of plants and insects. They are based on the accumulation of heat units above a specific baseline temperature, under the concept that a certain amount of heat is needed to develop from one stage to another in the life cycle. GDDs are used for various purposes in agriculture and horticulture, such as planting scheduling, pest management and crop monitoring. Peach growers use GDD to predict the peach cultivar maturity and schedule harvesting. However, peach cultivars' ripening time is reported in the calendar or Julian days (JD) or as the number of days before or after a reference cultivar, which is not amenable to climate change. Therefore, we modeled GDD in a diverse set of peach and nectarine cultivars and breeding accessions using the Baskerville-Emin (BE) method. The GDD was calculated from full bloom to fruit maturity using historical temperature, bloom and ripening data collected at the Musser Fruit Research Station in Seneca, South Carolina, in the 2017-2023 period. GDD and JD variability will be presented, and implication of providing GDD information on existing and newly released cultivars for producers and researchers will be discussed.
Speakers
MA

Matthew Almy

Clemson University
NA
Co-authors
JM

John Mark Lawton

Clemson University
NA
KG

Ksenija Gasic

Clemson University
Wednesday September 25, 2024 12:15pm - 12:30pm HST
Lehua Suite

12:30pm HST

PB 2 - Overexpression of the Coding Sequence of Ma1 Leads to Enhanced Anthocyanin Biosynthesis in Apple via MYB73.
Wednesday September 25, 2024 12:30pm - 12:45pm HST
Anthocyanins, a group of secondary metabolites synthesized in the phenylpropanoid pathway, largely determine fruit peel color of fleshy fruits, but it is not known if its synthesis is linked to vacuolar malate accumulation that determines fruit acidity. Here, we show that when the coding sequence of Ma1, the major gene controlling apple fruit acidity, is overexpressed in ‘Royal Gala’ (RG), anthocyanin biosynthesis in the fruit peel is enhanced, corresponding to the downregulation of the expression of MYB73, an R2R3-MYB transcription factor. RNAi suppression of MYB73 expression via virus-induced gene silencing increases anthocyanin biosynthesis whereas its transient overexpression decreases anthocyanin biosynthesis in apple fruit peel. MYB73 binds to the promoter of the gene encoding UDP-glycose: flavonoid-3-O-glycosyltransferase (UFGT), the enzyme that catalyzes the last step in anthocyanin synthesis, to repress its expression. When MYB73 expression is suppressed by RNAi, UFGT expression is enhanced, leading to more anthocyanin synthesis, but this effect is blocked by RNAi suppression of UFGT expression. RNAi suppression of MYB73 enhances anthocyanin synthesis in wild-type RG apples whereas its overexpression decreases anthocyanin synthesis in Ma1-OE fruit. In the meantime, MYB73 competes with MYB1, one of the key activators of anthocyanin biosynthesis, binding to the promoter of UFGT and regulating its expression. These results indicate that MYB73 negatively regulates anthocyanin biosynthesis via repressing UFGT expression in apple peel. In Ma1-OE fruit, down-regulation of MYB73 releases UFGT from MYB73 repression and allows more MYB1 binding to UFGT promoter, leading to enhanced anthocyanin biosynthesis.
Speakers
MZ

Mengxia Zhang

Cornell University
Co-authors
DH

Dagang Hu

Cornell University
NA
LC

Lailiang Cheng

Cornell University
NW

Nan Wang

Cornell University
NA
Wednesday September 25, 2024 12:30pm - 12:45pm HST
South Pacific 4

12:30pm HST

UG - Enhancing rose propagation using moisture sensor-controlled irrigation and LED supplemental lighting in greenhouses
Wednesday September 25, 2024 12:30pm - 12:45pm HST
This study addresses the critical need for precise irrigation management in the greenhouse production of high-value ornamental crops, focusing on the propagation of single-stem rose (Rosa rubiginosa) cuttings under light-emitting diode (LED) supplemental lighting. The current lack of effective monitoring and control systems for substrate moisture poses challenges in optimizing plant growth while minimizing water and nutrient losses. In this context, we propose the integration of moisture sensors for real-time monitoring and control of substrate moisture levels, coupled with LED supplemental lighting, to enhance the production of rose cuttings. Our approach involved assessing the feasibility and effectiveness of moisture sensor-controlled irrigation in greenhouses, considering the specific requirements of rose propagation and the influence of LED lighting on plant growth. We tested three Ө thresholds (0.25, 0.35, and 0.45 m3.m-3) and five light levels as supplemental lighting (100, 175, 250, 325, and 400 µmol.m-2.s-1) arranged on randomized complete block design with four replications. Rose Double Knock Out® ‘Radtko’ PP 16,202 CPBR 3,104 plants were grown in 15.6 L pots (Pioneer Pots; Blackmore Co., Belleville, MI) filled with 20% Canadian peat/58% aged pine/10% perlite/12% EZ Hydrafiber lime potting mix (Oldcastle HFC25; Oldcastle Lawn
Speakers
BT

Braylen Thomson

Undergrad Researcher, University of Georgia
Co-authors
AH

Alan Huber

University of Georgia
NA
BH

Brandon Heavern

James Greenhouses
NA
KJ

Ken James

James Greenhouses
NA
KQ

Kuan Qin

University of Georgia
LJ

Lars Jensen

Blackmore Company
NA
MH

Matthew Housley

University of Georgia
RF

Rhuanito Ferrarezi

University of Georgia
NA
Wednesday September 25, 2024 12:30pm - 12:45pm HST
Lehua Suite

12:45pm HST

PB 2 - Rapid Detection and Coinfection Analysis of Aspergillus flavus in Peanut Seeds
Wednesday September 25, 2024 12:45pm - 1:00pm HST
Aspergillus flavus is a widespread pathogen affecting crops like peanuts, contributing significantly to mycotoxin contamination and subsequent crop losses. Discriminating between toxigenic and non-toxigenic strains is crucial, yet conventional methods are often cumbersome and time-consuming. In this study, we developed rapid molecular tools to differentiate between these strains. Using morphological characteristics and species-specific PCR-sequencing, we identified isolates collected from peanut seeds in southern Georgia. Through primer optimization and qPCR targeting aflatoxin regulatory genes, we successfully distinguished aflatoxin-producing and non-producing isolates. Additional genes involved in aflatoxin biosynthesis were also analyzed, showing clear expression distinctions. Our findings demonstrate the specificity and efficiency of these primer sets, providing a valuable tool for managing A. flavus contamination in peanut seed lots. Additionally, research on the seed microbiome's impact on mycotoxin production remains limited. In this study, we assessed microbial communities in peanut seeds collected over various years using ITS gene sequencing. Our results revealed a diverse microbial population, including A. flavus and other fungal pathogens, highlighting the complexity of seed microbiota. This approach offers novel insights into peanut seed-associated microbiomes and aflatoxin contamination, shedding light on the correlation between microbial communities and aflatoxin pollution.
Speakers
EA

Emran Ali

Alcorn State University
Co-authors
SW

Sumyya Waliullah

Alcorn State University
NA
VN

Victor Njiti

Alcorn State University
NA
Wednesday September 25, 2024 12:45pm - 1:00pm HST
South Pacific 4

12:45pm HST

UG - A Comparative Study Analyzing Light Lengths for the Growth of Rex Butterhead Lettuce Utilizing GREENBOX Technology
Wednesday September 25, 2024 12:45pm - 1:00pm HST
Exponential population growth adds increasing pressure on the agriculture industry to grow and distribute fresh foods to rural and urban areas, leading to the development of GREENBOX technology, which utilizes Controlled Environment Agriculture (CEA) principles to optimize the desired conditions for growth of leafy green crops. Using commercially available equipment, GREENBOX technology has the capability to be integrated into existing urban infrastructure to help relieve the negative impact urbanization has on the availability of fresh foods. GREENBOX technology allows environmental variables, such as temperature, humidity, light intensity/ spectrum, and nutrient delivery, to be controlled to enhance the growth performance of leafy greens. Precursory experiments using GREENBOX Technology utilized the standard photoperiod of 16 hours of light, and 8 hours of dark for all crop production. The main objective of this study was to conduct a comparative analysis of Lactuca sativa Rex Butterhead Lettuce production grown under different photoperiods using GREENBOX technology. Using the standard 16 hours of light and 8 hours of dark as the control, two different photoperiod treatments were tested. Treatment one consisted of a 14-hour light period and a 10-hour dark period, while treatment two consisted of a 12-hour light period and a 12-hour dark period. The biomass and productivity of the crops were measured in addition to the environmental conditions for each lighting regimen to ascertain any significant differences. The biomass parameters included wet weight (g), dry weight (g), leaf area (cm2), leaf count (n), and chlorophyll concentration (mg/cm2). We derived additional data, including the Leaf Area Index (LAI, cm2/cm2), Specific Leaf Area (SLA, cm2/g), and biomass productivity (kg/m2). A statistical analysis of the biomass data was used to understand the differences in biomass parameters between crop growth and different light lengths. No statistically significant differences were found between the biomass and productivity parameters for the 12-hour and 14-hour photoperiods. However, the weight weights, dry weights, Leaf Count, SLA, and LAI from the 16-hour photoperiod showed statistically significant differences from the 12 and 14-hour photoperiods. All treatments still produced Rex Butterhead lettuce above the expected harvest weight of 180g and are viable for crop production in urban warehouse settings. The results of this experiment may help us understand the relationship between photoperiod and the biomass performance of leafy greens. Future GREENBOX experiments may use this information to increase the efficiency and productivity outputs of GREENBOX units. Keywords: CEA, Hydroponics, lettuce, soilless agriculture, urban agriculture
Speakers
MG

Mya Griffith

Florida Gulf Coast University
Co-authors
AS

Ankit Singh

University of Maine
NA
BR

Barry Rosen

Florida Gulf Coast University
NA
GP

Galen Papkov

Florida Gulf Coast University
NA
GB

George Buss

Florida Gulf Coast University
JG

John Griffis

Florida Gulf Coast University
NA
KJ

Kathryn Jackson

Independent Researcher
NA
PC

Paige Carroll

Florida Gulf Coast University
NA
SB

Sarah Bauer

Mercer University
NA
XY

Xiusheng Yang

University of Connecticut
NA
Wednesday September 25, 2024 12:45pm - 1:00pm HST
Lehua Suite

1:00pm HST

PB 2 - RNA-seq Analysis Reveals Differentially Expressed Genes in Sweetpotato cv. Beauregard under Lead Stress
Wednesday September 25, 2024 1:00pm - 1:15pm HST
Lead (Pb) is a widespread toxic element in agricultural soils and Pb accumulation in plant roots represents a potential health risk for human beings. The sweetpotato (Ipomoea batatas L.) is a globally important root crop and one of the leading raw products for baby food processing. Limited information is available about the mechanism by which sweetpotato responds to Pb stress at the molecular level. Understanding the genetic mechanism of Pb uptake is essential for developing management approaches to mitigate Pb uptake in this crop. To address this knowledge gap, RNA-seq was used to characterize the transcriptome and identify differentially expressed genes from Pb-treated and untreated sweetpotato cv. Beauregard. Samples were taken from adventitious root tips at 5, 10, and 15 days after planting (DAP). Transcriptomic analysis revealed 4,077, 5,159, and 3,206 differentially expressed genes at 5, 10, and 15 DAP respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis shows that ABC transporters and sulfur metabolism pathways are upregulated at 5 DAP but are downregulated at 15 DAP, indicating that there may be a threshold in sweetpotato Pb tolerance. The results provide a deeper insight into the species-specific response of sweetpotato to Pb stress which can lead to the development of screening methods and evaluation of management strategies that reduce Pb uptake in this crop.
Speakers
MA

Mary Ann Munda

Louisiana State University
Co-authors
AV

Arthur Villordon

LSU Agcenter
DL

Don La Bonte

Louisiana State Univ
NA
LA

Lisa Arce

Louisiana State University
MA

Mae Ann Bravo

Louisiana State University
MB

Marissa Barbosa

Lousiana State University
Wednesday September 25, 2024 1:00pm - 1:15pm HST
South Pacific 4

1:15pm HST

PB 2 - RNASeq Analysis Reveals Key Pathways Involved in Low Nitrogen Tolerance at the Onset of Storage Root Formation in Sweetpotato cv Bayou Belle
Wednesday September 25, 2024 1:15pm - 1:30pm HST
Nitrogen (N) is a key limiting macronutrient for crop growth and development and affects sweetpotato storage root formation and yield potential. In high-input production areas, excessive N application can suppress storage root formation and results in environmental pollution. The crop is also grown in low-input production systems with little or no N applications. In this study, sweetpotato cv Bayou Belle response to N deprivation during the establishment and storage root formation stages was investigated through a transcriptomic approach. RNA-seq data revealed a number of differentially expressed genes (DEGs) between N sufficient ( N) and N deficient (–N) conditions at 5, 10, and 15 days after planting (DAP). The number of significantly upregulated genes varied between timepoints. DEGs were further classified into functional categories and pathways to reveal putative functions. Gene Ontology annotation together with KEGG analysis revealed that majority of the DEGs are involved in sulfur compound metabolic process at 5 DAP and in ammonium transport for both 10 DAP and 15 DAP. These results provide valuable insights about the molecular mechanism of N regulation in sweetpotato adventitious roots undergoing storage root formation. These findings can lead to the development of tools and processes for improving N use efficiency and consistent storage root yields while reducing environmental impact in this globally important crop.
Speakers
avatar for Lisa Arce

Lisa Arce

Graduate Student, Louisiana State University
I am a PhD candidate focused on optimizing nutrient requirements for sweetpotatoes through advanced molecular techniques. My research utilizes expression data from qPCR assays and RNA sequencing to uncover genotype-specific responses to varying levels of nitrogen, phosphorus, and... Read More →
Co-authors
AV

Arthur Villordon

LSU Agcenter
CG

Cole Gregorie

LSU AgCenter
NA
DL

Don La Bonte

Louisiana State Univ
NA
MA

Mae Ann Bravo

Louisiana State University
MB

Marissa Barbosa

Lousiana State University
Wednesday September 25, 2024 1:15pm - 1:30pm HST
South Pacific 4

1:30pm HST

PB 2 - Introducing CHiDO – a No Code Genomic Prediction Software implementation for the Characterization & Integration of Driven Omics
Wednesday September 25, 2024 1:30pm - 1:45pm HST
Climate change represents a significant challenge to global food security by altering environmental conditions critical to crop growth. Plant breeders can play a key role in mitigating these challenges by developing more resilient crop varieties; however, these efforts require significant investments in resources and time. In response, it is imperative to use current technologies that assimilate large biological and environmental datasets into predictive models to accelerate the research, development, and release of new improved varieties. Leveraging large and diverse data sets can improve the characterization of phenotypic responses due to environmental stimuli and genomic pulses. A better characterization of these signals holds the potential to enhance our ability to predict trait performance under changes in weather and/or soil conditions with high precision. This presentation introduces CHiDO, an easy-to-use, no-code platform designed to integrate diverse omics datasets and effectively model their interactions. With its flexibility to integrate and process data sets, CHiDO's intuitive interface allows users to explore historical data, formulate hypotheses, and optimize data collection strategies for future scenarios. The platform's mission emphasizes global accessibility, democratizing statistical solutions for situations where professional ability in data processing and data analysis is not available.
Speakers
DJ

Diego Jarquin

University of Florida
Co-authors
FG

Francisco Gonzalez

University of Florida
NA
JG

Julian Garcia-Abadillo

University of Florida
NA
Wednesday September 25, 2024 1:30pm - 1:45pm HST
South Pacific 4

1:30pm HST

VCM 3 - Monitoring High Tunnel Soil Temperature Fluxes to Understand Soil Health Implications
Wednesday September 25, 2024 1:30pm - 1:45pm HST
High tunnel soil health is crucial for successful and sustainable crop production within protected environments. Soil microbial activity is highly temperature-dependent, and soils that are slightly warmer will foster increased metabolic rates within soil communities enhancing microbial diversity and enzymatic activity, promoting nutrient availability. However, little is understood about the potential for microbial activity during colder seasons in norther latitudes when high tunnels are taken out of production and soils are left fallow. Temperature variation in high tunnels could also create variation in microbial community activity, creating spatial nutrient variation with impacts on production the following season. To analyze soil temperature fluxes, we buried an array of 27 soil sensors four inches deep within the soil in a newly built, 30-foot-wideby 96-foot-long tunnel located in Brookings, South Dakota. The high tunnel was oriented east to west and soil was bare. Soil temperatures were recorded at 30-minute intervals from December 22 to March 15, (2023 – 2024). Air temperature and light (lux) data was also collected inside of the high tunnel as well as external weather data from a nearby (>1km) Mesonet weather station. We used multiple linear regression to model the relationship between average internal soil temperature and internal light and temperature data. We also compared sensor location (latitude, longitude, and Euclidean distance from the center of the high tunnel) on soil temperature within the high tunnel using an ANOVA and multiple linear regression to examine how sensor location was related to soil temperature. Our top model of internal soil temperature showed light, internal temperature, and the interaction between light and internal temperature explained a large amount of high tunnel soil temperature variation (R2 = 0.87, p < 0.0001). There was also significant variation in soil temperature throughout the high tunnel, with the daily mean difference of 3.12 degrees Celsius (p < 0.0001) observed between our sensor at the center of the high tunnel and our sensor near the northwest corner of the high tunnel. Our top model showed that latitude, the quadratic of longitude, and the Euclidean distance from the center of the high tunnel explained a moderate amount of high tunnel soil temperature variation (R2 = 0.44, p < 0.0001). This analysis demonstrates a need to further investigate how microbial communities react to temperature variation within high tunnels when they are not in production.
Speakers
BL

Bret Lang

Student, South Dakota State University
Co-authors
KL

Kristine Lang

South Dakota State University
LP

Lora Perkins

South Dakota State University
NA
Wednesday September 25, 2024 1:30pm - 1:45pm HST
Kahili

1:45pm HST

PB 2 - Tissue Culture-Free Genome Editing in Plants Using RNA Viruses
Wednesday September 25, 2024 1:45pm - 2:00pm HST
Genome editing represents a pivotal tool for advancing biological discovery and crop enhancement. However, its widespread application in crop improvement has been hindered by inefficient delivery methods and the dependence on tissue culture for generating gene-edited plants. RNA viral vectors present a promising alternative for delivering gene-editing reagents while circumventing the need for tissue culture. I have developed methods for: (1) Achieving multiplexed, heritable gene editing in tomato through viral delivery of isopentenyl transferase and single-guide RNAs to latent axillary meristematic cells; (2) Inducing heritable, multinucleotide deletions in Nicotiana benthamiana using viral delivery of a repair exonuclease and guide RNAs; and (3) Enabling heritable base editing in Arabidopsis via RNA viral vectors. These approaches are likely transferable to diverse plant species, paving the way for scalable gene editing in agriculture.
Speakers
DL

Degao Liu

Texas Tech
Wednesday September 25, 2024 1:45pm - 2:00pm HST
South Pacific 4

1:45pm HST

VCM 3 - Evaluating The Effect Of Cultivar On Garlic Growth And Yield
Wednesday September 25, 2024 1:45pm - 2:00pm HST
Assessing the impact of cultivar on garlic growth and yield ensures satisfactory productivity and better management of genetic resources for growers in North Dakota. A field experiment was conducted at the NDSU Horticulture Research Farm, located near Absaraka, ND to evaluate the effect of cultivar on the growth and yield of garlic. Twenty-nine garlic cultivars were arranged in a randomized complete block design (RCBD) with 4 replications. The leaf number, bulb diameter, bulb weight, scape weight and length were recorded throughout the growing season. The results showed significant differences between cultivars for all the variables evaluated. The highest bulb diameter(60.5 cm) was recorded in ‘German White’, while the lowest diameter (38.9 cm) was recorded in ‘German Red’. The highest bulb weight(73.4 g) was with ‘German White’ while ‘Italian Loiacono’ resulted in the lowest bulb weight(21.2 g).The number of leaves was recorded at 30, 45, 60, and 80 days after sprouting (DAS). The average number of leaves was similar for all cultivars until 60 DAS when ‘Ukrainian Red’ had the highest number of leaves (11) and ‘German Red’ had the fewest leaves (7). ‘Dakota White’ produced the longest scapes while ‘Italian Loiacono’ and ‘White Spring’ did not produce any scapes. ‘German White’ recorded the heaviest scapes (13.8 g). In conclusion garlic cultivar affected the growth and yield when grown under North Dakota environmental conditions. ‘German White’ appeared to be the most adapted to North Dakota environmental conditions while ‘Italian Loiacono’ and ‘German Red’ were the least adapted.
Speakers
avatar for Stephen Mensah

Stephen Mensah

Graduate Research Assistant, North Dakota State University
Greetings! I'm Stephen Mensah, proud son of Ghana. My journey began with a Bachelor's degree in Agriculture from the esteemed University of Cape Coast, Ghana. Now, I'm embarking on an exciting chapter as a graduate student at North Dakota State University, passionately pursuing a... Read More →
Co-authors
Wednesday September 25, 2024 1:45pm - 2:00pm HST
Kahili

2:00pm HST

CE 3 - Effects of Light Sources and Fertilizers on Biomass Production of Nine Lettuce Cultivars in a Hydroponic Nutrient Film Technique System
Wednesday September 25, 2024 2:00pm - 2:15pm HST
This study investigated the impact of two light sources and fertilizers on the growth of nine lettuce cultivars in a hydroponic nutrient film technique system. The research was prompted by reduced plant growth and acidity issues observed in the nutrient solutions in which Lettuce (Lactuca sativa cv. Salanova) was growing in previous experiments. The hypothesis posited that adjusting the ammonium/nitrate ratio in the nitrogen fertilizer source could mitigate acidity drops in the nutrient solution and consequently enhance biomass production. This experiment was conducted at Texas Tech University's Horticulture Gardens and Greenhouse Complex from October 10 to November 22, 2023. Treatments included combinations of two light sources (WhiteLEDs and LumiGrow TopLight Node™) and two fertilizer brands (Oasis and MaxiGro) containing different ratios of ammonium:nitrate; Oasis with 21.25:78.75, and MaxiGro with 15:85. Both fertilizers were maintained at the same concentration of nitrogen throughout the experiment, although the rates were changed according to developmental stage. The nutrient solutions initially contained 100 ppm N fertilizer for three weeks, followed by a water change and an increase to 150 ppm N.The pH and EC levels were closely monitored throughout the experiment. Results revealed significant differences among cultivars for all measured variables, with Salvius demonstrating superior performance in most aspects. The light source had no significant impact on aerial growth variables, while the MaxiGro fertilizer brand significantly and positively influenced plant weight, height, and root weight. Although there were significant interactions between light source, cultivar, and fertilizer for above-ground variables, these were highly dependent upon fertlizer. In conclusion, the choice of fertilizer brand is crucial for optimal lettuce growth in hydroponic systems. This study highlights the importance of selecting appropriate fertilizer characteristics to avoid detrimental effects on biomass production. Further trials are recommended to validate these findings and address concerns for home and commercial growers in hydroponic lettuce production.
Speakers
DR

Dario Rueda Kunz

Texas Tech University
Co-authors
CS

Catherine Simpson

Texas Tech University
NA
Wednesday September 25, 2024 2:00pm - 2:15pm HST
Coral 1

2:00pm HST

HEMP 2 - Variable Planting Date Influences on Growth and Development of Floral Hemp in North Dakota
Wednesday September 25, 2024 2:00pm - 2:15pm HST
Commercially produced floral hemp (Cannabis sativa L.) is high in cannabidiol (CBD) concentrations relative to tetrahydrocannabinol (THC); this is intentional due to regulatory pressures requiring low THC thresholds. Given the predominant role of genotype in plant development, it is crucial to also explore environmental factors that may allow for optimization of hemp growth, yield, and quality. The goal in this study is to evaluate the extent to which an extended vegetative growing period has on height, width, and yield in irrigated raised bed production of floral hemp in North Dakota. To survey this relationship between planting date, growth, and quality parameters, mother plants were germinated from seed at the beginning of the growing season. Each treatment group of cuttings, separated by approximately two weeks, were excised from their respective cultivar mother plant for four timing treatment groups. Cultivars evaluated were ‘ACDC’, ‘Bubbatonic’, ‘Sour Elektra’, and ‘Umpqua’. The main effect of cultivar did not significantly affect any measured parameters except for height and the top 1/3 portion of dry floral biomass. Planting date treatments significantly affected the wet weight of total above-ground biomass, total dry above-ground biomass, and total floral biomass. Average total above-ground biomass and dry floral biomass was statistically different for each planting date except for the last two planting dates (June 19 and July 3). Total above-ground dry biomass averaged over cultivars, were 4070 g, 2432 g, 1323 g, and 894 g, for dates May 19, June 5, June 19, and July 3, respectively. Mean yields for total dry floral biomass, averaged over cultivars, were 1779 g, 1279 g, 784 g, and 535 g, for dates May 19, June 5, June 19, and July 3, respectively. Earlier planting dates showed an increase in height for three of the four cultivars with the exception of ‘Umpqua’. A cultivar interaction with planting date treatment occurred for the top 1/3 portion of dry floral biomass and indicated that earlier planting date increased the biomass for ‘Bubbatonic’ and ‘Sour Elektra’ while planting date did not influence dry biomass for ‘ACDC’ and ‘Umpqua’. The insights gained from assessing the impact of variable vegetative growing periods on growth and quality parameters of photoperiod-dependent floral hemp could have broader implications for optimizing production practices. Understanding the intricate interplay between genotype, environmental factors, and cultivation practices is essential for advancing sustainable and efficient hemp cultivation strategies.
Speakers
BS

Brock Schulz

North Dakota State University
Co-authors
CA

Collin Auwarter

North Dakota State University
NA
HH

Harlene HattermanValenti

North Dakota State University
Wednesday September 25, 2024 2:00pm - 2:15pm HST
South Pacific 2

2:00pm HST

PROP - Enhancing Germination of Silver Saw Palmetto (Serenoa repens form glauca): Water Uptake, Temperature, and Pre Sowing Treatment Effects
Wednesday September 25, 2024 2:00pm - 2:15pm HST
Silver saw palmetto is a native palm of the southeast coast of the United States that is of high ornamental value for native landscapes and commercial potential production due to its fruit’s phytotherapeutic properties. The main propagation method for this palm is seed-based germination, which has very slow and low germination rates. This study assessed imbibition rates, germination in different temperatures that simulated Florida seasons, and pre-sowing treatments. Diaspores were exposed to seeds within the endocarp, intact seeds, scarified seeds, and seeds with their operculum removed. The maximum fresh weight of saw palmetto seeds after imbibition was observed at 11 days. Significant differences in imbibition rates and final weight were noted for seeds with an endocarp, with lower fresh mass, and scarified seeds, which showed the highest rates. Summer temperatures consistently yielded the highest final germination percentage and uniformity for seeds with or without an endocarp on constant summer temperatures or move-along experiments throughout Florida seasons. Pre-sowing treatments, such as the removal of the operculum, proved to be highly efficient in promoting the highest germination percentages and rates, while seeds with an endocarp demonstrated lower and uneven germination. The application of hormones, particularly GA3 at 10,000 ppm, also showed promise in improving germination rates.
Speakers
VP

Vania Pereira

University of Florida
Co-authors
HP

Hector Perez

University of Florida
NA
JO

Jena Osmani

University of Florida
NA
TS

Thiago Souza Campos

UNESP - FCAV
NA
WV

Wagner Vendrame

University of Florida
NA
Wednesday September 25, 2024 2:00pm - 2:15pm HST
Lehua Suite

2:00pm HST

VCM 3 - Optimizing Butterhead Lettuce Production in a High Tunnel Environment
Wednesday September 25, 2024 2:00pm - 2:15pm HST
The production of fast-growing vegetable crops (such as specialty type lettuces) in slightly modified environments using high tunnels are widely underutilized. These structures can be used in the Midwest for winter production of a wide variety of leafy greens, including specialty lettuce. These crops have potential to garner a market premium due to high demand when there are not many other local vegetables for sale. Therefore, a study was conducted in 2020 and 2021 to evaluate four butterhead lettuce varieties (‘Nancy’, ‘Rhapsody’, ‘Red Cross’ and ‘Skyphos’) to determine optimal density for maximum revenue generation on a 3 ft wide raised bed. Three rows per bed and at 9 in. between plants worked best for ‘Nancy’, ‘Rhapsody’ and ‘Skyphos’, while for ‘Red Cross’ (a small more erect growing variety), 4 rows per bed at 12-inch spacing between plants maximized productivity. Head diameters were also highest for ‘Nancy’, ‘Rhapsody’ and ‘Skyphos’ using the 3 row, 12 inch between plant spacings. Overall gross revenues obtained per high tunnel, depending on plant density and variety, ranged from $3,600 to $6,000 (sold per piece at $4 each) or $1,753 to $7,279 (sold by weight at $6/ lb) for a typical 26’ (wide) x 48’ (long) high tunnel. Although most revenues increased when sold by weight, some increased by 50% (e.g., Rhapsody when grown at 3 row and 12 in spacings). Additionally, ‘Nancy’ (green-leaf type) and ‘Skyphos’ (red-leaf type) tended to be of higher quality than the other varieties evaluated and would be the better varieties to grow in a lower Midwest high tunnel environment. Both ‘Nancy’ and ‘Skyphos’ had optimal gross revenues when grown at 3 rows per bed with 9 in-row spacings when sold by piece ($4,500) or weight ($6,979 and $6,426, respectively). Thus, it is important for growers to understand the importance of butterhead variety selection and plant density in a high tunnel, as well as the method sold to maximizes revenues.
Speakers
AW

Alan Walters

Southern Illinois University
Wednesday September 25, 2024 2:00pm - 2:15pm HST
Kahili

2:15pm HST

CE 3 - Enhancing Lettuce Yield: Strategies for Fertility Management in Soilless Growth Systems.
Wednesday September 25, 2024 2:15pm - 2:30pm HST
The focus on sustainability and effective resource management is expanding along with the upward trend in greenhouse production. Precise application of fertilizers is becoming more and more important in a variety of agricultural systems. The physical and chemical characteristics of soilless growth media differ from those of soil, which causes differences in their ability to retain nutrients. As such, accurate rates of fertilizer are crucial. This study looked at 14 different fertilizer blends with varying percentages of potassium (0-200ppm), phosphorus (0-100ppm), and nitrogen (0-200ppm). Pots were filled with Berger BM6 media and then ‘Buttercrunch’ lettuce seeds were planted. With each treatment fertilizer rate, the plants were hand-watered once a week to maintain a 10% leaching fraction. The number of leaves, dry shoot weight, fresh root weight, dried root weight, and SPAD readings were among the end measurements. The study found that a mix of high rates of nitrogen, phosphorous, potassium fertilizer treatments increased fresh shoot weight. This emphasizes the need for additional study to determine the best fertilizer rates for various specialty crops grown in soilless greenhouse environment.
Speakers
BW

Bryce Waugh

Grad Student, Oklahoma State University
Co-authors
BD

Bruce Dunn

Oklahoma State University
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Coral 1

2:15pm HST

GG 2 - Updates on Curation and Standardization of Phenotypic and Genotypic Data for Horticultural Databases
Wednesday September 25, 2024 2:15pm - 2:30pm HST
The Genome Database for Rosaceae (GDR, https://www.rosaceae.org/) and the Genome Database for Vaccinium (GDV, https://www.vaccinium.org/), are databases that support genomics, genetics and breeding in under-represented crops like small fruits. These fruit crops include Fragaria (strawberry), Rubus (red raspberry, black raspberry, and blackberry) in GDR, and Vaccinium (blueberry and cranberry) in GDV. Data include curated genome sequences, genetic maps, markers, QTL, genes, transcripts, germplasm, and publications, made accessible to browse, query and download through easy-to-use web interfaces and tools. One of the objectives of a 2022-funded SCRI- project ‘Advanced National Database Resources for Specialty Crop Research and Improvement’ is to collect, curate, and integrate all types of genomics, genetics, and breeding big data in easy-to-use and robust crop-specific databases. In this presentation, we summarize our progress towards curating and making available phenotype and genotype data for strawberry. We also present a strawberry Crop Ontology we have developed with input from crop researchers and breeders from North America and Europe. Public availability of phenotypic and genotypic data in GDR, GDV, and GRIN-GLOBAL will allow easy access to this data to use in genome-wide association studies. Crop Ontology will enable digital capture and trait data integration across locations and projects.
Speakers
avatar for Jill Bushakra
Co-authors
CH

Chun Huai Cheng

Washington State University
NA
DM

Doreen Main

Washington State University
JY

Jing Yu

Washington State University
NA
JH

Jodi Humann

Washington State University
KB

Katheryn Buble

Washington State University
NA
NB

Nahla Bassil

USDA-ARS
NA
PZ

Ping Zheng

Washington State University
NA
SJ

Sook Jung

Washington State University
NA
TL

Taein Lee

Washington State University
NA
Wednesday September 25, 2024 2:15pm - 2:30pm HST
South Pacific 1

2:15pm HST

HEMP 2 - In-vitro Screening of Native Plant Crude Extracts Against Major Plant Pathogens Affecting Cannabis and Specialty Food Crops of Louisiana
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Louisiana’s hot and humid climate provides the perfect environmental conditions for the growth of fungal and bacterial plant pathogens. These fungal infections are an obstacle to the success of commercial production of Cannabis sativa in the state. Two of the most recent and significant fungal diseases are southern blight caused by Sclerotium rolfsii and stem canker caused by Botrytis cinerea. However, there is a lack of formal and professional knowledge regarding fungi that infect medicinal hemp plants, and practical and effective methods for managing the casual agents of these diseases. The objective of this study was to identify natural plant products from two native plants of Louisiana, that have been reported in the Native American ethnobotanical literature to have antifungal/antibacterial properties. An in-vitro bioassay experiment was conducted using the agar plug diffusion method testing the antifungal inhibition of crude ethanol extracts from the two species against each of the two pathogens Sclerotium rolfsii and Botrytis cinerea, on four plates each of Extract 1 Diospyros virginiana L. and Extract 2 Equisetum hymale L. of 1/4PDA spiked at a dose of 250ppm, 500ppm, 750ppm, and 1000ppm against a control plate of 1/4PDA for six days. Based on this initial crude extract bioassay there is a highly significant difference in the two crude extracts (p=0.000105) when tested against Botrytis cinerea. There is also a significant difference in concentration. The test against Sclerotium rolfsii did not find any significant inhibition from either of the plant extracts tested. From our findings we will continue the research study to test the antifungal potential of crude ethanol extract as well as Hexane, chloroform, ethyl acetate soluble fractions of Extract 1 Diospyros virginiana. The goal of the study is to integrate the antifungal compounds and their application for the development of best practices in Cannabis production.
Speakers
avatar for Jennifer Blanchard

Jennifer Blanchard

Instructor Horticulture - Medicinal Plants (PhD Student), Louisiana State University
Jennifer Blanchard is a botanist and Instructor of Horticulture-Medicinal Plants, in the School of Plant Environmental and Soil Sciences (SPESS) at LSU. She has created a new course at LSU in Louisiana Medicinal Plants HORT 2080 that focuses on the ethnobotany of native indigenous... Read More →
Wednesday September 25, 2024 2:15pm - 2:30pm HST
South Pacific 2

2:15pm HST

PROP - Propagation Strategies and Epigenetic Variations in Vaccinium Berry Crops
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Blueberry (Vaccinium sect. Cyanococcus Rydb.), lingonberry (V. vitis-idaea L.) and huckleberry (V. membranaceum; also called black huckleberry or black blueberry) are three important Vaccinium small fruit crops native to the North. They are valuable resources for bioactive components that play important roles in anti-oxidant, anti-tumor, anti-ulcer, and anti-inflammatory activities. They can be propagated to produce true-to-type plants either conventionally or by micropropagation. Propagation in vitro is now well accepted worldwide for commercial production of Vaccinium crops. Proficient plant propagation technique using shoot organogenesis and somatic embryogenesis was successfully established in blueberry and lingonberry. Shoot regeneration and proliferation in in-vitro conditions using various liquid bioreactors have successfully been achieved in various Vaccinium species. One of the major concerns in commercial production is the occurrence of variation in micropropagated plants. This presentation describes the in-depth progress of genetic and epigenetic variations in different Vaccinium species during micropropagation. It addresses different molecular techniques used to monitor true-to-type and epigenetics along with application of epigenetic variation in micropropagated Vaccinium berry crops. Keywords: blueberry, bioreactor micropropagation, DNA-methylation, huckleberry, molecular markers, lingonberry, somaclonal variation
Speakers
avatar for Samir Debnath

Samir Debnath

St. John’s Research and Development Centre
Samir Debnath, Ph.D., P.Ag. Dr. Samir C. Debnath, a Research Scientist of Agriculture and Agri-Food Canada and an Adjunct Professor of Biology, Memorial University of Newfoundland, has authored and co-authored around 140 publications in peer-reviewed journals including review papers... Read More →
Co-authors
MS

Mehdi Sharifi

Summerland Research and Development Centre, AAFC, 4200 Highway 97, Summerland, British Columbia, Canada
Dr. Mehdi Sharifi is a “soil nutrient management” research scientist at Summerland Research and Development Centre in British Columbia, Canada. Before his current position, he was a professors at Trent and Dalhousie Universities. He completed two postdoctoral fellow positions... Read More →
RB

Rajesh Barua

Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
NA
SK

Sayani Kundu

Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
NA
SM

Sweety Majumder

Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
NA
US

Umanath Sharma

Department of Biology, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
NA
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Lehua Suite

2:15pm HST

VCM 3 - Resource Use Efficiency, Yield, and Quality of Amaranth Grown as a Summer Leafy Green in Alternative Soilless Systems
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Soilless growing systems (SGS) integrated into controlled environment agriculture (CEA) offer a viable solution for increasing food production in densely populated areas with limited land, water, and nutritional security. The design, components, inputs, and nutrient management of alternative SGS along with the plant genotype, directly impact crop yield, nutritional value, and resource use efficiency. As the adoption of CEA and SGS continues to expand, there is a growing need to compare and evaluate the performance of alternative SGS in terms of resource use efficiency, crop yield, and impact on crop nutritional quality. To this purpose, a study was undertaken to assess the performance of five alternative SGSs including Deep Water Culture (DWC), Nutrient Film Techniques (NFT), Ebb and Flow, Drip irrigation, and the Kratky system concerning yield, nutritional quality, and resource use efficiency, using green and red stripe amaranth cultivar as test crops. As expected, the Kratky system had the lowest dissolved oxygen levels in the nutrient solution compared to other SGSs. Among the growing systems, DWC and NFT exhibited higher fresh and dry biomass production compared to drip irrigation, ebb and flow, and the Kratky system. There was no distinct difference in leaf fresh and dry weight between cultivars, but green amaranth displayed higher stem fresh and dry weight than red stripe amaranth. Dry matter content remained unaffected by the SGS, while red stripe amaranth exhibited higher dry matter content compared to green amaranth. The Kratky and DWC systems utilized 34.2% and 25.6% less nutrient solution, respectively, compared to the ebb and flow system, which had the highest nutrient solution consumption compared to other methods. DWC had the highest water use efficiency (WUE, dry biomass produced per liter of water used). Nitrate content in amaranth leaves was higher when grown in NFT compared to drip irrigation, DWC, and ebb and flow, but was similar to Kratky. The red stripe cultivar displayed higher nitrate content than the green one. Regarding bioactive compounds, green amaranth exhibited higher total antioxidants and flavonoids, whereas DWC and NFT led to lower total phenols and flavonoids compared to the Kratky, ebb and flow, and drip irrigation systems. In conclusion, the DWC and NFT systems maximized yield, with DWC having higher water use efficiency, while Kratky, ebb and flow, and drip irrigation system resulted in higher nutritional quality of the amaranth grown as a summer leafy vegetable.
Speakers
PP

Pradip Poudel

The Penn State University
Pradip
Co-authors
FD

Francesco Di Gioia

The Pennsylvania State University
NA
Wednesday September 25, 2024 2:15pm - 2:30pm HST
Kahili

2:30pm HST

CE 3 - Effect of ZnO and SiO2 Nanoparticles on Growth and Physiology of Hydroponic Lettuce Under Salinity Stress
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Nanoparticles have unique physical and chemical properties, which can positively and negatively impact crop growth and tolerance to abiotic stresses. This study evaluated the potential of ZnO and SiO2 nanoparticles in alleviating salinity stress in hydroponically cultivated lettuce. Two-week-old lettuce seedlings (Lactuca sativa cv. Green Forest) were transplanted into a 5-L deep water culture system and grown for four weeks in a customized growth chamber set at 25°C with 230 µmol/m2/s PPFD. The nutrient solution was maintained at an electrical conductivity (EC) of 1.5 dS/m and pH 5.8, and replenished weekly. A factorial design was employed with four salinity stresses (non-saline, 50 mM NaCl, 33.3 mM CaCl2, 25 mM NaCl 16.6 mM CaCl2) and three nanoparticle treatments (no nanoparticle, 100 ppm ZnO, 100 ppm SiO2). Under non-saline conditions, both ZnO and SiO2 treatments showed no significant differences in shoot growth compared to the control plants. However, ZnO application reduced shoot biomass, leaf area, SPAD, chlorophyll fluorescence and net photosynthetic rate under CaCl2 and NaCl CaCl2 stress. SiO2-treated plants had higher SPAD than the control plants under CaCl2 stress but presented lower values under NaCl CaCl2 stress. Root growth also showed contrasting results based on the stress conditions. SiO2 application resulted in increased root dry weight, total root length and surface area under non-saline and CaCl2 stress, while they decreased under NaCl stress. Similarly, ZnO application enhanced root growth under non-saline conditions, but demonstrated negative effects under all salinity stress conditions. In conclusion, SiO2 nanoparticle application did not improve salinity tolerance in lettuce, except for root growth under CaCl2 stress, and ZnO nanoparticle treatments showed phytotoxicity in both shoots and roots under all salinity stress conditions.
Speakers
avatar for Chungkeun Lee

Chungkeun Lee

Texas A&M University
Co-authors
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Coral 1

2:30pm HST

GG 2 - Identification Of Branched-Chain Amino Acid Derived Volatile Loci In Tomato (Solanum Lycopersicum) Using GWAS And WGCNA
Wednesday September 25, 2024 2:30pm - 2:45pm HST
A major focus in plant breeding has been the improvement of crops through various traits that affect disease resistance and yield. However, the focus on productivity has led to an inattentiveness to other traits that specifically affect produce quality. An example of a critical fruit quality trait is its flavor, contributing to our perception of aromatic volatiles. Even at nanomolar concentrations, aromatic volatiles can be perceived by the olfactory system and influence the liking of the fruit. The focus of this study was to investigate the genetic aspect of the branched-chain amino acid (BCAA) volatiles, derived from L-valine, L-isoleucine and L-leucine, in tomato fruits. It is generally considered that these BCAA-derived volatiles contribute positively to overall liking, because these are essential amino acids required by the human diet. To identify quantitative trait loci (QTLs) affecting the biosynthetic pathway for 11 BCAA-derived volatiles, a Genome-Wide Association Study (GWAS) was conducted using a diverse and unique panel of 167 tomato accessions. The GWAS was run using the FarmCPU model in GAPIT-R, with a total of 21,893,681 SNPs, 2,735,297 INDELs, and 154 structural variants across the genome. Furthermore, a weighted gene co-expression network analysis (WGCNA) was conducted in parallel to identify modules of co-expressed genes that cluster with known genes that affect the BCAA-derived volatile pathway. A total of 113 QTLs were identified from GWAS and 3024 co-expressed genes were identified from the WGCNA. Candidate genes were screened based on annotated biochemical function, overlap within the GWAS QTLs, and gene expression in the red-ripe fruits. This led to the identification of two candidate genes, one on the long arm of chromosome 1 and another on the long arm of chromosome 11. These genes are being knocked-out using CRISPR-Cas9, and current progress is aimed to confirm the validity and function of these genes in the near-future.
Speakers
AH

Austin Hart

University of Georgia
Co-authors
DT

Denise Tieman

University of Florida
EV

Esther van der Knaap

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

Manoj Sapkota

University of Georgia
NA
Wednesday September 25, 2024 2:30pm - 2:45pm HST
South Pacific 1

2:30pm HST

HEMP 2 - Investigating Fiber Hemp Seed Size Impact on Germination, Emergence, and Early Growth Rate
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Fiber hemp (Cannabis sativa L. <0.30 % total THC) seed represents the highest input cost for growers, as it is often imported and seeding rates are high to create an ideal stem diameter for quality purposes. Seed size in other agronomic crops can impact germination rate and early season growth. Hemp seed size varies tremendously among hemp genotypes. We evaluated the impact of seed size on germination rate, emergence, and seedling growth and physiology in two Chinese industrial hemp varieties Yuma 1 and Zhongma. We found that seed size impacted germination and radicle length in both varieties. However, these results did not translate into significant differences on emergence rate, photosynthetic parameters, or harvested plant biomass in the greenhouse. We did observe differences in net photosynthetic rate, transpiration rate, and stomatal conductance between varieties. Further research should evaluate season-long plant performance and economics based on seed size. In doing so we can optimize production standards and consequently farmer profitability.
Speakers
SC

Samantha Carroll

Graduate Research Assistant, North Carolina State University
Co-authors
AC

Amanda Cardoso

North Carolina State University
NA
DS

David Suchoff

North Carolina State University
NA
RY

Rong Yin

North Carolina State University
NA
Wednesday September 25, 2024 2:30pm - 2:45pm HST
South Pacific 2

2:30pm HST

POM 2/HPRB/IPR - Do Plant “Growth Regulators” Really Regulate Growth? Plant Development And Plant Growth Are Not Synonymous.
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Much scientific literature refers to plant development and growth as though they are synonymous. While plant physiology texts (E.g., Taiz et al. 2015) and horticulture texts (E.g., Sansavini et al. 2019) emphasize the roles of various plant hormones in coordinating plant development, they simultaneously refer to them as plant growth regulators. On the other hand, the same texts emphasize assimilation processes and the important role of carbohydrate and nutrient availability as well as water relations in enabling growth to occur. The terms growth and development are often used interchangeably and the literature rarely emphasizes the difference between plant development and plant growth. This causes confusion and a lack of clear thinking when attempting to develop explanations for plant growth responses in specific circumstances. Hormone physiologists often try to explain particular growth responses in terms of hormonal theory whereas environmental physiologists will likely explain the same responses in terms of environmental conditions and availability for the resources required for achieving growth. In this paper I will argue for a clearer differentiation between plant development and plant growth and suggest that plant hormones should not be thought of as plant growth regulators, but rather as plant development coordinators. Plant development coordinators (plant hormones) set up the conditions necessary for plant growth but availability of plant growth substances; carbohydrate and nutrient availability along with temperature and water relations, are often what actually regulate plant growth rates. Treating development and growth as separate but interdependent processes could clarify much understanding of the underlying processes involved in the regulation of plant growth. These concepts will be discussed in the context of understanding the mechanisms involved in several physiological phenomenon of fruit trees.
Speakers
TD

Ted DeJong

UC Davis
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Nautilus

2:30pm HST

PROP - The Application Timing of a Cytokinin B-Mo-based Product Affects the Growth and Non-Structural Carbohydrates Contents of Cuttings During Adventitious Root Development
Wednesday September 25, 2024 2:30pm - 2:45pm HST
A large group of horticulture species are propagated vegetatively through shoot-tip cuttings harvested from stock plants and planted to form adventitious roots. Adventitious root development (ARD) leads to establishing a carbohydrate sink in the region of root regeneration, which is highly dependent on energy and carbon skeletons. We hypothesized that enhancing the source-to-sink relationship during ARD can lead to an efficient carbon allocation to growth, resulting in a well-rooted cutting. Thus, the research aimed to determine if the application time of a Cytokinin B-Mo-based product during the ARD of unrooted cuttings would impact the source-to-sink relationship and, hence, affect plug growth and quality. The product was applied at four application times plus a negative control as follows: T1: plants without product (control), T2: sticking stage (starting 24 h after the sticking); T3: callus formation stage; T4: root development stage; and T5: toning stage. The experiment was a complete randomized design with five treatments and 60 repetitions for treatment (n=60) in two experimental runs (n=120). The root and shoot length, the number of leaves, the leaf chlorophyll content, the root and shoot dry matter, and the root-to-shoot ratio were measured. Results indicate that applying the product at T2 in ARD's dedifferentiation and induction phase leads to the shortest root and shoot length, the lowest dry matter accumulation, and some phytotoxicity effects. For T3 in ARD's initiation phase, the application results in greater root, total dry matter, and total soluble sugar contents than the control. For T4 in ARD's expression phase, the application results in greater growth, total dry matter, and sucrose and starch contents than control and other treatments. Applying the product in T5 when the roots had grown and reached all the edges of the growing media did not have any benefit compared to the control. Our results suggest that the exogenous application of a product to strengthen the source-to-sink relationship during adventitious root development can potentially enhance the non-structural carbohydrate contents when applied at the root formation phase (T4), which correlates positively with the increase in the length and dry matter of the roots, generating a well-toned rooted cutting.
Speakers
avatar for Mayra Toro Herrera

Mayra Toro Herrera

Postdoctoral Research Associate, University of Connecticut
Co-authors
RR

Rosa Raudales

University of Connecticut
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Lehua Suite

2:30pm HST

VCM 3 - Differential performance of Radicchio cultivars in New Hampshire
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Radicchio (Cichorium intybus var. latifolium) is grown widely throughout Europe, especially northern Italy. This crop features several groups that differ in color, shape, and culinary use, and there is considerable phenotypic variation among and within groups and cultivars. The New England growing climate is very different from that of major production regions in Europe and the pacific northwestern U.S. The availability of varieties to commercial growers in the U.S. has expanded greatly, but there remains a need for regionally relevant information about performance of these varieties. In Durham, NH, USA we grew 30 (2022) and 34 (2023) cultivars of radicchio belonging to seven main groups (Chioggia, Castelfranco, Treviso, Sugarloaf, Verona, Rosa del Veneto, and Lusia). In both years, they were seeded on 20-21 June, and transplanted on 14-15 July. Plants were harvested and weighed as they reached market maturity, or considered unmarketable due to bolting, rot, tipburn, or failure to head. We used standard cultural practices for the region: plants were grown in double rows on 30-inch-wide raised beds covered with white-on-black plastic mulch with drip irrigation. The weather in 2022 and 2023 differed greatly, with 2022 experiencing warm and dry conditions, and 2023 much wetter and cooler. The percentage of heads that became marketable ranged from 0-94% in 2022, and from 10-95% in 2023. Several cultivars had very high percentages of unmarketable heads, due to tipburn, rot, bolting, or failure to head. We also observed cultivar differences in susceptibility to powdery mildew. In both years, the cv. Rubro developed powdery mildew early and developed severe symptoms, several others eventually developed symptoms, and some never did. For traditional round red Chioggia types, several cultivars had very high percentages of marketable heads, and appear to be well adapted to production in the northeast. We identified cultivars within both sugarloaf and Treviso types that were well adapted, with high percentages of marketable heads. The cultivars we evaluated within the Lusia and Rosa del Veneto types were especially interesting from a culinary and attractiveness point of view, but had high percentages of rot (Lusia types) and very long days to maturity required (Rosa del Veneto types).
Speakers
avatar for Becky Sideman

Becky Sideman

Member-At-Large
Co-authors
LH

Lilly Hartman

University of New Hampshire
MH

Mark Hutton

University of Maine
PG

Peyton Ginakes

University of Maine
Wednesday September 25, 2024 2:30pm - 2:45pm HST
Kahili

2:45pm HST

CE 3 - An Intermediate Calcium-mobilizing Biostimulant Concentration Controls Tipburn of Two Greenhouse Hydroponic Lettuce Cultivars Without Affecting Growth
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Lettuce (Lactuca sativa) tipburn is a physiological disorder that leads to unappealing browning or necrosis of young leaf tips and stems, caused by localized calcium deficiency. It negatively impacts crop quality and yield, making proactive management essential for achieving optimal production. The objective was to evaluate the efficacy of a calcium-mobilizing chemical biostimulant, applied in the nutrient solution, on lettuce growth and tipburn. We conducted a greenhouse experiment on two lettuce cultivars (‘Dragoon’ and ‘Rex’) using a randomized complete block design. The seedlings were grown indoors under continuous white light from light-emitting diodes (LEDs) with a mean daily light integral (DLI) of 26 mol⋅m−2⋅d−1. We transferred 11-day-old seedlings to deep-water-culture hydroponic trays in a greenhouse. The two cultivars were subjected to three replications and five biostimulant concentrations (BC) of 0 (control), 0.125, 0.25, 0.5, and 1 mL⋅L−1 of the nutrient solution. Plants were grown under an 18-h photoperiod with a mean DLI of 16.6 ± 2.0 mol⋅m−2⋅d−1 from both sunlight and supplemental white LEDs, an air temperature of 24.6 ± 3.1 °C, and relative humidity of 33.2% ± 9.5%. Plant data were collected 14, 21, 28, and 35 days after transplant (DAT). There was no visible tipburn 14 DAT; however, plant diameter and shoot mass (fresh and dry) decreased with increasing BCs. We observed tipburn 21 DAT in both cultivars. The control had the highest severity on a 0–5 scale (0 = no tipburn; 5 = severe tipburn) for ‘Dragoon’ (0.6) and ‘Rex’ (1.3), whereas no tipburn occurred under higher BCs (i.e., 0.5 and 1 mL⋅L−1). Tipburn progressed 28 DAT, when increasing the BC from 0 to 1 mL⋅L−1 decreased the tipburn rating from 3.3 to 0 for ‘Dragoon’ and from 4.1 to 0 for ‘Rex’. Plant growth was stunted under the highest BC (i.e., 1 mL⋅L−1). At 35 DAT, both cultivars had severe tipburn under the control but had decreasing tipburn severity as the BC increased. Plant growth was unaffected under the control and low BCs (i.e., 0, 0.125, 0.25 mL⋅L−1). Under the highest BC, ‘Dragoon’ had the longest roots, but ‘Rex’ had the shortest. In contrast, plants experienced phytotoxicity (reduced biomass and chlorophyll concentration) under the highest BC, i.e., (1 mL⋅L−1) though no tipburn was recorded. In conclusion, the optimal calcium-mobilizing BC was 0.5 mL⋅L−1, which minimized tipburn of greenhouse hydroponic lettuce without affecting biomass accumulation or causing phytotoxicity during later development stages.
Speakers
QM

Qingwu Meng

University of Delaware
Co-authors
SM

Shem Msabila

University of Delaware
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Coral 1

2:45pm HST

GG 2 - From 'Agawam' to 'Zinfandel': Fruit Quality And Metabolite Diversity In The USDA Grapevine Repository
Wednesday September 25, 2024 2:45pm - 3:00pm HST
The USDA National Plant Germplasm System is a network of germplasm repositories dedicated to conserving genetic diversity of crops and their wild relatives. The USDA grapevine (Vitis) repository contains 5000 unique accessions representing 36 species, and is divided between two locations: Davis, CA and Geneva, NY. While this material is available for distribution to researchers and breeders, there is currently limited characterization data to help requestors identify accessions with unique and valuable traits, particularly for fruit quality. Thus, we began a germplasm screening project to measure fruit quality traits of 481 unique accessions from both locations spanning three years (2022-2024). Fruit samples were juiced, filtered through cheesecloth, and analyzed for Brix, titratable acidity, and available nitrogen. Additionally, composition of phenolic compounds was assessed using liquid chromatography-mass spectrometry (LC-MS), and aromas were detected using solid phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Overall, there was a wide range of diversity in fruit quality traits across the collection. Brix values ranged from 8.5 to 30.1 (average=17.8), and titratable acidity ranged from 2.7 to 25.6 g mol-1 Tartaric acid equivalents (average=8.2). The phenolic compounds commonly detected in grape juice included the anthocyanins malvidin 3-O-glucoside and peonidin 3-O-glucoside, the hydroxycinnamic acid caftaric acid, and the flavonols quercetin 3-O-glucuronide and isoquercetin. Analysis of aromatic compounds revealed accessions that contained higher amounts of linalool, β-myrcene, and geraniol, which are associated with a “Muscat” flavor profile, while others contained methyl anthranilate, which is associated with a “Foxy” flavor profile. We hope this fruit quality dataset not only proves to be a valuable asset to researchers utilizing the USDA Vitis repository, but may also open new directions of exploration into improved grape flavor, nutrition, and quality.
Speakers Co-authors
Wednesday September 25, 2024 2:45pm - 3:00pm HST
South Pacific 1

2:45pm HST

HEMP 2 - Modified Media and Lighting for Repeated In Vitro Cutting Cycles of Cannabis Sativa
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Micropropagation usually involves cytokinin in single-harvest batches. We report two in vitro studies with multiple harvest: (1) fed batch process with modified physical states and (2) LED light treatments. In (1), genotypes of Cannabis sativa were observed in stationary agar (A), stationary Oasis® infused with liquid (OIL) and agitated Oasis® infused with liquid (AOIL).Fifteen explants were planted in vessels with 120 mL DKW medium harvested on 3-week cycles, with 0 or 15 mL additional media. Harvested shoots, length, and dry mass from repeated cycles were recorded. Genotypes T1 and Peach failed on multiple harvest cycles and were eliminated, although single cycle had higher quality in OIL. BaOx and Cherry1 on OIL/AOIL with additions were better quality than A in five cycles. Shoots harvested increased from 15 to 30 in cycles 1-3 in OIL/AOIL, but in A were approximately 20, while length was longest in OIL/AOIL. By cycle 3, all measured responses were decreasing until cycle 5 where a minimum of 7 shoots per vessel or more were only in OIL, but shoots were too short to plant in greenhouse. In (2), blue and supplemental far-red were observed with in vitro shoots of BaoX and Cherry1. OIL treatments were placed in LED polychromatic and dichromatic light (white, high red:blue, medium red:blue, white w/5% far-red, high red:blue 5% far-red, medium red:blue w/5% far-red, low red:blue w/ 5% far-red) at similar intensities (190-240 µmols·m-2·s-116 h-photoperiod). Media additions were made with responses recorded bi-weekly. Five randomly selected microcuttings per vessel rooted ex vitro on mist bench for 16 days. Over multi-cycles, plants treated with 5% far-red increased number and length, while plants under higher blue light increased dry mass. Shoot number increased to 28 in cycles 1-3 with far-red, and 18 without before decreasing to initial 15 during cycle 5. The accumulated shoots per vessel over 5-cycles (10-weeks) was 108 with far-red, and 84 without. Shoot length in far-red-treated plants increased from 19 - 25 mm in cycle 3 before decreasing to 10 mm in cycle 5. Plants without far-red had 10 – 15 mm length the entire experiment. Dry mass was highest during cycle 1 with blue light before decreasing 50% in cycle 3, where it remained until cycle 5. Sixty-eight percent of shoots rooted regardless of prior in vitro treatment. OIL with media addition allowed shoots to be harvested five cycles, while signaling response of far-red light allowed increased productivity and length.
Speakers
MM

Molly McKay

Clemson University
Co-authors
EL

Elizabeth Luscher

Curio Wellness
NA
JF

James Faust

Clemson University
NA
JA

Jeffrey Adelberg

Clemson University
NA
MT

Matt Taylor

Curio Wellness
RK

Raghupathy Karthikeyan

Clemson University
NA
Wednesday September 25, 2024 2:45pm - 3:00pm HST
South Pacific 2

2:45pm HST

POM 2/HPRB/IPR - Using GDR to Enable Rosaceae Research - New Data, Functionality and Future Direction
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Initiated in 2003, the Genome Database for Rosaceae (GDR, www.rosaceae.org) is a comprehensive community database that provides access to curated and integrated genomics, genetics, and breeding data for the biologically and economically important Rosaceae family. It serves as steward of critical research and breeding data, and provides access to online query and analysis tools that enable researchers to readily interrogate this wealth of data, facilitating basic and applied research across Rosaceae. This presentation will highlight the impact of GDR on Rosaceae research, demonstrate new data and tools, and share plans for future development and sustainability options.
Speakers
avatar for Dorrie Main

Dorrie Main

Professor, Washington State University
I am a member of the Pullman Charter School Initiative team and am particularly interested in how to set up and maintain a thriving Washington State Charter School to serve the needs of Eastern Washington students.
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Nautilus

2:45pm HST

PROP - Characterizing the effects of PPFD and VPD during indoor acclimation of Chrysanthemum cuttings
Wednesday September 25, 2024 2:45pm - 3:00pm HST
During acclimation of unrooted cuttings (URC) under mist irrigation, the moisture status of URC is greatly affected by environmental conditions such as high photosynthetic photon flux density (PPFD) and vapor pressure deficit (VPD), both of which can cause rapid dehydration. The objective of this study was to characterize the effects of PPFD and VPD on indoor acclimation of Chrysanthemum ‘Olympia White’ URC. Cuttings were stuck in a peat-perlite substrate in propagation trays, placed under sole-source lighting in chambers where ultrasonic fog was used to automatically control relative humidity (RH). Mist irrigation was applied every 20 to 30 min for 3 h. Over 12 h, URC were exposed to 0, 35, 70, 80, 105, 140, or 210 µmol·m–2·s–1 PPFD and 70, 80, 90, or 100% RH setpoints, resulting in air VPD levels ranging from 0.02 to 0.59 kPa. In the chambers, there was a high level of environmental control, and PPFD did not affect air VPD (P = 0.712), which were therefore considered as independent climatic factors. Leaf temperature minus air temperature was considered an indicator of plant energy balance, where a warmer leaf than air temperature is a driver of evapotranspiration. Plant leaf temperature became cooler than the air temperature as air VPD increased (P = 0.024), likely caused by evaporative cooling of leaves. In contrast, increasing PPFD increased leaf temperature relative to air temperature, likely through radiant heating. Leaf VPD was positively correlated with air VPD (adjusted-R2 = 0.88) but was also affected by the interaction of PPFD and air VPD (P < 0.05). Two hours after misting was terminated (5 h total), some plants showed clear wilting especially under low RH. At 5 h, stomatal conductance and evapotranspiration of URC was increased by PPFD and decreased by air VPD (P < 0.01), although there was an interaction between PPFD and air VPD for stomatal conductance (P < 0.005). Further results highlighting responses to RWC, water uptake, and water loss will be presented.
Speakers
AS

Ana Sofia Gomez

Purdue University
Co-authors
CG

Celina Gomez

Purdue University
PF

Paul Fisher

University of Florida
NA
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Lehua Suite

2:45pm HST

VCM 3 - Comparative Analysis of Biodegradable Mulch Use in Hill-side Strawberry Production
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Comparative analysis of biodegradable mulch use in hill-side strawberry production Plastic film (PF) is widely used in crop production, yet global environmental concerns urge for reduced plastic waste. Biodegradable and bio-based mulches emerge as promising alternatives, potentially crucial for sustainable agriculture. This significance is emphasized by the hypothesis that small farms prioritize sustainability and seek to reduce plastic waste in soil and food systems, especially if these alternatives match or exceed the benefits of plastic mulch. However, there is limited data available on the effectiveness of biodegradable paper (BP) and bio-based film (BB) in small-scale crop production, an area frequently affected by heat and drought stress. A field experiment was conducted on a strawberry field in Redlands, San Bernardino County, California during the seasons of 2022 and 2023, respectively. This study was conducted to identify the most appropriate alternative to plastic mulch in hill-side production systems under the Mediterranean climate as it relates to yield and fruit quality at harvest day. We used four common mulches in small farms in California, polyethylene mulch (PE), landscape paper mulch (PA), Coconut liner mulch (CL), Biodegradable plastic mulch (MB), and bare soil (control) with the most popular ever-bearing variety, ‘Albion’. To investigate the suitability and efficacy of his mulches, we recorded the soil properties (temperature, moisture, and pH) daily, fruit yield (fruit weight and fruits/plant) biweekly, and fruit quality (Soluble solid and color) at harvest considering farm stand or U-pick sale service. Our results indicate that the highest total yield in terms of total fruit weight and number of fruits per plant grows under MB, CL, and PF mulch respectively. No notable differences were observed among treatments in fruit quality parameters such as soluble solids and color. The soil under the coconut coir liner had the highest moisture content, compared to PE, BDM, and bare ground treatments. No significant difference was found among the treatments in weed control. By the end of the cropping period, all treatments adequately covered the soil surface. However, in the buried part of the mulches, the PA mulch exhibited considerable degradation before the end of the season, while the MB showed faster signs of biodegradation. Based on crop productivity and the different mulch efficacy observed in our study, this production system with CL and MB is a good alternative to compare to PE and PA mulches for ever-bearing hillside strawberry production in the Mediterranean climate.
Speakers
avatar for Amrita Mukherjee

Amrita Mukherjee

University of California Agriculture and Natural Resources (UCANR)
Co-authors
NP

Nolton Pattio

Jehovah Jireh Farm
NA
Wednesday September 25, 2024 2:45pm - 3:00pm HST
Kahili

3:00pm HST

CE 3 - Optimizing Sampling Methods for Sap Extraction to Enhance Plant Nutrient Analysis in CEA
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Plant sap analysis is a technique for monitoring plant nutrient status in real-time, enabling precise nutrient management to enhance growth and yield in controlled environment agriculture (CEA). Comprehensive sampling techniques are vital for accurate determination of nutrient concentrations, considering the variability of nutrients across different developmental phases of plants. However, questions remain regarding the selection of the appropriate plant tissues, including the number of leaves collected, sampling time, type and age of plant tissue, and frequency. Different crops need specific sampling procedures due to their unique leaf morphology, growth habits, and physiology. Many commercial laboratories only distinguish between new and old leaves. In this series of studies, we determined the most effective sampling method including the number of leaves, the type and age of tissue, as well as the timing and frequency of the collection. Optimal sampling techniques were identified for lettuce and tomato by conducting five different experiments across three cultivars. These experiments varied the number of leaves sampled (10, 20, 30 per sample with three replicates), types of tissue (leaves for lettuce with three replicates, and petioles and leaves for tomatoes with 20 each per sample), age of tissue (new vs. old with 20 leaves per sample and three replicates), time of collection (6, 8, 10 am with three replicates). For lettuce, two developmental stages (half and final harvest maturity), while for tomatoes, sampling frequency at four different growth stages was investigated (first fully expanded leaves, 1/3 and 2/3 of crop development, and final harvest). The results indicate that collecting 20 fully expanded leaves at 8 am, particularly at the final harvest, was considered the best sampling technique for nutrient analysis for both lettuce and tomatoes, providing the most effective sampling technique for optimizing nutrient management.
Speakers
HR

Husnain Rauf

University of Georgia
Co-authors
DJ

Daniel Jackson

University of Georgia
NA
JL

Jason Lessl

University of Georgia
NA
JS

Jessica Staha

Local bounti
NA
MP

Miguel Puebla

Pure flavor
NA
RS

Rhuanito S. Ferrarezi

University of Georgia
NA
TC

Timothy Coolong

University of Georgia
ZR

Zilfina Rubio

University of Georgia
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Coral 1

3:00pm HST

GG 2 - Moving Beyond Montmorency: Exploring the Genetic Diversity of Tart Cherry
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Genetic diversity is invaluable to the sustainability of American horticulture. In the case of tart cherry, production in the United States is precariously reliant on a single cultivar, ‘Montmorency.’ Our research explores diverse genetic resources in tart cherry to promote utilization of high quality and locally adapted cultivars for plant breeding and improved production. Tart cherry nutritional quality is of particular interest to consumers. The United States Department of Agriculture Tart Cherry collection in Geneva, New York maintains 100 cultivars of tart cherry, including their wild relatives. Over a five-year period, we assayed fruit quality traits, including Brix, titratable acidity, and phenolic content. Total soluble solids (TSS) ranged from 10.9 to 20.7% (average=14.8%) and acidity (TA) ranged from 5.3 to 32.1 g/L (average=16.3%). The sugar/acid ratio ranged from 3.7 to 27.6 (average=10.2). Individual fruit weight ranged from 0.2 to 8.6 g (average of 5.0 g) and pit weight percentage ranged from 6-32% (average=11%). Total anthocyanin content varied from 75.2 to 3760.0 μg/g, with an average of 771.4 μg. We also evaluated bloom phenology over a three-year period. The distribution of bloom ranged from 56.7 to 134.4 GDD, with an average value of 86.0 Growing Degree Days (GDD ). ‘Montmorency’ bloom was above average with values around 95.8 GDD. Sweet cherries (63.5 – 90.6 GDD) tended to bloom much earlier than tart cherries (64.9 –118.0 GDD) and P. fruticosa, the wild progenitor of the tart cherry, bloomed the latest with a range of 85.3 to 134.4 GDD. For Brix, acidity, and phenolic content, ‘Montmorency’ falls significantly below average, though it has a balanced sugar/acid ratio. ‘Montmorency’ is lacking in anthocyanin content which is increasingly relevant for the juice industry. It tends to bloom later than other tart cherries evaluated, though there are some more extreme late bloomers. This data will be available through GRIN-Global, the USDA germplasm database to facilitate future research and breeding.
Speakers Co-authors
Wednesday September 25, 2024 3:00pm - 3:15pm HST
South Pacific 1

3:00pm HST

HEMP 2 - QTL mapping and gene discovery for seed traits in hemp (Cannabis sativa L.) F2 mapping populations
Wednesday September 25, 2024 3:00pm - 3:15pm HST
The emergence of a thriving hemp industry in the U.S. will depend on the breeding of high-yielding regionally adapted cultivars. Despite the latest research efforts, little is known regarding the genetic basis of important agronomic traits in hemp. The objective of this research was to identify and characterize genomic regions associated with seed morphology and quality traits. F 2 mapping populations were developed by crossing hemp germplasm bred or cultivated for cannabinoids (‘FL 58’ × ‘TJ’s CBD’), grain (GVA- H-20-1179 × ‘Picolo’), or fiber (‘Si-1’ × GVA-H-21-1003) market classes. These populations were investigated due to their variation in seed size and seed crude protein. The cannabinoid, grain, and fiber populations were grown and seed was harvested in 2021, 2022, and 2023, respectively. Harvested seeds were phenotyped for thousand seed weight (TSW) and crude protein content predicted by near-infrared (NIR) spectroscopy. The high-cannabinoid population was genotyped using an Illumina array, while the fiber and grain populations were genotyped using an Agilent SureSelect Custom Target Enrichment Probe Set. Marker-associated sequences were aligned to the CBDRx v.2.0 reference genome to align the physical and genetic maps. The TSW and protein content in the cannabinoid population ranged from 9.62 to 23.93 g and 19.25 to 31.89 %, respectively. In contrast, the TSW of the fiber and grain populations ranged from 7.34 to 45.17 g and 8.73 to 31.42 g, respectively. Numerous quantitative trait loci (QTL) of varying effect sizes were identified genome-wide. Notably, in the high- cannabinoid population, major and minor effect QTL for TSW were detected on Chr01 corresponding to 642 kb and 5.56 Mb genetic regions, respectively. Our results in the cannabinoid population highlight the importance of developing more than one F 2 mapping population in a given cross to capture the effect of more alleles due to high heterozygosity in hemp and evaluating distinct pedigrees to sample additional alleles in diverse genetic backgrounds. Narrowing the region around or identifying candidate genes will allow the development of high-throughput molecular markers for beneficial alleles across mapping pedigrees. These findings will accelerate hemp breeding programs through the implementation of marker-assisted selection for high-yielding and high-quality hemp cultivars for grain production.
Speakers
LM

Luis Monserrate

Cornell University
Co-authors
AW

Alexander Wares

Cornell University
NA
DW

Dustin Wilkerson

Cornell University
NA
GS

George Stack

Cornell University
NA
JT

Jacob Toth

Cornell University
NA
LS

Larry Smart

Cornell University
NA
LV

Lucia Vignale

Cornell University
NA
MQ

Michael Quade

Cornell University
NA
Wednesday September 25, 2024 3:00pm - 3:15pm HST
South Pacific 2

3:00pm HST

POM 2/HPRB/IPR - Raspberry Cultivar Evaluation Trial in Mississippi
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Many states in the US produce raspberries, however, most of the production is concentrated in three states: California, Oregon and Washington as most raspberry cultivars grow best in regions with cool summers and mild winters. However, newer raspberry cultivars have been developed exhibiting heat tolerance. Cultivars with heat tolerance provide an opportunity for the growers in the Southern states to include raspberries in their crop production. Local Mississippi growers are interested in incorporating raspberries into their productions. However, there lacks research-based recommendations on raspberry cultivars suitable for Mississippi's climate. The objective of this study was to evaluate raspberry cultivars in terms of plant growth, heat and cold tolerance, pest and disease resistance, berry yield, quality, and fruiting season to identify the best-suited cultivars for Mississippi. This experiment was conducted in a randomized complete block design with two types of fertilizer: conventional and organic. Data collection included measurements of plant growth and performance, berry yield and quality and fruiting season. The results showed that raspberry yield, single berry weight and fruit size were influenced by fertilizer treatment. The soluble solid contents, acidity, and fruit color were not influenced by fertilizer treatment. Raspberry yield was higher for “Polka”, “Encore”, “Heritage”, and “Latham” under conventional fertilizer. Cultivars “Himbo”, “Prelude”, ‘Bp1”, and “Encore” treated with conventional fertilizer had higher single berry weight. The average fruit size of cultivars “Prelude”, “Himbo”, “Encore”, “Bp1” treated with conventional fertilizer produced larger fruits in comparison to the other cultivars. The fruit's soluble solid content was highest in “Heritage”, indicating a sweeter taste. Cultivars “Polana” and “Anne” produced fruits with the highest acidity, indicating a tarter taste compared to other cultivars. Fruit color varied between cultivars, with differences in lightness, redness, and yellow coloration.
Speakers
avatar for Apphia Santy

Apphia Santy

Graduate Student, Mississippi State University
Hello! I'm passionate about the world of horticulture and am eager to explore and discuss various opportunities within the industry. I am particularly interested in pursuing a PhD in horticulture, with a specialization in either specialty crops or ornamentals. Additionally, I have... Read More →
Co-authors
GB

Guihong Bi

Mississippi State University
NA
TL

Tongyin Li

Mississippi State University
NA
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Nautilus

3:00pm HST

PROP - Asexual Propagation of Salix humilis Using Dormant Hardwood Cuttings After Stock Plant Coppicing and Fungicide Application
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Prairie willow (Salix humilis) is a naturally compact and adaptable shrub willow native to the eastern United States. This taxon has potential for use in managed landscapes because of its desirable habit, attractive flowers and foliage, and its purported tolerance to fluctuations in soil moisture. This adaptability could be advantageous for urban green infrastructure applications. However, unlike most willows, S. humilis is thought to exhibit recalcitrance to standard asexual propagation techniques. This recalcitrance is exacerbated by observed susceptibility to fungal infections that cause cutting mortality during propagation. Because juvenility can improve the rooting of propagules, we questioned whether stock plant rejuvenation (coppicing) and propagule treatment with fungicide would influence rooting and survival of S. humilis dormant hardwood cuttings. In February 2024, 300 full-length dormant stems were harvested at the USDA Plant Introduction Station in Ames, Iowa from stock plants that were either coppiced or not coppiced the previous year. Uniformly-sized basal cuttings were acquired by removing the proximal 23 cm of each stem. Experimental trials (N=300; n=75) evaluating the full factorial of stock plant status [non-coppiced (-coppice) or coppiced ( coppice)] and fungicide application [non-treated (-fungicide) or treated ( fungicide) by submerging propagules in T-Bird with 46.2% Thiophanate-methyl for 15 minutes] were conducted in a cool greenhouse at the University of Minnesota Horticultural Research Center in Chaska, MN. All cuttings were treated with 0.8% indole-3-butyric acid via Hormodin-3 Talc powder and stuck in 50 cell trays (5 × 5 × 12.5 cm cells) with a 1:1 perlite:bark-based media and placed on heat mats (22ºC) using a completely randomized design. Total number of propagules rooted, length of the longest three roots, and number of roots were recorded. Propagules were ranked on their overall rooting performance using a Likert Scale. Rooting percentage was 77%, 56%, 87%, and 69% for coppice/ fungicide, coppice/-fungicide, -coppice/ fungicide, and -coppice/-fungicide, respectively. Compared to the non-coppiced propagules, mean count of roots decreased by 41% for coppiced propagules, across fungicide applications. Compared to propagules not treated with fungicide, mean count of roots increased by 19% for propagules treated with fungicide, across coppice treatments. Future research will evaluate different types of cuttings to generate a complete vegetative propagation protocol for Salix humilis. This work supports the introduction of this versatile plant into commercial production, thereby augmenting the ornamental plant palette for challenging urban landscapes.
Speakers
HS

Hazel Schrader

Graduate Research Assistant, University of Minnesota Twin Cities
Co-authors
BM

Brandon Miller

University of Minnesota Twin Cities
Wednesday September 25, 2024 3:00pm - 3:15pm HST
Lehua Suite

3:15pm HST

CE 3 - Effects of Potassium and Iron Supplements and Late Nitrogen Restriction on Aquaponic Taro (Colocasia esculenta) Corm Production
Wednesday September 25, 2024 3:15pm - 3:30pm HST
The growing of taro in aquaponic systems has yielded corms significantly smaller than those grown terrestrially. Previous trials only partially supported the hypothesis that these low yields were due to excessive water and nitrogen levels late in vegetative development. A 2×2 (nitrogen restricted × supplemental fertilizer) factorial designed experiment was replicated 4 times in dual-tub systems. The 4 treatments tested were: 1) Fish effluent supplied throughout 10 months of plant development (T1); 2) Fish effluent restricted from the system at 6 months and fresh water supplied for the remaining 4 months of development (T2); 3) T1 plus supplemental potassium and iron fertilizer (T3); 4) Treatment 2 plus supplemental potassium and iron fertilizer (T4). The results indicate that the supplemental fertilizer was more important than effluent restriction late in development in enhancing corm growth, although effluent restriction did result in a higher maturity index of corms under supplemental fertilizer treatment. The corm yields were 140% higher in T3 (1.5 kg plant-1) than in T2 (0.63 kg plant-1). T4 had significantly more biomass partitioned into the corm (56% of total biomass) compared to T3 (44% of total biomass). The ratio of corm: total biomass is a key indicator of plant maturity and suggests restriction of high nitrogen effluent enhanced photosynthate translocation to the corm under supplemental fertilizer. Corm density was highest in T3 and lowest in T4, perhaps due to starch conversion to sugar in over-mature corms in T4. These results demonstrate the importance of supplementing potassium and iron fertilization, as well as restricting high nitrogen fish effluent late in taro corm development, to optimize taro yields and quality in aquaponic production systems.
Speakers
avatar for Andrew Bohringer

Andrew Bohringer

University of Hawai'i at Manoa
Co-authors
BK

Bradley Kai Fox

University of Hawai'i at Manoa
NA
EC

Eric Collier

University of Hawai'i at Manoa
NA
KW

Koon-Hui Wang

University of Hawai'i at Manoa
NA
RP

Robert Paull

University of Hawai'i at Mānoa
NA
TR

Theodore Radovich

University of Hawai’i at Mānoa
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Coral 1

3:15pm HST

GG 2 - Population affects growth and plant architecture in wild-collected Hydrangea quercifolia
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Hydrangea quercifolia, oakleaf hydrangea, a flowering shrub native to woodlands of the southeastern United States. Oakleaf hydrangea has immense ornamental potential with four-season interest, including traits like showy panicles, striking foliage textures, red fall color, and exfoliating bark. Cultivars are often derived from wild selections either directly or only a few generations removed. Full genetic and phenotypic variation has not been evaluated for the species, and little is known about the diversity in horticulturally important traits for oakleaf hydrangea. For this study, growth and plant architecture of wild-collected oakleaf hydrangea seedlings were observed at the Otis L. Floyd Nursery Research Center in McMinnville Tennessee over a 3-year period. Seedlings from 14 populations of oakleaf hydrangea spanning the species’ native range were planted in a randomized complete block design containing six blocks and nine replications per block. Two-way ANOVA was used to partition variation in height, width, growth rate, and number of stems into sources attributable to block, population, and block × population. There were significant differences among populations for growth rate, size, and number of stems in all years. Southern populations were smaller than northern populations and showed a slower growth rate. Genetic and phenotypic variation shown among populations will guide conservation efforts and supplement breeding efforts for oakleaf hydrangea.
Speakers
avatar for Lisa Alexander

Lisa Alexander

Research Geneticist, USDA-ARS U.S. National Arboretum
Co-authors
AS

A. Sherwood

USDA-ARS, Agricultural Research Service, North Central Regional Plant Introduction Station
CJ

C. Jennings

Tennessee State University
SH

S.C. Hokanson

University of Minnesota
Wednesday September 25, 2024 3:15pm - 3:30pm HST
South Pacific 1

3:15pm HST

HEMP 2 - Dynamics of Cannabinoid Accumulation and Morphological Changes in Cannabis Inflorescences
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Cannabis (Cannabis sativa L.) is cultivated for its cannabinoids, which have applications for therapeutic and recreational use. This phenomic evaluation explores accumulation of 16 cannabinoids of interest and associated morphological changes in Cannabis flowers. Eight cultivars of interest were grown in containers within an environmentally controlled greenhouse for 150 days (72 days reproductive). Light intensity, light duration, temperature, and relative humidity were regulated. Monitoring floral development, we observed a consistent increase in cannabinoid concentration as flowers matured, peaking in advanced stages of development. This accumulation pattern was consistent across diverse cultivars, which indicates this accumulation pattern to be the result of a fundamental biological mechanism. Concurrent with cannabinoid accumulation, we noted morphological changes in trichomes, which are widely utilized as markers of maturation within industry. Trichomes transitioned from sparse and translucent to abundant, enlarged, and displaying orange/amber hues as flowers matured, signifying floral maturation and trichome senescence. Importantly, a significant linear correlation emerged between cannabinoid accumulation and trichome morphological changes across all cultivars. This underscores a tight relationship between cannabinoid biosynthesis and trichome development, shaped by genetic factors. In summary, our findings demonstrate the intricate relationship between cannabinoid accumulation and floral morphology in Cannabis. Insights gained are invaluable for cultivar selection, breeding, and cultivation practices aimed at optimizing cannabinoid quantity and time to harvest. Understanding the underlying molecular mechanisms of cannabinoids promises tailored approaches for the optimization of cannabinoid production and the fostering of therapeutic and industrial advancements in Cannabis.
Speakers
SD

Samuel des Bordes

Ph.D. Candidate, Louisiana State University
Co-authors
BJ

Babitha Jampala

Louisiana State University
NA
HK

Heather Kirk Ballard

SPESS
Heather Kirk-Ballard is an Assistant Professor and state extension specialist of Consumer Horticulture for the LSU AgCenter. She is the host of the Get It Growing ™ extension program focusing on home gardening that is disseminated weekly through video to news stations and in print... Read More →
Wednesday September 25, 2024 3:15pm - 3:30pm HST
South Pacific 2

3:15pm HST

POM 2/HPRB/IPR - Evaluating Sufficiency Levels and Peach Leaf Analysis for Fertilizer Decision-Making
Wednesday September 25, 2024 3:15pm - 3:30pm HST
The increasing demand for tree fruit production necessitates optimizing nutrient balance in intensified orchard systems to maximize profits efficiently. While peach growers are advised to follow Extension and recommended guidelines for fertilization, such recommendations may not align with orchard-specific variables and environmental conditions. As a consequence, crop sufficiency ranges may require updating to reflect modern growing practices and environmental factors. Although leaf nutrient analysis is the most reliable method for diagnosing tree nutritional status, the prevalence of annual fertilizer application, driven by the low cost of fertilizers relative to crop value, often leads to excessive fertilization in peach orchards. Consequently, our objective was to evaluate established sufficiency levels and leaf analysis as tools for determining the need for annual fertilizer applications. To achieve this, we implemented a two-year study involving two fertilization programs in an orchard with three rows of 17 peach trees: two rows adhered to grower standard, annual fertilization, while the remaining row followed a rational fertilization program. The latter implied applying fertilizer only when leaf analyses indicated nutrient concentrations below established sufficiency thresholds for peaches. Leaf analyses were conducted annually in July, and if nutrient concentrations were within or exceeded sufficiency thresholds, no fertilizer was applied postharvest or the following spring. If nutrient concentrations fell below sufficiency thresholds associated with a significant difference in yield and fruit quality between the two programs, fertilization occurred in late summer and during bloom time the following spring. We assessed tree quality and productivity by measuring yield (total weight of all the fruit per tree) and fruit quality (size and brix) annually. The results of the first year showed that despite deficient leaf nitrogen and phosphorus concentrations and other nutrients such as potassium, calcium, and magnesium remaining within or above their sufficiency ranges, we observed no significant differences in yield or fruit quality between trees subjected to rational and standard fertilization practices. Consequently, fertilization for the upcoming year was deemed unnecessary in trees following the rational program. The outcomes of this study are expected to guide peach growers in making informed decisions based on updated data, reducing the environmental impact of overfertilization, which is inefficient for fruit production and uneconomical, and enhancing farm profitability.
Speakers
avatar for Richardson Bien Aime

Richardson Bien Aime

Graduate student, Clemson University
- Plant and environmental sciences- Horticulture- Optimization of Peach Fertilization- Peach rootstocks- Agricultural economics- Sports- Music
Co-authors
JC

Juan Carlos Melgar

Clemson University
NA
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Nautilus

3:15pm HST

PROP - Evaluation of Auxin Application and the Presence or Absence of Roots or Inflorescences in the Propagation of Variegated Carex wahuensis subsp. wahuensis
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Carex wahuensis subsp. wahuensis is an endemic Hawaiian species extensively used as a ground cover in landscaping and restoration. In recent years, a variegated form was identified and is now starting to be utilized in a handful of landscaping projects. While the green wild-type has been primarily propagated through seeds, protocols for single plant divisions are lacking and limits the commercialization and availability of the variegated form. In this study, we investigated the effect of indole-3-butyric acid (IBA) application as well as the presence or absence of roots and inflorescences on propagating single plant divisions of variegated C. wahuensis subsp. wahuensis. Container grown clumps were divided into single plantlets, with or without flowers and with or without roots (trimmed 7.6 to 10.2 cm length). For the first experiment, plantlets without flowers but with pre-existing roots were treated with or without 3000 ppm IBA and planted in 1:1 perlite and vermiculite. For the second experiment, plants with roots but with or without flowers, and plants without roots and flowers were also planted in 1:1 perlite and vermiculite. Both experiments were located on a mist bench, which activated every 2 minutes for 12 seconds, and both were allowed to root for up to 135 days. Root length and rooting index was recorded for the first experiment at 45 and 90 days after planting while rooting index was recorded for the second experiment at 45, 90 and 135 days after planting. Application of IBA did not improve root length and rooting index of plantlets. However, there was an observed difference in root length and rooting index between experimental runs. In the second experiment, plants with roots and no flowers exhibited the highest rooting index (3.3 = light rooting) followed by plants with no flowers and no roots (2.9 = alive but no roots to light rooting). Plants with flowers and roots exhibited the lowest rooting index (1.7 = mostly dead). Results of the study indicate that vegetative single plantlets of variegated Carex wahuensis subsp. wahuensis can be successfully rooted within 135 days after planting under mist.
Speakers
PM

Paulo Matos

Teaching Assistant, University of Hawai'i
Co-authors
OB

Orville Baldos

University of Hawaii
Wednesday September 25, 2024 3:15pm - 3:30pm HST
Lehua Suite

3:30pm HST

CE 3 - Advantages of a novel in situ pH measurement for soilless media
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Rhizosphere pH determines nutrient bioavailability, but this pH is difficult to measure. Standard pH tests require adding water to growth media. This dilutes hydrogen ion activity and increases pH. We used a novel, in situ, pointed-tip electrode to estimate rhizosphere pH without dilution. Measurements from this electrode matched a research-grade pH meter in hydroponic nutrient solutions. We then compared measurements from this electrode to saturated paste and pour-through methods in peat moss, coconut coir, and pine bark. The pointed-tip electrode was unable to accurately measure pH in the highly-porous pine bark media. Adding deionized water to the other media at container capacity using the saturated paste method resulted in a pH that was 0.59 ± 0.30 units higher than the initial in situ measurement at the top of the container. This increase aligns with established solution chemistry principles. Measurements of pH using the pour-through method were 0.38 ± 0.24 pH units higher than in situ measurements at the bottom of the container. We conclude that in situ pH measurements are not subject to dilution and are thus more representative of the rhizosphere pH than the saturated paste and pour-through techniques.
Speakers Co-authors
BB

Bruce Bugbee

Utah State University
NA
NL

Noah Langenfeld

Utah State University
NA
RH

Royal Heins

Utah State University
NA
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Coral 1

3:30pm HST

POM 2/HPRB/IPR - Common Mechanisms Controlling Fruit Shapes may be Mediated by Changes in Cell Wall Properties
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Fruit shape variation is abundantly present in horticultural crops. This variation is critical to highlight the market class as well as the culinary purpose of the produce. Many of the underlying genes have been cloned in tomato, offering insights into the molecular mechanisms of morphological diversity. Specifically, members of the OFP, TRM and SUN family regulate produce shape variation in tomato and other crops, thereby highlighting the importance of these three families in regulating phenotypic diversity. Despite the knowledge of the genes, mechanistic insights into the function of members of these three gene families are lacking. Our research on the tomato genes OVATE and OFP20 has shown that changes in produce shapes are noticeable early in the development of the flower. Cell counts in ovaries at anthesis implied that changes in cell division patterning may underlie morphological diversity. However, gene expression studies showed that morphological changes were associated with cell wall processes and not with changes in cell division patterning.
Speakers
EV

Esther van der Knaap

University of Georgia
Co-authors
YW

Yanbing Wang

University of Georgia
NA
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Nautilus

3:30pm HST

PROP - Evaluating the Effect of Plant Growth Hormone Types and Rates on Osmanthus spp. Propagation
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Osmanthus is a genus of ornamental plants with valuable qualities such as pest resistance, evergreen foliage, and aromatic flowers. However, different species respond differently to growth hormones for propagation. This study aimed to evaluate the types and rates of plant growth hormones on different species of Osmanthus propagation. Six distinct Osmanthus species (Osmanthus heterophyllus ‘Kaori Hime’, Osmanthus armatus ‘Jim Porter’, Osmanthus x fortunei ‘Patty's Secret’, Osmanthus heterophyllus ‘Rotundifolius’, Osmanthus delavayi, and Osmanthus x fortunei ‘Fruitlandii’) were treated with Indole-3-butyric acid (IBA) powder, 500 mg/L and 2000 mg/L of Potassium Indole-3-butyric acid (K-IBA), 10% Kelpak (seaweed extract), and water dip (the control). The cuttings’ survival rates, rooting rates, callus rate and area, and root length were recorded. The results showed the O. heterophyllus ‘Kaori Hime’ exhibited the best survival and rooting rates, while the O. heterophyllus ‘Rotundifolius’ had the lowest survival rate, the O. armatus ‘Jim Porter’ had the highest callus quantity. Plants treated with IBA powder had significantly larger callus area than those seaweed treatments. In conclusion, O. x fortunei 'Fruitlandii' and O. heterophyllus 'Kaori Hime' exhibit superior performance in all six measurements compared to other plant species and are highly recommended. Conversely, O. delavayi and O. heterophyllus 'Rotundifolius' have displayed considerably weaker performance and are not recommended. Further research is necessary to determine the effectiveness of other propagation methods and treatments for Osmanthus.
Speakers
avatar for Yulong Chen

Yulong Chen

The University of Georgia
Co-authors
LC

Lilin Chen

The University of Georgia
NA
PY

Ping Yu

University of Georgia
Wednesday September 25, 2024 3:30pm - 3:45pm HST
Lehua Suite

3:45pm HST

POM 2/HPRB/IPR - Pomological Nomenclature: Recent Developments and Problems
Wednesday September 25, 2024 3:45pm - 4:00pm HST
In addition to botanical names, at least a dozen distinct categories of nomenclature are applied to plant cultivars, including various forms of cultivar denominations, breeders references, and trade names. Two sets of rules, the International Code of Nomenclature for Cultivated Plants (9th ed., 2016), and the Explanatory Notes on Variety Denominations Under the UPOV Convention (2022) provide current guidelines for plant cultivar nomenclature. In some instances UPOV and ICNCP rules differ, and stakeholders may wish to consider whether it would be feasible to seek harmonization, and the mechanisms by which that might be achieved. This session will trace a brief history of cultivar denomination rules for U.S. plant patents. The United States Patent and Trademark Office, which issues plant patents, does not provide detailed nomenclatural guidelines. In the past two decades a new model for plant nomenclature has prevailed, in which an alphanumeric code serves as the official cultivar denomination, and this is paired with a trademark, either registered or unregistered. The relationship between cultivar denominations and trade names can be complex and fluid. As co-editor of the Register of New Fruit and Nut Cultivars, the presenter professionally researches all new pomological cultivar denominations and trade names, to avoid publishing names that conflict with previous names or nomenclatural standards. The establishment of an official cultivar denomination has important practical consequences that are sometimes ignored by breeders and rights owners. When a cultivar has been granted a plant patent or plant breeders’ rights, the cultivar denomination recorded by the statutory plant registration authority that issues the grant becomes officially established (a “statutory epithet”), and cannot be casually changed or replaced by the rights owner. When such informal synonyms are used, they are best regarded as trade names, often as unregistered trademarks. Common mistakes and pitfalls in nomenclature are described.
Speakers
DK

David Karp

University of California, Riverside
Wednesday September 25, 2024 3:45pm - 4:00pm HST
Nautilus

4:00pm HST

OPB 2 - QTL and Transcriptomic Analysis of Fragrance in the Auto-tetraploid Rose Population
Wednesday September 25, 2024 4:00pm - 4:15pm HST
For centuries, roses have been treasured for their therapeutic, cosmetic, and ornamental qualities. Among its many qualities, flower fragrance holds significant economic value. Over 400 volatile compounds contribute to the complex aroma of roses, with terpenoids, phenylpropanoids, and benzenoids playing dominant roles. Among these, geraniol, a monoterpene, contributes notably to the signature scent of rose oil. However, the fragrance of modern roses has gradually diminished as breeders have focused on enhancing other traits like appearance, adaptation, durability, and vase life. To gain a better molecular understanding of specialized metabolic pathways related to floral scent in roses we carried out QTL studies in the SWxBE autotetraploid rose population [Rosa L. ‘ORAfantanov’ (Stormy Weather™) x Rosa L. ‘Radbrite’ (Brite Eyes™)]. Our study suggests that the QTL for the fragrance was identified on chromosome 2 which colocalized with the genes involved with fragrance such as ODO1, EOBIII, and NUDIX. Two rose genotypes from the SWxBE population, ‘16401-N055’ (slightly fragrant) and ‘16089-N051’ (highly fragrant), were used for transcriptomic analysis. Gene expression analysis suggests that the monoterpenoid pathway was highly active in the highly fragrant rose with the NUDIX gene being highly expressed. Thus, NUDIX, a gene involved in geraniol biosynthesis, is a strong candidate gene for the QTL on chromosome 2. This study lays the groundwork for further exploration of the molecular pathways responsible for the scent of roses.
Speakers
HG

Haramrit Gill

University of California, Davis
NA
Co-authors
DB

David Byrne

Texas A
NA
JL

Jeekin Lau

US Department of Agriculture
NA
Wednesday September 25, 2024 4:00pm - 4:15pm HST
South Pacific 2

4:00pm HST

WCPM 2/IPR - Planting-hole Steam Application for Pathogen and Weed Control in Organic Strawberry in Southern California
Wednesday September 25, 2024 4:00pm - 4:15pm HST
Organic strawberry production has been expanding in California, but opportunities for crop rotation are limited due to lack of organically certified fields. Continuous strawberry production promotes soil-borne pathogens, such as Macrophomina phaseolina, the causal agent of charcoal rot and increases populations of weeds. These problems are exacerbated by lack of cost-effective management tools. In summer and fall production seasons at Oxnard, CA we evaluated pre-plant steam injection to raise soil temperature to 70 C or above for at least two minutes. Steam generated on-site was applied via four 25-cm long spikes to planting holes in raised beds covered with the plastic mulch. Five to ten days later, bare-root strawberry plants were placed in six steamed and six untreated plots and their performance and fruit production assessed. Additionally, we collected soil at 0-25 cm for analyses of resident Macrophomina phaseolina abundance before and after treatment and evaluated weed densities in planting holes. Steam application reduced M. phaseolina microsclerotia levels 80% in summer and 96% in fall. Steaming provided near 100% control of weeds germinated from the soil seed bank, but had no effect on germination of wind-dispersed weeds deposited to holes after steaming as was the case with fumigants. In summer season, strawberry mortality due to soil-borne pathogens was 12-18% in steamed plots and 70-75% in untreated soil. Due to loss of plants, marketable fruit yields in untreated plots were reduced 95% compared to steam treatment. No early-season plant mortality occurred in fall season but strawberry plants were 39 and 54% larger at two evaluation dates in steamed plots compared to untreated soil. We continue evaluations of fruit production and plant responses to soil pathogens. The completed work suggests that hole steaming may be very effective in suppressing soil-borne pathogens and weeds interfering with organic strawberry production in coastal California.
Speakers
OD

Oleg Daugovish

University of California Cooperative Extension
Co-authors
JB

Jenny Broome

UC Davis
NA
KI

Kelly Ivors

Driscolls
NA
OB

Oddbjorn Bergem

SoilSteam
NA
PH

Peter Henry

USDA-ARS
NA
Wednesday September 25, 2024 4:00pm - 4:15pm HST
South Pacific 3

4:15pm HST

OPB 2 - Assessing Micropropagation Traits in Anthurium Towards Breeding and Cultivar Development
Wednesday September 25, 2024 4:15pm - 4:30pm HST
The major bottleneck in anthurium cultivar release is the availability of microprogated plants for field testing. Genotype has been a major consideration for anthurium protocol development. Different genotypes vary in in vitro performance even when using optimized media, therefore assessing proliferative variation under in vitro conditions could help identify cultivars that could introgress tissue culture traits and provide guidelines for future protocol development. The objective of this study is to assess the in vitro performance of different anthurium accessions from the University of Hawaii anthurium breeding program under the RITA® temporary immersion system and to observe how lineage affects in vitro performance. To evaluate shoot initiation/proliferation, 20 accessions of anthurium (parents, interspecific hybrids, complex hybrids, and wild relatives) were placed in RITA® supplemented with a liquid medium containing 0.3X MS salts with 0.2 mg/L BA, 15% coconut water and 20 g/L sucrose. Primary shoots were excised after 45 days to allow axillary buds to develop into secondary shoots. Bud masses (trimmed explant bases) were placed on a solid medium containing ½ MS salts with 15% coconut water, 20 g/L sucrose and 2g/L gellan gum to observe shoot proliferation and growth. Parameters were analyzed using mixed models with time block as random effects and accessions as fixed effects. Previously identified check cultivars (‘Marian Seefurth’ and ‘New Pahoa Red’) were used as controls in this study. Significant differences among the genotypes were observed in terms of the number of primary shoots, the number of secondary shoots, total axillary bud mass volume (cm3), number of explants with shoot, and number of explants with roots. Three selections and an accession were identified to have potential use for breeding. UH2053, UH2409, UH2327 and ‘New Pahoa Red’ showed superior or comparable number of primary and secondary shoots, explant volume, and rooting compared to the check cultivars. These lines will be considered as parents in future crosses for cultivar development. Cluster analysis was also performed and was cross-referenced to existing pedigree and breeding records. Our analysis revealed five clusters which indicate that that parentage influenced in vitro shoot production particularly in lines with Anthurium andraeanum, A. amnicola, A. formosum and A. kamemotoanum in their background. Pedigree and breeding records are valuable resources for predicting response profiles of anthurium in vitro performance.
Speakers
JN

Jaclyn Nicole Uy

University of Hawaii
Co-authors
JO

Jacob Olarti

University of Hawaii
NA
TA

Teresita Amore

University of Hawaii
Wednesday September 25, 2024 4:15pm - 4:30pm HST
South Pacific 2

4:15pm HST

WCPM 2/IPR - Elucidating the Impact of Anaerobic Soil Disinfestation on Organic Watermelon Production in South Carolina
Wednesday September 25, 2024 4:15pm - 4:30pm HST
Weeds and soil-borne pathogens are limiting factors in organic watermelon (Citrullus lanatus) production. Yellow nutsedge (Cyperus esculentus) is a problematic weed for Southeastern watermelon growers. Fusarium wilt caused by Fusarium oxysporum f.sp. niveum (FON), is responsible for significant yield loss in watermelon production. Inefficient non-chemical tactics are an impediment to curtail weeds and soil-borne diseases in organic watermelon; and necessitate the adaption of an alternative strategic and holistic approach. Anaerobic soil disinfestation (ASD) has the potential to control weeds and soil-borne pathogens across a range of environments and crop production systems. ASD is a preplant chemical independent technique, which requires incorporation of labile organic carbon (C) sources into the soil, followed by tarping the soil with plastic mulch, and irrigating the soil to the saturation. Shifts in soil microbial communities and production of volatile organic compounds during ASD process are the main mechanisms that are believed to kill soil-borne pathogens and weeds seeds. The objectives of this study were to 1) determine whether ASD can suppress the emergence of yellow nutsedge, 2) compare the efficacy of locally available C sources, 3) evaluate if ASD can influence grafted and non-grafted watermelon yield. A field trial was conducted at Clemson University’s, Coastal Research and Education Center in Charleston, South Carolina in 2023. The study was arranged in a randomized complete block design with four replications. Main C sources were subjected to control (CT) with no C, chicken manure molasses (CMM), and cotton seed meal (CSM). All treatments were assigned as ASD with non-grafted (Powerhouse) and grafted (Carolina strongback) rootstock grafted to scion Powerhouse. Indicators of reduction in soils (IRIS) tubes paint removal (%), yellow nutsedge shoot count, and crop yield data were recorded. Higher anaerobic soil conditions and lower yellow nutsedge shoot count were observed in ASD plots. At the time of watermelon harvest, total number of yellow nutsedge shoot count were recorded as 65, 25, and 22 in CT, CSM, and CMM, respectively. Higher marketable fruit yield was recorded in ASD plots treated with CMM. Based on weed control and yield assessments, CMM to facilitate ASD is an ideal practice for growing organic watermelon in South Carolina.
Speakers
avatar for Sohaib Chattha

Sohaib Chattha

Graduate Research Assistant, Clemson University
Co-authors
BW

Brian Ward

Clemson University
MC

Matthew Cutulle

Clemson University
Wednesday September 25, 2024 4:15pm - 4:30pm HST
South Pacific 3

4:30pm HST

OPB 2 - Genotype Comparisons of Anthurium In Vitro Shoot Production in RITA® Bioreactors
Wednesday September 25, 2024 4:30pm - 4:45pm HST
Anthuriums are Hawaii’s top cut flower with its sales valued at USD1.6 M in 2022. It is an important floriculture crop as it is both used as cut flower and foliage. Development of new genotypes allows the growers in Hawaii to produce new cultivars desired by the market. The University of Hawaii anthurium breeding program has identified new selections to field test with commercial growers. In order to do so, the breeding program propagates these selections to send to growers. Recently the use of bioreactors, such as RITA® on ‘New Pahoa Red’, resulted in three times more shoot production than in traditional flasks placed on a platform shaker. Shoot and root production and axillary bud mass volume of three new selections, UH2647, UH2651, and UH2652, were compared against the control ‘New Pahoa Red’. Ten nodes of each genotype were placed in a RITA® bioreactor, and replicated five times in a completely randomized design. Nodes were cultured in liquid medium consisting of 0.3MS, 0.1 mg l-1 BA, 15% coconut water, 20 g l-1 sucrose, and 1 ml l-1 NaSiO3. The plants were cultured in the bioreactors for 1.5 months, and then removed to obtain the number of shoots, roots, and axillary bud mass volume. Primary shoots were excised and transferred to 0.3 MS, 15% coconut water, 20 g l-1 sucrose, and solidified with 6 g l-1 Gelzan® to promote axillary bud growth and shoot development. The pH for all media was adjusted to 5.8. One month later, shoots (~0.5 cm in height) were excised from the axillary bud masses. Shoot counts excised after initial culture in the liquid medium and after placement in the shoot development solid medium were analyzed using one-way ANOVA on R studio. Axillary bud mass volume and root number were analyzed. UH2647 significantly produced more shoots than UH2652 and ‘New Pahoa Red’, while UH2651 was not different from any genotype. UH2647 also had the highest average axillary bud mass volume. UH2651 and UH2652 produced significantly more roots than the control. Knowing the genotypic differences in shoot production will assist propagation facilities in developing guidelines to schedule production of individual genotypes.
Speakers
JO

Jacob Olarti

University of Hawaii
NA
Co-authors
JN

Jaclyn Nicole Uy

University of Hawaii at Manoa
TA

Teresita Amore

University of Hawaii
Wednesday September 25, 2024 4:30pm - 4:45pm HST
South Pacific 2

4:30pm HST

WCPM 2/IPR - Alternative Carbon Sources for Anaerobic Soil Disinfestation in California Strawberry
Wednesday September 25, 2024 4:30pm - 4:45pm HST
Anaerobic soil disinfestation (ASD) has been adopted in approximately1,000 ha in California strawberry production as an alternative to chemical fumigation of soil. Rice bran, the predominant carbon source for ASD, has become increasingly expensive. In 2022-2024 field studies at Santa Paula and Oxnard, CA we evaluated 20-30% lower-priced wheat middlings (Midds) at 6 or 7 t/acre as alternative carbon sources to rice bran. The ASD treatments were applied in August at each location in preparation for strawberry planting in October. Soil and air temperatures were 18-35 C during that time. After incorporation of carbon sources into the top 30 cm of bed soil, beds were shaped, irrigation drip lines installed and covered with totally impermeable film (TIF) to prevent gas exchange. Beds were irrigated to full capacity within 24 to 72 hours after TIF installation. Anaerobic conditions were measured with oxidation reduction potential (ORP) sensors placed at 15 cm depth. Midds plots maintained Eh at -180 to 0 mV during the two ASD weeks at Santa Paula and -300 to 0 mV during five weeks at Oxnard, while untreated soil was aerobic at 200 to 400 mV. At Santa Paula, permeable bags with inoculum of Macrophomina phaseolina, a key soil borne pathogen of strawberry, and tubers of Cyperus esculentus, the most difficult to control weed, were placed 15 cm deep in soil and retrieved two weeks after ASD initiation for analyses. At Oxnard, resident populations of M. phaseolina and C. esculentus in soil were assessed before and after ASD. Two weeks after the completion of ASD, holes were cut to aerate beds and bare-root strawberry were transplanted into them: ‘Fronteras’ at Santa Paula and ‘Gaviota’ at Oxnard. ASD with Midds reduced viable microsclerotia of M. phaseolina 75% at Santa Paula and 98% at Oxnard. ASD treatments reduced tuber germination of C. esculentus 68-74% compared to untreated soil. Additionally, Midds and DDG provided greater sufficiency of plant-available nitrogen and increased fruit yields 40%, compared to untreated soil at Santa Paula. We continue fruit production evaluations at Oxnard in 2024. ASD with wheat middlings as a carbon source can suppress soil pathogens and weeds and help sustain organic strawberry production in California.
Speakers
OD

Oleg Daugovish

University of California Cooperative Extension
Co-authors
PH

Peter Henry

USDA-ARS
NA
Wednesday September 25, 2024 4:30pm - 4:45pm HST
South Pacific 3

4:45pm HST

OPB 2 - Treatment with Oryzalin Induces Chromosomal Changes in Salvia coccinea and Salvia splendens
Wednesday September 25, 2024 4:45pm - 5:00pm HST
Salvia coccinea (diploid) and Salvia splendens (tetraploid) and their associated cultivars are widely available, commercially profitable, and environmentally supportive flowering annuals. In recent years, exciting cultivars have been successfully introduced. This investigation explores further development of S. coccinea ‘Summer Jewel Lavender’, S. coccinea ‘Hummingbird Forest Fire’, and S. splendens ‘Mojave Red and White Bicolor’ through treatments by oryzalin for the potential development of novel cultivars. Surflan™ or oryzalin (4-(dipropylamino)-3,5-dinitrobenzenesulfonamide) and the nonionic surfactant SilEnergy™ were applied as a foliar spray for one, two, three, and six days to induce changes in chromosome numbers. Data collected included morphological observations, measurements of foliage and flowers, flower numbers, and ploidy analysis via a CytoFLEX™ flow cytometer. Ploidy changes were achieved in seedlings across all the treatment groups. Novel traits were identified, ranging from smaller overall growth habits and foliage, larger and increased numbers of flowers, and new floral pigmentation while maintaining vigor and potential for container production. Optimization of treatments will be discussed. The findings of this research have practical implications for plant breeders, landscape designers and architects, horticulturists, and environmental researchers as the market continues to demand drought-tolerant, low-growing, long-flowering, and pollinator-attracting plants.
Speakers
avatar for Brad Davis

Brad Davis

UGA College of Environment and Design
Co-authors
JR

John Ruter

University of Georgia
Wednesday September 25, 2024 4:45pm - 5:00pm HST
South Pacific 2

4:45pm HST

WCPM 2/IPR - Sweetpotato (Ipomoea batatas) Variety Tolerance to Different Herbicidal Weed Control Methods
Wednesday September 25, 2024 4:45pm - 5:00pm HST
There are limited herbicides labeled for use in sweetpotato (Ipomoea batatas) production in the United States. Therefore, the registration of additional herbicides with different modes of action (MOA) would provide growers added weed control options to enhanced crop yield and provide a more sustainable sweetpotato (SP) production system. As herbicide-resistant weed populations continue to emerge and become more prevalent, weed control strategies need to include herbicides with different MOAs for the long-term success of (SP) cultivation. This research will identify herbicides, along with rate and application time that could be registered for use in sweetpotato. Herbicide tolerance of four (SP) varieties (Beauregard, Orleans, Dianne, and Covington) were evaluated in a screening study. These varieties were selected to represent sweetpotato production areas across the United States in Arkansas, California, Louisiana, Mississippi, and North Carolina. Herbicides evaluated include fluridone, glyphosate, glufosinate, carfentrazone, saflufenacil, acifluorfen, and others. The study involved the foliar application of herbicide treatments at 1X and 0.5X rates, laid out in a completely randomized design, using a spray chamber onto individual (SP) plants cultivated in 4x4 inch containers within the controlled environment of the Dorman Hall Greenhouse at Mississippi State University. Visual assessments of herbicide-induced injury were conducted at regular intervals of 7, 14, 21, and 28 days after treatment (DAT), accompanied by measurements of vine length in centimeters. Furthermore, dry root and shoot biomass were quantified at 28 DAT to provide a comprehensive assessment of herbicide impacts on (SP) growth and development. Data was analyzed using ANOVA and means separated by Fisher’s protected LSD (α=0.05). Results indicate varying levels of tolerance among the (SP) varieties to specific herbicides and application rates. Noteworthy trends in visual injury, vine length, and biomass measurements highlight the nuanced responses of the cultivars to different herbicide chemistries.
Speakers Co-authors
MS

Mark Shankle

Mississippi State University
Wednesday September 25, 2024 4:45pm - 5:00pm HST
South Pacific 3

5:00pm HST

WCPM 2/IPR - Assessment of Various Carbon Sources for Anaerobic Soil Disinfestation to Manage Weeds in Organic Sweetpotato
Wednesday September 25, 2024 5:00pm - 5:15pm HST
Yellow nutsedge (Cyperus esculentus L.) management in organic plasticulture systems is challenging as it reproduces both by seeds and tubers. Yellow nutsedge has a strong midrib and sharp leaf tip which allows it to puncture plastic mulch and creates favorable conditions for other weeds to grow, compete for resources with crop plants, and decrease crop yield. Lack of available herbicide options in specialty crops make weed management more challenging. Anaerobic soil disinfestation (ASD) is a technique that has shown potential to manage weeds in organic production systems. ASD is facilitated by incorporating carbon sources into the soil, tarping the soil with plastic mulch, and irrigating to the soil saturation. A field study was conducted at Clemson University’s Coastal Research and Education Center, Charleston, South Carolina, to evaluate the impact of various carbon sources in ASD on weed management in organic sweetpotato. This treatment structure for this study consisted of a factorial with four carbon source treatments (cotton seed meal, chicken manure molasses, brassica waste, and non-amended control) and four sweetpotato cultivars (Bayyou Belle, Muraski, Monaco, and USDA 18-040). These sweetpotato cultivars have two different growth habits, either bunch type (USDA 18-040 and Monaco) or spreading type (Bayyou Belle and Muraski). The primary purpose of using different plant architecture is to evaluate the impact of the sweetpotato vine growth habit on weed emergence. Experimental plots receiving chicken manure molasses and cotton seed meal as carbon source resulted in the greatest cumulative anaerobic conditions (
Speakers
SS

Simardeep Singh

Clemson University
Co-authors
Wednesday September 25, 2024 5:00pm - 5:15pm HST
South Pacific 3

5:15pm HST

WCPM 2/IPR - Evaluation of saturated steam with boiling water to control Guinea grass (Megathyrsus maximus) in riparian landscapes in Hawaii.
Wednesday September 25, 2024 5:15pm - 5:30pm HST
Boiling water and steam have been effectively used as a non-chemical means to control weeds in croplands and urban areas. In Hawaii, it is a relatively new technology with limited trials done on local conditions and weeds. Guinea grass (Megathyrsus maximus) is a noxious weed that invades landscapes and agricultural fields in Hawaii and throughout the world. While it is typically controlled using herbicide sprays, this may be restricted if the guinea grass being controlled is located in riparian areas. In this study, we evaluated the efficacy of saturated steam with boiling water in controlling mature clumps of guinea grass growing along a streambank. Guinea grass bunches were divided into small (less than 15.2 cm) and large clumps (15.2 to 30.5 cm) and then cut 5 to 15 cm from the ground. Cut clumps were either not treated (control) or treated with saturated steam and boiling water for 1 minute using a 15cm long spike injector inserted into different points of the crown. Percent green color and number of resprouts were collected 7, 14, and 21 days after application. Dry biomass was collected 22 days after application. Results indicate that saturated steam with boiling water was effective in controlling guinea grass clumps. Small clumps were completely controlled (no resprouts and new biomass) while large clumps had significantly reduced the number of resprouts and reduced production of new biomass. Saturated steam with boiling water offers a non-chemical means to control guinea grass in riparian areas in Hawaii.
Speakers
avatar for Hannah Lutgen

Hannah Lutgen

Extension Faculty, University of Hawaii at Manoa, College of Tropical Agriculture & Human Resources (CTAHR)
As an Extension Agent faculty member at the University of Hawaiʻi at Mānoa College of Tropical Agriculture and Human Resources (CTAHR), I analyze issues, create programs, and conduct activities that meet client needs to support landscape professionals, ornamental and cut flower... Read More →
Co-authors
OB

Orville Baldos

University of Hawaii at Manoa
RG

Rosemary Gutierrez Coarite

University of Hawaii at Manoa
Wednesday September 25, 2024 5:15pm - 5:30pm HST
South Pacific 3
 


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