ASHS 2024 Conference: Full Schedule

4:00pm HST

Surfing the Professional Pipeline at the Career and Graduate School Fair

Monday September 23, 2024 4:00pm - 5:30pm HST

Companies, organizations, universities, and government offices are invited to reserve a free exhibitor table.

Click here to reserve a table.

Students and professional attendees are invited to meet with representatives of hiring companies and organizations, and to learn more about potential jobs and graduate school programs.

Monday September 23, 2024 4:00pm - 5:30pm HST
Coral 1

Career and Professional Development, Student Activities

SUBJECT Professional Development/Career

9:59am HST

Growth Chambers and Controlled Environments 1 (CE 1)

Tuesday September 24, 2024 9:59am - 12:00pm HST

Coral 1

Transcriptomic Analysis of Kale (Brassica oleracea) Grown Under Different Light Emitting Diode Wavelengths Revealed Potential Genes Responsible for Phenotypic Changes - Tristan Sanders
Blue Light Mediates Far-Red Light Effects on Increasing Leaf Area and Shoot Mass of Kale and Lettuce - Jiyong Shin
Interactions Between Blue Light and Far-Red Light on Growth of Culinary Herbs - Bridget Knight
Blue and Green Light and Temperature Interactively Regulate Growth, Morphology, Physiology, and Phytochemicals of Lettuce - Sangjun Jeong
Switching From Low to High Blue Light Before Harvest Increases Nutritional Quality While Maintaining High Biomass in Red-leaf Lettuce Under Elevated CO2 - Shem Msabila
Supplemental Blue and UV-B Light Enhances Amino Acid-Derived Flavor Compounds in Greenhouse-Grown Tomatoes - Samikshya Bhattarai
Characterizing the effect of blue light on water relations of unrooted cuttings during indoor acclimation - Ana Sofia Gomez
Shedding Light on Nutrition: The Influence of Supplemental Lighting on Glucosinolate Concentrations in Brassica Plants and Their Potential Anticarcinogenic Effects in Human Diets - Skyler Brazel

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Tuesday September 24, 2024 9:59am - 12:00pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:00am HST

CE 1 - Transcriptomic Analysis of Kale (Brassica oleracea) Grown Under Different Light Emitting Diode Wavelengths Revealed Potential Genes Responsible for Phenotypic Changes

Tuesday September 24, 2024 10:00am - 10:15am HST

Coral 1

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

Speakers

Tristan Sanders

West Virginia University

Co-authors

Janet Tou

West Virginia University

Nicole Waterland

West Virginia University

Youyoun Moon

West Virginia University

Tuesday September 24, 2024 10:00am - 10:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:15am HST

CE 1 - Blue Light Mediates Far-Red Light Effects on Increasing Leaf Area and Shoot Mass of Kale and Lettuce

Tuesday September 24, 2024 10:15am - 10:30am HST

Coral 1

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

Speakers

Jiyong Shin

Michigan State University

Co-authors

Erik Runkle

Michigan State University

Tuesday September 24, 2024 10:15am - 10:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:30am HST

CE 1 - Interactions Between Blue Light and Far-Red Light on Growth of Culinary Herbs

Tuesday September 24, 2024 10:30am - 10:45am HST

Coral 1

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

Speakers

Bridget Knight

Michigan State University

Co-authors

Erik Runkle

Michigan State University

Tuesday September 24, 2024 10:30am - 10:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

10:45am HST

CE 1 - Blue and Green Light and Temperature Interactively Regulate Growth, Morphology, Physiology, and Phytochemicals of Lettuce

Tuesday September 24, 2024 10:45am - 11:00am HST

Coral 1

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

Speakers

Sangjun Jeong

Texas A

Co-authors

Genhua Niu

Texas A

Shuyang Zhen

Tuesday September 24, 2024 10:45am - 11:00am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:00am HST

CE 1 - Switching From Low to High Blue Light Before Harvest Increases Nutritional Quality While Maintaining High Biomass in Red-leaf Lettuce Under Elevated CO2

Tuesday September 24, 2024 11:00am - 11:15am HST

Coral 1

Growing food crops in space supports astronauts’ dietary needs in long-duration space missions and necessitates efficient use of light. In red-leaf lettuce (Lactuca sativa), sufficient red (R) and far-red (FR) light promote extension growth, whereas sufficient blue (B) light restricts extension growth but enhances secondary metabolite accumulation. Green (G) light also contributes to photosynthesis and improves visual quality. Compared to fixed light spectra, we evaluated dynamic light spectra to balance harvestable biomass and nutritional quality of red-leaf lettuce ‘Outredgeous’ under elevated CO2 concentration (≈2794 μmol⋅mol–1) and intermediate relative humidity (≈48%), typical on the International Space Station. This ground-based growth chamber experiment was performed twice following a randomized complete block design. We grew plants hydroponically at ≈22 °C under light-emitting diodes (LEDs) with four fixed light spectra and four dynamic light-spectrum alternations. The four fixed light spectra from seed to harvest were B60R140, B10R190, B10G50R140, and B10R140FR50 (the subscript following each waveband denotes its photon flux density in μmol·m−2·s−1). The four dynamic light-spectrum alternations switched among B10R190, B10G50R140, and B10R140FR50 in the lag (day 0–11) and exponential growth (day 11–25) phases, followed by B60R140 in the finish phase (day 25–28). Plant data were collected 11 and 28 days after sowing for seedlings and mature plants, respectively. Among the fixed light spectra, increasing the B photon flux density decreased shoot mass by 28% to 39% but increased total phenolic concentration by 27% to 45% in mature plants. Partial substitution of R light with G light decreased shoot mass by 31% to 42% in seedlings, but not mature plants. Partial substitution of R light with FR light did not influence shoot mass of seedlings or mature plants. Compared with fixed low B light treatments, dynamic light-spectrum alternations with high B light in the finish phase did not affect shoot mass, root mass, or leaf number while increasing total phenolic concentration by 8% to 25%. In addition, partial substitution of R light with G or FR light during the lag or exponential growth phase did not influence shoot or root mass. We conclude that low B light in the lag and exponential growth phases followed by short-term high B light in the finish phase improves lettuce nutritional quality without decreasing biomass as seen under long-term high B light. Spectrum selection in the earlier phases should prioritize the photosynthetic photon efficacy of LEDs to maximize light use efficiency.

Speakers

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

Tuesday September 24, 2024 11:00am - 11:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:15am HST

CE 1 - Supplemental Blue and UV-B Light Enhances Amino Acid-Derived Flavor Compounds in Greenhouse-Grown Tomatoes

Tuesday September 24, 2024 11:15am - 11:30am HST

Coral 1

Tomato production under controlled environmental conditions presents challenges due to the selective permeation of solar radiation within enclosed structures or the limited wavelengths produced by artificial light sources. Despite these challenges, growers increasingly opt for such production systems due to the enhanced uniformity and yield of fruit compared to open-field cultivation. However, controlled environment conditions, particularly greenhouses, often limit specific wavelengths of light, including blue and UV-B radiation. This limitation has the potential to alter flavor and overall fruit quality. Therefore, the present investigation examined how supplemental blue and UV-B light, independently and in combination, influence the levels of amino acid–derived flavor compounds, particularly those derived from branched-chain and aromatic amino acids, in two tomato varieties, Plum Regal (PR, commercial) and TAM HOT-Ty (THT, Texas A

Speakers

Samikshya Bhattarai

Graduate Research Assistant, Texas A&M University

Co-authors

Bhimanagouda Patil

Texas A

Deepak Jha

Texas A

Shuyang Zhen

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:30am HST

CE 1 - Characterizing the effect of blue light on water relations of unrooted cuttings during indoor acclimation

Tuesday September 24, 2024 11:30am - 11:45am HST

Coral 1

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

Speakers

Ana Sofia Gomez

Purdue University

Co-authors

Celina Gomez

Purdue University

Tuesday September 24, 2024 11:30am - 11:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

11:45am HST

CE 1 - Shedding Light on Nutrition: The Influence of Supplemental Lighting on Glucosinolate Concentrations in Brassica Plants and Their Potential Anticarcinogenic Effects in Human Diets

Tuesday September 24, 2024 11:45am - 12:00pm HST

Coral 1

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

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Caleb Zepeda

University of Tennessee - Knoxville

Carl Sams

University of Tennessee

Samantha Nuzzi

Donald Danforth Plant Science Center

Tessa Burch-Smith

Donald Danforth Plant Science Center

Tuesday September 24, 2024 11:45am - 12:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 1

SUBJECT Growth Chambers and CE

12:15pm HST

Interest Group Session: Growing Together: Enhancing Accessibility, Engagement and Inclusion in the Horticulture Society

Tuesday September 24, 2024 12:15pm - 1:45pm HST

Coral 1

Growing Together: Enhancing Accessibility, Engagement, and Inclusion in the Horticulture Society

Accessibility, inclusion, and engagement are foundational to any society, including our own American Society for Horticultural Sciences, ensuring that every community member can contribute to and benefit from the diverse array of knowledge, perspectives, and experiences within the fields of horticulture and plant sciences. This special interest group session is dedicated to fostering these principles within the broader horticultural society, the green industry, and the gardening community. The meeting aims to unite ASHS members who share a passion for the art, science, and business of plants, gardens, landscapes, and gardening, making these accessible to everyone, irrespective of their abilities or backgrounds.

Committee members Heather Kirk-Ballard, Assistant Professor of Consumer Horticulture at Louisiana State University and Sam Humphrey, Graduate Research Association at North Carolina State will lead a discussion to address key topics such as strategies for creating more inclusive systems. We will discuss practical ways to interact, cultivate, and enhance diversity within our workforce and society, aiming to break down barriers that can perpetuate disparities.

In this session, we will discuss the findings from the recent ASHS DEIJA committee climate survey that examined the feedback from members regarding the impact of diversity, equity, inclusion, and justice within the American Society for Horticultural Sciences. We acknowledge the resistance some may have towards the formation of a diversity and inclusion committee. As many organizations face similar backlash against DEI initiatives, often due to misunderstandings or perceived threats to the status quo, it is essential to engage in transparent and constructive dialogue. Our aim is to clarify the objectives and benefits of DEI, underscoring its role in promoting fairness, opportunity, and representation for all members of the organization.

The session will include discussions about accessible practices, presentations and workshops that can be designed for individuals with physical disabilities or mobility issues. Strategies to increase participation from diverse community members. This could involve outreach programs for schools, collaboration with a greater community, and events that cater to a wide demographic. Developing programs that cater to people of all ages, abilities, and ethnic backgrounds. This may include bilingual garden tours, programs for the visually impaired, and workshops tailored for elderly gardeners. The meeting also provides a platform for members to share their experiences and best practices in creating inclusive environments. There will be networking opportunities to foster collaborations and partnerships among participants, aiming to build a supportive community that values diversity and inclusion in horticulture. The objective of this meeting is to establish clear, actionable steps that the society can implement to enhance accessibility and engagement. This will ensure that all members of the broader community can fully benefit from the opportunities offered by horticulture.

Coordinator(s)

Heather Kirk Ballard, SPESS, School of Plant, Environmental and Soil Sciences, Baton Rouge, EBR, United States
Samson Humphrey, NCSU, Raleigh, North Carolina, United States

Moderator

Heather Kirk Ballard

Samson Humphrey

NCSU

N/A

Tuesday September 24, 2024 12:15pm - 1:45pm HST
Coral 1

Interest Group Session

SUBJECT Professional Development/Career

2:00pm HST

Interest Group Session: Speed Networking: Making Collaboration Easy

Tuesday September 24, 2024 2:00pm - 4:00pm HST

Coral 1

Meeting new people is one of the best ways to start collaborating. It can be difficult to meet new people even at the annual conference with so many disciplines represented. This session /event will provide the following impacts:

Enhance and develop connections of ASHS members with each other.
Create a structured time and space for low-pressure conversations and introductions.
Practice elevator speeches and first impressions for aspiring and experienced professionals.
Increase potential collaborations across disciplines and ASHS members.

The goal of this session is for participants to meet 10 to 15 people at the conference in a fast but low-pressure time.

The Partnership Development Committee (PDC) will create a signup sheet for the event to gauge the number of participants so that the room can best be set along with the time each pair has to converse. All members are welcome, even those who did not sign up prior to the conference.
We will promote this event via social media, the ASHS newsletter, and by members of the PDC personally reaching out to other ASHS Professional Interest Groups. Participants will be encouraged to bring business cards, resumes, CVs, and job opportunities to this event.

Introduction (10-15 minutes)
1. Establish groundwork for the networking event.
2. Provide tips and potential questions for participants to ask.
Networking session 1 (30 to 35 minutes)
1. Split into two groups.
2. Pairs have 6-7 minutes (will determine based on # of participants).
3. 1 person from each pair will stand up and move to the next chair at the end of the designated time.
Break (10-15 minutes)
1. Opportunity for participants to talk more with someone they connected with.
Networking session 2 (30 to 35 minutes)
1. Moving sets from Groups 1 and 2 swap.
2. Pairs have 6-7 minutes (will determine based on # of participants).
3. 1 person from each pair will stand up and move to the next chair at the end of the designated time.
Recap and discussion (15-30 minutes)
1. Sharing opportunity for participants.
2. Promotion of the collaboration center and other collaborative events.
3. Opportunity for participants to talk more with someone they connected with.

The amount of time each pair has to discuss will depend on the number of participants and will be determined shortly before the session.

Moderator

Nathan Jahnke

Tuesday September 24, 2024 2:00pm - 4:00pm HST
Coral 1

Interest Group Session, Industry Related

SUBJECT Professional Development/Career

4:14pm HST

Ecological Physiology 1 (EcoPhys 1)

Tuesday September 24, 2024 4:14pm - 6:00pm HST

Coral 1

Evaluating Plasticity and Acclimation of Linked Hydraulic Traits of Different Taxa Across a Climatic Gradient in the Western U.S. - Amelia Keyser Gibson
Climate Ready Stomata: Stomata Morphology and Physiology Varies Across Western US Sites and Irrigation Deficit Treatments in Rosa and Hibiscus syriacus Cultivars - Miro Stuke
Ice Formation and Progression in Rhododendron, and a Mechanistic Hypothesis for Winter Thermonasty of Leaves - Rajeev Arora
Trade-Offs in Reproductive Traits and Buds' Freezing Survival Strategies Among Prunus Species - Camilo Villouta
Potential Genes Involved in the Adaptation of Potato to Long Term Heat Stress - Jiwan Palta
Species-specific Differences in Leaf Photosynthetic Rate when Substituting Far-red Light for PAR Photons - John Ertle
Investigating Dormancy and Germination Characteristics to Promote Restoration Success in the Northern Great Plains - Bret Lang

Moderator

John Ertle

PP Systems

Tuesday September 24, 2024 4:14pm - 6:00pm HST
Coral 1

Oral Sessions

SUBJECT Ecological Physiology

4:15pm HST

EcoPhys 1 - Evaluating Plasticity and Acclimation of Linked Hydraulic Traits of Different Taxa Across a Climatic Gradient in the Western U.S.

Tuesday September 24, 2024 4:15pm - 4:30pm HST

Coral 1

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

Speakers

Amelia Keyser-Gibson

University of Washington

Co-authors

Darren Haver

South Coast Research and Extension Center

Jared Sisneroz

University of California, Davis

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 →

Loren Oki

University of California, Davis

Miro Stuke

University of Washington

Soo Hyung Kim

University of Washington

Ursula Schuch

University of Arizona

Youping Sun

Utah State University

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

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

4:30pm HST

EcoPhys 1 - Climate Ready Stomata: Stomata Morphology and Physiology Varies Across Western US Sites and Irrigation Deficit Treatment

Tuesday September 24, 2024 4:30pm - 4:45pm HST

Coral 1

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

Speakers

Miro Stuke

University of Washington

Co-authors

Jared Sisneroz

University of California Davis

Lloyd Nackley

Oregon State University

Lorence Oki

University of California Davis

Natalie Levy

University of California South Coast Research and Extension Center

Ryan Contreras

Oregon State University

Soo Hyung Kim

University of Washington

Youping Sun

Utah State University

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

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

4:45pm HST

EcoPhys 1 - Ice Formation and Progression in Rhododendron, and a Mechanistic Hypothesis for Winter Thermonasty of Leaves

Tuesday September 24, 2024 4:45pm - 5:00pm HST

Coral 1

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

Speakers

Rajeev Arora

Iowa State University

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

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

5:00pm HST

EcoPhys 1 - Trade-Offs in Reproductive Traits and Buds' Freezing Survival Strategies Among Prunus Species

Tuesday September 24, 2024 5:00pm - 5:15pm HST

Coral 1

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

Speakers

Camilo Villouta

Assistant Professor, University of Rhode Island

Tuesday September 24, 2024 5:00pm - 5:15pm HST
Coral 1

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

5:15pm HST

EcoPhys 1 - Potential Genes Involved in the Adaptation of Potato to Long Term Heat Stress

Tuesday September 24, 2024 5:15pm - 5:30pm HST

Coral 1

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

Speakers

Jiwan Palta

UW Madison

Co-authors

Alfonso DelRio

University of Wisconsin Madison

John Bamberg

University of Wisconsin Madison

Justin Schabow

University of Florida

Jyostna Mura

University of Wisconsin

Tuesday September 24, 2024 5:15pm - 5:30pm HST
Coral 1

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

5:30pm HST

EcoPhys 1 - Species-specific Differences in Leaf Photosynthetic Rate when Substituting Far-red Light for PAR Photons

Tuesday September 24, 2024 5:30pm - 5:45pm HST

Coral 1

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

Speakers

John Ertle

PP Systems

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

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

5:45pm HST

EcoPhys 1 - Investigating Dormancy and Germination Characteristics to Promote Restoration Success in the Northern Great Plains

Tuesday September 24, 2024 5:45pm - 6:00pm HST

Coral 1

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

Speakers

Bret Lang

Student, South Dakota State University

Co-authors

Gregory Cooper

South Dakota State University

Lora Perkins

South Dakota State University

Tuesday September 24, 2024 5:45pm - 6:00pm HST
Coral 1

Oral presentation (Individual talk), Ecological Physiology 1

SUBJECT Ecological Physiology

7:59am HST

Genetics and Germplasm 1 (GG 1)

Wednesday September 25, 2024 7:59am - 9:45am HST

Coral 1

Assembling a Reference Panel of DNA Profiles for U.S. Heirloom Apple Cultivars - Cameron Peace
Rediscovering Lost Heirloom Apple Cultivars with DNA Fingerprinting - Dongyun Lee
Air or Soil Temperature: Understanding the Cues for Dormancy Transition in Peach - Ksenija Gasic
Selection and Evaluation of Citrus Resistobiome for HLB Resistance/Tolerance - Yongping Duan
Population Genetics and Genome-wide Association Studies Provide Insights into the Genetic Basis of Persea Fruit Quality Traits - Gul Ali
Genome Assembly of Persia Americana cv. Simmonds Provides Insights on Genetic Relationships Among Avocado Hybrids Exhibiting Tolerance To Laurel Wilt - Vincent Njung'e Michael
Utilizing Haploid Pollen Grains and Diploid Leaf Tissue Genomic Sequence Data to Phase the ‘Wonderful’ Pomegranate Genome - Giuseppe Lana

Moderator

Cameron Peace

Washington State University

Wednesday September 25, 2024 7:59am - 9:45am HST
Coral 1

Oral Sessions, Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

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

Coral 1

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

Cameron Peace

Washington State University

Co-authors

Dongyun Lee

Washington State University

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

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

8:15am HST

GG 1 - Rediscovering Lost Heirloom Apple Cultivars with DNA Fingerprinting

Wednesday September 25, 2024 8:15am - 8:30am HST

Coral 1

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

Dongyun Lee

Washington State University

Co-authors

Amy Dunbar-Wallis

University of Colorado

Cameron Peace

Washington State University

John Bunker

Maine Heritage Orchard

Rebecca McGee

USDA-ARS Pullman

Todd Little-Siebold

College of the Atlantic

Wednesday September 25, 2024 8:15am - 8:30am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

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

Coral 1

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

Ksenija Gasic

Clemson University

Co-authors

Christopher Saski

Clemson University

John Lawton

Clemson University

Stephen Parris

Clemson University

Zhigang Li

Clemson University

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

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

8:45am HST

GG 1 - Selection and Evaluation of Citrus Resistobiome for HLB Resistance/Tolerance

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

Coral 1

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

Yongping Duan

USDA ARS

Co-authors

Bo Wu

Clemson University

Desen Zheng

USDA ARS

Feng Luo

Clemson University

Zhanao Deng

University of Florida

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

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

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

Coral 1

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

Gul Ali

Geneticist/Lead Scientist, USDA ARS Subtropical Horticulture Research Station

Co-authors

Barbie Freeman

USDA ARS Subtropical Horticulture Research Station

Jin Li

USDA ARS Subtropical Horticulture Research Station

Shamseldeen Eltaher

USDA ARS Subtropical Horticulture Research Station

Wednesday September 25, 2024 9:00am - 9:15am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

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

Coral 1

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

Vincent Njung'e Michael

University of Florida

Co-authors

Amanda Hulse-Kemp

USDA

Jonathan H Crane

University of Florida, TREC

Romina Gazis

University of Florida

Xingbo Wu

Chair 2023-2024, University of Florida

Wednesday September 25, 2024 9:15am - 9:30am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

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

Coral 1

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

Giuseppe Lana

University of Florida

Co-authors

Danelle Seymour

UC-Riverside

Donald Merhaut

UC-Riverside

Han Qu

UC-Riverside

John Chater

University of Florida

Mikeal Roose

UC-Riverside

Ryan Traband

UC- Riverside

Sergio Pietro Ferrante

UC-Riverside

Taylor Beaullieau

UC-Riverside

Zhenyu Jia

UC-Riverside

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

Oral presentation (Individual talk), Genetics and Germplasm 1

SUBJECT Genetics and Germplasm

9:59am HST

Ornamentals/Landscape and Turf 1 (O/LT 1)

Wednesday September 25, 2024 9:59am - 12:00pm HST

Coral 1

BeeGardens Mobile Application Improves Pollinator Plant Knowledge Gain in Landscaping and Gardening Courses - Sandra Wilson
Pesticide Management Decisions Affect Contamination of Nectar in Containerized Ornamental Plant Production - Patrick Wilson
Comparing Pollinator Species Richness and Abundance Between Pycnanthemum Species and Accessions - Kaitlin Swiantek
The Art and Technique of Producing Unique Lagerstroemia Plants - Donglin Zhang
Effects of Different Pruning Regimes on Growth Reallocation and Carbon Storage in Buxus microphylla var. japonica ‘Winter Gem’ - Andrew Loyd
Establishment, Growth, and Physiology of Container-Grown Trees Following Root Remediation at Planting - Bert Cregg
The Effects of Mulch Color and Depth on Soil Temperature and Light Transmission - Damon Abdi
Subterranean Termite Landscape Mulch Consumption Challenge - Edward Bush

Moderator

Donglin Zhang

University of Georgia

Wednesday September 25, 2024 9:59am - 12:00pm HST
Coral 1

Oral Sessions, Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

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

Heather Kalaman

UF IFAS Extension Orange County

Rachel Mallinger

University of Florida

Wednesday September 25, 2024 10:00am - 10:15am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

Patrick Wilson

University of Florida

Co-authors

Mia Cabrera

university of florida

sandra wilson

University of Florida

Vanesa Rostan

university of florida

Wednesday September 25, 2024 10:15am - 10:30am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

Kaitlin Swiantek

Ball FloraPlant

Co-authors

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

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

10:45am HST

O/LT 1 - The Art and Technique of Producing Unique Lagerstroemia Plants

Wednesday September 25, 2024 10:45am - 11:00am HST

Coral 1

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

Donglin Zhang

University of Georgia

Co-authors

Xi Li

Sichuan Agricultural University

Xiaoling Hou

Chongqing Yuexin Valley Ecological Agriculture Co. Ltd

Wednesday September 25, 2024 10:45am - 11:00am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

Andrew Loyd

Plant Pathologist, Bartlett Tree Research Laboratories

Co-authors

Caitlin Littlejohn

Bartlett Tree Research Laboratories

Chad Rigsby

Bartlett Tree Research Laboratories/Morton Arboretum

Wednesday September 25, 2024 11:00am - 11:15am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

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

Riley Johnson

Michigan State University

Wednesday September 25, 2024 11:15am - 11:30am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

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

Coral 1

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

Damon Abdi

Louisiana State University Agricultural Center

Co-authors

Ashley Hickman

Louisiana State University Agricultural Center Hammond Research Station

Jeb Fields

LSU AgCenter Hammond Research Station

Wednesday September 25, 2024 11:30am - 11:45am HST
Coral 1

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

11:45am HST

O/LT 1 - Subterranean Termite Landscape Mulch Consumption Challenge

Wednesday September 25, 2024 11:45am - 12:00pm HST

Coral 1

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

Edward Bush

LSU AgCenter

Co-authors

Payton Floyed

LSU

Qian Sun

LSU AgCenter

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

Oral presentation (Individual talk), Ornamentals/Landscape and Turf 1

SUBJECT Ornamental Landscape Turf

12:19pm HST

Growth Chambers and Controlled Environments - (CE)

Wednesday September 25, 2024 12:19pm - 1:40pm HST

Coral 1

Urban Agriculture Efficiency: A Year-Long Evaluation of Kale Yield and Energy Use in a Shipping Container Farm - Skyler Brazel
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila
Production of Red Leaf Lettuce at Vertical Farm Equipped with Blue LED According to Anthocyanin Concentration and Its Gene Analysis - Junjira Satitmunnaithum
Interlighting Improves Tomato Yield in Northern Greenhouses - Meriam Karlsson
Assessing the Impact of UV-C Treatment on Growth Parameters and Nutrient Levels in Hydroponic Systems for Romaine Lettuce Cultivation - Markanna Moore
Effect of low root-zone temperature and UV radiation on growth and gene expression of secondary metabolite pathways in Nicotiana benthamiana - KiHo Son
Effects of Short-Wavelength UV-B, UV-A, and Blue Light on the Rose Flower Color Transition Phenotype - Navdeep Kaur
Arduino Uno Can Reliably Log Substrate Moisture from a Bus of Digital Sensors and Control a Drip-Irrigation System - Stephanie E Burnett
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Wednesday September 25, 2024 12:19pm - 1:40pm HST
Coral 1

Poster Session, Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:20pm HST

CE - Urban Agriculture Efficiency: A Year-Long Evaluation of Kale Yield and Energy Use in a Shipping Container Farm

Wednesday September 25, 2024 12:20pm - 12:30pm HST

Coral 1

Urban expansion is a threat to agricultural land. As cities increase in size and residential areas are being built on arable land, a new solution to growing food in urban area needs to be considered. Shipping container farms are designed to grow a high number of plants in a small area. These farms are programmable to fit the environmental parameters that are optimal for each type of crop. In this experiment, ‘Toscano’ kale was grown inside the farm and harvested weekly for one year to simulate farm production. The average day/night temperature in the farm was 22.8C and 15.6C with a photoperiod of 20 hours. Sole sourced lighting was supplied by light emitting diodes with an 80:20 red:blue ratio and an intensity of 100 mol . m -2. s -1 for a daily light integral of 7.2 mol . d -1 . Electrical energy use of the farm was collected on three categories of energy usage: Lighting, HVAC, and all Other Energy usage. Seeds were sown four weeks prior to transplant. Plants were transplanted weekly into vertical channels and harvested 12 weeks after sowing. This experiment was a complete block design with block nested in time. Yield data was collected at time of harvest, including plant number, fresh mass, dry mass, plant height, canopy area, and leaf number. The mean number of plants per replication was 320. The mean fresh mass per plant by block was 43.34g, 48.84g, 53.17g, 59.15g, 57.88g, and 53.29g, respectively, while mean dry mass was 3.31g, 3.66g, 3.94g, 4.42g, 4.3g, and 4.08g, respectively. Daily mean lighting and other energy consumption exhibited no variation across all 48 harvests. Daily mean HVAC energy consumption varied based on outdoor environmental conditions, with increased usage during summer months and a maximum of 33.53 kWh/day. Overall, fluctuations across mean fresh mass needs to be investigated further as the optimal harvest date for this farm may occur prior to 12 weeks, for both plant yield and energy consumption levels.

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Carl Sams

University of Tennessee

Katelynn Rector

University of Tennessee - Knoxville

Wednesday September 25, 2024 12:20pm - 12:30pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:30pm HST

CE - Production of Red Leaf Lettuce at Vertical Farm Equipped with Blue LED According to Anthocyanin Concentration and Its Ge

Wednesday September 25, 2024 12:30pm - 12:40pm HST

Coral 1

At the last ASHS annual conference, I, Satitmunnaithum et al., (2023), presented our study on the effect of blue and white LED light ratio on red leaf lettuce, however, the effect of blue LED on red coloration during its growth is still unclear. Thus, at this year’s conference, we aim to clarify the mechanisms of red coloration under blue LED based on anthocyanin biosynthesis gene analysis and its content in vertical farming condition to stabilize its production for high market demand. To elucidate the effect of blue LED light on the red coloration of red leaf lettuce, green and red leaf lettuce (Lactuca sativa L.) were selected for this study. Both were hydroponically cultivated at the Advanced Plant Factory Research Center at Meiji University, Japan. The cultivation temperature was set at 22 ℃ with a humidity of 60%. Seeds were sown under white LED for 24 hours. Ten-day-old seedlings were transplanted to different light conditions: white LED and blue LED. The photoperiod was set for 16 hours. The nutrient solution was supplied at an EC of 1.6 mS/m^2 with a pH of 6.0 ± 0.5. Both light treatments had a PPFD of 100-120 µmol/m^2/s. After 20, 25, and 30 days of transplantation, lettuces were harvested. The red area on leaf lettuce, along with the total anthocyanin content and its precursors, as well as the expressions of anthocyanin biosynthesis-related genes such as ANS, CHS, bHLH, DFR, and HY5, were evaluated. Blue light shows a large red area on red leaf lettuce at most of the development stages resulting in a high red area percentage, while green leaf lettuce remained completely green in both light conditions. The interested genes were upregulated mostly in blue light irradiated red leaf lettuce which led to high total anthocyanin content. This can be assumed that blue LED light enhances anthocyanin synthesis in red leaf lettuce which can contribute to the stable production of red leaf lettuce in vertical farms.

Speakers

Junjira Satitmunnaithum

Organization for the Strategic Coordination of Research and Intellectual Properties, Meiji University , Japan

Co-authors

Chiharu Inoue

Daiwa House Co. Ltd.,

Takao Otsuka

Daiwa House Co. Ltd.,

Takashi Ikeda

School of Agriculture, Meiji university

Wednesday September 25, 2024 12:30pm - 12:40pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:40pm HST

CE - Interlighting Improves Tomato Yield in Northern Greenhouses

Wednesday September 25, 2024 12:40pm - 12:50pm HST

Coral 1

Low natural light and high heating costs limit northern winter greenhouse production. Technology advancements now offer opportunities to improve delivery of light to and within crop canopies. The greenhouse tomato cultivars Bigdena and Beorange were chosen to evaluate high pressure sodium irradiance with LED interlighting. Plants were grown in a high-wire drip irrigation system using dutch (bato) buckets (17.7 L volume) filled with a 50/50 mixture of perlite and a peatlite medium (Pro-Mix BX). The containers were placed in alternating rows across a drainpipe. Seeds were sown on 8 Sep and two seedlings were transplanted into each container 38 d later (17 Oct). Day temperature was 22 ± 2°C and reduced to 18 ± 2°C during the night. Lower leaves were removed as fruit ripened and the study was terminated at a plant height of ~250 cm (128 d from transplanting). The photoperiod was 18-h. In addition to overhead 400-W HPS lighting, LED fixtures designed for placement within the canopy were evaluated (GE current Arize® Integral). Two horizontal LED bars were positioned 30 cm (12 inches) apart with the upper bar adjusted within 30 cm of the top of the plants throughout the study. The integral lighting provided a spectrum with blue (peak 450 nm) and red (peak 660 nm) wavelengths in a 12:88 ratio. The perpendicular horizontal distance from the LED bars to the plant stems was 30 to 35 cm. The intensity (400-700 nm) measured at the plant stems horizontally from the LEDs averaged 195 ± 30 µmol m-2s-1. Overhead HPS provided ~130 ± 20 µmol m-2s-1, 100 cm below the fixtures. Seasonally short days and low sun angles limited natural light during the study. The first ripe tomatoes were harvested 62 d from transplanting (18 Dec). Interlighting resulted in higher plant yields with 6.3 ± 0.82 kg for Bigdena and 4.9 ± 0.67 kg for Beorange. In comparison, 4.1 ± 0.37 kg (Bigdena) or 3.4 ± 0.80 kg (Beorange) was recorded for plants receiving only HPS lighting. Five or six additional tomatoes were harvested with interlighting for Bigdena (25 ± 2.0 versus 19 ± 1.8) and Beorange (22 ± 2.5 versus 17 ± 1.9). Average tomato size increased from 217 ± 11.9 g to 250 ± 19.3 g (Bigdena) or from 199 ± 36.1 g to 227 ± 20.2 g (Beorange) with interlighting.

Speakers

Meriam Karlsson

University of Alaska Fairbanks

Co-authors

Eric Cook

University of Alaska Fairbanks

Wednesday September 25, 2024 12:40pm - 12:50pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

12:50pm HST

CE - Assessing the Impact of UV-C Treatment on Growth Parameters and Nutrient Levels in Hydroponic Systems for Romaine Lettuc

Wednesday September 25, 2024 12:50pm - 1:00pm HST

Coral 1

Introduction: Preliminary studies have shown that ultraviolet treatment is able to reduce microbial contamination in the nutrient water of hydroponic systems. However, it is not known how these ultraviolet treatments may impact nutrient water chemistry or crop growth and yield. Purpose: The objective of this study is to examine the impact of an ultraviolet light treatment on romaine lettuce growth parameters and nutrient levels in the treated hydroponic water. Methods: Commercially-available DWC (Deep Water Culture) hydroponic systems were used to grow romaine lettuce (Latticua lettuceia var. Sparx) in a two-part nutrient solution (Hydro-Gro Leafy and calcium nitrate). The electrical conductivity (EC) was maintained between 1.6 and 1.8 mS/cm during the study. The nutrient solution was treated with a UV-C device (MiniPure MIN-1; 500ml capacity) emitting peak irradiance at 254nm at flow rates of 0, 3 and 6 L/min. Water samples were collected before and after each treatment and the experiment will be repeated twice for a total of three times. Twice weekly during the six-week growth period, parameters including plant height, SPAD value, and chlorophyll fluorescence were measured. At the end of the production, fresh weight and dry weight of each plant sample were measured. Results: Low and high UV doses resulted in 1.17 and 1.36 log reductions of Escherichia coli in hydroponic nutrient water. Preliminary findings for the effect of UV light on the concentration of nutrients (NPK) yielded no significant difference in the nutrient level. The study is underway for assessing the effect on the lettuce growth parameters and therefore we are not reporting any results on the crop growth parameters. Significance: UV light technology at optimized dosage levels has the potential to improve the safety of hydroponic systems with minimal effect on the plant growth and nutrient water.

Speakers

Markanna Moore

Kansas State University

Co-authors

Eleni Pliakoni

Kansas State University

Majid JaberiDouraki

Kansas State University

Manreet Bhullar

Kansas State University

Teng Yang

Kansas State University

Wednesday September 25, 2024 12:50pm - 1:00pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:00pm HST

CE - Effect of low root-zone temperature and UV radiation on growth and gene expression of secondary metabolite pathways in N

Wednesday September 25, 2024 1:00pm - 1:10pm HST

Coral 1

This study explored the effects of low root-zone temperature (LT) and UV radiation (UV) alone and combined on changes in growth, transcription, and gene expression related to secondary metabolite in Nicotidana benthamiana. The plants were grown in a controlled environment (25/20°C, 16/8 h [light/dark], 70% relative humidity, 1,000 µmol·mol−1 CO2 with photosynthetic photon flux densities of 100 and 200 µmol·m−2·s−1 for 10 and 18 d, respectively). Twenty-eight days after sowing, the seedlings were treated with LT (15°C), 0.3 W·m−2 of UV radiation, and a combined treatment with LT and UV (LT*UV) for 3 d. Results found that the treatment with UV alone decreased the quantum efficiency of photosystem II by approximately 1.5 times, and most growth characteristics decreased under the UV (approximately 1.5 times) and LT*UV treatments. Combined treatment with LT*UV significantly inhibited the growth characteristics and photosynthetic rates compared to those under the single LT and UV treatments. In particular, the transcriptome levels of phenylpropanoid and flavonoid biosynthesis were the most significantly affected by LT*UV. This suggests the potential of using LT treatment in hydroponic systems and UV radiation to control the synthesis of health-promoting compounds of secondary metabolites in greenhouses and controlled-environment agricultural facilities.

Speakers

KiHo Son

Gyeonsang National University

Co-authors

Eiji Goto

China university

Wednesday September 25, 2024 1:00pm - 1:10pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:10pm HST

CE - Effects of Short-Wavelength UV-B, UV-A, and Blue Light on the Rose Flower Color Transition Phenotype

Wednesday September 25, 2024 1:10pm - 1:20pm HST

Coral 1

Light quality plays a crucial role in the growth and development of plants. In this study, we aimed to assess the effects of short-wavelength light on rose genotype '16401-N055’, which exhibits the flower color transitioning trait: the flowers change colors from yellow to pink in sunlight. Roses that exhibit this flower phenotype are termed transitioning-type roses. Specifically, we analyzed and compared the impact of six different light treatments [a sunlight control in open field and five spectral treatments created using light-emitting diodes (LEDs)] on various physiological and morphological characteristics. The five LED treatments included white light, blue light, UV-A white light, UV-B white light, and 80% blue 20% white light. Each treatment had two replications where one-year-old rose plants were the experimental unit. The total light intensity was maintained at 300-350 micromol m-2 s-1 for a photoperiod of 16 h light and 8 h darkness. The morphological traits measured included height, width, number of buds, number of flowers, and node density. The color scale parameters L* [luminance of the color ranging from 0 (black) to 100 (white)], a* [red (positive values) and green (negative values) color levels], and b* [yellow (positive values) and blue (negative values) color levels] were measured using a colorimeter. Additionally, the chlorophyll concentration index (CCI) was measured using a chlorophyll meter. Fully pigmented pink flowers were only observed in the UV-B white light treatment with an average L* value of 44.1 and a* value of 50.6. A slight pink hue was observed on the outer sections of petals in blue and blue white light treatments. The average L* and a* values of flowers in the blue treatment were 87.21 and 6.24, and in blue white treatment were 90.9 and 1.86, respectively. The flowers in the white UV-A treatment remained white with the highest average L* value of 92.4 and the lowest average a* value of -1.86. The CCI of plants under sunlight (23.5) was significantly lower than the plants treated with blue (34.4), and blue white (33.7) light. No significant differences in morphological traits were detected after two weeks. The plants will be monitored for longer periods and more data will be collected every two weeks for one month to document additional changes. The results obtained will provide additional information on morphological and floral changes in this genotype under different light treatments.

Speakers

Navdeep Kaur

Texas A and M university

Co-authors

David Byrne

Texas A and M University

Oscar Riera-Lizarazu

Texas A and M University

Shuyang Zhen

Texas A and M University

Wednesday September 25, 2024 1:10pm - 1:20pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:20pm HST

CE - Arduino Uno Can Reliably Log Substrate Moisture from a Bus of Digital Sensors and Control a Drip-Irrigation System

Wednesday September 25, 2024 1:20pm - 1:30pm HST

Coral 1

Inexpensive Arduino microcontrollers can be programmed to operate and log data from environmental sensors and operate other accessories such as irrigation solenoids. We describe our efforts to build a modified version of Arduino Uno systems previously developed at the University of Georgia, which operated analog moisture sensors and opened solenoid valves to drip emitters when moisture fell below user-defined thresholds. We attempted to 1) replace analog sensors with a bus of digital sensors that use the SDI-12 communication protocol, 2) include programming to parse digital output from two popular SDI-12 sensors (Decagon GS3 and Campbell Scientific 5TM), 3) use 12VDC solenoid valves that were less expensive and smaller (1/2”) than alternatives, and 4) overcome several challenges encountered in the construction and programming of the Arduino-based system. These included an approach to more easily manage the connection of numerous wires, the inclusion of a reversed diode at the solenoid terminals to prevent electrical interference from intermittently resetting the Arduino program, and the adoption of programming strategies to work around memory limitations that initially rendered our Arduino systems with digital sensors unreliable. We overcame these challenges to develop a robust, reliable, and easy-to-deploy Arduino-based environmental logger and automated drip-irrigation system that can operate numerous digital sensors. Sensor type and thresholds for volumetric water content are defined in a single location within the program, enabling the user to easily make minor adjustments to the system. We also included extensive line-by-line documentation of the source code. A list of the hardware used in this system is available. In 2023, eight of these systems operating 64 total sensors proved their reliability over a two-month experiment on the drought stress physiology of wetland shrubs. We conclude that this system is an effective solution for in-house sensor-automated irrigation with high customizability for end users.

Speakers

Stephanie E. Burnett

University of Maine

Co-authors

Adam J. Peterson

Unaffiliated

Bryan Peterson

University of Maine

Jessica Hutchinson

University of Maine

Rhuanito S. Ferrarezi

University of Georgia

Wednesday September 25, 2024 1:20pm - 1:30pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:30pm HST

CE - Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination

Wednesday September 25, 2024 1:30pm - 1:40pm HST

Coral 1

Spinach (Spinacia oleracea) is a nutritionally and commercially significant crop grown in controlled environments; however, its seeds are difficult to germinate in soilless culture. Excess moisture in the root zone can inhibit germination and impede seedling establishment. To address this, we conducted an experiment with a randomized complete block design (three replications) to identify the optimal moisture content for spinach ‘Space’ germination. In each of 63 sealed containers, we placed 20 seeds on a double-layered paper towel pre-moistened with varying amounts of reverse-osmosis water. We quantified visible germination percentages daily in response to seven moisture indices [moisture mass ÷ (paper mass moisture mass)] ranging from 50% to 94% over an 11-day period. Air temperature and relative humidity were 22.12 ± 0.02 °C and 34.35% ± 8.80%, respectively. The optimal moisture index was 80%, which resulted in the highest cumulative visible germination percentage (92%, which is close to the labelled 93% on the seed package). Deviating from the optimal moisture index in either direction decreased the germination percentage to 0%–22% and delayed germination by up to 5 days. The response of the cumulative visible seed germination percentage to the moisture index followed a normal distribution. The daily new visible germination percentage peaked on day 3 under most moisture indices; it was 55% under the optimal moisture index and < 24% under the other moisture indices. In conclusion, a moisture index of 80% resulted in the highest germination percentage (92%) and the fastest germination time (2–5 days) in spinach ‘Space’, whereas lower or higher moisture indices caused poorer (0%–67%), delayed, and less uniform germination. Once transplanted, the spinach seeds germinated with this moistened-paper method under the optimal moisture index adapt and perform well in soilless substrates, including rockwool, which is notoriously difficult to germinate spinach seeds in.

Speakers

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

Wednesday September 25, 2024 1:30pm - 1:40pm HST
Coral 1

Poster presentation (individual talk), Growth Chambers and Controlled Environments

SUBJECT Growth Chambers and CE

1:59pm HST

Growth Chambers and Controlled Environments 3 (CE 3)

Wednesday September 25, 2024 1:59pm - 3:45pm HST

Coral 1

Effects of Light Sources and Fertilizers on Biomass Production of Nine Lettuce Cultivars in a Hydroponic Nutrient Film Technique System - Dario Rueda Kunz
Enhancing Lettuce Yield: Strategies for Fertility Management in Soilless Growth Systems. - Bryce Waugh
Effect of ZnO and SiO2 Nanoparticles on Growth and Physiology of Hydroponic Lettuce Under Salinity Stress - Chungkeun Lee
An Intermediate Calcium-mobilizing Biostimulant Concentration Controls Tipburn of Two Greenhouse Hydroponic Lettuce Cultivars Without Affecting Growth -Shem Msabila
Optimizing Sampling Methods for Sap Extraction to Enhance Plant Nutrient Analysis in CEA - Husnain Rauf
Effects of Potassium and Iron Supplements and Late Nitrogen Restriction on Aquaponic Taro (Colocasia esculenta) Corm Production - Andrew Bohringer
Advantages of a novel in situ pH measurement for soilless media - Hikari Skabelund

Moderator

Theodore Radovich

University of Hawai’i at Mānoa

Wednesday September 25, 2024 1:59pm - 3:45pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Dario Rueda Kunz

Texas Tech University

Co-authors

Catherine Simpson

Texas Tech University

Wednesday September 25, 2024 2:00pm - 2:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Bryce Waugh

Grad Student, Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Chungkeun Lee

Texas A&M University

Co-authors

Daniel Leskovar

Texas A

Seunghyun Choi

Texas A

Wednesday September 25, 2024 2:30pm - 2:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Shem Msabila

University of Delaware

Co-authors

Qingwu Meng

University of Delaware

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Husnain Rauf

University of Georgia

Co-authors

Cristian Toma

Kalera

Daniel Jackson

University of Georgia

Jason Lessl

University of Georgia

Jessica Staha

Local bounti

Miguel Puebla

Pure flavor

Rhuanito S. Ferrarezi

University of Georgia

Timothy Coolong

University of Georgia

Zilfina Rubio

University of Georgia

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Andrew Bohringer

University of Hawai'i at Manoa

Co-authors

Bradley Kai Fox

University of Hawai'i at Manoa

Eric Collier

University of Hawai'i at Manoa

Koon-Hui Wang

University of Hawai'i at Manoa

Robert Paull

University of Hawai'i at Mānoa

Theodore Radovich

University of Hawai’i at Mānoa

Wednesday September 25, 2024 3:15pm - 3:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

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

Coral 1

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

Hikari Skabelund

Texas A

Co-authors

Bruce Bugbee

Utah State University

Noah Langenfeld

Utah State University

Royal Heins

Utah State University

Wednesday September 25, 2024 3:30pm - 3:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 3

SUBJECT Growth Chambers and CE

4:00pm HST

Interest Group Session: Using Applied Economics to Explore the Many Facets of Adding Value to the Horticultural Industry

Wednesday September 25, 2024 4:00pm - 6:00pm HST

Coral 1

The business environment in the horticultural industry is evolving and consumer preferences for value-added products are shaping market trends. With an increasing emphasis on health, sustainability, and convenience, consumers are seeking horticultural products that offer added value and benefits. This shift in consumer preferences presents both challenges and opportunities for horticultural businesses. Understanding these evolving consumer demands is crucial for horticulture businesses to develop innovative products and marketing strategies that resonate with their target audience.

The session aims to explore consumer behavior and preferences for value-added horticultural products, providing attendees with valuable insights to inform strategic decision-making and drive business growth in the competitive market. Presentations will explore the specific information consumers seek on wine packages and labels, and the influence of state marketing programs on consumer preferences for tomato transplants. Additionally, the session will explore the return on investment of social media marketing for US green industry firms, consumer preferences and willingness to pay for Florida-grown fresh blueberries, strategies for expanding marketing potential to appeal to all horticulture consumers, and the influence of demographics on the perception of flatheaded borer damage on ornamental plants. Through these diverse presentations, attendees will gain insights into key factors shaping consumer behavior, industry dynamics, and marketing strategies in the horticulture sector.

Coordinator(s)

Alicia L Rihn, University of Tennessee, Knoxville, United States
Melinda Knuth, North Carolina State University, Horticultural Science, Raleigh, North Carolina, United States
Chengyan Yue, University of Minnesota-Twin Cities (Minneapolis, MN), St. Paul, Minnesota, United States

Moderator(s)

Alicia L Rihn, University of Tennessee, Knoxville, United States
Melinda Knuth, North Carolina State University, Horticultural Science, Raleigh, North Carolina, United States

Speaker/Participant(s)

Alicia L Rihn, University of Tennessee, Knoxville, United States
Do State Marketing Programs Impact Consumer Preferences for Tomato Transplants? (15 mins)
Ariana P Torres, Purdue University, United States
The Return of Investment of Social Media Marketing: A Case of U.S. Green Industry Firms (15 mins)
Chengyan Yue, University of Minnesota-Twin Cities (Minneapolis, MN), St. Paul, Minnesota, United States
What Information Consumers Are Looking for On Wine Packages and Labels? (15 mins)
Hayk Khachatryan, University of Florida, United States
Analyzing Consumer Preferences and Willingness to Pay for Florida-Grown Fresh Blueberries (15 mins)
Melinda Knuth, North Carolina State University, Horticultural Science, Raleigh, North Carolina, United States
Expanding Marketing Potential to Appeal to All Horticulture Consumers (15 mins)
Ben Campbell, University of Georgia, United States
Demographic Influences on the Perception of Flatheaded Borer Damage on Ornamental Crops (15 mins)
Summary: Mounata Dahal, Tate Norman, Ben Campbell, and Alicia Rihn

Moderator

Melinda Knuth

North Carolina State University

Alicia L Rihn

Speakers

Ben Campbell

University of Georgia

Chengyan Yue

University of Minnesota-Twin Cities (Minneapolis, MN)

Ariana P Torres

Hayk Khachatryan

Wednesday September 25, 2024 4:00pm - 6:00pm HST
Coral 1

Interest Group Session

SUBJECT Consumer Hort and Master Gardeners, Marketing and Economics, Hort Industry

6:00pm HST

Graduate Student Poster Competition

Wednesday September 25, 2024 6:00pm - 7:00pm HST

Coral 1

This competition is open to graduate students that have a poster presentation scheduled during the ASHS conference AND have also signed up to participate in this competition (Note: This is separate of the assigned time to present your abstract during the conference program).

Please note that if you do not also present your poster during the regularly scheduled Poster session, you will be disqualified from the Poster Competition.

Competition participants will be assigned to a room to present for the competition (this information will be emailed to you the week prior to the conference). You will be responsible for bringing your poster on a thumb drive to your assigned room in order to participate.

Wednesday September 25, 2024 6:00pm - 7:00pm HST
Coral 1

Competitions, Student Activities

SUBJECT Competition

7:59am HST

Growth Chambers and Controlled Environments 4 (CE 4)

Thursday September 26, 2024 7:59am - 9:45am HST

Coral 1

Night Light Pollution Delays Flowering in Soybean and Cannabis - Madigan Eckels
Pre-breeding Leafy Green Watercress (Nasturtium officinale; Brassicaceae) In an Indoor Vertical Farm: A Discovery Trial - Yufei Qian
Precise Moisture Control Promotes Optimal, Fast, and Uniform Spinach Seed Germination - Shem Msabila
Planting Density on the Growth and Production of Select Fruiting Crops in Aquaponic Systems - Teal Hendrickson
Global Sensitivity Analysis and Validation of the Modified Energy Cascade Crop Model for Controlled Environment Agriculture - Donald Coon
Planting Density and the Growth of Kale and Cilantro in Year-round Aquaponics - Teal Hendrickson
The Physiological Responses of Citrus Tree Roots to Soil Acidification - Duplicate Sambani
Towards Sustainable Controlled Environment Agriculture Systems: Developing An Intelligent Decision-Making Tool For Improved Resource Use Efficiency - Eshwar Ravishankar

Speakers

Madigan Eckels

Utah State University

Thursday September 26, 2024 7:59am - 9:45am HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:00am HST

CE 4 - Night Light Pollution Delays Flowering in Soybean and Cannabis

Thursday September 26, 2024 8:00am - 8:15am HST

Coral 1

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

Speakers

Madigan Eckels

Utah State University

Co-authors

Bruce Bugbee

Utah State University

Mitch Westmoreland

Utah State University

Paul Kusuma

Utah State University

Thursday September 26, 2024 8:00am - 8:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:15am HST

CE 4 - Pre-breeding Leafy Green Watercress (Nasturtium officinale; Brassicaceae) In an Indoor Vertical Farm: A Discovery Trial

Thursday September 26, 2024 8:15am - 8:30am HST

Coral 1

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

Speakers

Yufei Qian

PhD candidate, University of California, Davis

Co-authors

Daniel Klibenstein

University of California, Davis

Ella Katz

University of California, Davis

Gail Taylor

University of California, Davis

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:30am HST

CE 4 - Planting Density on the Growth and Production of Select Fruiting Crops in Aquaponic Systems

Thursday September 26, 2024 8:30am - 8:45am HST

Coral 1

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

Speakers

Teal Hendrickson

Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Mitchell Sommer

Symbiotic Aquaponic

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

8:45am HST

CE 4 - Planting Density and the Growth of Kale and Cilantro in Year-round Aquaponics

Thursday September 26, 2024 8:45am - 9:00am HST

Coral 1

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

Speakers

Teal Hendrickson

Oklahoma State University

Co-authors

Bruce Dunn

Oklahoma State University

Mitchell Sommer

Symbiotic Aquaponic

Thursday September 26, 2024 8:45am - 9:00am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:00am HST

CE 4 - The Physiological Responses of Citrus Tree Roots to Soil Acidification

Thursday September 26, 2024 9:00am - 9:15am HST

Coral 1

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

Speakers

Duplicate Sambani

PhD Student, University of Florida

Co-authors

Davie Kadyampakeni

University of Florida

Thursday September 26, 2024 9:00am - 9:15am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:15am HST

CE 4 - Towards Sustainable Controlled Environment Agriculture Systems: Developing An Intelligent Decision-Making Tool For Impro

Thursday September 26, 2024 9:15am - 9:30am HST

Coral 1

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

Speakers

Eshwar Ravishankar

Assistant Professor, Cal Poly Pomona

Co-authors

Lahari Sandepudi

Cal Poly Pomona

Ricardo Hernandez

North Carolina State University

Thursday September 26, 2024 9:15am - 9:30am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

9:30am HST

CE 4 - Global Sensitivity Analysis and Validation of the Modified Energy Cascade Crop Model for Controlled Environment Agricult

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

Coral 1

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

Speakers

Donald Coon

University of Florida

Co-authors

Ana Martin Ryals

University of Florida

Chiara Amitrano

University of Naple

Gerardo Nunez

University of Florida

Melanie Correll

University of Florida

Rafael Carpena

University of Florida

Ying Zhang

University of Florida

Ziynet Boz

University of Florida

Thursday September 26, 2024 9:30am - 9:45am HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 4

SUBJECT Growth Chambers and CE

10:14am HST

Plant Nutrient Management 2 (PNM 2)

Thursday September 26, 2024 10:14am - 11:15am HST

Coral 1

Soil Amendments Alter Soil Chemical Properties and Toxic Elements Accumulation in Sweetpotato cvs. Bayou Belle and Beauregard - Mae Ann Bravo
Methods of Fertilization in Commercial Production of Saw Palmetto (Serenoa repens Small (Bartr.) form green and glauca) -Vania Pereira
Iron Biofortification in Radish and Pea Microgreens Using Alternative Iron Sources and Ascorbic Acid -Rishi Ravichandran
Combined Agronomic Biofortification of Iron and Zinc in Radish and Sunflower Microgreens - Rishi Ravichandran

Moderator

Mae Ann Bravo

Louisiana State University

Thursday September 26, 2024 10:14am - 11:15am HST
Coral 1

Oral Sessions, Plant Nutrient Management 2

SUBJECT Plant Nutrient Mgmt

10:15am HST

PNM 2 - Methods of Fertilization in Commercial Production of Saw Palmetto (Serenoa repens Small (Bartr.) form green and glauca)

Thursday September 26, 2024 10:15am - 10:30am HST

Coral 1

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

Speakers

Vania Pereira

University of Florida

Co-authors

Karen Williams

University of Florida

mica mcmillan

University of Florida

Patricia Ramos Barros

University of Maryland

Thiago Souza Campos

University of Florida

Wagner Vendrame

University of Florida

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

Oral presentation (Individual talk), Plant Nutrient Management 2

SUBJECT Plant Nutrient Mgmt

10:30am HST

PNM 2 - Soil Amendments Alter Soil Chemical Properties and Toxic Elements Accumulation in Sweetpotato cvs. Bayou Belle and Beauregard

Thursday September 26, 2024 10:30am - 10:45am HST

Coral 1

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

Speakers

Mae Ann Bravo

Louisiana State University

Co-authors

Arthur Villordon

Louisiana State University

Brenda Tubana

Louisiana State University

Cole Gregorie

Louisiana State University

Don La Bonte

Louisiana State Univ

Lisa Arce

Louisiana State University

Marissa Barbosa

Lousiana State University

Mary Ann Munda

Louisiana State University

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

Oral presentation (Individual talk), Plant Nutrient Management 2

SUBJECT Plant Nutrient Mgmt

10:45am HST

PNM 2 - Iron Biofortification in Radish and Pea Microgreens Using Alternative Iron Sources and Ascorbic Acid

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

Coral 1

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

Speakers

Rishi Ravichandran

Student, Pennsylvania State University

Co-authors

Benedikt Nuesslein

Pennsylvania State University

Erin Connolly

Pennsylvania State University

Francesco Di Gioia

Pennsylvania State University

Thursday September 26, 2024 10:45am - 11:00am HST
Coral 1

Oral presentation (Individual talk), Plant Nutrient Management 2

SUBJECT Plant Nutrient Mgmt

11:00am HST

PNM 2 - Understanding the Boron-Yield Relationship in Pistachio Orchards

Thursday September 26, 2024 11:00am - 11:15am HST

Coral 1

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

Speakers

Mukesh Mehata

University of California, Davis

Co-authors

Blake Mccullough Sanden

University of California Davis

Donald Williams III

CSU Fresno

Gary Banuelos

USDA ARS

Giulia Marino

University of California, Davis

Joseph Coehlo

Valley Orchard LLC

Louise Ferguson

University of California, Davis

Mae Culumber

University of California, Davis

Marta Saludes

Universidad de Salamanca

Thursday September 26, 2024 11:00am - 11:15am HST
Coral 1

Oral presentation (Individual talk), Plant Nutrient Management 2

SUBJECT Plant Nutrient Mgmt

11:44am HST

Undergraduate Student Poster 2 (UG 2)

Thursday September 26, 2024 11:44am - 1:25pm HST

Coral 1

Perceptions of Gardens and Gardeners - Belinda Brain
Horticultural Activities Impact the Perceived Stress Levels of Undergraduate Students - Baylie Weld Latter
Perceptions of Media Literacy in Undergraduate Students and Master Gardeners - Caleb Spry
Identifying the Role of the Chloroplast-Mediated CEBP Transcription Factor in Petunia Flower Senescence - Colin Krisulevicz
Optimal production densities and storage conditions for five microgreens - Sam Petrovich
Irrigation Level Affects Bloom Number and Pollinator Visits in Herbaceous Perennials - Madison Coyle
Strawberry Response to Compost Versus Inorganic Nitrogen - Kauai Paule
SOFT Science: Cultivating Sustainable Horticulture Leaders Through the Student Organic Farm Training Program - Alana Marie Barros
Phenological Modeling of Pollenizing Crabapple Cultivars (Malus spp.) and Commercial Apple Cultivars (Malus X domestica - Miranda Woodcock
Determining Sap Yield, Sugar Content, and Mineral Composition of European White Birch Trees - Abby Porter

Thursday September 26, 2024 11:44am - 1:25pm HST
Coral 1

Poster Session, Undergraduate Student 2

SUBJECT Undergraduate Student

11:45am HST

UG 2 - Perceptions of Gardens and Gardeners

Thursday September 26, 2024 11:45am - 11:55am HST

Coral 1

Studies have been conducted on the preferences and opinions of individuals for garden and landscape spaces with varying amounts of plants (Zheng et al., 2011). However, little data exists on the perceptions individuals hold about the gardeners that grow these garden spaces. An online survey was created containing images that represent three outdoor spaces with three different amounts of plant material and complexity. The images with different amounts of plant material were created with artificial intelligence assisted software to modify the identical base backgrounds. Participants were asked a variety of questions about each space, then about the “gardener” who created the space. The survey contained twenty short answer questions and eighteen sliding scale questions to provide a diverse data set. Participants in the survey were undergraduate students in an introductory horticulture class, high school students in agriculture education classes, and adults training to be Master Gardeners. Data from undergraduate students reveals there was a positive correlation between the amounts of plant material and the respondent’s opinions on the gardener’s level of education, age, socioeconomic status, and gardening experience. Less plant material corresponded to a perception of lower levels of education, age, status, and experience. Thus, respondents consider areas with the highest amount of plant material to be created by more highly educated, older individuals with higher socioeconomic status and more gardening experience. These results allow us to better understand the public’s perception of gardens and gardeners, assisting us in creating more applicable materials for classes and facilitating more productive interactions with the public.

Speakers

Belinda Brain

Iowa State University

Thursday September 26, 2024 11:45am - 11:55am HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

11:55am HST

UG 2 - Horticultural Activities Impact the Perceived Stress Levels of Undergraduate Students

Thursday September 26, 2024 11:55am - 12:05pm HST

Coral 1

After the COVID-19 pandemic, the topic of gardening activities and their impact on stress gained much attention. Undergraduate students often complain of being overwhelmed or stressed, and gardening activities have been shown to reduce stress for some people (Makayla et al., 2023). Therefore, as instructors, we thought it would be interesting to see if undergraduate students realize a benefit from hands-on, horticulture labs. The purpose of this study was to determine if hands-on horticulture activities reduced stress in undergraduate students in a horticulture class at Iowa State University. We investigated the perceived stress of undergraduate students before and after lab activities for Home Horticulture (Hort 121) course. We used a modified ten-question Perceived Stress Scale (PSS) to measure and assess students’ stress levels (Cohen, 1983). Four labs (out of 14) were selected for this study. Each lab lasted 50 minutes and included a hands-on, experiential activity. Three lab sections with approximately 25 students in each section, participated in this study. Two of the labs were administered outdoors and two were administered indoors. Students completed the modified PSS immediately before and after these lab activities. Data were compiled and analyzed in Excel. Preliminary results indicated moderate improvement in stress levels by students in all lab sections. In addition, almost all students enjoyed these lab activities. Future data analysis will determine if there are differences in stress reduction between indoor or outdoor lab activities. The results from this study can give undergraduate students alternative stress management practices to help them thrive in stressful times. Practical and effective stress management skills are important for their academic performance and general well-being.

Speakers

Baylie Weld Latter

Iowa State University

Thursday September 26, 2024 11:55am - 12:05pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:05pm HST

UG 2 - Perceptions of Media Literacy in Undergraduate Students and Master Gardeners

Thursday September 26, 2024 12:05pm - 12:15pm HST

Coral 1

Media literacy is the ability to decipher a source’s reliability and credibility. In a 2023 Axiom Market survey about home gardeners and vegetables, participants were asked, “what is the most important place to learn about new vegetables?” Only 1% of respondents said university extension service (Axiom, 2023). As online gardening resources continue to grow so does the need for accurate and reliable information. In this study, we surveyed Iowa State University undergraduate students and Master Gardeners on their perceptions of media literacy. The survey was created in Qualtrics and contained ten Likert scale questions, eight multiple choice questions, and five gardening-based case studies. In these case studies participants were asked to rank sources based on their perceived “trustworthiness.” The survey was distributed in April 2024. Across the five case studies, Iowa State University students ranked “.org” and “.edu” sources higher than sources whose domains contained “.com.” Eighty-two percent of undergraduate students responded that they have not shared incorrect information on social media. Eighty-seven percent of students consider themselves confident internet users. Eighty-four percent of students consider themselves to be media literate. Seventy-eight percent of students consider themselves media literate and confident internet users. These results indicate that undergraduate students may not fully recognize the difference between being a confident internet user and being media literate. These data will serve as a pilot to assist with the creation of a media literacy training module for undergraduate students and Master Gardeners to strengthen their critical thinking skills around online gardening resources.

Speakers

Caleb Spry

Iowa State University

Thursday September 26, 2024 12:05pm - 12:15pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:15pm HST

UG 2 - Identifying the Role of the Chloroplast-Mediated CEBP Transcription Factor in Petunia Flower Senescence

Thursday September 26, 2024 12:15pm - 12:25pm HST

Coral 1

The Carnation Ethylene-responsive element-Binding Protein (CEBP), a nuclear-encoded transcription factor found in plants, is believed to be involved in the senescence of flowers. Previous studies have elucidated the putative role of this protein in the nucleus, however the role of CEBP in the chloroplast remains unknown. An RNAi construct to silence CEBP mRNA expression was developed under control of the Clarkia breweri linalool synthase (LIS) promoter, a flower specific promoter, in addition to Kanamycin resistance. The construct was transformed into E. coli, and then the plasmid containing the construct was then transferred into Agrobacterium. Next, Agrobacterium mediated transformation was utilized to insert the RNAi into the petunias using leaf disk infiltration. Four independent transgenic lineages were transferred from tissue culture to the greenhouse. QRTPCR confirmed expression of the RNAi construct as well as knock down effect on CEBP expression. Senescence timeframes, physiological changes, and downstream effects will be reported.

Speakers

Colin Krisulevicz

West Virginia University

Co-authors

Joseph Lynch

West Virginia University

Sven J Verlinden

West Virginia University

Thursday September 26, 2024 12:15pm - 12:25pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:25pm HST

UG 2 - Optimal production densities and storage conditions for five microgreens

Thursday September 26, 2024 12:25pm - 12:35pm HST

Coral 1

Microgreens, or very young vegetable seedlings, are an increasingly common appearance in dishes for garnish, flavor, and even nutrient content. As microgreens become more relevant, this study analyzed the optimal density by which to sow a variety of microgreen species as well as the optimal temperatures to store them once harvested. Seeds of arugula, cilantro, red leaf beet, and Russian kale were sown at 5.27g/m2, 10.54g/g/m2, 21.10g/m2, 42.18g/m2, 84.35g/m2, 168.71g/m2, and 337.42g/m2. Sowing density was randomly assigned in a randomized complete block design with three replications. The average height was measured before harvest and fresh weight was determined upon harvest. Fresh weights of microgreens sown at 337.42g/m2 was always more than those sown at any other density. Interestingly, this treatment did not always produce the tallest plants. Lower densities, notably arugula and beet, produced the tallest plants at 21.10g/m2 and 42.18g/m2. Considering cost seed and harvestable yield, optimal sowing densities were for 168.71g/m2, and 337.42g/m2. In a separate experiment the same microgreens were stored in clamshells at 0.0°C, 2.5°C, 5.0°C, 7.5°C, 10.0°C, 12.5°C, and 20°C. Microgreens were observed at 3, 7, 10 and 14 days after harvest and rated on a 1 to 5 scale. Storage at room temperature (20°C) caused severe yellowing and quick decline where none of the microgreens were of acceptable quality at 3 days after harvest. Temperatures below 7.5°C allowed acceptable storage of each of the microgreens for up to one week. Decay was most significant in arugula at two weeks of storage while others only showed moderately better performance.

Speakers

Sam Petrovich

West Virginia University

Co-authors

Sven J Verlinden

West Virginia University

Thursday September 26, 2024 12:25pm - 12:35pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:35pm HST

UG 2 - Irrigation Level Affects Bloom Number and Pollinator Visits in Herbaceous Perennials

Thursday September 26, 2024 12:35pm - 12:45pm HST

Coral 1

Heat and drought in cities can be exacerbated by limitations on water availability for irrigation. While many perennials are drought-tolerant, decreases in bloom number and quality are common. This study has two objectives. First, does bloom number in perennials decrease under limited irrigation. Second, how does this affect the number of pollinator visits. Twenty perennials were randomly planted in twelve beds, arranged in a randomized complete block design, with three beds per block. One plant of each perennial species was planted per bed. Beds within each block were randomly assigned to one of three irrigation levels: ET (evapotranspiration) 0.6, 0.3, and 0.0. Pollinators were counted by standing in front of the plant for 60 seconds and counting each pollinator within the canopy. Bloom number was determined by counting the number of blooms on one quarter of the plant and multiplying by four. Across all species, both bloom number and pollinator visits remained the same across all irrigation levels. However, individual species had very different results. Blue mist flower (Conoclinum coelestinum) had more blooms and pollinator visits in the ET 0.6 treatments (119.4 blooms and 1.3 pollinators per plant) than the ET 0.3 treatments (75.6 blooms and 0.6 pollinators per plant), while fennel (Foeniculum vulgare) had more average blooms per plant in the ET 0.3 (64.1) and ET 0 (54.9) than the ET 0.6 (15.9), though a similar average number of pollinators per plant across all treatments. Interestingly, while blooms and soil water content across all species were not correlated, pollinators and soil water content had a moderate, positive correlation (P=0.01, r=0.49).

Speakers

Madison Coyle

Texas A

Co-authors

Derald Harp

Texas A

Lindsey Trinkle

Texas A

Thursday September 26, 2024 12:35pm - 12:45pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:45pm HST

UG 2 - Strawberry Response to Compost Versus Inorganic Nitrogen

Thursday September 26, 2024 12:45pm - 12:55pm HST

Coral 1

Plant nitrogen use efficiency (NUE) is important in reducing fertilizer costs and mitigating negative impacts on agriculture and the environment. The goal of this research was to differentiate various strawberry cultivars based on their growth on compost versus inorganic nitrogen sources. The hypothesis posits that different strawberry cultivars display varying effects on the soil and plant microbiome. Given the variability in cultivars and their effects on the soil and plant microbiome, it is possible that different cultivars may influence the soil differently. Moreover, plants play a pivotal role in the development of microbiomes, subsequently supporting plant growth. For instance, plants exude amino acids from their roots to foster their beneficial microbiome. This hypothesis was tested by growing 7 cultivars of strawberries for six weeks in a mixture of peat moss and turface with and without added compost and seven replicates. Four of the replicates were used for destructive sampling at the end and three for the microbiome work. The plants were watered daily with a complete soluble fertilizer with and without added nitrogen. Leachate was collected daily and the nitrogen content (loss of nitrogen) determined. Relative growth rate and tissue N uptake was determined for each cultivar at the end of the experiment. To study the microbiome, leaf stamps on agar plates were conducted, enabling the cultivation and analysis of both bacterial and fungal communities associated with the strawberry leaves. This method provided direct insights into the microbial diversity and density present on the plant surfaces. The results of this research revealed that all cultivars grew better on soluble fertilizer than compost but some strawberry cultivars grew better on compost than others. Moreover, the strawberries developed a distinctive leaf microbiome when grown on compost, and variations specific to each cultivar were pronounced. Differential cultivar response to compost and soluble fertilizer supports the hypothesis that different cultivars influence the soil and hence nutrient uptake differently, demonstrating the importance of plant selection for sustainable agriculture and environmental protection. Further research is needed to determine the exact mechanisms.

Speakers

Kauai Paule

University of Hawaii at Manoa

Co-authors

Elizabeth De La Torre

University of Illinois Urbana-Champaign

Thursday September 26, 2024 12:45pm - 12:55pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

12:55pm HST

UG 2 - SOFT Science: Cultivating Sustainable Horticulture Leaders Through the Student Organic Farm Training Program.

Thursday September 26, 2024 12:55pm - 1:05pm HST

Coral 1

The Student Organic Farm Training (SOFT) program, established in 2007, is a student-run organic mini farm that serves as a co-curricular, hands-on learning environment for several classes at the University of Hawaii. The program's three-fold mission is to 1) highlight the role of ecological processes in organic food production through an interactive learning garden, 2) promote community health and sustainability via local food production, and 3) cultivate skills in entrepreneurship, management, and leadership among student participants in relation to agriculture. Key objectives include facilitating peer-to-peer knowledge sharing, increasing student access to affordable local organic produce, and improving student proficiency in regenerative management of horticultural systems. Specific initiatives include developing a themed educational garden, hosting workshops led by faculty/students, providing internships and volunteer opportunities, conducting on-site research, distributing produce to underserved populations, coordinating volunteer workdays, and community outreach through off-site volunteering and attending events/markets. In partnership with Noelani Public Elementary School, SOFT has engaged over 400 students in hands-on STEM learning. Through "soup" and "pizza" themed gardens, these first graders explored topics such as photosynthesis, soil, nutrition, and food safety, fostering a lifelong love for gardening and healthy eating. SOFT’s long-term goals include further integration with university curricula, transitioning to a self-sustaining operation, and expanding the program's scope to incorporate diverse horticultural systems.

Speakers

Alana Marie Barros

University of Hawai’i at Manoa

Co-authors

Eric Collier

University of Hawai’i at Manoa

Megdelena Perkins

University of Hawai’i at Manoa

Theodore Radovich

University of Hawai’i at Mānoa

Thursday September 26, 2024 12:55pm - 1:05pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

1:05pm HST

UG 2 - Phenological Modeling of Pollenizing Crabapple Cultivars (Malus spp.) and Commercial Apple Cultivars (Malus X domestica

Thursday September 26, 2024 1:05pm - 1:15pm HST

Coral 1

Commercial apple cultivars require a pollinizer for cross-pollination to ensure fruit-set yields when planted in contiguous blocks found in modern apple orchards. Pollinizers must have compatible viable diploid pollen and have bloom overlap with the variety grown in the orchard block. Climate change can influence the viability of a pollenizer cultivar by shifting the bloom times of the pollinizers and the commercial apple cultivar, depleting the source of pollen for that block, and decreasing yield potential. 4 commercially available pollenizing crabapple cultivars (Indian Summer, Mt. Blanc™, Mt. Evereste™, Snow Drift) were replicated 5 times in completely randomized design. Pollinizers were analyzed weekly for developmental stages from silver tip to petal fall. 7 apple cultivars were also analyzed for comparison. The stage progression data for each pollenizer cultivar was modeled using growing degrees days base 6.6°C. These models were used to compare the stage progression and bloom dates of the pollenizer cultivars, and compared to the production apple cultivars to assess bloom overlap and determine pollinizer feasibility. All 4 crabapples began to bloom earlier than the scion cultivars leading to little bloom overlap. Indian Summer was the first crabapple to bloom on 3/28 with cumulative growing degree days (GDD) 166.4. The latest to bloom was Mt. Blanc on 4/13 with cumulative GDD 250.1. The commercial cultivars did not begin to bloom until 4/6 with cumulative GDD 199.6 through 4/13 with cumulative GDD 250.1. While the first commercial cultivar to bloom was Gold Rush and most at full bloom around 4/13, at which time all but Mt. Blanc crabapples were past bloom. Results suggest most pollinizer cultivars have poor bloom overlap with commercial cultivars in Kentucky, with Mt. Blanc offering the best, though limited overlap. Furthermore, the crabapple cultivars are seemingly responding to environmental cues such as chilling and GDD accumulation differently to leave dormancy and progress through bloom at a more rapid rate. These early results suggest that the use of crabapple cultivars as pollinizers and their overlap with commercial apple cultivars could be an area of concern as climate change brings earlier springs in major apple producing regions.

Speakers

Miranda Woodcock

University of Kentucky

Co-authors

Brent Arnoldussen

University of Kentucky

Thursday September 26, 2024 1:05pm - 1:15pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student 2

SUBJECT Undergraduate Student

1:15pm HST

UG 2 - Determining Sap Yield, Sugar Content, and Mineral Composition of European White Birch Trees

Thursday September 26, 2024 1:15pm - 1:25pm HST

Coral 1

The demand for locally sourced agricultural products in the United States is growing, with consumers increasingly seeking unique items and willing to pay premium prices for them. Currently, birch products such as birch sap and birch syrup are primarily produced in Alaska and the Eastern United States. However, there may be an opportunity for birch tree owners in the western United States to enter this market with their own local birch products. European white birch (Betula pendula), a common landscaping tree in the cooler northern regions of Utah, presents a potential resource for this industry. Despite the prevalence of these trees, there is a lack of research on the feasibility of tapping them for sap in the Intermountain West. This study aims to address this gap by evaluating the sap yield, sugar content, and mineral composition of European white birch trees in Northern Utah. In the spring of 2024, birch trees in Logan, North Logan, Hyde Park, and Smithfield, UT, were tapped using plastic sap buckets. Daily sap yields were recorded for each tree from 16 March to 11 April 2024, and sap samples were analyzed for sugar and mineral content. This preliminary research provides crucial data for assessing the viability of a birch tapping industry in Northern Utah. While further research is necessary for a comprehensive evaluation, this project lays the groundwork for understanding the potential of tapping European white birch trees in this region.

Speakers

Abby Porter

Utah State University

Co-authors

Xin Dai

Utah State University

Youping Sun

Utah State University

Thursday September 26, 2024 1:15pm - 1:25pm HST
Coral 1

Poster presentation (individual talk), Undergraduate Student

SUBJECT Undergraduate Student

1:44pm HST

Growth Chambers and Controlled Environments 6 (CE 6)

Thursday September 26, 2024 1:44pm - 3:45pm HST

Coral 1

Timing Kale Growth for Peak Nutrition and Energy Efficiency in a Vertical, Hydroponic Indoor Container Farm - Skyler Brazel
Effects of Beneficial Bacterial Endophytes on Growth of Lettuce Plants, Transcriptome, and Root Microbiome in Hydroponic Systems - Chuansheng Mei
Soybean Speed Breeding: Optimizing Photoperiod for Maximizing Yield and Minimizing Time - Cristiane da Silva
Energy Modeling and Management to Improve the Sustainability of Indoor Farming - Ying Zhang
Increasing Circularity in Controlled Environment Agriculture using Anaerobic Digester Effluent as an Organic Fertilizer - Ana Martin Ryals
Utilizing Deep Learning for Hydroponic NFT Channel Spacing Optimization - Azlan Zahid
Modeling Evapotranspiration in Greenhouse and Indoor Cutting Propagation - Daniel Crawford
Effect of Nutrient Correction Intervals on Nutrient Imbalance, Plant Growth, Yield, and Fruit Quality of Melon (Cucumis melo L.) in a Closed Hydroponic System - Minju Shin

Moderator

Skyler Brazel

University of Tennessee - Knoxville

Thursday September 26, 2024 1:44pm - 3:45pm HST
Coral 1

Oral Sessions, Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

1:45pm HST

CE 6 - Timing Kale Growth for Peak Nutrition and Energy Efficiency in a Vertical, Hydroponic Indoor Container Farm

Thursday September 26, 2024 1:45pm - 2:00pm HST

Coral 1

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

Speakers

Skyler Brazel

University of Tennessee - Knoxville

Co-authors

Carl Sams

University of Tennessee

Devin Vitello

University of Tennessee - Knoxville

Katelynn Rector

University of Tennessee - Knoxville

Thursday September 26, 2024 1:45pm - 2:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:00pm HST

CE 6 - Effects of Beneficial Bacterial Endophytes on Growth of Lettuce Plants, Transcriptome, and Root Microbiome in Hydroponic Systems

Thursday September 26, 2024 2:00pm - 2:15pm HST

Coral 1

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

Speakers

Chuansheng Mei

Institute for Advanced Learning and Research

Co-authors

Robert Chretien

Institute for Advanced Learning and Research

Sajeewa Amaradasa

Institute for Advanced Learning and Research

Scott Lowman

Institute for Advanced Learning and Research

Thursday September 26, 2024 2:00pm - 2:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:15pm HST

CE 6 - Soybean Speed Breeding: Optimizing Photoperiod for Maximizing Yield and Minimizing Time

Thursday September 26, 2024 2:15pm - 2:30pm HST

Coral 1

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

Speakers

Cristiane da Silva

Postdoctoral Research Scholar, North Carolina State University

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

Co-authors

Cristian Collado

North Carolina State University

Jan Van Butsele

BASF

Ricardo Hernandez

North Carolina State University

Richard Jack

BASF

Will Bednarz

BASF

Thursday September 26, 2024 2:15pm - 2:30pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:30pm HST

CE 6 - Energy Modeling and Management to Improve the Sustainability of Indoor Farming

Thursday September 26, 2024 2:30pm - 2:45pm HST

Coral 1

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

Speakers

Ying Zhang

University of Florida

Co-authors

German Sandoya

University of Florida

Kale Harbick

USDA-ARS

Nikolay Bliznyuk

University of Florida

Tanapol Leelertkij

University of Florida

Thursday September 26, 2024 2:30pm - 2:45pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

2:45pm HST

CE 6 - Increasing Circularity in Controlled Environment Agriculture using Anaerobic Digester Effluent as an Organic Fertilizer

Thursday September 26, 2024 2:45pm - 3:00pm HST

Coral 1

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

Speakers

Ana Martin Ryals

University of Florida

Co-authors

Haimanote Bayabil

University of Florida

Kelsey Vought

University of Florida

Thursday September 26, 2024 2:45pm - 3:00pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:00pm HST

CE 6 - Utilizing Deep Learning for Hydroponic NFT Channel Spacing Optimization

Thursday September 26, 2024 3:00pm - 3:15pm HST

Coral 1

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

Speakers

Azlan Zahid

Texas A

Thursday September 26, 2024 3:00pm - 3:15pm HST
Coral 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:15pm HST

CE 6 - Modeling Evapotranspiration in Greenhouse and Indoor Cutting Propagation

Thursday September 26, 2024 3:15pm - 3:30pm HST

Coral 1

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

Speakers

Daniel Crawford

University of Florida

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

3:30pm HST

CE 6 - Effect of Nutrient Correction Intervals on Nutrient Imbalance, Plant Growth, Yield, and Fruit Quality of Melon (Cucumis melo L.) in a Closed Hydroponic System

Thursday September 26, 2024 3:30pm - 3:45pm HST

Coral 1

In South Korea, where many fruit vegetable crops are grown in greenhouses, the practice of continuous cropping in the same soil environments often leads to significant issues To mitigate these problems, there has been a shift from soil-based to hydroponic cultivation. While hydroponics is recommended as a sustainable agricultural practice, non-recirculating systems can lead to environmental contamination as the nutrient-rich drainage is discharged outside, affecting soil and water quality. However, recirculating hydroponics, which reuses the drained nutrient solution, conserves water and fertilizer, thereby promoting sustainable and eco-friendly agriculture. As plants grow, their nutrient requirements change with each growth stage. Reusing the drainage without adjusting its nutrient content can lead to imbalances. Periodic nutrient correction is crucial in recirculating hydroponic systems. This study was conducted to find the optimal nutrient correction intervals for growing melons hydroponically in a recirculating system, analyzing the effects of different correction intervals (every 2 weeks, every 4 weeks, and no correction) on nutrient imbalances and their impact on melon growth and fruit development. In the case of melons, post-fruit set, as plants shift from vegetative to reproductive growth, changes in nutrient uptake lead to imbalances. In this experiment, the nutrient composition between treatments corrected periodically did not differ significantly, but was markedly different from the uncorrected treatments. In uncorrected systems, the continual reuse of the drainage altered the balance of anions and cations, with anions increasing by approximately 4% and cations decreasing by the same margin, disrupting the nutrient balance and causing pH fluctuations. Specifically, there was a 10-12% difference in the ratios of cations such as K+ and Ca2+, and a 7% difference in anions like NO3-. Despite these nutritional variances, statistical analysis revealed no significant differences in the growth and fruit characteristics among the treatments.

Speakers

Minju Shin

Rural Development Administration

Co-authors

Ho Jeong Jeong

Rural Development Administration

Jin Hyun Kim

Rural Development Administration

Seungri Yoon

Seoul National University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 6

SUBJECT Growth Chambers and CE

4:00pm HST

Interest Group Session: Using AI in Teaching: Examples and Methods

Thursday September 26, 2024 4:00pm - 6:00pm HST

Coral 1

As Artificial Intelligence (AI) continues development at a rapid pace, our current teaching and learning methods are also swiftly transforming. AI itself is often combined with various technologies such as image recognition, virtual reality (VR), machine learning, adaptive learning algorithms, and gamification. With the merger of existing technology, AI and education will change the way we teach as well as how students learn. Some examples for teaching Horticulture, Landscape Architecture or Plant Science include individualized teaching, deep learning, adaptive learning environments, AI-based assessment and image recognition. In this Professional Interest Group Session speakers will provide examples of how they are using AI in their teaching methods, followed by an open discussion with the audience that should provide additional examples and applications.

Coordinator(s)

Kathryn Orvis, Purdue Univ, Horticulture and Landscape Architecture, West Lafayette, Indiana, United States

Speaker/Participant(s)

Mary Rogers, University of Minnesota, Department of Horticultural Science, St Paul, Minnesota, United States
How to Incorporate Generative AI in Teaching a Writing Intensive Urban Agriculture Course (15 mins)
Summary:
Aaron Thompson, Purdue University, Horticulture and Landscape Architecture, West Lafayette, IN, United States
Teaching with AI in Landscape Architecture (15 mins)
Summary:
Cynthia Haynes, Iowa State University, Horticulture, Ames, Iowa, United States
Potential benefits and pitfalls of using AI software in Horticulture teaching. (15 mins)
Summary:

Moderator

Kathryn Orvis

Professor, Purdue Univ

Speakers

Aaron Thompson

Mary Rogers

Cynthia Haynes

Iowa State University

Thursday September 26, 2024 4:00pm - 6:00pm HST
Coral 1

Interest Group Session

SUBJECT Technology, Teaching, Ornamental Landscape Turf

9:44am HST

Genetics and Germplasm 3 (GG 3)

Friday September 27, 2024 9:44am - 11:15am HST

Coral 1

Transcriptomic responses underlying host-pathogen interactions between resistant and susceptible Prunus accessions and two Armillaria Root Rot fungi - Stephen Parris
Fine mapping of Linkage Group 7 (LG7) Eastern Filbert Blight (EFB) Resistance in Hazelnut - Rion Mooneyham
Estimation of Breeding Values to Improve Kernel Weight in Almond (Prunus dulcis) - Shashi Goonetilleke
Alternative RNA Splicing Associated with Pecan Dichogamy - Xinwang Wang
Alaska Can Grow More Than Giant Vegetables: The Potential of Rhubarb for Specialty Crop Producers - Carol Miles
Utilization of Germplasm to Improve Illinois Horseradish - Alan Walters

Moderator

Shashi Goonetilleke

The University of Queensland

Friday September 27, 2024 9:44am - 11:15am HST
Coral 1

Oral Sessions, Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

9:45am HST

GG 3 - Transcriptomic responses underlying host-pathogen interactions between resistant and susceptible Prunus accessions and two Armillaria Root Rot fungi

Friday September 27, 2024 9:45am - 10:00am HST

Coral 1

Armillaria root rot (ARR) caused by Desarmillaria caespitosa and Armillaria mellea represents the main cause of premature stone fruit and nut tree decline in the United States. A. mellea is a primary concern for almond and peach growers in California, while D. caespitosa threatens peach production in the southeast region of the U.S. These fungi survive as facultative necrotrophs and colonize roots of several agriculturally important crops, including peach, almond, and sweet cherry. This colonization ultimately kills the woody roots and therefore host, severely limiting the tree’s lifespan and ability to provide a return on investment for the grower. Few management options are available to slow down ARR disease progression, and no management practice eliminates ARR fungi presence in an infested field. Additionally, most of the commercially available rootstocks are susceptible to infection, with only two peach/plum hybrid commercial rootstocks (Prunus umbellata × P. persica ‘MP-29’ and P. cerasifera × P. persica ‘Krymsk® 86’) showing partial resistance to ARR. The shared plum genetic background in these hybrids, paired with the lack of ARR resistance observed in peach germplasm suggests the source of resistance originated from plum. In this work, induced genetic responses in one susceptible accession, P. persica ‘Guardian®’, and two resistant accessions, P. cerasifera ’14-4’ and ‘MP-29’, when infected with D. tabescens and A. mellea were analyzed. Additionally, expression of genes encoding effectors and cell wall degrading enzymes (CWDEs) were investigated in the ARR fungi while infecting the three hosts. The results of the infection assays revealed unique responses between each of the three hosts in their progression of disease symptoms over time and in their transcriptomes while under infection by the two ARR fungi. Analysis identified key hub genes expressed by the two resistant Prunus accessions involved in the sensing and enzymatic degradation of chitin and the upregulation of GSTs, oxidoreductases, and transcription factors. Investigation of the ARR fungi transcriptomes similarly identified host-dependent expression of fungal effectors and CWDEs responsible for degrading the cell wall components cellulose, hemicellulose and pectin. Comprehensive analyses considering transcriptomes produced by both the host and pathogen during the infection course provides a deeper understanding of the factors driving resistant and susceptible responses to ARR infection, and their effects on the infecting pathogen’s gene expression.

Speakers

Stephen Parris

Clemson University

Co-authors

Christopher Saski

Clemson University

Guido Schnabel

Clemson University

Jared Weaver

Clemson University

Jeffrey Adelberg

Clemson University

Ksenija Gasic

Clemson University

Lichun Cai

Clemson University

Friday September 27, 2024 9:45am - 10:00am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

10:00am HST

GG 3 - Fine mapping of Linkage Group 7 (LG7) Eastern Filbert Blight (EFB) Resistance in Hazelnut

Friday September 27, 2024 10:00am - 10:15am HST

Coral 1

Eastern filbert blight (EFB) disease caused by the fungal pathogen Anisogramma anomala (Peck) E. Müller is a major threat to Oregon’s hazelnut (Corylus avellana) industry. The Oregon State University (OSU) hazelnut breeding program has used ‘Gasaway’ as a source of resistance in many releases. Cultivars with ‘Gasaway’ resistance mapped to linkage group 6 (LG6) including ‘Jefferson’ and ‘McDonald’ have been extensively planted throughout Oregon’s Willamette Valley over the past decade. However ,‘Jefferson’ and ‘McDonald’ have exhibited small cankers in commercial orchards under high disease pressure. In New Jersey, cultivars with ‘Gasaway’ resistance develop large cankers. Thus, there are concerns about the long-term durability of ‘Gasaway’ resistance and the sustainability of Oregon’s hazelnut industry. The disease is also a main limiting factor to commercial hazelnut production in the eastern USA. New sources of resistance would be interesting, and a few major resistance genes have been mapped to LG7. Four populations were developed for fine mapping the LG7 resistance region using the ‘Ratoli’ (from Spain) and OSU 1166.123 (from Sochi, Russia) resistance sources. SSRs narrowed the resistance region to < 20 cM, and recombinant individuals were identified using 4-5 SSR loci within the region. Recombinants were inoculated with Anisogramma anomala in the greenhouse and in the field, and disease was evaluated 18 months later. A set of 22 new SSR markers were developed from di- and tri-nucleotide repeats between the flanking markers in the ‘Jefferson’ genome (v4). SSR markers were characterized using a diversity panel of 50 hazelnut accessions. To develop KASP/PACE primers for SNPs in the region, an initial set of 3000 SNPs was reduced to 100 using a SNP array. High density genetic linkage maps with new SSR and KASP markers were constructed for all four mapping populations. The results of this study will aid marker-assisted selection and the breeding of EFB-resistant cultivars with these new sources, and facilitate the pyramiding of R-genes in a single clonal selection for more durable resistance.

Speakers

Rion Mooneyham

Oregon State University

Co-authors

Jacob Snelling

Oregon State

Shawn Mehlenbacher

Oregon State University

Friday September 27, 2024 10:00am - 10:15am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

10:15am HST

GG 3 - Estimation of Breeding Values to Improve Kernel Weight in Almond (Prunus dulcis)

Friday September 27, 2024 10:15am - 10:30am HST

Coral 1

Improving nut and kernel quality traits is a high priority in almond breeding programs around the world. Almond has a long juvenile period and phenotypic selection for nut and kernel traits can only be conducted after three years from planting. In early stages of planting, individuals with desirable nut and kernel traits can be identified by marker-trait associations (MTAs) using molecular markers. Currently, MTAs are identified by quantitative trait locus (QTL) mapping using progeny from bi-parental crosses or association mapping panels. However, the efforts of identifying MTAs using current QTL detection methods are hampered either by unavailability of genomic information or required genetic linkage maps. In addition, most kernel traits have polygenic inheritance, and many genes and genomic regions affect genetic variations. In crop research, genomic selection would provide promising approach to accelerate the genetic gains and reduce the length of breeding cycle. Yet, application of genomic selection in almond breeding and research is limited. We present results demonstrating the predictive ability of whole-genome and pedigree-based models to identify elite candidate parents for almond kernel weight. In this work, we used ancestral pedigree and phenotypic data from 13,000 progeny that were derived from 57 parents and 291 families. Ancestral pedigrees were recorded from the available literature from the almond breeding programs in USA, Spain, Italy, France, and Australia. Average kernel weight was obtained for each progeny tree from 30 nuts. All parents were resequenced using whole-genome sequencing at a depth of 15x. Over 80k high quality, independent single-nucleotide polymorphisms were used to construct realised genomic relationship matrix and linkage disequilibrium (LD) regions were used to compute LD weights. Genomic best linear unbiased prediction (GBULP) using Asreml-R was used to predict genomic estimated breeding values (GEBV). Pedigree model derived from linear mixed model was used to predict individual tree effects (PEBV) to validate the predicted GEBVs. EBVs were compared using Pearson correlation coefficient (r) and elite candidate parents were selected based on the selection index. For kernel weight, both pedigree and genomic models resulted similar EBVs, and r was 0.97. A high level of correlation in EBVs obtained from two methods indicates the suitability of these models in estimating BVs for future predictions. Predicted elite candidate parents from this study can reduce the conventional breeding cycle of almond by 6 years. The constructed models mainly represent Australian context and multi-environmental trials are required to identify the broader applicability of these models.

Speakers

Shashi Goonetilleke

The University of Queensland

Co-authors

Craig Hardner

The University of Queensland

Michelle Wirthensohn

The University of Adelaide

Friday September 27, 2024 10:15am - 10:30am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

10:30am HST

GG 3 - Alternative RNA Splicing Associated with Pecan Dichogamy

Friday September 27, 2024 10:30am - 10:45am HST

Coral 1

Pecan (Carya illinoinensis), a North American native nut crop, exhibits two distinct flowering habits where male and female flowering occur at separate times. Trees that shed pollen before their pistillate flowers become receptive are classified as protandrous or type 1 (recessive homozygous, pp), while those with pistillate flowers receptive before pollen shed are protogynous or type 2 (dominant heterozygous, PP/Pp). Establishing commercial pecan orchards requires planting both types of pecan cultivars to ensure optimal pollination for maximum production. To investigate critical genes associated with pecan heterodichogamous flowering, we collected tissues from four stages (dormant buds, swollen buds, immature catkins, and immature pistils) of three genotypes (PP, Pp, and pp). Paired-end RNA sequencing at 125/150 bp read lengths was conducted on an Illumina platform. Clean and unique reads were mapped to an annotated 'Pawnee’ reference genome. Out of 32,267 annotated genes, over 5,000 (~15%) were identified to have alternative splicing events associated with pecan flowering dichogamy. We illustrate by three genes that present significant alternative splicing patterns associated with dichogamy genotypes, distinguishing the pp genotype from PP and Pp genotypes. These genes exhibited 6-18 nucleotide differences in RNA sequence between the pp genotype and PP/Pp genotypes, potentially resulting in an altered protein product with 2-6 amino acid differences between type 1 and type 2 genotypes. This study provides evidence for the prevalence of alternative RNA splicing in the transcription regulation of pecan dichogamy.

Speakers

Xinwang Wang

Plant Geneticist, USDA ARS

Co-authors

Jennifer Randall

New Mexico State University

Joe Song

New Mexico State University

Warren Chatwin

USDA ARS Southern Plains Agricultural Research Center

Yiyi Li

New Mexico State University

Friday September 27, 2024 10:30am - 10:45am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

10:45am HST

GG 3 - Alaska Can Grow More Than Giant Vegetables: The Potential of Rhubarb for Specialty Crop Producers

Friday September 27, 2024 10:45am - 11:00am HST

Coral 1

Specialty crop producers in Alaska need consistent, suitable crop and varietal options for successful commercial production, as food security is a major concern in this state that imports 95% of its food. The climate in much of Alaska is ideal for cool season, perennial corps that are winter hardy, such as Rhubarb (Rheum sp.). Rhubarb was brought to Alaska through several waves of immigration from regions extending from Russia through England and is now established throughout the state. Once a site for the National Plant Germplasm System (NPGS) Arctic and Subarctic Plant Gene Bank, the University of Alaska Fairbanks Matanuska Experiment Farm and Extension Center still maintains a collection of 41 accessions of Rheum sp. in the field. In addition, a new collection of heirloom rhubarb plants has been assembled by a local grower and maintained in large pots. In this project, we collected leaf samples from the heirloom collection plants for genotyping and phenotyping, as well as benchmark samples from plants remaining in the former germplasm collection, to provide an understanding of relatedness and desirable characteristics. A 5 cm square sample of leaf tissue was harvest from each plant, dried, and sent to a commercial laboratory for genotyping. Size and color of leaves and petioles, dates of emergence, plant vigor, and juice quality were measured on plants from the heirloom collection. Finally, surveys carried out of the last 12 years targeted a diversity of stakeholders (commercial producers, business owners, and the general public) to identify rhubarb quality expectations, including flavor, juice content, petiole color, and plant vigor. Based on genotyping results, plants not genetically redundant to those in the NPGS rhubarb collection currently located in Pullman, Washington, will be added to the collection. We present recommendations for variety suitability for different climate regions of Alaska based on the traits measured, taking into account varieties of rhubarb currently available wholesale to Alaska. Recommendations are also presented for further research into commercial production and added-value characteristics.

Speakers

Carol Miles

Washington State University

Co-authors

Alex Cornwall

USDA ARS

Ann Kowenstrot

University of Alaska Fairbanks

Marilyn Warburton

USDA ARS

Friday September 27, 2024 10:45am - 11:00am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

11:00am HST

GG 3 - Utilization of Germplasm to Improve Illinois Horseradish

Friday September 27, 2024 11:00am - 11:15am HST

Coral 1

Horseradish (Armoracia rusticana, Brassicaceae) is an important specialty crop in Illinois, with most commercial production adjacent to St. Louis, Missouri in what is known as the Mississippi Bottoms. The continued development of new, improved horseradish cultivars is critical to sustain this important specialty crop industry, since horseradish clonal cultivars tend to "run out" and lose their productivity over a period of about 10 years. A small germplasm collection of clones from eastern Europe and Russia, as well as old cultivars no longer in wide use and other breeding materials that were saved from the breeding program has been maintained since the 1960s, first at University of Illinois until the early 2000s and now at Southern Illinois University-Carbondale. During the last 20 years, germplasm has been utilized from various sources to improve horseradish so this industry can sustain itself for the near future. The following examples are provided to illustrate the importance of new germplasm in new horseradish cultivar development. Accession 761A collected from Drążgów, Poland was instrumental in developing horseradish cultivars with tolerance to internal root discoloration which is caused by a soil-borne pathogen complex. The germplasm clone Czech has been very effective in transmitting its large root size trait to its resulting progeny and was used in many crosses made from 2005 to 2010. Many cultivars grown today have this germplasm source in their background. Another important clonal cultivar known as 9705 was widely grown during the 2000s and resulted from outcrossing accession 758A collected from Ribnica, Slovenia with an unknown male. Additionally, 315 is another very important cultivar that was the workhorse for the industry from 2005 to 2015 having lineage also from 758A. 15K was another industry workhorse in the late 1990s to early 2000s, and had its primary lineage traceable to 856A, an accession from the Czech Republic. These are a few examples of how germplasm sources have contributed to sustaining the Illinois horseradish industry and each will be discussed in further detail regarding their specific benefits. Moreover, most are still used in some capacity in the breeding program today.

Speakers

Alan Walters

Southern Illinois University

Friday September 27, 2024 11:00am - 11:15am HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 3

SUBJECT Genetics and Germplasm

11:29am HST

Vegetable Breeding (VGBR)

Friday September 27, 2024 11:29am - 12:30pm HST

Coral 1

The Power of Breeding and Genetics in Controlled Environment Horticulture - Krishna Bhattarai
Novel Summer Squash: Breeding Tromboncino Types for U.S. Markets - James Myers
Mapping QTL for Bacterial wilt resistance and plant height in Tomatoes - Dilip Panthee
Effects of Prolonged Photoperiod on Chile Pepper Plant Architecture and Growth Habit - Shahab Nourbakhsh
Seasonal Lettuce Germplasm Trials in Northeast Florida Hydroponics - Evelyn Fletcher
Marker Development for Cadmium Accumulation in Spinach - Danyelle Forte

Moderator

Shahab Nourbakhsh

New Mexico State University

Friday September 27, 2024 11:29am - 12:30pm HST
Coral 1

Poster Session, Vegetable Breeding

SUBJECT Vegetable Breeding

11:30am HST

VGBR - The Power of Breeding and Genetics in Controlled Environment Horticulture

Friday September 27, 2024 11:30am - 11:40am HST

Coral 1

Controlled environment (CE) horticulture production has shown its potential to cope with the impact of climate change such as rising temperatures and declining water availability. Drives like “locally grown”, and “food miles reduction” favor CE-based food production which represents a $50 billion market for fresh, local, and sustainable food. CE production systems use advanced technology for climate control and mechanized growing practices for which infrastructure and software development have taken a good start. Contrastingly, the breeding and development of plants designed to best perform in CEs to reduce energy usage, allow automation, and increase profits are just beginning. The US CE producers can benefit from the breeding and development of new cultivars with modified stature that offer high-density planting and shortened crop cycles, ease in maintaining and harvesting, and allow automation. Utilization of plant genetics to breed for plant statures will increase crop diversity in CEs. Additionally, discovering new genetics in plant germplasms to enhance crop quality for nutrition, flavor, taste, color, and texture through breeding can meet consumer needs for fresh, high-quality, nutritious, and sustainably produced food. Several other opportunities exist where leveraging genetics to breed new crops that produce nutraceuticals, biofuel, macro and micronutrients, and bioactive compounds can sustain the CE horticulture industry, feed the increasing population, improve health, and cope with climate change.

Speakers

Krishna Bhattarai

Texas A

Friday September 27, 2024 11:30am - 11:40am HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding

SUBJECT Vegetable Breeding

11:40am HST

VGBR - Novel Summer Squash: Breeding Tromboncino Types for U.S. Markets

Friday September 27, 2024 11:40am - 11:50am HST

Coral 1

Cucurbitaceae family squash and pumpkins are all New World domesticates from different parts of the Americas. While many types are eaten as winter squash at full maturity, others – termed summer squash – are used as vegetable where the immature fruit is eaten. The summer squash we are most familiar with belong to the species Cucurbita pepo. The immature fruit of C. maxima and C. moschata are sometimes used as summer squash and a few land race types have been developed mainly for summer squash use. ‘Tromboncino’ (also called Trombetta or Zucchetta Rampicante), is one such C. moschata summer squash from the Ligura region of Italy. It is most closely related to the butternut winter squashes. Originally domesticated in the tropical lowlands of Middle America, it is more tolerant of high temperatures, humidity and pest and diseases. Tromboncino is essentially a butternut squash with an extended neck that has been adapted to use as an immature vegetable but can also be used as a winter squash. The heritage varieties of Tromboncino are long-vined with prolific fruit production and produce few seeds. The seeds are found in a bulb at the end of the fruit, leaving a long seedless neck for culinary preparation. It has a firmer, meatier texture and a flavor profile that is more similar to a mature butternut squash. Tromboncinos are at their highest quality when used at 6-12" long, but they can be eaten at later stages until fully mature. The main breeding objective of the OSU vegetable breeding program was to develop a tromboncino type with better adaptation to the cool summers of Western Oregon, shift plant architecture to a bush plant habit while retaining prolificacy, and shorten fruit length for fresh market production. Another objective was to combine the tromboncino type with skin colors other than the traditional tan color of the heritage variety. We have been able to accomplish most objectives although the plant architecture is not yet comparable to the bush habit of C. pepo summer squash. Some types have dark green as well as yellow skin colors (conditioned by the precocious yellow gene). Two advanced lines are in the process of being released.

Speakers

James Myers

Oregon State University

Co-authors

Emma Landgraver

Oregon State University

Joel Davis

Oregon State University

Friday September 27, 2024 11:40am - 11:50am HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding

SUBJECT Vegetable Breeding

11:50am HST

VGBR - Mapping QTL for Bacterial wilt resistance and plant height in Tomatoes

Friday September 27, 2024 11:50am - 12:00pm HST

Coral 1

Bacterial wilt (BW) of tomatoes, caused by Ralstonia solanacearum, is a devastating dis-ease that results in large annual yield losses worldwide. Management of BW of toma-toes is difficult due to the soil-borne nature of the pathogen. One of the best ways to mitigate the losses is through breeding for disease resistance. Moreover, plant height (PH) is a crucial element related to plant architecture which determines nutrient management and mechanical harvesting in tomatoes. An intra-specific F2 segregating population (NC 11212) of tomatoes was developed by crossing NC 84173 (tall, BW susceptible) x CLN1466EA (short, BW resistant). We performed quantitative trait loci (QTL) mapping using single nucleotide polymorphic (SNP) markers and the NC 11212 F2 segregating population. The QTL analysis for BW resistance revealed a total of three QTLs on chromosomes 1, 2, and 3, explaining phenotypic variation (R2) ranging from 3.6% to 14.9%. Whereas, QTL analysis for PH also detected three QTLs on chromo-somes 1, 8, and 11 explaining R2 ranging from 7.1% to 11%. This work thus provides information to improve BW resistance and plant architecture-related traits in toma-toes.

Speakers

Frank Louws

NCSU

Co-authors

Dilip Panthee

North Carolina State University

Emily Silverman

North Carolina State University

Muhammad Irfan Siddique

North Carolina State University

Friday September 27, 2024 11:50am - 12:00pm HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding

SUBJECT Vegetable Breeding

12:00pm HST

VGBR - Effects of Prolonged Photoperiod on Chile Pepper Plant Architecture and Growth Habit

Friday September 27, 2024 12:00pm - 12:10pm HST

Coral 1

This experiment sought to examine the effects of prolonged photoperiod and modified temperature and humidity in chile peppers, aiming to develop a protocol to accelerate their growth and enhance breeding efficiency. Four genotypes from three Capsicum species (C. annuum - Chimayo, Early Jalapeno; C. chinense - Orange Habanero; Chiltepin - C. annuum var. glabriusculum) were planted in two randomized flat trays per entry using SunGro propagation soil. After reaching the 2-3 leaf stage, they were transplanted into 8” pots, incorporating sterilized and LM-AP soil mixtures. The experimental population was grown in an improvised growth chamber with an average temperature of 25°C and humidity of 60% and exposed to a 20-hour daily cycle of 450 nm full spectrum LED grow lights and 730 nm Far Red LED grow lights and 4 hours of darkness. The control group grew in normal greenhouse conditions, exposed to normal daylight intensity and duration and an average temperature of 21°C and humidity of 40%. Weekly data recordings included plant growth measurements of plant height and leaf count. Basal branches were counted approximately 12 weeks after planting, and leaf widths were recorded 14 weeks after transplanting. Number of flowers and fruits were also recorded at 14 weeks after transplanting. Data were analyzed using RStudio, and Tukey HSD was used to detect differences between treatments and among genotypes. In terms of plant height, all experimental plants demonstrated a significant increase compared to the control group, both in absolute amounts and in rates, especially later in the growth stage. The leaf numbers in experimental plants were significantly lower than the control group, except for Orange Habanero, which showed no significant difference. Early Jalapeno, in both treatments, exhibited no significant difference in basal branches. In contrast, the remaining experimental plants displayed fewer or no basal branches compared to the control group. All experimental plants exhibited significantly wider leaves in comparison with the control group. While most experimental plants started flowering earlier, no significant differences were observed between numbers of flowers and fruits. The faster growth rates observed hold the promise of accelerated progress and improved efficiency in breeding initiatives, offering a fundamental shift in the way we approach crop development. Additionally, fewer number of basal branches may have implications for machine harvestability, as fewer basal branches is considered a desirable trait for machine harvesting.

Speakers

Shahab Nourbakhsh

New Mexico State University

Co-authors

Dennis Nicuh Lozada

New Mexico State University

Isaac Porras

New Mexico State University

Rhiannon Rodriguez

New Mexico State University

Tyra Trumble

New Mexico State University

Friday September 27, 2024 12:00pm - 12:10pm HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding

SUBJECT Vegetable Breeding

12:10pm HST

VGBR - Seasonal Lettuce Germplasm Trials in Northeast Florida Hydroponics

Friday September 27, 2024 12:10pm - 12:20pm HST

Coral 1

The Hastings Agricultural Extension Center adopted the lettuce variety trials in 2018 for the demonstration of alternative row crops. Within the Tri-County Agricultural Area (TCAA), the term "alternative" refers to any crops outside of the traditional rotations - potatoes and cabbage. While these crops are the staple of the community, the acreage has been reduced due to tight profit margins and competitiveness for chipping contracts. Lettuce, along with artichokes and pumpkins, have been one of the newly adopted commodities for North Florida. What initially began as field trials expanded into the controlled systems of protected agricultural and hydroponics. Three seasons of germplasm trials with 14 newly developed lines in the hydroponic towers were conducted in Hastings to evaluate their soilless potential. Under 20% shade, lettuce was grown in the Verti-Gro system with 40% perlite, 30% coconut coir and 30% peat moss. These trials were also home to many field tours for the community, and opportunities for local growers to witness and observe their growth habits. Data evaluations included marketability, timing (if observed) of bolting, tip burn, and head weights. Weights ranged from 0.10 - 0.85 kg, with Botrytis and Sclerotinia being the most common disease pest identified. Since the trials began, our lettuce acreage has increased from 15 to 100 in the county, including two organic growers and one conventional, and with opportunities for more research to benefit these diversified growers.

Speakers

Evelyn Fletcher

University of Florida

I am the commercial row-crop Extension Agent for St. Johns County, FL.

Co-authors

German Sandoya

University of Florida

Friday September 27, 2024 12:10pm - 12:20pm HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding

SUBJECT Vegetable Breeding

12:20pm HST

VGBR - Marker Development for Cadmium for Accumulation in Spinach

Friday September 27, 2024 12:20pm - 12:30pm HST

Coral 1

California is the largest spinach producing state in the USA, accounting for 75% of hectares planted. The major production area is the Salinas Valley, which is known to have geogenic cadmium soils. Spinach is a hyperaccumulator and its affinity for divalent cations, like zinc and iron, likely contributes to the accumulation of Cd. Cadmium has known adverse health effects in humans, so California’s Office of Environmental Health Hazard Assessment’s (OEHHA) set a limit of 4.1 ug Cd per day by consumption. Consequently, growers do not produce spinach on high cadmium soils, limiting their ability to rotate crops throughout the valley. Even so, a few fresh leaf market spinach samples with foliar concentrations of Cd above the limit have been reported.

Our long-range objective is to develop improved fresh market spinach germplasm that restricts Cd uptake while maintaining nutritional quality. We have observed phenotypic variation for foliar cadmium concentration in a wide diversity of spinach germplasm with over 500 accessions originating from 42 countries, showed that greenhouse evaluations in high Cd soil largely reflected phenotypic performance in the field, and developed populations segregating for Cd uptake. We have also developed a hydroponic system that reflects field and greenhouse Cd uptake, but that is more controlled and scalable. Our current objectives are to identify quantitative trait loci (QTL) in the spinach genome associated with Cd accumulation. We have developed a biparental mapping population for genetic mapping by crossing high and low individuals which was evaluated in hydroponics earlier this year and will be evaluated in field conditions this fall. Markers tagging major QTL loci will be developed into high-throughput KASP markers for routine use in breeding.

Speakers

Danyelle Forte

Graduate Student First Year, University of California - UC Davis

Co-authors

Allen Van Deynze

University of California Davis

Allison Krill-Brown

University of California Davis

Daniel Pap

University of California Davis

E. Charles Brummer

University of California Davis

Marcia Carvalho

University of California Davis

Richard Smith

University of California Davis

Friday September 27, 2024 12:20pm - 12:30pm HST
Coral 1

Poster presentation (individual talk), Vegetable Breeding 1

SUBJECT Vegetable Breeding

12:44pm HST

Genetics and Germplasm 4 (GG 4)

Friday September 27, 2024 12:44pm - 2:15pm HST

Coral 1

Safeguarding Herbaceous Ornamental Plant Diversity: The Ornamental Plant Germplasm Center - Yu Ma
SNP-Enabled Genetic Diversity and Population Structure of Gladiolus (Gladiolus ×hybridus) Cultivars - Marie Abbey
Development of Genetic Fingerprinting of Azalea Cultivars Using SSR Markers - Seth Wannemuehler
A Chromosome-Scale Haplotype-Resolved Reference Genome of Lantana camara and Insights into Unreduced Female Gamete Production - Brooks Parrish
Identification of Flowering Dogwood QTLs for Bract Color using a Pseudo-F2 Population - Trinity Hamm
Evaluation of Hibiscus cannabinus as an Alternative Fiber Crop for Florida: Identification of Valuable Traits and Germplasm for Cultivar Improvement - James Webb

Moderator

Trinity Hamm

University of Tennessee, Knoxville

Friday September 27, 2024 12:44pm - 2:15pm HST
Coral 1

Oral Sessions, Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

12:45pm HST

GG 4 - Safeguarding Herbaceous Ornamental Plant Diversity: The Ornamental Plant Germplasm Center

Friday September 27, 2024 12:45pm - 1:00pm HST

Coral 1

Ornamental crops play an indispensable role in enriching our daily lives, offering not just visual delight but also therapeutic benefits. Moreover, the floriculture industry stands as a pivotal pillar within the nation’s agriculture sector, experiencing a substantial 16% increase in sales from 2019-2022, marking it as one of the fastest-growing industries. Safeguarding ornamental plant diversity has become more crucial than ever to sustain this industry and ensure its continued growth and resilience in the face of climate changes and evolving consumer preferences. Located in Columbus, OH, the Ornamental Plant Germplasm Center (OPGC) is one of 20 gene banks in the U.S. National Plant Germplasm System. Established through a cooperative effort between the USDA-ARS and The Ohio State University, it began operations in 2001. The center’s main goals are to acquire, document, maintain, characterize, and distribute herbaceous ornamental genetic resources and associated information for conservation, and to enhance scientific research as well as the floriculture and nursery industry. Current priority genera include Begonia, Coreopsis, Lilium, Phlox, Rudbeckia, and Viola. Since the OPGC began operation, 7350 accessions have been acquired, representing significant diversity within the 432 genera and over 2000 species of herbaceous ornamentals conserved. More than 13,000 germplasm items have been delivered free of charge to researchers, breeders and educators around the world. This presentation will outline the core functions of OPGC, including its germplasm collection, conservation techniques, and collaborative research initiatives.

Speakers

Yu Ma

Ohio State University

Co-authors

Susan Stieve

The Ohio State University

Friday September 27, 2024 12:45pm - 1:00pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

1:00pm HST

GG 4 - SNP-Enabled Genetic Diversity and Population Structure of Gladiolus (Gladiolus ×hybridus) Cultivars

Friday September 27, 2024 1:00pm - 1:15pm HST

Coral 1

Studies on genetic diversity and population structure provide important insights for determining ancestry and target trait enhancement in breeding programs. Gladiolus(-i), Gladiolus ×hybridus (Iridaceae), is a tetraploid, asexually-propagated, herbaceous perennial floricultural crop. Gladioli have tall flower stalks which make them ideally suited for cut flowers (floral design) and annual garden plants. Gladiolus is an important cut flower crop (in the top 5) for floral design. The purpose of this study was to analyze the genetic diversity of cultivated gladiolus germplasm to determine ancestry and relatedness. In this study we examine 549 unique gladiolus cultivars using DNA marker-based analysis. Samples were collected from the public (University of Minnesota) and private (Meyer, Otto) sector breeding programs in Minnesota and Europe. Population genetic diversity was analyzed using 17,556 single nucleotide polymorphism (SNP) markers developed by low-density DArTseq technology. Despite phenotypic differences, primarily in flower color or type (ruffled, etc.), the genetic diversity of gladiolus cultivars is low. The heterozygosity value was Ho=0.09 and the Fischers (FHOM) inbreeding coefficient was FHOM=0.40. SplitsTrees showed no differentiation, the average minor allele frequency (MAF) and polymorphism information content (PIC) was MAF=0.12 and PIC=0.15. The lack of significant genetic diversity among cultivars as well as breeding programs demonstrates a narrow germplasm base for this important cut flower crop. We discuss our findings and recommend ways to use these conclusions to improve future genome-wide association studies (GWAS) as well as increase efficiency and diversity in breeding goals.

Speakers

Marie Abbey

University of Minnesota

Marie Abbey is a researcher at the University of Minnesota Horticultural Science department. She has studied perceptions of biotechnology, invasive plant species, and aquaponics. Her current research is in flower breeding and molecular genetics.

Co-authors

Neil O Anderson

University of Minnesota

Rajmund Eperjesi

University of Minnesota

Friday September 27, 2024 1:00pm - 1:15pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

1:15pm HST

GG 4 - Development of Genetic Fingerprinting of Azalea Cultivars Using SSR Markers

Friday September 27, 2024 1:15pm - 1:30pm HST

Coral 1

Azaleas (Rhododendron spp.) are economically important ornamental flowering shrubs in landscapes around the world with thousands of cultivars representing many species of Rhododendron. Because azalea is an asexually propagated crop, potential discrepancies in plant identity may occur throughout the propagation pipeline, which can lead to mislabeling during propagation and commercialization processes. For example, the University of Minnesota (UMN) cultivar ‘Electric Lights Double Red’ is currently being propagated but flower morphology of the propagules differed from the original plant leading to uncertainty of propagule identity. Previous studies have identified DNA markers, specifically simple sequence repeats (SSRs), capable of differentiating azalea hybrid offspring from different species of the section Pentanthera. This study aims to leverage these previously developed SSR markers to authenticate the identity of breeding germplasm at the UMN and uniquely fingerprint other cultivars on the market. The evaluated azaleas pedigrees include up to 15 different species of deciduous azalea. Therefore, a total of 15 SSR markers that amplified fragments from several species of section Pentanthera were selected for this study. DNA was extracted from lyophilized leaf samples of 139 azalea cultivars using a Qiagen DNeasy Plant Pro Kit. Preliminary analysis of the azalea DNA using the selected SSR markers has identified the presence of 16 expected unique cultivars and 3 pairs of previously known duplicates. The outcome of this research will demonstrate the feasibility of providing azalea breeders, growers, and producers a marker-based system for assuring cultivar trueness-to-type and protection of intellectual property.

Speakers

Seth Wannemuehler

University of Minnesota

Co-authors

Diana Lopez Arias

University of Minnesota

Stan Hokanson

University of Minnesota

Steve McNamara

University of Minnesota

Friday September 27, 2024 1:15pm - 1:30pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

1:30pm HST

GG 4 - A Chromosome-Scale Haplotype-Resolved Reference Genome of Lantana camara and Insights into Unreduced Female Gamete Production

Friday September 27, 2024 1:30pm - 1:45pm HST

Coral 1

This comprehensive study unveils the first annotated, haplotype-resolved, chromosome-scale reference genome of Lantana camara, alongside insights into candidate genes for unreduced female gamete production through ovary transcriptome sequencing. L. camara, a native of the Caribbean, plays a dual role as a valued ornamental plant and a challenging invasive species. The absence of a high-quality genomic resource has previously limited the exploration of its ornamental and invasive characteristics. This work closes this gap by delivering a critical genomic resource for L. camara, essential for ornamental breeding programs and invasive species management. The genome of a diploid L. camara breeding line UF-T48 was assembled de novo, utilizing HiFi and Hi-C reads, achieving phased genome assemblies with a BUSCO score of 97.7% and LAI score of 19.37, indicating high quality. This assembly resolved all 22 chromosomes into pseudochromosomes, with an average length of 117 Mb, and annotated 83,775 protein-coding genes, laying a foundational step for Verbenaceae family genomic research. Simultaneously, this research delves into the plant’s reproductive biology, specifically targeting the mechanism of unreduced female gamete production, a trait that has played an important role in the evolution and spread of lantana, contributed to the plant’s invasiveness, and and complicated the development of sterile triploids. By aligning RNA-seq data to the reference genome, we identified differentially expressed genes associated with cell division and meiosis, crucial for understanding the genetic underpinnings of unreduced gamete production. These findings not only enhance the genetic comprehension of L. camara but also provide invaluable genomic resources for future genetic studies, conservation efforts, and breeding strategies aimed at producing non-invasive sterile cultivars. This pioneering genomic and transcriptomic analysis marks a significant leap forward in researchers’ ability to manipulate L. camara for both horticultural innovation and environmental management.

Speakers

Brooks Parrish

University of Florida

Co-authors

Zhanao Deng

University of Florida

Friday September 27, 2024 1:30pm - 1:45pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

1:45pm HST

GG 4 - Identification of Flowering Dogwood QTLs for Bract Color using a Pseudo-F2 Population

Friday September 27, 2024 1:45pm - 2:00pm HST

Coral 1

Flowering dogwoods (Cornus florida L.), known for their showy spring display and year-round appeal, are extensively planted as ornamental trees. In 2019, dogwoods ranked third in value for deciduous flowering trees in the U.S., generating more than $31 million in wholesale and retail sales. Tennessee is vital to this industry. The state leads the country in the number of dogwood plants sold, with almost double the number of trees sold as the next top producing state in the country. The showy bracts of dogwoods are modified leaves with a spectrum of color ranging from white to red, with many intermediate colors and patterns. Cornus florida ‘Cherokee Brave’ with deep pink bracts and ‘Appalachian Spring’ with creamy white bracts are two popular cultivars. Partially phased reference genomes have recently been assembled and annotated for these cultivars, ranging from 1,253 to 1,266 Mbp in length with 28,558 to 28,768 annotated protein coding genes. With these newly annotated genomes providing greater context, a QTL analysis was conducted using a pseudo-F2 population of ‘Cherokee Brave’ × ‘Appalachian Spring’ which segregates for bract color. Genotyping was completed using double-digest restriction-site associated DNA sequencing (ddRADseq) with PstI and MspI. With increasing demand for high-throughput phenotyping, six different phenotypic methods were utilized to determine which method was optimal for QTL detection. The phenotyping methods included: 1) manual characterization into binary classes (white or pink); 2) manual characterization into five classes (white, light blush, medium blush, pink, red); 3) colorimeter readings; 4) image analysis using full inflorescence; 5) image analysis using bracts detached from inflorescence; and 6) one bract per inflorescence. QTLs were identified using all phenotyping methods. The QTLs identified here will be used as the foundation for developing a marker assisted selection system for bract color in flowering dogwoods.

Speakers

Trinity Hamm

University of Tennessee, Knoxville

Co-authors

Denita Hadziabdic

University of Tennessee, Knoxville

DeWayne Shoemaker

University of Tennessee - Knoxville

Marcin Nowicki

University of Tennessee, Knoxville

Margaret Staton

University of Tennessee, Knoxville

Robert Trigiano

University of Tennessee, Knoxville

Sarah Boggess

University of Tennessee, Knoxville

William Klingeman

University of Tennessee, Knoxville

Friday September 27, 2024 1:45pm - 2:00pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

2:00pm HST

GG 4 - Evaluation of Hibiscus cannabinus as an Alternative Fiber Crop for Florida: Identification of Valuable Traits and Germplasm for Cultivar Improvement

Friday September 27, 2024 2:00pm - 2:15pm HST

Coral 1

Hibiscus cannabinus, commonly referred to as Kenaf, is an annual warm-season plant that can thrive in the Southeastern United States. It serves as a vital source of natural fiber with diverse applications, such as biocomposites, paper pulp, textiles, industrial absorbents, animal bedding, and potting medium. A set of 86 accessions of Hibiscus cannabinus, acquired from USDA-GRIN, underwent evaluation in Central Florida for various parameters, including plant height, basal width, stem width 50 cm above the plant base, stalk fresh weight, stem fresh weight, stalk dry weight, leaf dry weight, bast weight, and core weight. Significant variations were observed among accessions for all the measured variables. Notably, stalk dry weight emerged as the key trait of interest, representing the plant portion with desirable fibers for various applications. The top Duncan grouping for stalk dry weight comprised eight accessions: PI 329191 (18-85), PI 639889 (18-157) known as "Whitten," PI 270111 (18-55) known as "G-32," PI 603071 (18-152) known as "Dowling," PI 638930 (18-154) known as "74200 I4," PI 638932 (18-156) known as "Yue 74-3," PI 270106 (18-50) known as "G-14," and PI 468077 (18-137). Out of the 86 USDA-GRIN accessions examined, these eight have been identified as the top-performing choices for field production in Central Florida. Furthermore, these selected accessions are deemed desirable parents for future cultivar improvement endeavors, aiming to develop enhanced cultivars of Hibiscus cannabinus specifically tailored for production in Central Florida.

Speakers

James Webb

University of Florida

Co-authors

Conner Austin

University of Florida

Friday September 27, 2024 2:00pm - 2:15pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 4

SUBJECT Genetics and Germplasm

2:29pm HST

Genetics and Germplasm 5 (GG 5)

Friday September 27, 2024 2:29pm - 4:15pm HST

Coral 1

Breeding for Photoperiod Insensitive and Indeterminate Flowering Habit in Pigeonpea - Diego Viteri
Breeding for Improved Tomato Flavor - Denise Tieman
Genome-Wide Association Study Identifies Key SNPs Associated with Mineral Element Accumulation in Spinach (Spinacia oleracea) - haizheng xiong
Comparative Analyses of Tissue-Specific Transcriptome Responses to Salt Stress in Lettuce Roots and Leaves - Modan Das
QTL Mapping Of Horticulturally Important Plant Architectural Traits In Cucumber (Cucumis sativus L.) - Thi Nguyen
Screening Sweetpotato Germplasm for Resistance to Meloidogyne incognita - Phillip Wadl
Variation for Non-Acclimated and Acclimated Heat Tolerance Among Potato Germplasm: Indication of Separate Genetic Control - Jiwan Palta

Moderator

Phillip Wadl

USDA, ARS, U.S. Vegetable Laboratory

Friday September 27, 2024 2:29pm - 4:15pm HST
Coral 1

Oral Sessions, Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

2:30pm HST

GG 5 - Breeding for Photoperiod Insensitive and Indeterminate Flowering Habit in Pigeonpea

Friday September 27, 2024 2:30pm - 2:45pm HST

Coral 1

Pigeonpea [Cajanus cajan (L.) Mill.] is an important legume consumed in the Caribbean basin. Cultivars with indeterminate flowering habit have sensitivity to the photoperiod in Puerto Rico. The objectives of this research were to: (1) develop two breeding lines with indeterminate flowering habit that can be planted year-round, and (2) evaluate their agronomic performance. IIPG-7 and IIPG-11 breeding lines, derived from the bi-parental cross ‘ICPL 86012’/‘Guerrero’, were developed by pedigree and bulk breeding methods. Both breeding lines, their parents, and cultivars checks were tested in field trials in Isabela and Lajas, Puerto Rico in 2022 and 2023. IIPG-7 and IIPG-11 were early genotypes that initiated flowering between 73-84 days after planting (dap), and reached harvesting maturity at 121-127 dap compared with indeterminate cultivars ‘Ariel’, ‘Blanco Yauco’, ‘Kaki’, ‘Pinto Berrocales’, and ‘Super Pinto’ that initiated flowering between 91 to 102 dap and reached maturity at 138-148 dap. These cultivars had seed yield values over 1,000 kg/ha while IIPG-7 and IIPG-11 produced between 721 to 1,010 kg/ha under short day conditions in both locations. In contrast, IIPG-7 and IIPG-11 were the only indeterminate genotypes that initiated flowering between 42-88 dap, reached maturity between 88-172 dap, and seed yields varied from 626 to 2,449 kg/ha under long day conditions in Isabela and Lajas. These new breeding lines can be used to develop pigeonpea cultivars with insensitivity to the photoperiod.

Speakers

Diego Viteri

University of Puerto Rico at Mayagüez

Co-authors

Angela Linares Ramirez

University of Puerto Rico

Friday September 27, 2024 2:30pm - 2:45pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

2:45pm HST

GG 5 - Breeding for Improved Tomato Flavor

Friday September 27, 2024 2:45pm - 3:00pm HST

Coral 1

Consumers are dissatisfied with the flavor of modern commercial tomatoes; however, modern tomato varieties have many desirable agronomic traits such as shelf life, disease resistance and yield. The flavor deficiency in modern tomatoes is due to a cumulative loss of superior alleles affecting flavor volatiles while breeding for other traits. The lack of breeder focus on the consumer is largely due to the genetic complexity of the tomato flavor phenotype as well as a lack of a simple assay that can define consumer preferences. Tomato flavor is a result of interactions between sugars, acids and aroma volatiles, with volatile compounds giving the tomato fruit its characteristic aroma and flavor. We have quantified 68 flavor biochemicals in over 700 tomato varieties, including modern, heirloom and ancestral tomato accessions. Over 160 of these varieties were evaluated by a large consumer panel for fruit flavor quality traits including overall liking. Genome Wide Association Studies (GWAS) identified genetic loci associated with altered levels of acids, sugars and aroma volatiles. We have used marker-assisted breeding to introgress loci associated with flavor biochemical levels from heirloom varieties into modern tomato varieties. Introduction of seven flavor loci affecting a variety of flavor volatiles into a modern tomato variety has resulted in altered flavor volatile profiles and improved flavor as assessed by a consumer panel.

Speakers

Denise Tieman

University of Florida

Co-authors

Harry Klee

University of Florida

Modesta Abugu

North Carolina State University

Friday September 27, 2024 2:45pm - 3:00pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

3:00pm HST

GG 5 - Genome-Wide Association Study Identifies Key SNPs Associated with Mineral Element Accumulation in Spinach (Spinacia oler

Friday September 27, 2024 3:00pm - 3:15pm HST

Coral 1

Understanding the genetic basis of mineral element contents in crops is crucial for improving their nutritional value. This study conducted a comprehensive Genome-Wide Association Study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with the accumulation of 14 essential mineral elements in spinach (Spinacia oleracea). Utilizing a diverse collection of 281 spinach accessions, we assessed the content of Boron (B), Calcium (Ca), Cobalt (Co), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Molybdenum (Mo), Sodium (Na), Nickel (Ni), Phosphorus (P), Sulfur (S), and Zinc (Zn), expressed in micrograms or milligrams per gram of dry weight (µg/gDW or mg/gDW). Genotyping revealed 83,952 SNPs across the spinach genome, analyzed using GAPIT3 and TASSEL5 software platforms. Statistical models employed included General Linear Model (GLM), Mixed Linear Model (MLM), FarmCPU, and BLINK within GAPIT, alongside SMR and GLM in TASSEL. Our analysis uncovered 33 significant SNP-trait associations distributed among the minerals: one for B, Cu, P, and K; two for Ca, Ni, Fe, Zn, and S; three for Mo and Mg; four for Na and Co; five for Mn. These findings highlight the genetic diversity influencing mineral nutrient accumulation in spinach and offer valuable markers for breeding nutritionally enhanced spinach varieties.

Speakers

haizheng xiong

University of Arkansas

Co-authors

Ainong Shi

Associate Professor, University of Arkasnas

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

Hanan Alkabkabi

University of Arkansas

Ibtisam Alatawi

University of Arkansas

Kenani Chiwina

University of Arkansas

Friday September 27, 2024 3:00pm - 3:15pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

3:15pm HST

GG 5 - Comparative Analyses of Tissue-Specific Transcriptome Responses to Salt Stress in Lettuce Roots and Leaves

Friday September 27, 2024 3:15pm - 3:30pm HST

Coral 1

Lettuce is one of the most important leafy vegetable crops world-wide. Salt stress adversely affects lettuce production, leading to considerable yield losses. Understanding the molecular mechanisms underlying the salt stress response is essential for breeding and development of lettuce cultivars with improved salt tolerance. Thus, the objective of this research was to identify differentially expressed genes (DEGs) in lettuce root and leaf tissues under salt stress and non-salt stress conditions. We have compared two salt-stress tolerant and two salt-sensitive accessions from crisphead and leaf horticultural types. Differential gene expression was compared between salt-tolerant and salt-sensitive accessions from the same horticultural type to minimize the effect of horticultural types on the comparison. In the root samples of the salt-tolerant accessions, we identified 3,789 and 4,022 DEGs, while for the salt-sensitive accessions 9,030 and 9,945 DEGs were identified, for the crisphead and leaf types, respectively. In leaf tissues, we observed 5,683 and 9,445 DEGs in the salt-tolerant accessions and 5,836 and 10,172 DEGs in the sensitive accessions, respectively, for the crisphead and leaf types. Thus, the number of DEGs was higher in sensitive accessions of both root and leaf tissues, with a notably greater disparity in root tissues. Functional annotations of the DEGs indicated stress response as a common biological process in both root and leaf tissues. Protein phosphatase inhibitor and peroxidase were the most significantly enriched molecular function terms in roots, while chaperone and glycosyltranferase molecular function terms were most significantly enriched in leaves. Gene Ontology (GO) enrichment analysis determined that genes related to the organic substance biosynthetic process were most significantly enriched in roots, while genes related to photosynthesis, response to light stimulus, chlorophyll binding and regulation of the jasmonic acid-mediated signaling pathway were significantly enriched in leaves. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that plant hormone signal transduction, biosynthesis of secondary metabolites, and the MAPK signaling pathway were significantly enriched terms in both root and leaf tissues, while cysteine and methionine metabolism terms were most significantly enriched in roots and photosynthesis was most significantly enriched in leaves. Identification of the salt-stress responsive genes and the results on their expression patterns in salt-tolerant vs salt-sensitive cultivars obtained in the present study open the door for further functional analysis of these genes and their utilization in improving salt-stress tolerance in lettuce.

Speakers

Modan Das

USDA-ARS

Co-authors

Beiquan Mou

USDA-ARS

Ivan Simko

USDA-ARS

Friday September 27, 2024 3:15pm - 3:30pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

3:30pm HST

GG 5 - QTL Mapping Of Horticulturally Important Plant Architectural Traits In Cucumber (Cucumis sativus L.)

Friday September 27, 2024 3:30pm - 3:45pm HST

Coral 1

Cucumber (Cucumis sativus L.) is an economically important vegetable crop cultivated worldwide. Plant architectural traits, such as lateral branch number (LBN), vine length (VL), number of nodes (NN) and internode length (IL), may directly influence production practices, plant performances, fruit yield and quality. Despite their importance, investigation on the genetic basis of these traits in cucumber is limited. In this study, we conducted QTL mapping for VL, NN, IL and LBN using bi-parental F2, F2-derived F3 and recombinant inbred line (RIL) populations. There are significant positive correlations between LBN, VL and NN. Estimated board-sense heritability using entry-mean basis of the RIL population was high, ranging from 0.66 to 0.84. Two linkage maps were developed through genotyping-by-sequencing of 140 F2 individuals and Diversity Arrays Technology (DArTag) SNP genotyping of 135 RIL, containing 1912 and 334 SNP loci in seven linkage groups and spanning 1077 and 948 cM, respectively. QTL mapping analysis detected a total of 79 QTLs associated with the four traits in six environments or populations. Based on their physical locations, 66 QTLs were distributed in ten QTL clusters harboring four major-effect and six minor-effect QTLs. Each of the major- and minor-effect QTLs was supported by consistent and reproducible detection from at least three environments. Notably, major-effect QTLs for VL, NN and LBN were co-localized in two genomic regions on Chr1 (3.73 Mbp) and Chr6 (3.78 Mbp), and the major-effect QTL for IL was mapped in a 3.98-Mbp region on Chr5. These findings provide a framework for dissecting the genetic architecture of these complex traits, and valuable genetic information for cucumber breeders to employ molecular-assisted breeding approaches and develop improved varieties with enhanced productivity.

Speakers

Thi Nguyen

Research Assistant, University of Wisconsin- Madison

Co-authors

Yassine Yahia

University of Wisconsin-Madison

Yiqun Weng

University of Wisconsin-Madison

Friday September 27, 2024 3:30pm - 3:45pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

3:45pm HST

GG 5 - Screening Sweetpotato Germplasm for Resistance to Meloidogyne incognita

Friday September 27, 2024 3:45pm - 4:00pm HST

Coral 1

Meloidogyne incognita is the most common root-knot nematode found in agricultural regions worldwide. It can cause severe damage to many crops including sweetpotato storage roots, causing them to be unmarketable and resulting in significant yield losses. Identifying resistant crop varieties is one of the most effective ways to manage M. incognita. To identify germplasm with resistance to M. incognita, 47 sweetpotato accessions obtained from the USDA germplasm repository were screened in replicated greenhouse assays. ‘Beauregard’ was used as a susceptible control and ‘Regal’ as a resistant control. Sweetpotato slips containing 3 nodes each were planted in an autoclaved 1:1 mixture of sand and potting mix in Deepot D25L containers and arranged in a randomized block design, with 2-3 replicates per an accession. Two weeks after planting, each plant was inoculated with 10,000 M. incognita eggs. Eight weeks after inoculation, plants were harvested and rated for fibrosity, galling, number of egg masses, and eggs per gram of root. Resistance was defined as accessions with mean galling ≤ 10% and mean eggs per gram of root ≤ 500. Based on these criteria, 12 accessions were identified as having resistance to M. incognita.

Speakers

Phillip Wadl

USDA, ARS, U.S. Vegetable Laboratory

Co-authors

Catherine Wram

USDA, ARS, Mycology and Nematology Genetic Diversity and Biology Laboratory

Hannah Baker

USDA, ARS, U.S. Vegetable Laboratory

William Rutter

USDA-ARS

Friday September 27, 2024 3:45pm - 4:00pm HST
Coral 1

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm

4:00pm HST

GG 5 - Variation for Non-Acclimated and Acclimated Heat Tolerance Among Potato Germplasm: Indication of Separate Genetic Control

Friday September 27, 2024 4:00pm - 4:15pm HST

Coral 1

Several studies have documented variation in potato germplasm for heat tolerance of leaf tissue. Most researchers have relied on screening for heat stress by exposing excised leaf tissue (grown under non-stress condition) to a short-term (minutes-hours) of acute heat stress (37-55C). It is well known that plants vary in their ability to acclimate to heat stress know as priming. This priming can enable plant to survive subsequent temperatures that are lethal to plants grown under non-stress condition. Our recent studies show that potato plants under prolonged heat stress (35/25C, day/night, for 3-5 weeks) newly developed leaves (acclimated) can maintain health under heat stress by modifying anatomy and physiology. These results show that potato plants have the ability to acclimate to heat stress that results in increased heat tolerance. In the present study, we screened to potato germplasm for heat tolerance of leaf tissue before and after heat acclimation. Ion leakage after exposure of excised leaf tissue to 50C, was used as a screening assay and a reduction in this leakage was used to assess the heat acclimation ability. Wide variety of potato germplasm including commercial cultivars and accessions of various wild species were screened. Our result show significant genotypic variations in acclimated and non-acclimated heat tolerance. Furthermore, the heat acclimation ability appears to be independent of non- acclimated heat tolerance. For example, certain clones of the species Solanum commersonnii had similar non-acclimated heat tolerance but large variation in acclimated tolerance was found among various clones of this species. Similar results were obtained for different clones of Solanum microdontum and Solanum kurtzianum. As expected, the cultivars Zarewo, DTO and Papa Cacho were found to have higher non-acclimated heat tolerance than the others, but Papa Cacho had the highest heat acclimation ability. Our results suggest that non-acclimated heat tolerance and acclimated heat tolerance are under separate genetic control and that selection for both non-acclimated and acclimated heat tolerance may be useful for successful breeding for heat tolerance of potato leaf tissue.

Speakers

Oral presentation (Individual talk), Genetics and Germplasm 5

SUBJECT Genetics and Germplasm