ASHS 2024 Conference: Full Schedule

9:00am HST

SCRI DB Project Annual Meeting

Monday September 23, 2024 9:00am - 4:00pm HST

Speakers

Dorrie Main

Professor, Washington State University

I am a member of the Pullman Charter School Initiative team and am particularly interested in how to set up and maintain a thriving Washington State Charter School to serve the needs of Eastern Washington students.

Monday September 23, 2024 9:00am - 4:00pm HST
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Meetings - Committee/Division/interest Group

Area SCRI

6:00pm HST

Student and Early Career Attendee Reception

Monday September 23, 2024 6:00pm - 7:00pm HST

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All students and early career professionals are invited to a reception/mixer. This is a chance to meet and learn from each other. The GRAD group has organized a fun ice breaker activity, Human Bingo!

Monday September 23, 2024 6:00pm - 7:00pm HST
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Ticketed Events, Student Activities | Meals and Tours, Student Activities

SUBJECT Professional Development/Career, Social Event

9:59am HST

Pomology 1 (POM 1)

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

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Prohexadione Calcium Does Not Affect Thinning Efficacy of 1-aminocyclopropane-1-carboxylic Acid in ‘Golden Delicious’ - Annie Vogel
Carbohydrate Status of Apple Fruitlets following Chemical Thinner Application Informs Sink Strength and Fruit Set - Laura Hillmann
Performance of a reflectance spectroscopy model to predict apple fruitlet thinning efficacy - James Larson
Overexpression of the Coding Sequence of Ma1 Decreases Fruit Acidity in ‘Royal Gala’ Apple - Lailiang Cheng
Striking the Right Balance: Innovative PGR Strategies for Fruit Drop Mitigation and Color Enhancement in Apples - Sherif Sherif
Rapid Fruit Growth Rates of Honeycrisp Apples Cause Premature Dysfunction of Xylem, Reduced Peel Calcium, and Increased Susceptibility to Bitter Pit - Chayce Griffith
Carbohydrate And Nitrogen Storage Are Inversely Affected By Crop Load For 'Honeycrisp' And 'Gala' Apples - Thiago Campbell
Impacts of Rootstock and Crop Load Adjustment on Fruit Quality and Mineral Nutrients in ‘Honeycrisp’ Apple - Esmaeil Fallahi

Moderator

Lailiang Cheng

Cornell University

Tuesday September 24, 2024 9:59am - 12:00pm HST
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Oral Sessions, Pomology 1

SUBJECT Pomology

10:00am HST

POM 1 - Prohexadione Calcium Does Not Affect Thinning Efficacy of 1-aminocyclopropane-1-carboxylic Acid in ‘Golden Delicious’

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

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Apple’s (Malus × domestica Borkh.) tendency towards biennial bearing necessitates management strategies such as fruit thinning and vigor control. Applications of plant growth regulators to manage crop load and vigor overlap in the spring. A precursor to ethylene, 1-aminocyclopropane-1-carboxylic acid (ACC; Accede®) was recently registered as a chemical fruit thinner in the USA. Prohexadione-calcium (P-Ca) is a gibberellin biosynthesis inhibitor widely used to manage vigor. It is suspected that P-Ca may interfere with ACC precursors, decreasing thinning efficacy of ACC. We evaluated the effects and interactions of ACC and P-Ca on shoot growth, ethylene evolution, leaf area, and yield responses of mature ‘Golden Delicious’. The experiment was conducted in 2023, in Mills River, NC, USA. Treatments included ACC (400 mg∙L-1), P-Ca (250 mg∙L-1), ACC P-Ca, and an untreated control. Application of P-Ca occurred on three dates. ACC was applied when average fruit diameter was ~20 mm. Across all measured responses, there were no interactions between ACC and P-Ca. P-Ca had a negative main effect on shoot growth rate (48.7–75.4% reduction). ACC reduced leaf number of spurs 4 and 9 days after treatment (DAT). Ethylene evolution in fruit and spurs was increased by ACC 1, 4, and 9 DAT (spur: 1.1e4%, 5300%, and 515%, respectively; fruit: 9200%, 725%, and 222%, respectively). ACC had a negative effect on fruit number, yield, and crop density (60.1%, 56.5%, and 60.3% reduction, respectively). These results indicate that ACC and P-Ca can be used simultaneously to manage crop load and vigor, respectively

Speakers

Annie Vogel

North Carolina State University

Co-authors

Christopher Clavet

North Carolina State University

James Larson

Utah State University

Thomas Kon

North Carolina State University

Tuesday September 24, 2024 10:00am - 10:15am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

10:15am HST

POM 1 - Carbohydrate Status of Apple Fruitlets following Chemical Thinner Application Informs Sink Strength and Fruit Set

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

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

Speakers

Laura Hillmann

Michigan State University

Co-authors

Thomas Sharkey

Michigan State University

Todd Einhorn

Michigan State University

Tuesday September 24, 2024 10:15am - 10:30am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

10:30am HST

POM 1 - Performance of a reflectance spectroscopy model to predict apple fruitlet thinning efficacy

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

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

Speakers

James Larson

Utah State University

Co-authors

Laura Hillmann

Michigan State University

Luis Gonzalez Nieto

Cornell University

Terence Robinson

Cornell University

Thomas Kon

North Carolina State University

Todd Einhorn

Michigan State University

Tuesday September 24, 2024 10:30am - 10:45am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

10:45am HST

POM 1 - Overexpression of the Coding Sequence of Ma1 Decreases Fruit Acidity in ‘Royal Gala’ Apple

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

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

Speakers

Lailiang Cheng

Cornell University

Co-authors

Chunlong Li

Cornell University

Kenong Xu

Cornell University

Mengxia Zhang

Cornell University

Miguel Pineros

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

Srinivasan Krishnan

Cornell University

Tuesday September 24, 2024 10:45am - 11:00am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

11:00am HST

POM 1 - Carbohydrate And Nitrogen Storage Are Inversely Affected By Crop Load For 'Honeycrisp' And 'Gala' Apples

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

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Biennial or alternate bearing is characterized by an abundance of blooming and fruiting in “on” years and a lack of blooming and fruiting in “off” years. Biennial bearing in fruit tree production has been extensively studied. However, it continues to be problematic in certain crops and cultivars. Fundamental physiological mechanisms controlling this behavior are still poorly understood. Along with carbohydrates in plant tissues, reserve nitrogen influences early-season growth in apples, with the percent contribution of reserve nitrogen being dependent on the current nitrogen supply. Because flowering and fruit set occur in spring alongside bud break, reserve nitrogen can significantly affect these processes too. We sought to understand the role carbohydrate and nitrogen storage in various plant tissues has on biennial bearing for ‘Honeycrisp’ apple. Apical buds, terminal shoots, and one-year-old spurs were collected in 2022

Speakers

Thiago Campbell

Washington State University

Co-authors

Lee Kalcsits

Washington State University

Tuesday September 24, 2024 11:00am - 11:15am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

11:15am HST

POM 1 - Striking the Right Balance: Innovative PGR Strategies for Fruit Drop Mitigation and Color Enhancement in Apples

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

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

Speakers

Sherif M. Sherif

Associate Professor, Virginia Tech

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

Co-authors

Khalil Jahed

Virginia Tech

Mohammad Tipu

Virginia Tech

Tuesday September 24, 2024 11:15am - 11:30am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

11:30am HST

POM 1 - Impacts of Rootstock and Crop Load Adjustment on Fruit Quality and Mineral Nutrients in ‘Honeycrisp’ Apple

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

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

Speakers

Esmaeil Fallahi

University of Idaho

Professor

Co-authors

Bahar Fallahi

University of Idaho

Michael Kiester

University of Idaho

Tuesday September 24, 2024 11:30am - 11:45am HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

11:45am HST

POM 1 - Rapid Fruit Growth Rates of Honeycrisp Apples Cause Premature Dysfunction of Xylem, Reduced Peel Calcium, and Increased Susceptibility to Bitter Pit

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

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

Speakers

Chayce Griffith

Michigan State University

Co-authors

Randolph Beaudry

Michigan State University

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

Todd Einhorn

Michigan State University

Tuesday September 24, 2024 11:45am - 12:00pm HST
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Oral presentation (Individual talk), Pomology 1

SUBJECT Pomology

12:14pm HST

Vegetable Crops Management 1 (VCM 1)

Tuesday September 24, 2024 12:14pm - 1:50pm HST

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Effect of Biostimulants on Emergence and Growth of Watermelon (Citrullus lanatus) Transplants. - Evan Christensen
Evaluation of Specialty Cucumber Cultivars in a High Tunnel Production System - Jacob Arthur
Are Locally Sourced Biochar and Poultry Litter the Solution to Improving Soil Health and Sustainably Producing Tomatoes? - Emilio Suarez Romero
Is Trellising Beneficial to High Tunnel Melon Yield? - Lewis Jett
Interseeded Clover Does Not Impact Pumpkin Yield - Charlie Rohwer
Protecting New Mexico’s Chile Crops from Curly Top Virus through Agrivoltaics - Mariela Estrada
Integrating High-resolution Satellite Imagery to Monitor Crop Growth and Yield: A Case Study of Japanese Squash and Onion in Hollister, California - Elia Scudiero
A New Tool to Manage Water and Nutrients in High Tunnel Tomato Production - Rebecca Brown
Soil Moisture Sensors Allow for Resilient Tomato Production in Organic Systems - Andre Luiz Biscaia Ribeiro da Silva
Physiology of Heat Tolerant Tomatoes: Transplanting Through Harvest - Courtney DeKalb-Myers

Moderator

Charlie Rohwer

Scientist, University of Minnesota

Tuesday September 24, 2024 12:14pm - 1:50pm HST
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Poster Session, Vegetable Crops Management 1

SUBJECT Vegetable Crops

12:15pm HST

VCM 1 - Effect of Biostimulants on Emergence and Growth of Watermelon (Citrullus lanatus) Transplants.

Tuesday September 24, 2024 12:15pm - 12:25pm HST

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The impacts of climate change and drought threatens water supplies that are necessary for watermelon production. Most production in the U.S. is seedless watermelon, typically grown in greenhouses and transplanted due to poor seed establishment in the field. Given the significance of high-quality transplants for the industry, we conducted a study to evaluate whether biostimulant products would improve transplant quality. In this study seven biostimulant products were tested on greenhouse-grown watermelon seedlings to measure seedling emergence and growth. Three bacterial (Continuum, Spectrum Ds, and Tribus Original), two mycorrhizal (MycoApply Endo, and Mighty Mycorrhizae), one humic (Huma Pro 16), and one seaweed extract product (Kelpak) were used. All products, except Kelpak, were incorporated into the growing media before sowing. Kelpak was applied at the first true leaf stage as a soil drench. Leaf area and root/shoot fresh and dry weight were measured over a 30-day period after stand establishment and data underwent analysis of variance (ANOVA) using SAS statistical software. Though some biostimulant products tended to have higher shoot and root weight they were not always significantly different, and the results were variable from trial to trial and analysis is ongoing.

Speakers

Evan Christensen

Utah State University

Tuesday September 24, 2024 12:15pm - 12:25pm HST
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Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

12:25pm HST

VCM 1 - Evaluation of Specialty Cucumber Cultivars in a High Tunnel Production System

Tuesday September 24, 2024 12:25pm - 12:35pm HST

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Cucumbers are popular and high-value vegetable crops mainly marketed through local food markets for fresh consumption. Vegetable growers in Mississippi mainly operate on small to medium size farms. High value crops including tomatoes, peppers and cucumbers could be grown to increase competitiveness. Specialty cucumber cultivars including the parthenocarpic and mini types are in high demand due to their superior eating quality, these are often produced in protected environments like high tunnels or greenhouses. The objective of this study is to evaluate specialty cucumber cultivars and identify cultivars for superior yield and quality in the local climate under protected culture. This study was conducted in a high tunnel production system located at Mississippi State University through two growing seasons in 2022 and 2023. Twenty cucumber cultivars were evaluated including ten long Dutch/English slicer types: ‘Asteroid Long’, ‘Bologna Long’, ‘Boncanale Long’, ‘Davida Long’, ‘Durance Long’, ‘Georgia’, ‘Kasja Long’, ‘Tyria Long’, ‘Verdon Bio Long’, ‘Verdon Long’; five mini types: ‘Jawell Mini’, ‘Katrina’, ‘Manar Mini’, ‘Picolino’, ‘Socrates’; and four Asian types: ‘Itachi’, ‘Nokya’, ‘Unagi’, ‘Wokue’. The last cultivar ‘Striped Armenian’ is not a true cucumber and is actually part of the melon family. Plants were grown in 6-gallon containers using a modified drop line trellis system. Plant vegetative growth that was measured included plant height, stem diameter as well as soil plant analysis of development (SPAD). Cucumber fruits were harvested twice weekly, weighed for individual fruit weight, counted, and separated into marketable yield and unmarketable yield. Various fruit quality characteristics including: fruit diameter, fruit length, skin color, soluble solids content and fruit firmness were collected twice in each growing season. Cultivars varied in marketable and unmarketable yields in both growing seasons. In 2022, the cultivar ‘Picolino’ produced the highest marketable yield of 4.79 kg per plant with a majority of the other cultivars having statistically similar marketable fruit yields ranging from 2.87 kg in ‘Unagi’ to 4.75 kg in ‘Katrina’. The lowest marketable yield was produced by ‘Striped Armenian’ with 2.05 kg of marketable fruit for the entire growing season. Fruit quality parameters including soluble solids content, firmness, and fruit length had significant differences between cultivars. The cultivar ‘Kasja Long’ produced fruits with the highest soluble solids content of 4.18 °Brix, the other cultivars in this study had values ranging from 2.47 °Brix to 4.12 °Brix. The cultivars ‘Itachi’ and ‘Socrate’ produced the firmest fruit with values of 6.75 N and 6.70 N, respectively.

Speakers

Jacob Arthur

Mississippi State University

Co-authors

Guihong Bi

Mississippi State University

Tongyin Li

Mississippi State University

Tuesday September 24, 2024 12:25pm - 12:35pm HST
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Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

12:35pm HST

VCM 1 - Are Locally Sourced Biochar and Poultry Litter the Solution to Improving Soil Health and Sustainably Producing Tomatoes?

Tuesday September 24, 2024 12:35pm - 12:45pm HST

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Agriculture is challenged by nutrient runoff, declining soil health, and high costs of inorganic fertilizers. This study investigates the potential of locally sourced biochar and poultry litter to address these issues by enhancing soil health and tomato production. Conducted in Spring 2023, the field trial assessed biochar application rates of 0, 10, 15, and 20 (tons/acre), combined with either organic (poultry litter) or inorganic fertilizer providing (225 N lbs/acre) for the growing period of the tomatoes. Utilizing a randomized complete block design, the experiment had four replications across ten treatments. The findings from this study revealed no significant differences in tomato yield between plants fertilized organically or inorganically across the various biochar application rates. Notably, the use of poultry litter as an organic fertilizer showcased promising results, particularly evident in the increased production of extra-large tomatoes. However, it also led to a higher count of culls. Biochar application significantly enhanced several key soil chemical properties, including pH levels, cation exchange capacity (CEC), and nutrient retention, especially at higher application rates. The incorporation of biochar was observed to substantially elevate soil pH by the season's end, attributed mainly to its considerable calcium content. A biochar application rate of (20 tons/acre) notably increased the pH to 6.8 in the inorganic treatment and even higher to 7.2 in the organic treatment when combined with calcium-rich poultry litter. In scenarios without biochar, the sandy loam soils exhibited a decrease in pH levels by the end of the season, indicating biochar's crucial role in counteracting soil acidification. The study also highlighted that a high biochar application rate significantly improved CEC in both inorganic and organic production systems by the season's end, facilitating better nutrient retention in sandy loam soils. Furthermore, higher biochar applications were associated with lower nitrate concentrations, while the absence of biochar in both treatments led to increased nitrate levels. This pattern was similarly observed with ammonium levels, where higher biochar applications resulted in reduced concentrations, suggesting that biochar effectively prevents the volatilization of ammonia. The research supports the hypothesis that biochar functions like a sponge, retaining essential nutrients within the soil matrix. This study provides evidence that biochar presents a viable strategy for organic and inorganic farmers to enhance soil chemical properties over the long term, offering a sustainable solution to improve agricultural practices and tomato production.

Speakers

Emilio Suarez Romero

University of Georgia

Co-authors

Henry Y Sintim

University of Georgia

Juan Carlos Diaz Perez

University of Georgia

Kate Cassity Duffey

University of Georgia

Ted McAvoy

University of Georgia

Tuesday September 24, 2024 12:35pm - 12:45pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

12:45pm HST

VCM 1 - Is Trellising Beneficial to High Tunnel Melon Yield?

Tuesday September 24, 2024 12:45pm - 12:55pm HST

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Cantaloupes (Cucumis melo var. reticulatis) are a fruiting vegetable which grow best in warm environments. Cantaloupes also are infected by many foliar diseases which are triggered or exacerbated by rainfall and high relative humidity which is common during the growing season in Central Appalachia. One potential option for growing cantaloupes in West Virginia is high tunnel production. High tunnels significantly increase the air and soil temperature. In addition, the crop can be drip irrigated so there is no wet foliage for disease infection. Trellising may be necessary to facilitate harvest. Vertical trellising with pruning may be necessary for high tunnel production. Trellising can potentially increase marketable yield. However, trellis and pruning labor can be as high as $150/1000 ft2. Cantaloupes (cv. ‘Sugar Cube’) were transplanted within a high tunnel in 2023 and 2024. Vertical trellising and pruning were compared with non-trellised and non-pruned plants. Inputs such as labor and trellising supplies were recorded. In 2023, trellising did not significantly increase marketable yield of cantaloupes, but did significantly improve harvest efficiency.

Speakers

Lewis Jett

WVU

Tuesday September 24, 2024 12:45pm - 12:55pm HST
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Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

12:55pm HST

VCM 1 - Interseeded Clover Does Not Impact Pumpkin Yield

Tuesday September 24, 2024 12:55pm - 1:05pm HST

Nautilus 1

Pumpkins are usually grown using wide row spacing, and in Minnesota, the canopy does not close until mid-summer and the canopy senesces in early- to mid-autumn. This provides opportunity for establishing frost-tolerant or winter-hardy cover crops between rows before the canopy closes, which will continue to grow after pumpkin foliage is gone. To understand more about competition between interseeded cover crops and pumpkins, four species of clover (berseem, crimson, Persian, and red) were sown between pumpkin rows (10-ft spacing) in late June, and pumpkin yield and clover growth and N content were measured in the fall. Both ‘Cotton Candy’ and ‘Kratos’ pumpkins were studied. ‘Kratos’ yield (68.4 Mg / ha; 1185 fruit / ha), fruit size (9.7 kg), and fruit size variability (28%) were 1.8 times, 0.55 times, 3.2 times, and 1.1 times as much as ‘Cotton Candy’, but none of these responses were impacted by clover. Above-ground biomass of berseem, Persian, and red clovers averaged 0.41 Mg / ha in late fall (16 kg N / ha), but crimson clover yielded 1.2 Mg / ha (33.3 kg N / ha). Clover grown with ‘Kratos’ yielded 69% of the dry matter and 73% of the aboveground nitrogen (per ha) compared to clover grown with ‘Cotton Candy’. The average C:N ratio of all treatments was 18.3. These results show that clover interseeded into pumpkins, especially crimson clover, can grow successfully without impact on pumpkins. High-vigor pumpkins can reduce clover yield, however.

Speakers

Charlie Rohwer

Scientist, University of Minnesota

Tuesday September 24, 2024 12:55pm - 1:05pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

1:05pm HST

VCM 1 - Protecting New Mexico’s Chile Crops from Curly Top Virus through Agrivoltaics

Tuesday September 24, 2024 1:05pm - 1:15pm HST

Nautilus 1

Chile (Capsicum annuum) consumption and production have been integral to New Mexican culture for over four centuries, and the state is the leading producer of chile (non-bell peppers) in the United States. Chile farmers face adverse conditions due to climate change, water scarcity and disease control. One of the most prevalent chile diseases in NM is Beet Curly Top Virus (BCTV; Curtovirus). BCTV causes chlorotic curled leaves, stunted growth, abnormal or minimal fruit production, and a potentially substantial yield reduction. BCTV is transmitted by beet leafhoppers (Circulifer tenellus), insects that prefer feeding in areas exposed to full sun. Agrivoltaic systems (AVS), the co-location of solar panels in agricultural fields, increases field shade. Advantages of AVS have been examined, but its potential role as a deterrent for pests remains unknown. The aim of this study was to determine the impact of AVS shade on chile yields, beat leafhopper abundance, and BCTV incidence. On 16 May 2023 ‘NuMex Odyssey’, a New Mexico pod-type green chile was transplanted into four solar panel plots and a full sun control at the New Mexico State University Leyendecker Plant Science Research Center, Las Cruces, NM. Plots shaded by solar panels had an average of 15% less light radiation compared to the full sun control. Fruit was harvested on 21 Aug 2023 and sorted into marketable green, blossom end-rot affected, and curly top affected fruit. Preliminary results show that marketable green and blossom end-rot affected fruit yields did not differ between solar panel shaded and the full sun control plots. BCTV affected fruit yield was significantly greater in the full sun control, which also had 55% more trapped beet leafhoppers than the solar panel plots. Initial results show potential for AVS as a method to mitigate the adverse effects on chile yield caused by BCTV. In addition to alleviating crop stress, AVS has the potential to deter beet leaf hoppers while generating electricity, a potential extra revenue for the farmer.

Speakers

Mariela Estrada

New Mexico State University

Tuesday September 24, 2024 1:05pm - 1:15pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

1:15pm HST

VCM 1 - Integrating High-resolution Satellite Imagery to Monitor Crop Growth and Yield: A Case Study of Japanese Squash and Onio

Tuesday September 24, 2024 1:15pm - 1:25pm HST

Nautilus 1

Accurate monitoring of crop growth and estimations of yield are essential for optimizing agricultural practices and ensuring food security. Traditional approaches to monitor crop and map yield in vegetable crops often rely on ground-based observations, which can be time-consuming and labor-intensive. Remote sensing techniques offer a promising alternative by providing frequent and spatially extensive information on crop health and vigor. In this study, we aimed to assess the feasibility of using high-resolution satellite imagery to monitor crop growth and predict yield in Japanese squash (Cucurbita maxima) and onion varieties (Allium cepa) in Hollister, California, over the growing seasons of 2022 and 2023. Daily imagery from PlanetScope with a resolution of 3 m and on-demand 0.5 m imagery from Planet SkySat were utilized. Vegetation indices including the Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI) were calculated at various times during the growing season. Statistical analyses were performed to explore the correlations between these indices and crop yield. The results indicate significant correlations between vegetation indices such as NDVI and SAVI and crop yield in Japanese squash and onion varieties. Higher vegetation index values were associated with increased crop yield, suggesting that these indices can serve as reliable indicators of crop health and vigor. The use of high-resolution satellite imagery allowed for timely and accurate monitoring of crop growth dynamics, facilitating informed decision-making for growers. This study describes the potential of high-resolution satellite imagery and vegetation indices for monitoring crop growth and predicting yield in Japanese squash and onion varieties. The importance of integrating remote sensing techniques into agricultural practices to improve crop management strategies and enhance productivity will be discussed in the presentation.

Speakers

Elia Scudiero

University of California, Riverside

Co-authors

Nan Li

Univeristy of California, Riverside

Todd Skaggs

USDA-ARS

Tuesday September 24, 2024 1:15pm - 1:25pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

1:25pm HST

VCM 1 - A New Tool to Manage Water and Nutrients in High Tunnel Tomato Production

Tuesday September 24, 2024 1:25pm - 1:35pm HST

Nautilus 1

Much of the tomato production on market farms in the northeastern United States utilizes high tunnels. Tunnels protect soils from rainfall, reducing leaching of nutrients. However, if nutrients are accumulating below the root zone in tunnel soils lateral flow could be moving the nutrients beyond the covered area, resulting in leaching. From July 2020 to October 2022 we monitored soil moisture, soil temperature, and mineralization and movement of nitrate and phosphate in high tunnel tomato production on five commercial market farms (2 in Connecticut and 3 in Rhode Island). We also tracked irrigation water and fertilizer applications. Activated mixed-bed resin capsules were buried at 30 cm depth in transects running across the width of each high tunnel and extending 1 m past the tunnel perimeter on each side. Resin capsules were exchanged in March, July and October of each year and analyzed for captured nitrate, ammonium and phosphate. Soil P in the tunnels ranged from 16 to 363 kg/ha and soil K from 207 to

Speakers

Rebecca Brown

Co-authors

Josef Gorres

University of Vermont

Shuresh Ghimire

University of Connecticut

Tuesday September 24, 2024 1:25pm - 1:35pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

1:35pm HST

VCM 1 - Soil Moisture Sensors Allow for Resilient Tomato Production in Organic Systems

Tuesday September 24, 2024 1:35pm - 1:45pm HST

Nautilus 1

Soil moisture sensors have enabled continuous soil water status monitoring and became widely available to commercial growers. The use of soil moisture sensors that measure volumetric soil water content can be a useful tool to diminish or avoid over-irrigation addressing specific water requirements according to soil characteristics. However, the frequency of irrigation events, or a proper irrigation scheduling, using soil moisture sensor varies according to soil type, and the performance of soil moisture sensors as a tool to determine irrigation events on sandy soils used for organic vegetable production, particularly tomato, have not been evaluated up to date. Thus, the study objective was to evaluate the use of three irrigation scheduling strategies to enhance irrigation management in organic tomato production in the southeastern U.S. Field experiments were conducted on the organic unit at E.V. Smith Research and Extension Center from Auburn University, located in Shorter, AL in 2022 and 2023. Three irrigation scheduling treatments were tested: systematic irrigation (SYS), crop water demand (CWD), and soil water status method (SWS). In both years, results indicated that SWS had a higher biomass accumulation than CWD and SYS; consequently, tomato yield increased in the SWS compared to the two other treatments. Yield increments were 14% between SWS and CWD, and 25% between SWS and SYS. Irrigation water savings were also the highest for the SWS treatment, resulting in 72% water savings compared to SYS and 54% to CWD in 2022; while the SWS used 65% less water than SYS and 55% less than CWD in 2023. In general, rainfall events had an impact on strategies used to determine irrigation events. Among the studied irrigation scheduling methods, the SWS had a better performance in terms of fruit growth, biomass accumulation, and overall yield compared to CWD and SYS. Considering the global need for sustainable practices, the SWS treatment shows up as one of the best alternatives to the current grower standard practice, which consist in the SYS.

Speakers

Andre Luiz Biscaia Ribeiro da Silva

Auburn University

Co-authors

Camila Rodrigues

Auburn University

Guilherme Bueno

Auburn University

Timothy Coolong

University of Georgia

Wheeler Foshee

Auburn University

Tuesday September 24, 2024 1:35pm - 1:45pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

1:45pm HST

VCM 1 - Physiology of Heat Tolerant Tomatoes: Transplanting Through Harvest

Tuesday September 24, 2024 1:45pm - 1:55pm HST

Nautilus 1

Consumers are motivated to purchase locally grown tomatoes for a maximum flavor experience. With this demand, tomatoes are highly valuable in the local food system and one of the most profitable crops for small, diversified farms. Tomato production in Oklahoma, and other warm climates, can be difficult with the fruit’s temperature requirements for fruit set. Optimum conditions are available for a short period in Oklahoma. The additional threat of climate change could present even more challenging growing conditions in the future. There are heat tolerant tomatoes available, but these cultivars still have an upper limit for stress exposure. Previous research shows that there are distinct physiological differences between heat tolerant and heat sensitive cultivars, but these evaluations focus primarily on the early stages of the plant’s development. We aim to investigate the differences in cultivars throughout the entire plant life cycle. A field experiment will include six cultivars at different planting dates, showing a range of responses. The three planting dates will impose different temperature regimes throughout plant development. Physiological measurements will be recorded at regular intervals from transplanting through harvest. These parameters will include chlorophyll fluorescence, stomatal conductance, and electrolyte leakage. The results will assist with development of a model that enhances Oklahoma tomato production capacity through optimizing cultivar selection.

Speakers

Courtney DeKalb-Myers

Co-authors

Justin Moss

Oklahoma State University

Tuesday September 24, 2024 1:45pm - 1:55pm HST
Nautilus 1

Poster presentation (individual talk), Vegetable Crops Management 1

SUBJECT Vegetable Crops

2:14pm HST

Viticulture and Small Fruits 1 (VSF 1)

Tuesday September 24, 2024 2:14pm - 3:30pm HST

Nautilus 1

Prospects for Grapes in High Tunnels - Paul Read
Growing Grapes on the Texas High Plains: A Review of Grower Concerns and Recent Research - Thayne Montague
Improving the Climate Resilience of Wine Grape Vineyards via Trellis Selection and Applied Water Amounts in Warm/Hot Viticultural Regions - Runze Yu
Heat Stress Effects on South Mississippi Grown Bunch Grapes - Haley Williams
Rethinking Chill Models: The Role of Cold Hardiness, Freezing Temperatures and Daily Fluctuation on Promoting Dormancy Progression and Release - Amaya Atucha

Moderator

Haley Williams

Mississippi State University

Tuesday September 24, 2024 2:14pm - 3:30pm HST
Nautilus 1

Oral Sessions, Viticulture and Small Fruits 1

SUBJECT Viticulture

2:15pm HST

VSF 1 - Prospects for Grapes in High Tunnels

Tuesday September 24, 2024 2:15pm - 2:30pm HST

Nautilus 1

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

Speakers

Paul Read

University of Nebraska

Tuesday September 24, 2024 2:15pm - 2:30pm HST
Nautilus 1

Oral presentation (Individual talk), Viticulture and Small Fruits 1

SUBJECT Viticulture

2:30pm HST

VSF 1 - Growing Grapes on the Texas High Plains: A Review of Grower Concerns and Recent Research

Tuesday September 24, 2024 2:30pm - 2:45pm HST

Nautilus 1

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

Speakers

Thayne Montague

Professor, Texas Tech University / Texas A&M AgriLife Research

Dr. Thayne Montague received his Ph.D. in Horticulture Plant Physiology from Utah State University, and is employed by Texas Tech University Department of Plant and Soil Science and Texas A&M AgriLife Research. Dr. Montague's teaching responsibilities include Plant Propagation, Woody... Read More →

Co-authors

Daniel Hillin

Texas A

Patrick O'Brien

Texas A

Tuesday September 24, 2024 2:30pm - 2:45pm HST
Nautilus 1

Oral presentation (Individual talk), Viticulture and Small Fruits 1

SUBJECT Viticulture

2:45pm HST

VSF 1 - Improving the Climate Resilience of Wine Grape Vineyards via Trellis Selection and Applied Water Amounts in Warm/Hot Viticultural Regions

Tuesday September 24, 2024 2:45pm - 3:00pm HST

Nautilus 1

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

Speakers

Runze Yu

Assistant Professor, California State University, Fresno

Co-authors

Nazareth Torres

Universidad Pública de Navarra

Sahap Kaan Kurtural

Kurtural Vineyard Consulting

Tuesday September 24, 2024 2:45pm - 3:00pm HST
Nautilus 1

Oral presentation (Individual talk), Viticulture and Small Fruits 1

SUBJECT Viticulture

3:00pm HST

VSF 1 - Heat Stress Effects on South Mississippi Grown Bunch Grapes

Tuesday September 24, 2024 3:00pm - 3:15pm HST

Nautilus 1

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

Speakers

Haley Williams

Mississippi State University

Co-authors

Eric Stafne

Mississippi State University

Jenny Ryals

Mississippi State University

Tuesday September 24, 2024 3:00pm - 3:15pm HST
Nautilus 1

Oral presentation (Individual talk), Viticulture and Small Fruits 1

SUBJECT Viticulture

3:15pm HST

VSF 1 - Rethinking Chill Models: The Role of Cold Hardiness, Freezing Temperatures and Daily Fluctuation on Promoting Dormancy Progression and Release

Tuesday September 24, 2024 3:15pm - 3:30pm HST

Nautilus 1

This study addresses fundamental questions in bud dormancy, specifically the impact of temperature on chill accumulation and cold hardiness on dormancy release. We evaluated bud cold hardiness (CH) and time to budbreak responses of grapevines throughout chill accumulation under three treatments: constant (5°C), fluctuating (-3.5 to 6.5 °C daily), and field conditions (Madison, WI, USA), during three dormant seasons. Findings reveal that lower temperatures in chill treatments result in greater cold hardiness gains (CHfield>CHfluctuating>CHconstant). All treatments reduce time to budbreak with increased chill accumulation. However, when time to budbreak was adjusted to remove cold acclimation effects, treatment effectiveness changed. Notably, existing chill models (North Carolina, Utah, and Dynamic) fail to accurately describe adjusted budbreak responses. Our results demonstrate how chill treatment effectiveness changes when adjustments for uneven acclimation are considered. We propose a new model that includes freezing temperatures and enhances chill accumulation under fluctuating conditions.

Speakers

Amaya Atucha

University of Wisconsin Madison

Co-authors

Al Kovaleski

University of Wisconsin-Madison

Beth Ann Workmaster

University of Wisconsin Madison

Michael G North

University of Wisconsin Madison

Tuesday September 24, 2024 3:15pm - 3:30pm HST
Nautilus 1

Oral presentation (Individual talk), Viticulture and Small Fruits 1

SUBJECT Viticulture

3:59pm HST

Water Utilization and Management 2 (WUM 2)

Tuesday September 24, 2024 3:59pm - 6:00pm HST

Nautilus 1

Irrigation Management With Spreadsheets in Small Farms - Gustavo Haddad Souza Vieira
Assessing Micro-Irrigation Clogging Risk Through Water Quality Classification Systems - Juan Cabrera Garcia
Development of an Open-source, Autonomous Irrigation Controller for Horticultural Applications - Andrew Bierer
Microbial Community Composition and Accumulation Of Biofilms In Irrigation Pipes Using Nutrient Solutions with Different Organic Loads - Juan Cabrera Garcia
ATP vs Petrifilm: Techniques to Quantify Microbial Communities for Water Quality Analysis - Dharti Thakulla
Water use and crop coefficients for outdoor nursery ornamentals in 15-gal containers - Gerry Spinelli
Quantification of irrigation and stormwater runoff volume, sediment load, and nutrient load when producing nursery crops - James Owen
Water Supply Resilience Through Florida-Friendly Landscaping - Michael Dukes

Moderator

Gerry Spinelli

University of California Cooperative Extension

Irrigation management in nurseries and greenhouses

Tuesday September 24, 2024 3:59pm - 6:00pm HST
Nautilus 1

Oral Sessions, Water Utilization and Management 2

SUBJECT Water Utilization and Management

4:00pm HST

WUM 2 - Irrigation Management With Spreadsheets in Small Farms

Tuesday September 24, 2024 4:00pm - 4:15pm HST

Nautilus 1

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

Speakers

Gustavo Haddad Souza Vieira

Full Professor, IFES campus Santa Teresa

Agronomist,Ph. D. in Agricultural Engineering. Full Professor. Irrigation, Agrometeorology, Horticulture, Coffee Crop.

Co-authors

Cesar Santos Carvalho

Incaper

Paola Alfonsa Vieira Lo Monaco

Ifes Santa Teresa

Raphael Magalhaes Gomes Moreira

Ifes Itapina

Tuesday September 24, 2024 4:00pm - 4:15pm HST
Nautilus 1

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

4:15pm HST

WUM 2 - Assessing Micro-Irrigation Clogging Risk Through Water Quality Classification Systems

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

Nautilus 1

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

Speakers

Juan Cabrera Garcia

University of Missouri

Co-authors

Mayra Toro Herrera

University of Connecticut

Rosa Raudales

University of Connecticut

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

4:30pm HST

WUM 2 - Development of an Open-source, Autonomous Irrigation Controller for Horticultural Applications

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

Nautilus 1

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

Speakers

Andrew Bierer

USDA-ARS, AFRS

Co-authors

Lisa Tang

USDA-ARS Appalachian Fruit Research Station

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

4:45pm HST

WUM 2 - Microbial Community Composition and Accumulation Of Biofilms In Irrigation Pipes Using Nutrient Solutions with Different

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

Nautilus 1

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

Speakers

Juan Cabrera Garcia

University of Missouri

Co-authors

Rosa Raudales

University of Connecticut

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

5:00pm HST

WUM 2 - ATP vs Petrifilm: Techniques to Quantify Microbial Communities for Water Quality Analysis

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

Nautilus 1

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

Speakers

Dharti Thakulla

University of Florida

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

5:15pm HST

WUM 2 - Water use and crop coefficients for outdoor nursery ornamentals in 15-gal containers

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

Nautilus 1

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

Speakers

Gerry Spinelli

University of California Cooperative Extension

Irrigation management in nurseries and greenhouses

Co-authors

Chris Shogren

University of California Cooperative Extension Los Angeles

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

5:30pm HST

WUM 2 - Quantification of irrigation and stormwater runoff volume, sediment load, and nutrient load when producing nursery crops

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

Nautilus 1

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

Speakers

James Owen

USDA ARS

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

Co-authors

Mohammad Nayeb Yazdi

Arlington County Virginia

Steve Lyon

The Ohio State University

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

5:45pm HST

WUM 2 - Water Supply Resilience Through Florida-Friendly Landscaping

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

Nautilus 1

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

Speakers

Michael Dukes

Professor & Director, University of Florida

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

Oral presentation (Individual talk), Water Utilization and Management 2

SUBJECT Water Utilization and Management

7:59am HST

Floriculture 1 (FLOR 1)

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

Nautilus 1

Phosphate Solubilizing Bacteria: Leveraging The Soilless Substrate For Improved Phosphorus Nutrition In Controlled Environment Agriculture. - Michelle Jones
Phosphate Solubilizing Bacteria Isolated From Greenhouse Ornamentals Solubilize Phosphate In Vitro And Ameliorate P Deficiency Symptoms In Marigold ‘Durango Yellow’ Fertilized With Calcium Phosphate. - Juan Quijia Pillajo
Activated Aluminum Amended Substrates Reduce Phosphorus Leaching in Floriculture Production - Damon Abdi
Iron-coated Sand as a Sustainable Substrate Amendment for Nutrient Management of Containerized Floriculture Crops - Savannah Mead
Phosphorous Restriction Suppresses Growth of Containerized Coneflower - Garrett Owen
Investigating Synergistic Effects of Biostimulants and Biochar on Water Use Efficiency for Containerized Celosia (Argentea cristata) and Gomphrena (Gomphrena globose) Production - Lilin Chen
Effects of Reduced Water Usage During Production on Economic Value, Growth, And Quality of Flowering Indoor Plants - Kaitlin Hopkins

Moderator

Damon Abdi

Louisiana State University Agricultural Center

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

Oral Sessions, Floriculture 1

SUBJECT Floriculture

8:00am HST

FLOR 1 - Phosphate Solubilizing Bacteria: Leveraging The Soilless Substrate For Improved Phosphorus Nutrition In Controlled Environment Agriculture.

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

Nautilus 1

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

Speakers

Michelle Jones

Professor, The Ohio State University

Co-authors

Juan Quijia Pillajo

The Ohio State University

Laura Chapin

The Ohio State University

Sachin Naik

The Ohio State University

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

8:15am HST

FLOR 1 - Phosphate Solubilizing Bacteria Isolated From Greenhouse Ornamentals Solubilize Phosphate In Vitro And Ameliorate P Deficiency Symptoms In Marigold ‘Durango Yellow’ Fertilized With Calcium Phosphate.

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

Nautilus 1

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

Speakers

Juan Quijia Pillajo

The Ohio State University

Co-authors

Michelle Jones

The Ohio State University

Nathan Nordstedt

FMC Corporation

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

8:30am HST

FLOR 1 - Activated Aluminum Amended Substrates Reduce Phosphorus Leaching in Floriculture Production

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

Nautilus 1

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

Speakers

Damon Abdi

Louisiana State University Agricultural Center

Co-authors

Jeb Fields

LSU AgCenter Hammond Research Station

Jeffrey Beasley

University of North Carolina - Pembroke

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

8:45am HST

FLOR 1 - Iron-coated Sand as a Sustainable Substrate Amendment for Nutrient Management of Containerized Floriculture Crops

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

Nautilus 1

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

Speakers

Savannah Mead

West Virginia University

Co-authors

Eugenia Pena Yewtukhiw

West Virginia University

Karen Buzby

West Virginia University

Lance Lin

West Virginia University

Nicole Waterland

West Virginia University

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

9:00am HST

FLOR 1 - Phosphorous Restriction Suppresses Growth of Containerized Coneflower

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

Nautilus 1

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

Speakers

Garrett Owen

Extension Specialist and Assistant Professor of Sustainable Greenhouse & Nursery Systems, The Ohio State University

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

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

9:15am HST

FLOR 1 - Investigating Synergistic Effects of Biostimulants and Biochar on Water Use Efficiency for Containerized Celosia (Argentea cristata) and Gomphrena (Gomphrena globose) Production

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

Nautilus 1

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

Speakers

Lilin Chen

Graduate Research Assistant, University of Georgia

I'm interested in biochar effect on containerized plants, especially the effect under abiotic stresses such as drought and salinity.

Co-authors

Ping Yu

University of Georgia

Yulong Chen

The University of Georgia

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

9:30am HST

FLOR 1 - Effects of Reduced Water Usage During Production on Economic Value, Growth, And Quality of Flowering Indoor Plants

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

Nautilus 1

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

Speakers

Kaitlin Hopkins

Sam Houston State University

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

Oral presentation (Individual talk), Floriculture 1

SUBJECT Floriculture

9:59am HST

Postharvest 2 (PH 2)

Wednesday September 25, 2024 9:59am - 12:30pm HST

Nautilus 1

Postharvest Performance of Tomato Fruit at Shelf-life Conditions in Relation to Fertilization Rate During Plant Production and Fruit Ripening Stage at Harvest - Sotirios Tasioulas
Identification of NAC Transcription Factors Involved in the Ripening and Senescence of Pepper (Capsicum annuum L.) Fruit - Kyeonglim Min
Comparative Analysis of Volatile Organic Compounds of Eight Microgreens in the Brassicaceae Family - Jinhe Bai
Nutritional Quality and Shelf-Life of “Living Lettuce” Through 28 Days of Cold Storage - Marlee Trandel Hayse
Comparing the Postharvest Phytonutrient Content of Red and Green Butterhead Lettuce Cultivars - Marlee Trandel Hayse
Production System Alters Phytonutrient Content of ‘Skyphos’ Butterhead Lettuce - Marlee Trandel Hayse
Improving Postharvest Storage and Late-Season Production of Caladium Tubers in Florida Through Chemical Treatments - Gasselle Cordova
Impact of Storage Environment on Dormancy Progression and Microbiome of Potato Tubers - Munevver Dogramaci
Strawberry Anthocyanins, Extraction, Assessments and Storage - Toktam Taghavi
Isolation of Pathogenic Strain of Trichoderma atroviride from Symptomless, Disease-Free Sweetpotato (Ipomoea batatas L.) Storage Roots - Richard Noel Torres

Moderator

Munevver Dogramaci

United States Department of Agriculture

Wednesday September 25, 2024 9:59am - 12:30pm HST
Nautilus 1

Oral Sessions, Postharvest 2

SUBJECT Postharvest

10:00am HST

PH 2 - Postharvest Performance of Tomato Fruit at Shelf-life Conditions in Relation to Fertilization Rate During Plant Producti

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

Nautilus 1

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

Speakers

Sotirios Tasioulas

SWFREC - University of Florida/IFAS

Co-authors

Jessie Watson

SWFREC - University of Florida/IFAS

Pavlos Tsouvaltzis

Southwest Florida Research and Education Center, University of Florida

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

10:15am HST

PH 2 - Identification of NAC Transcription Factors Involved in the Ripening and Senescence of Pepper (Capsicum annuum L.) Fruit

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

Nautilus 1

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

Speakers

Kyeonglim Min

Student, Seoul National University

Co-authors

Eun Jin Lee

Seoul National University

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

10:30am HST

PH 2 - Comparative Analysis of Volatile Organic Compounds of Eight Microgreens in the Brassicaceae Family

Wednesday September 25, 2024 10:30am - 10:45am HST

Nautilus 1

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

Speakers

Jinhe Bai

USDA-ARS

Co-authors

Anne Plotto

USDA-ARS

Erin Rosskopf

USDA-ARS

Francesco Di Gioia

Pennsylvania State University

Jason Hong

USDA Agricultural Research Service

Libin Wang

Nanjing Agricultural University,

Wei Zhao

USDA-ARS

Wednesday September 25, 2024 10:30am - 10:45am HST
Nautilus 1

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

10:45am HST

PH 2 - Nutritional Quality and Shelf-Life of “Living Lettuce” Through 28 Days of Cold Storage

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

Nautilus 1

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

Speakers

Marlee Trandel Hayse

Auburn University

Co-authors

Camila Rodrigues

Auburn Univeristy

Caroline Blanchard

Auburn University

Daniel Wells

Auburn University

MD Hasibur Rahman

Auburn University

Tanzeel Rehman

Auburn University

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

11:00am HST

PH 2 - Comparing the Postharvest Phytonutrient Content of Red and Green Butterhead Lettuce Cultivars

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

Nautilus 1

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

Speakers

Marlee Trandel Hayse

Auburn University

Co-authors

Alan Walters

Southern Illinois University

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

11:15am HST

PH 2 - Production System Alters Phytonutrient Content of ‘Skyphos’ Butterhead Lettuce

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

Nautilus 1

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

Speakers

Marlee Trandel Hayse

Auburn University

Co-authors

Alan Walters

Southern Illinois University

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

11:30am HST

PH 2 - Improving Postharvest Storage and Late-Season Production of Caladium Tubers in Florida Through Chemical Treatments

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

Nautilus 1

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

Speakers

Gasselle Cordova

University of Florida

Co-authors

Zhanao Deng

University of Florida

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

11:45am HST

PH 2 - Impact of Storage Environment on Dormancy Progression and Microbiome of Potato Tubers

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

Nautilus 1

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

Speakers

Munevver Dogramaci

United States Department of Agriculture

Co-authors

Dipayan Sarkar

United States Department of Agriculture

Evandro Fortini

United States Department of Agriculture

Malick Bill

United States Department of Agriculture

Shyam Kandel

United States Department of Agriculture

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

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

12:00pm HST

PH 2 - Strawberry Anthocyanins, Extraction, Assessments and Storage

Wednesday September 25, 2024 12:00pm - 12:15pm HST

Nautilus 1

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

Speakers

Toktam Taghavi

Wednesday September 25, 2024 12:00pm - 12:15pm HST
Nautilus 1

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

12:15pm HST

PH 2 - Isolation of Pathogenic Strain of Trichoderma atroviride from Symptomless, Disease-Free Sweetpotato (Ipomoea batatas L.) Storage Roots.

Wednesday September 25, 2024 12:15pm - 12:30pm HST

Nautilus 1

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

Speakers

Richard Noel Torres

University of Missouri - Columbia

Co-authors

James Schoelz

University of Missouri - Columbia

Peng Tian

University of Missouri - Columbia

Xi Xiong

University of Missouri - Columbia

Wednesday September 25, 2024 12:15pm - 12:30pm HST
Nautilus 1

Oral presentation (Individual talk), Postharvest 2

SUBJECT Postharvest

12:44pm HST

Floriculture (FLOR)

Wednesday September 25, 2024 12:44pm - 2:05pm HST

Nautilus 1

Peperomia mauiensis can tolerate low indoor light conditions for up to 12 months - Orville Baldos
Effect of LED Lighting, Fertilization Rates and Gibberellin A3 Application to Greenhouse Grown Geranium (Pelargonium x hortorum) 'Red Maverick' Plants - Sonja Maki
Investigating the Effect of Hydrafiber and Biochar As a Substitute for Peat-based Substrate for Zinnia (Zinnia elegans) - Lilin Chen
The Impact of Cold and Darkness on Osmanthus fragrans Flowering and Growth - Yulong Chen
Growth and Quality of Four Zinnia Cultivars Grown in Eastern South Dakota - Kristine Lang
Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Callirhoe involucrata - James Klett
Consumer testing and surveys indicate a market for Peperomia mauiensis, an endemic succulent with potential use as an indoor potted plant - Orville Baldos
Trials of Low Elevation Tolerant Leucospermum Hybrids on Oahu, HI - Russell Galanti

Moderator

Sonja Maki

University of Wisconsin-River Falls

Wednesday September 25, 2024 12:44pm - 2:05pm HST
Nautilus 1

Poster Session, Floriculture

SUBJECT Floriculture

12:45pm HST

FLOR - Peperomia mauiensis can tolerate low indoor light conditions for up to 12 months

Wednesday September 25, 2024 12:45pm - 12:55pm HST

Nautilus 1

Peperomia mauiensis is an endemic peperomia found on west Maui, and the islands of Molokai and Lanai. Its short stature and reddish stems and leaves make it highly ornamental. To evaluate its feasibility as an indoor foliage plant, potted plants (n=6) were grown under three light levels (0.2 mol·m-2·d-1 [low], 0.4 mol·m-2·d-1 [office] and 2.9 mol·m-2·d-1 [high] for 12 hours) in airconditioned settings (22°C, 61% RH) for 1 year. Plant height and diameter as well as visual quality [1 = poor, 2 = fair (not saleable), 3 = acceptable (saleable), 4 = good, and 5 = excellent quality) were recorded 0, 3, 6 and 12 months after placing in light chambers. Height and diameter of plants between light treatments were similar at 0 (height = 5.9 cm; diameter = 10.5 cm) and 3 (height = 7.1 cm and diameter = 15.0 cm) months after the plants were placed in light chambers. Visual quality ratings also did not differ between light treatments at 0 (3.5) and after 3 (3.6) months. After 6 months, plants under office light conditions were the tallest (10.8 cm) and the widest (18.2 cm). Visual quality ratings between treatments at 6 months were similar (3.4). At 12 months, plant height between treatments were similar (8.8 cm), but office light plants exhibited the widest diameter (23.2 cm). Visual quality ratings between treatments at 12 months were similar (2.1) but was no longer acceptable. Results of the study indicate that Peperomia mauiensis can tolerate low indoor light levels and can be used as an indoor potted foliage plant.

Speakers

Orville Baldos

University of Hawaii at Manoa

Co-authors

Christyn Wong

Hawaii Department of Agriculture

Lindsey Watanabe

University of Hawaii at Manoa

Sherry Ann Hara

University of Hawaii at Manoa

Wednesday September 25, 2024 12:45pm - 12:55pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

12:55pm HST

FLOR - Effect of LED Lighting, Fertilization Rates and Gibberellin A3 Application to Greenhouse Grown Geranium (Pelargonium x hortorum) 'Red Maverick' Plants

Wednesday September 25, 2024 12:55pm - 1:05pm HST

Nautilus 1

The effect of LED lighting, fertilization rate and gibberellin application on geranium (Pelargonium x hortorum) 'Red Maverick' plants in a greenhouse setting was evaluated. Seeds were germinated in 288 plug trays, transplanted to 3-1/2 inch geranium pots in a peat-based media (ProMix) and grown in a greenhouse environment. Twelve treatments consisting of plants that received either no, 150 ppm or 300 ppm 20-20-20 weekly fertilizer applications following transplant, abmbient or LED (Phillips Red/Blue) greenhouse lighting, and a treatment of either no or 10 ppm gibberellin A3 (GA3; ProGibb) were evaluated by recording weekly height measurements, pH, electrical conductivity (EC), and floral bud appearance was recorded for each treatment. The tallest, most advanced plants were obtained from ambient light, high fertility and ProGibb application with the shortest plants were produced by the ambient light, no fertilization, and no gibberellin application treatment. Visible bud was first noticed in the LED light grown plants at low and high fertility with and without gibberellin application. The results of this study will aid greenhouse growers producing geranium crops under different greenhouse lighting conditions to consider fertility rates and gibberellin application to decrease the production time of geranium crops.

Speakers

Sonja Maki

University of Wisconsin-River Falls

Co-authors

Zachary Endreas

University of Wisconsin-River Falls

Wednesday September 25, 2024 12:55pm - 1:05pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:05pm HST

FLOR - Investigating the Effect of Hydrafiber and Biochar As a Substitute for Peat-based Substrate for Zinnia (Zinnia elegans)

Wednesday September 25, 2024 1:05pm - 1:15pm HST

Nautilus 1

The increasing environmental concerns and economic pressures necessitate the search for peat moss alternative as a substrate component, aiming to balance ecological sustainability with cost-effectiveness. This study aims to assess whether the biochar (BC) and hydrafiber (HF) could be a partially replacement for peat moss for zinnia and snapdragon production. Twelve substrates were formulated by either mixing BC (20%,40%, or 60% by vol) with HF (20%, 40%, or 60% (by vol), with the remaining being peat moss or blending BC (0%, 20%,40%, and 60%, by vol) with the commercial peat moss-based substrates (CS). The physical properties of substrate, including container capacity (CC), total porosity (TP), air space (AS), bulk density (BD), and water holding capacity (WHC), and chemical properties including leachate pH and electrical conductivity (EC) were measured. Plant growth parameters including growth index (GI) and leave greenness (indicated with SPAD value), biomass, and numbers of flowers were measured biweekly. The results showed all the substrate mixes had similar AP, BD and SPAD. Treatment with 20

Speakers

Lilin Chen

Graduate Research Assistant, University of Georgia

I'm interested in biochar effect on containerized plants, especially the effect under abiotic stresses such as drought and salinity.

Co-authors

Ping Yu

University of Georgia

Yulong Chen

The University of Georgia

Wednesday September 25, 2024 1:05pm - 1:15pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:15pm HST

FLOR - The Impact of Cold and Darkness on Osmanthus fragrans Flowering and Growth

Wednesday September 25, 2024 1:15pm - 1:25pm HST

Nautilus 1

Osmanthus fragrans, a culturally and economically significant plant in Asian countries, exhibits unique floral characteristics influenced by endogenous metabolites. Previous studies suggest its flowering timing and intensity may be affected by environmental factors including cold and darkness. This study aimed to investigate the effects of cold and darkness factors on the response of Osmanthus fragrans flowering and growth. This experiment included 7 cold and dark treatments (plants were sitting in the dark coolers from 0-15 days) and dark-only treatments (plants were sitting in the GH with plastic bags from 0-9 days). Plant responses were assessed based on the number of flowers, height, and width measurements on the 5th, 7th, 9th, 11th, 13th, and 15th days post-treatment. The results showed there was no significant difference in plant height across treatments. Dark-only treatment for 7 days significantly increased width growth compared to the control group (9 days), and dark-cold treatment for 5, 7, 9, 11, and 13 days. The increase in the number of flowers in the cold-dark treatment for 9 and 15 days was significantly higher than in other treatments, except for the control. In conclusion, the cold and darkness could promote flowering in Osmanthus fragrans without negatively affecting plant growth.

Speakers

Yulong Chen

The University of Georgia

Co-authors

Lilin Chen

The University of Georgia

Ping Yu

University of Georgia

Wednesday September 25, 2024 1:15pm - 1:25pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:25pm HST

FLOR - Growth and Quality of Four Zinnia Cultivars Grown in Eastern South Dakota

Wednesday September 25, 2024 1:25pm - 1:35pm HST

Nautilus 1

Over the past two decades, interest in local specialty cut flower production in Eastern South Dakota has grown with several new flower farms being established across the region. However, there is currently no local, research-based information available to support growers in this new wave of interest. The purpose of this study was to assess the production and quality of four zinnia cultivars grown in Eastern South Dakota to support local specialty cut flower growers in their operations. This was a randomized complete block study with four zinnia cultivars (Zinderella Peach, Oklahoma Ivory, Queen Red Lime, and Benary’s Giant Purple) grown in 2022 and 2023. Zinnias were started in the greenhouse and then transplanted into the field in early summer each season. Harvest began each year when flowers reached maturity (July), with one harvest event taking place each week until the first frost. Harvested flowers were rated as marketable or non-marketable based on categories of stem length (18 -inch-long, 13-17.99-inch-long, 8-12.99-inch-long, and

Speakers

Kristine Lang

South Dakota State University

Co-authors

Alexis Barnes

South Dakota State University

Ellen Fitzpatrick

South Dakota State University

Hannah Voye

South Dakota State University

Wednesday September 25, 2024 1:25pm - 1:35pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:35pm HST

FLOR - Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Callirhoe involucrata

Wednesday September 25, 2024 1:35pm - 1:45pm HST

Nautilus 1

Effects of Photoperiod Treatments on Stock Plants and Cutting Rooting of Callirhoe involucrata James E. Klett and Ronda Koski Colorado State University Department of Horticulture and LA Production of attractive and desirable plants, native to the plains and prairies of central North America, can sometimes be limited due to problems associated with successful rooting of vegetative cuttings. Species that have a long period of bloom can be challenging to vegetatively propagate during the growing season, because sufficient juvenile (vegetatively) growth is necessary for high-quality cuttings. Callirhoe involucrata (winecups) is a native herbaceous perennial with sprawling stems, palmately divided leaves, and dark pink flowers that creates a long lasting, colorful groundcover in landscapes with limited or no supplemental irrigation. Winecups can be difficult to propagate due to seed dormancy and poor rooting of vegetative cuttings. Manipulating the growing conditions of stock plants to suppress reproductive growth may improve rooting success of vegetative cuttings. Based on previous research at Colorado State University with other ornamental perennials and programmed photoperiods, winecups were grown under three programmed photoperiods to determine if a particular photoperiod could be used to suppress reproductive growth and promote vegetative growth. The research was replicated three times, all conducted in a similar fashion, but at different times of the year. Results indicate that plants grown under 10-hour light and 8-hour light photoperiods remained vegetative longer when compared to plants grown under 12-hour photoperiod. Plants grown under 12-hour photoperiods had greater mean ending dry weight when compared to plants grown under 10 hour and 8-hour photoperiods. Cuttings harvested from plants grown under 8-hour photoperiod had higher percent rooting and greater number of roots per cutting when compared to vegetative cuttings harvested from plants grown under 12-hour photoperiod. Based on these research findings, plant propagators may be able to increase production of winecups by growing stock plants under 8-hour photoperiod.

Speakers

James Klett

Colorado State University

FLOR POSTER KLETT pdf

Wednesday September 25, 2024 1:35pm - 1:45pm HST
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Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:45pm HST

FLOR - Consumer testing and surveys indicate a market for Peperomia mauiensis, an endemic succulent with potential use as an indoor potted plant

Wednesday September 25, 2024 1:45pm - 1:55pm HST

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Peperomia mauiensis is an endemic succulent found on the islands of Maui, Molokai and Lanai. Its reddish stems and foliage as well as its small stature make it a potential indoor ornamental plant. To assess consumer acceptance, a public plant giveaway with surveys was conducted. Fifty-six plants in plastic and ceramic pots were distributed to the public with the completion of a survey. A six-month follow up survey was conducted to assess the condition of the plant and obtain consumer feedback. During the plant giveaway, 77% of participants completed the survey. Nearly all respondents are willing to buy the plant and recommend it to friends and co-workers. Thirty percent of respondents are willing to buy the plant for $5 in a ceramic pot and $3 to $5 for a plastic pot. Six months after the giveaway, 39.5% of initial respondents completed the follow-up survey. About half of the respondents (52.9%) reported the plant was growing healthy and vigorous. The majority of the respondents did not fertilize the plant (81.3%) and did not report any pest (94.1%) and disease (88.2%) issues. Most responded that they liked it as a houseplant (88.2%) and it was easy to maintain (82.4%). Most respondents (35.3%) were willing to buy the plant again for $5. Results of the surveys indicate that there is consumer interest in Peperomia mauiensis as a new native indoor plant.

Speakers

Orville Baldos

University of Hawaii at Manoa

Co-authors

Hannah Lutgen

CTAHR

Wednesday September 25, 2024 1:45pm - 1:55pm HST
Nautilus 1

Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

1:55pm HST

FLOR - Trials of Low Elevation Tolerant Leucospermum Hybrids on Oahu, HI

Wednesday September 25, 2024 1:55pm - 2:05pm HST

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Leucospermum species are temperate climate plants native to South Africa and have restricted production regions in Hawaii limited to elevations of 457 m or higher. This limitation and competition for land has been partially responsible to a decline in Leucospermum production in Hawaii. Agriculture land at lower elevations is more abundant and cheaper, and is an option for growing low elevation tolerant varieties. Breeding programs at the University of Hawaii at Manoa have focused on developing hybrids that will perform to commercial standards for plant growth, yield and quality, and grow at or near sea level. 14 hybrids of Leucospermum were trialed at 152 m elevation on Oahu HI. 10 hybrids exhibited adequate survival and were selected for continued trial. Weahter, plant growth (height and width), flower count, flowering seasonality, and plant health data were collected from 2021-2023. Flower length and quality data, and vase life data were collected in 2024. Average relative humidity was 79%, average monthly rainfall was 3.53 cm, and average temperature was 21.8 C with maximum temperature of 33.4 C and low of 14.2 C. The 10 hybrids all had acceptable fitness at 500’ elevation. Some hybrids showed more fitness than others. Hybrid 602 had the highest overall average health (3.8) and highest total flower count. Hybrids 620 and 626 also showed excellent fitness as well as highest flower counts. While none of the hybrids are considered unfit for production in similar conditions, some did perform less well. Hybrid 88 and Hybrid 633 had the lowest average health at 3.0 followed closely by Hybrids 583 (3.2), 679 (3.3), and 563 (3.3). These varieties also had some of the lowest total flower counts. All of the hybrids in this study are considered potential candidates for release and continued trialing. Future work can include long term trialing of these plants, and trialing at different microclimates across the State.

Speakers

Russell Galanti

Extension Educator, University of Hawaiʻi

Co-authors

Alberto Ricordi

University of Hawaii at Manoa

Kenneth Leonhardt

University of Hawaii at Manoa

Wednesday September 25, 2024 1:55pm - 2:05pm HST
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Poster presentation (individual talk), Floriculture

SUBJECT Floriculture

2:29pm HST

Pomology 2/Horticultural Plant Reproductive Biology/Intellectual Property Rights (POM 2/HPRB/IPR)

Wednesday September 25, 2024 2:29pm - 4:30pm HST

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Do Plant “Growth Regulators” Really Regulate Growth? Plant Development And Plant Growth Are Not Synonymous. - Ted DeJong
Using GDR to Enable Rosaceae Research - New Data, Functionality and Future Direction - Dorrie Main
Deployment of Multi-location Genomic Prediction Models for Fruit Crops Using GDR-BIMS - Craig Hardner
Raspberry Cultivar Evaluation Trial in Mississippi - Apphia Santy
Performance of AU Gold-fleshed Kiwifruit in Alabama - James Spiers
Evaluating Sufficiency Levels and Peach Leaf Analysis for Fertilizer Decision-Making - Juan Carlos Melgar

Moderator

David Karp

University of California, Riverside

Wednesday September 25, 2024 2:29pm - 4:30pm HST
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Oral Sessions, Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology, Intellectual Property Rights

2:30pm HST

POM 2/HPRB/IPR - Do Plant “Growth Regulators” Really Regulate Growth? Plant Development And Plant Growth Are Not Synonymous.

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

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

Speakers

Ted DeJong

UC Davis

Wednesday September 25, 2024 2:30pm - 2:45pm HST
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Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology

2:45pm HST

POM 2/HPRB/IPR - Using GDR to Enable Rosaceae Research - New Data, Functionality and Future Direction

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

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Initiated in 2003, the Genome Database for Rosaceae (GDR, www.rosaceae.org) is a comprehensive community database that provides access to curated and integrated genomics, genetics, and breeding data for the biologically and economically important Rosaceae family. It serves as steward of critical research and breeding data, and provides access to online query and analysis tools that enable researchers to readily interrogate this wealth of data, facilitating basic and applied research across Rosaceae. This presentation will highlight the impact of GDR on Rosaceae research, demonstrate new data and tools, and share plans for future development and sustainability options.

Speakers

Dorrie Main

Professor, Washington State University

Wednesday September 25, 2024 2:45pm - 3:00pm HST
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Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology

3:00pm HST

POM 2/HPRB/IPR - Deployment of Multi-location Genomic Prediction Models for Fruit Crops Using GDR-BIMS

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

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Multi-location genomic prediction models have been proposed as a strategy for aggregating disconnected phenotypic datasets to enable performance prediction of individuals into new environments. This approach also offers improved prediction accuracy and understanding of environmental stability. Multi-location GBLUP prediction models have been developed and used to study patterns in genotype-by-environment interaction for: flowering date in cherry across four locations in USA, France, and Italy; for sweetness in peach across four locations in USA; in strawberry across eight locations in USA, Australia, and Europe; and for fruit firmness in apple across five locations in USA and Europe. Here we present an online bioinformatics platform for the deployment of these models via the Breeding Information Management System (BIMS) in the Genome Database for Rosaceae (GDR). This platform enables performance of new material that has not been physically tested to be predicted for the traits across the environmental space included in the multi-environment GBLUP models. The predicted genetic value of each individual included in the GBLUP models for each trait in each environment was used with the GBLUP individual-by-marker allele frequency matrix to predict the genetic effect of each marker allele for each trait in each environment. A portal was then developed on BIMS to host this vector of marker effects and enable new users to upload tables of new individual-by-SNP marker data for the loci used in the original GBLUP model. Predictions for the new individuals are produced by multiplying the new sample-by-marker frequency matrix by the vector of predicted allelic effects. Predictions of the new material for each trait across environments are delivered alongside predicted performance of publicly available genetic material to enable comparison and evaluation of reliability of predictions. The use of this portal is demonstrated with genome-wide SNP genotypic data collected on new apple selections evaluated for an Australian genetic improvement program.

Speakers

Craig Hardner

University Of Queensland

Assocaite Professor in quantitative genetic s and tree breeding of horticultural and forestry crops with particular foci on multi-variate mixed linear models, G-by-E, genomic prediction, multi-trait selection, modelling breeding strategies, conservation genetics, low-cost genotyping... Read More →

Co-authors

Cameron Peace

Washington State University

Dorrie Main

Washington State University

Shashi Goonetilleke

University Of Queensland

Sook Jung

Washington State University

Taein Lee

Washington State University

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

Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology

3:15pm HST

POM 2/HPRB/IPR - Raspberry Cultivar Evaluation Trial in Mississippi

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

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

Speakers

Apphia Santy

Graduate Student, Mississippi State University

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

Co-authors

Guihong Bi

Mississippi State University

Tongyin Li

Mississippi State University

Wednesday September 25, 2024 3:15pm - 3:30pm HST
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Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology

3:30pm HST

POM 2/HPRB/IPR - Performance of AU Gold-fleshed Kiwifruit in Alabama

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

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The performance of kiwifruit, primarily gold-fleshed cultivars, has been evaluated for many years in central Alabama, with the earliest plantings occurring at the Chilton Research and Extension Center, Clanton, AL in the mid-1990s. The objective of this study was to determine bloom times of female and potential male pollinizers, appropriate harvest times, and fruit quality attributes of ‘AU Golden Dragon’, ‘AU Gulf Coast Gold’, and ‘AU Golden Sunshine’. The female cultivar ‘AU Golden Dragon’ blooms earlier than other cultivars evaluated and had good bloom overlap with the male cultivar Hortkiwi ‘Meteor’. The female cultivars ‘AU Golden Sunshine’ and ‘AU Gulf Coast Gold’ bloom approximately 2 weeks after ‘AU Golden Dragon’ and had good bloom overlap with the male ‘AU Golden Tiger’. The harvest period in central AL for each cultivar based on flesh color (hue

Speakers

James Spiers

Auburn University

Wednesday September 25, 2024 3:30pm - 3:45pm HST
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Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Pomology, Horticultural Plant Reproductive Biology

3:45pm HST

POM 2/HPRB/IPR - Evaluating Sufficiency Levels and Peach Leaf Analysis for Fertilizer Decision-Making

Wednesday September 25, 2024 3:45pm - 4:00pm HST

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

Speakers

Richardson Bien Aime

Graduate student, Clemson University

- Plant and environmental sciences- Horticulture- Optimization of Peach Fertilization- Peach rootstocks- Agricultural economics- Sports- Music

Co-authors

Juan Carlos Melgar

Clemson University

Wednesday September 25, 2024 3:45pm - 4:00pm HST
Nautilus 1

Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Horticultural Plant Reproductive Biology, Pomology, Intellectual Property Rights

4:00pm HST

POM 2/HPRB/IPR - Common Mechanisms Controlling Fruit Shapes may be Mediated by Changes in Cell Wall Properties

Wednesday September 25, 2024 4:00pm - 4:15pm HST

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Fruit shape variation is abundantly present in horticultural crops. This variation is critical to highlight the market class as well as the culinary purpose of the produce. Many of the underlying genes have been cloned in tomato, offering insights into the molecular mechanisms of morphological diversity. Specifically, members of the OFP, TRM and SUN family regulate produce shape variation in tomato and other crops, thereby highlighting the importance of these three families in regulating phenotypic diversity. Despite the knowledge of the genes, mechanistic insights into the function of members of these three gene families are lacking. Our research on the tomato genes OVATE and OFP20 has shown that changes in produce shapes are noticeable early in the development of the flower. Cell counts in ovaries at anthesis implied that changes in cell division patterning may underlie morphological diversity. However, gene expression studies showed that morphological changes were associated with cell wall processes and not with changes in cell division patterning.

Speakers

Esther van der Knaap

University of Georgia

Co-authors

Yanbing Wang

University of Georgia

Wednesday September 25, 2024 4:00pm - 4:15pm HST
Nautilus 1

Oral presentation (Individual talk), Horticultural Plant Reproductive Biology

SUBJECT Horticultural Plant Reproductive Biology, Pomology

4:15pm HST

POM 2/HPRB/IPR - Pomological Nomenclature: Recent Developments and Problems

Wednesday September 25, 2024 4:15pm - 4:30pm HST

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

Speakers

David Karp

University of California, Riverside

Wednesday September 25, 2024 4:15pm - 4:30pm HST
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Oral presentation (Individual talk), Intellectual Property Rights

SUBJECT Pomology, Horticultural Plant Reproductive Biology, Intellectual Property Rights

6:00pm HST

Graduate Student Poster Competition

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

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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
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Competitions, Student Activities

SUBJECT Competition

7:59am HST

Postharvest 3 (PH 3)

Thursday September 26, 2024 7:59am - 10:15am HST

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Assessing Apple Cultivar Responses to Low Oxygen Limit Determination Using Chlorophyll Fluorescence and Respiratory Quotient - Hnin Phyu Lwin
Understanding how physiological maturity and storage regime affect skin greasiness on WA 38 apples - Carolina Torres
Chlorophyll to Carotenoid Ratio Measured Nondestructively Correlates with Peel Pigment Content and Canopy Attachment Position of ‘Granny Smith’ Apples - Manoella Mendoza
Early Spectral Differences on Scald Disorders in ‘Granny Smith’ Apples - Rene Mongollon
Apple Ripening After DCA Storage: Assessing The Risk Of Flavor Loss - Randolph Beaudry
The Impact Of Hot Water Treatment On Organic Apple Quality With Different Storage Systems - Sadat Amankona
Fungicides and Scald Inhibitor Diphenylamine Shift Microbiomes of ‘Fuji’ Apples Through Short Term Cold and Room Temperature Storage - Connor Lane
Pyrus communis: A Model for Studying Climacteric Ripening and Senescence - Amit Dhingra
Characterization of Postharvest Rots and the Susceptibility to Decay of 38 European Pear Genotypes during Cold Storage. - Tamara Collum

Moderator

Manoella Mendoza

WA State University

Thursday September 26, 2024 7:59am - 10:15am HST
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Oral Sessions, Postharvest 3

SUBJECT Postharvest

8:00am HST

PH 3 - Assessing Apple Cultivar Responses to Low Oxygen Limit Determination Using Chlorophyll Fluorescence and Respiratory Quotient

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

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

Speakers

Hnin Phyu Lwin

Washington State University

Co-authors

Carolina Torres

Washington State University

David Rudell

USDA-ARS

Sadat Amankona

Washington State University-TFREC

I am a second-year Ph.D student at Washington State University-TFREC

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

8:15am HST

PH 3 - Understanding how physiological maturity and storage regime affect skin greasiness on WA 38 apples

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

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

Speakers

Carolina Torres

Washington State University

Co-authors

David Rudell

USDA-ARS

Oswaldo Gonzalez

Washington State University

Rene Mogollon

Washington State University

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

8:30am HST

PH 3 - Chlorophyll to Carotenoid Ratio Measured Nondestructively Correlates with Peel Pigment Content and Canopy Attachment Position of ‘Granny Smith’ Apples

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

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

Speakers

Manoella Mendoza

WA State University

Co-authors

Carolina Torres

Washington State University

David Rudell

USDA - ARS

Lee Kalcsits

Washington State University

Rene Mogollon

Washington State University

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

8:45am HST

PH 3 - Early Spectral Differences on Scald Disorders in ‘Granny Smith’ Apples

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

Nautilus 1

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

Speakers

Rene Mogollon

Washington State University

Co-authors

Carolina Torres

Washington State University

David Rudell

USDA-RS

Manoella Mendoza

WA State University

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

9:00am HST

PH 3 - Apple Ripening After DCA Storage: Assessing The Risk Of Flavor Loss

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

Nautilus 1

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

Speakers

Randolph Beaudry

Michigan State University

Co-authors

Jiarui Xu

Michigan State University

Nobuko Sugimoto

Michigan State University

Ozge Horzum

Ankara University

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

9:15am HST

PH 3 - The Impact Of Hot Water Treatment On Organic Apple Quality With Different Storage Systems

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

Nautilus 1

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

Speakers

Sadat Amankona

Washington State University-TFREC

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

Co-authors

Carolina Torres

Washington State University

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

9:30am HST

PH 3 - Fungicides and Scald Inhibitor Diphenylamine Shift Microbiomes of ‘Fuji’ Apples Through Short Term Cold and Room Temperature Storage

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

Nautilus 1

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

Speakers

Connor Lane

Cornell University

Co-authors

Chris Watkins

Cornell University

Jenny Kao Kniffin

Cornell University

Yosef Al Shoffe

Cornell Univeristy

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

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

9:45am HST

PH 3 - Pyrus communis: A Model for Studying Climacteric Ripening and Senescence

Thursday September 26, 2024 9:45am - 10:00am HST

Nautilus 1

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

Speakers

Amit Dhingra

Head of the Department of Horticultural Sciences, Texas A&M University

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

Co-authors

Evan C. Stowe

Washington State University

Seanna L. Hewitt

Washington State University

Thursday September 26, 2024 9:45am - 10:00am HST
Nautilus 1

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

10:00am HST

PH 3 - Characterization of Postharvest Rots and the Susceptibility to Decay of 38 European Pear Genotypes during Cold Storage.

Thursday September 26, 2024 10:00am - 10:15am HST

Nautilus 1

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

Speakers

Tamara Collum

USDA ARS

Co-authors

Breyn Evans

USDA ARS

Caitlin Barnes

USDA ARS Appalachian Fruit Research Station

Christopher Gottschalk

USDA ARS

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

John Bennett

USDA ARS

Thursday September 26, 2024 10:00am - 10:15am HST
Nautilus 1

Oral presentation (Individual talk), Postharvest 3

SUBJECT Postharvest

10:29am HST

Plant Biotechnology 3 (PB 3)

Thursday September 26, 2024 10:29am - 11:45am HST

Nautilus 1

Leaf Culture and Regeneration in Two Cultivated Strawberries (Fragaria x ananassa) - Kedong Da
Leaf Culture and Regeneration in Hydrangea Macrophylla - Kedong Da
Immature Embryo Germination of Camellia sinensis (L) O. Kuntze. - Sarita Paudel
Development of an In Vitro Transformation System for Gene Editing Powdery Mildew Resistance in Gerbera jamesonni - Heather Gladfelter
Declining Phosphorus Availability Increases Sucrose Synthase Activity and Storage Root Formation in Sweetpotato cv Beauregard Adventitious Roots - Marissa Barbosa

Moderator

Heather Gladfelter

University of Georgia

Thursday September 26, 2024 10:29am - 11:45am HST
Nautilus 1

Oral Sessions, Plant Biotechnology 3

SUBJECT Plant Biotechnology

10:30am HST

PB 3 - Leaf Culture and Regeneration in Two Cultivated Strawberries (Fragaria x ananassa)

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

Nautilus 1

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

Speakers

Kedong Da

North Carolina State University

Director of plant transformation lab at North Carolina State University

Co-authors

Anna Nelson

NC State University

Calyssa Stevenson

North Carolina State University

Ezra Kinsch

North Carolina State University,

Gina Fernandez

NC State University

Huani Leng

North Carolina State University

Keren Molina Morale

NC State University

Sydney McLennan

North Carolina State University

Tianbao Yang

USDA-ARS

Wusheng Liu

North Carolina State University

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

Oral presentation (Individual talk), Plant Biotechnology 3

SUBJECT Plant Biotechnology

10:45am HST

PB 3 - Leaf Culture and Regeneration in Hydrangea Macrophylla

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

Nautilus 1

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

Speakers

Kedong Da

North Carolina State University

Director of plant transformation lab at North Carolina State University

Co-authors

Anna Nelson

NC State University

Callie Nix

North Carolina State University

Huani Leng

North Carolina State University

John Nix

NC State University

Keren Morales

NC State University

Sydney McLennan

North Carolina State University

Thomas Ranny

North Carolina State University

Wusheng Liu

North Carolina State University

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

Oral presentation (Individual talk), Plant Biotechnology 3

SUBJECT Plant Biotechnology

11:00am HST

PB 3 - Immature Embryo Germination of Camellia sinensis (L) O. Kuntze.

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

Nautilus 1

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

Speakers

Sarita Paudel

University of Georgia

Co-authors

Donglin Zhang

University of Georgia

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

Oral presentation (Individual talk), Plant Biotechnology 3

SUBJECT Plant Biotechnology

11:15am HST

PB 3 - Development of an In Vitro Transformation System for Gene Editing Powdery Mildew Resistance in Gerbera jamesonni

Thursday September 26, 2024 11:15am - 11:30am HST

Nautilus 1

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

Speakers

Heather Gladfelter

University of Georgia

Co-authors

Dayton Wilde

University of Georgia

Khuram Tanveer

University of Georgia

Thursday September 26, 2024 11:15am - 11:30am HST
Nautilus 1

Oral presentation (Individual talk), Plant Biotechnology 3

SUBJECT Plant Biotechnology

11:30am HST

PB 3 - Declining Phosphorus Availability Increases Sucrose Synthase Activity and Storage Root Formation in Sweetpotato cv Beauregard Adventitious Roots

Thursday September 26, 2024 11:30am - 11:45am HST

Nautilus 1

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

Speakers

Marissa Barbosa

Lousiana State University

Co-authors

Arthur Villordon

LSU Agcenter

Cole Gregorie

LSU AgCenter Sweetpotato Research Center

Don La Bonte

Louisiana State Univ

Lisa Arce

Louisiana State University

Mae Ann Bravo

Louisiana State University

Thursday September 26, 2024 11:30am - 11:45am HST
Nautilus 1

Oral presentation (Individual talk), Plant Biotechnology 3

SUBJECT Plant Biotechnology

12:14pm HST

Genetics and Germplasm 2 (GG 2)

Thursday September 26, 2024 12:14pm - 1:25pm HST

Nautilus 1

Exploration of Salt-Tolerant Germplasm to Increase Specialty Rice Production in South Carolina - Gursewak Singh
Independent Domestication of Cucumber (Cucumis sativus L.) Fruit Revealed by Cucurbitacin and Volatile Compound Profiling - Eun Jin Lee
Evaluation of watermelon and Citrullus crop wild relatives for resistance to whiteflies and whitefly transmitted viruses - Alexander Luckew
Development of Specialty Pumpkin Cultivars with Potential to be Released for Organic and Conventional Resilient Cropping - Angela Linares Ramirez
SSR Marker Development and Fine Mapping of Linkage Group 2 Eastern Filbert Blight Resistance from ‘Georgian OSU 759.010’ - Brianna Heilsnis
Enhancing the Fruit Set of NJ BP1-1 Beach Plum (Prunus maritima) - Megan Muehlbauer
The wonderful world of worms: Microbiota of rabbit manure vermicompost at different maturities - Amanda Birnbaum

Moderator

Gursewak Singh

Clemson University

Thursday September 26, 2024 12:14pm - 1:25pm HST
Nautilus 1

Poster Session, Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

12:15pm HST

GG 2 - Exploration of Salt-Tolerant Germplasm to Increase Specialty Rice Production in South Carolina

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

Nautilus 1

The significance of Carolina Gold specialty rice in South Carolina's (SC) agricultural history is deeply rooted, dating back to colonial times. Its unique flavor and texture have made it a prized variety among chefs and food enthusiasts. Currently, saltwater intrusion and weed infestation threaten this specialty rice production in SC. Understanding salt tolerance and weed interactions is crucial for ensuring the continued production and quality of this specialty rice. Preliminary experiments assessed the impact of different concentrations of ocean water and native weed pressure on rice plant vigor when cultivated organically under controlled environmental conditions. In brief, we screened rice germplasm under various seawater concentrations (0, 0.375, 0.75, 1.5%, and 3%) in both weed-free and weed competition conditions. In our preliminary greenhouse studies, we observed weed competition reduced the rice plant biomass by 2-3 times and yield up to 5 times at a 3% seawater concentration. M202 and Doble Carolina exhibited the highest salt tolerance and higher photosynthesis rate when compared to local genotypes, Carolina Gold and Santee Gold. The cultivars demonstrating superior performance under these conditions were subsequently subjected to further testing in organic research plots, incorporating supplemental irrigation with tidal ocean water. A field experiment was designed to evaluate and validate the salinity tolerance of six rice genotypes (Carolina Gold, Santee Gold, Doble Carolina, M202, Jupiter, and JN100) under different seawater concentrations (0%, 1.5%, 3%, 6%, and 12%), both in weed-free and weed-competition scenarios. Using a gasoline pump, we collect brackish water from the adjacent marsh in a 4000-gallon-capacity reservoir/pool. The calculated volumes are then pumped into the field plots based on each plot's fresh and seawater volumes. The salinity level of treated plots is monitored by measuring the EC values. The results indicated that M202, Doble Carolina and JN100 showed the highest salt tolerance. Weed competition reduced the rice plant height, number of tillers, panicles, dry root, and shoot weight across the entire salinity gradient. Weed competition led to an approximately 50% reduction in both the aboveground (shoot) and belowground (root) weights of rice plants, as compared to weed-free plots, across the tested salinity levels. Weed biomass, weeding time and regrowth of weeds declined significantly above 3 % seawater concentration when compared to control. Eventually, the most promising cultivars identified are being incorporated into a breeding program to integrate salt-tolerant genes into the Carolina Gold specialty rice.

Speakers

Gursewak Singh

Clemson University

Co-authors

Brian Ward

Clemson University

Jai Rohila

USDA-ARS

Matthew Cutulle

Clemson

Michael Marshall

Clemson University

Raghupathy Karthikeyan

Clemson University

Sarah White

Clemson University

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

12:25pm HST

GG 2 - Independent Domestication of Cucumber (Cucumis sativus L.) Fruit Revealed by Cucurbitacin and Volatile Compound Profiling

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

Nautilus 1

Cucumber (Cucumis sativus L.) fruit has characteristic taste and aroma, the important organoleptic qualities influencing consumer preference and marketability. Profiling of metabolites conferring bitterness and aroma is required to improve cucumber fruit quality and produce preferred fruit. In this study, we profiled cucurbitacins responsible for bitterness and volatile compounds using fruit of 69 cucumber genotypes with different fruit shape, color, and origin and provided qualitative and quantitative information of metabolites involved in the organoleptic quality. Among six types of cucurbitacis (CuA-E, I), only CuC was detected in six inbreds while most genotypes didn’t contain them. It means bitterness has been lost in modern cucumber cultivars with domestication process. The 69 genotypes were classified into four clusters according to the profiles of cucurbitacins and volatile compounds. Clusters 2 and 3 accumulated the highest and lowest volatile contents, respectively. Clusters 1 and 4 were discriminated by minor volatiles rather than major ones, suggesting they have distinct background flavor. Clusters 1 and 4 also showed different phenotypes such as length and color, implying a relationship between fruit phenotype and background flavor. However, the clustering was inconsistent with cultivar types or origins. It suggests independent domestication for bitterness and flavor has been conducted for cultivars in different origins. We further examined hybridization effect on metabolite compositions using 15 F1 hybrids from selected inbreds. Total volatile compound (TVC) content was reduced in the F1 hybrids, especially due to decrease in total alcohol content affecting increase in ratio of aldehyde to TVC. These findings will contribute to improvements of cucumber organoleptic qualities and will provide useful information for selecting cucumber materials to produce preferred fruit.

Speakers

Eun Jin Lee

Seoul National University

Co-authors

Jeongyun Kim

Dankook University

Kyeonglim Min

Seoul National University

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

12:35pm HST

GG 2 - Evaluation of watermelon and Citrullus crop wild relatives for resistance to whiteflies and whitefly transmitted viruses

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

Nautilus 1

In the Southeastern U.S., cucurbit production is vulnerable to the sweetpotato whitefly Bemisia tabaci and the viruses it transmits. There are limited control methods for the whitefly pest, including mulches, row covers, and spray programs. Unfortunately, none of these practices reduce the whitefly populations to zero, leaving whiteflies behind to transmit viruses. Therefore, host resistance is the best management practice, and the identification of resistant genotypes to whitefly transmitted viruses is a top priority. To aid watermelon breeding for resistance, 21 Citrullus genotypes were evaluated over two field seasons in Tifton, GA in 2022 and 2023. The traits evaluated were viral disease severity (AUDPC), Cucurbit leaf crumple virus (CuLCrV), Cucurbit yellow stunting disorder virus (CYSDV), and Cucurbit chlorotic yellows virus (CCYV) viral loads and in 2022 only, whitefly counts were collected to evaluate whitefly preference. Leaf tissue was collected 5 weeks after transplanting (WAT) in 2022 and 7 WAT in 2023. Total nucleic acids were extracted, and qPCR was performed to determine viral loads. Grif 16444 was the only genotype that had lower adult whitefly counts, indicating non-preference of this genotype. Over the two years there were three consistent genotypes with the statistically lowest AUDPC, two C. mucosospermus (PI 595203 and PI 494528) and one C. ecirrhosus (Grif 16444). In 2022, these three genotypes had significantly lower CuLCrV viral loads than the cultivar checks, however, in 2023 due to low CuLCrV presence there were no significant differences. For CYSDV and CCYV, there were no genotypes with significantly lower viral loads than the cultivar checks in both years. These wild crop relatives provide sources of resistance that can be used by breeders to improve cultivated watermelon.

Speakers

Alexander Luckew

University of Georgia

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

12:45pm HST

GG 2 - Development of Specialty Pumpkin Cultivars with Potential to be Released for Organic and Conventional Resilient Cropping

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

Nautilus 1

Specialty pumpkins, such as the tropical pumpkin or “calabaza” (Cucurbita moschata Duchesne), are widely grown and consumed in Puerto Rico, ranking second among the most important vegetables on the island. This crop is also increasingly becoming a lucrative emerging market in the United States, particularly in communities with a high density of households of Latino/Hispanic and Caribbean heritage. Yield, fruit quality, and disease resistance of 21 genotypes were evaluated under conventional and certified organic management conditions in Puerto Rico at the University of Puerto Rico Lajas Research Station from January to May 2022, and from November 2022 to March 2023. The genotypes were evaluated using a randomized complete block design with three replications. The number of marketable fruits, total fruits per plot, yield (kg ha-1), and incidence of whiteflies, among other variables, were recorded. Overall, the number of fruits per plot and marketable fruits ranged from 2 and 12, while the yield reached 9,229 kg ha-1 to 65,707 kg ha-1. Under organic certified management, the highest yield was obtained by UFTP42 with 46,567 kg ha-1, while UFTP4 obtained the lowest yield with 5,110 kg ha-1. Under conventional conditions, the UFTP34, UFTP80, and ‘Soler’ lines obtained the highest performance, with 66,677; 63,974, and 75,971 kg ha-1, respectively. On the other hand, the genotypes UFTP4, UFTP10, UFTP22, and UFTP46 obtained lower yields with 9,229; 10,881; 17,635, and 15,408 kg ha-1, respectively. Verde Luz, showed the lowest incidence of whiteflies (< 10%), under both management conditions, while the remaining genotypes showed no significantdifferences between them. In summary, UFTP34, UFTP44, UFTP45, and UFTP80 could be released as prospective cultivars for the southern area of Puerto Rico and could be used as parents for breeding purposes under organic and conventional cropping systems.

Speakers

Angela Linares Ramirez

University of Puerto Rico

Co-authors

Geoffrey Meru

University of Florida

Jorge Ruiz Menjivar

University of Florida

Miguel Garcia Carrucini

University of Puerto Rico - SEA

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

12:55pm HST

GG 2 - SSR Marker Development and Fine Mapping of Linkage Group 2 Eastern Filbert Blight Resistance from ‘Georgian OSU 759.010’

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

Nautilus 1

Anisogramma anomala, causal agent of Eastern Filbert Blight (EFB), is endemic to eastern North America and was accidentally introduced to the Pacific Northwest hazelnut (Corylus avellana) growing regions around 1960. A single gene conferring resistance was identified in the pollinizer ‘Gasaway’ by the OSU Hazelnut Breeding Program, and deployed across the Willamette Valley in the majority of cultivars released since 2008. In preparation for a mutation or second accidental new introduction, research has focused on discovering, mapping, and developing useful molecular markers for new sources of resistance. In October 2023, a new isolate of A. anomala was detected in a grower’s orchard in Woodburn, OR, growing on the previously resistant ‘Jefferson’. The results of this study focus on linkage group 2 resistance (LG2), conveyed by ‘Georgian OSU 759.010’. Using two populations from a cross between ‘OSU 1477.047’ with Georgian resistance and ‘Sacajawea’ with quantitative resistance, n=272 recombinant offspring were identified using existing SSR markers. Marker development resulted in 40 new SSR markers covering an 8.5Mbp region, and a linkage map of the resistance region was constructed. Characterization of the 40 new SSR markers is in progress.

Speakers

Brianna Heilsnis

Oregon State University

Co-authors

Jacob Snelling

Oregon State University

Shawn Mehlenbacher

Oregon State University

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

1:05pm HST

GG 2 - Enhancing the Fruit Set of NJ BP1-1 Beach Plum (Prunus maritima)

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

Nautilus 1

Wild plum, Prunus maritima, has a native habitat that ranges from coastal Virginia to Nova Scotia and is well known to be associated with beach communities with sandy soils. Recent trials by Rutgers, New Jersey Agricultural Experiment Station suggests beach plum has the potential to be grown throughout the state where higher clay content, fertile soils contribute to increased vegetative growth leading to a dense bush habit. Crop potential is abundant due to high natural bloom density. However fruit set has been challenging under traditional commercial growing systems, partly due to self-incompatibility. BP1-1 Jersey Jems cultivar was bred and selected by the Rutgers University Plant Breeding program for its high yield, large size and superior flavor in costal locations where there are diverse beach plum pollen clouds. In order to establish clonal orchards of this cultivar, a pollen parent must be identified. In this study, a total of 7 controlled test crosses were made in triplicate on BP 1-1. Fruit yields were collected from BP1-1 and top yielding crosses were noted. The purpose of this study is to find compatible pollen parents, ensuring quality and uniform yield to base future pollen parent recommendations in New Jersey commercial tree fruit orchards.

Speakers

Megan Muehlbauer

Rutgers University

Co-authors

Peter Nitzsche

Rutgers NJAES Cooperative Extension

Rebecca Magorn

Rutgers Cooperative Extension

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

1:15pm HST

GG 2 - The wonderful world of worms: Microbiota of rabbit manure vermicompost at different maturities

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

Nautilus 1

Vermicompost, derived from the processing of organic waste by earthworms, is a beneficial soil amendment known to improve plant and soil health due to the presence of beneficial microorganisms. Vermicompost microbiome can vary radically depending on the starting substrate, environmental conditions, and earthworm species, making it important to characterize the microbial community over time under a variety of vermicomposting conditions. To characterize the microbial community of vermicompost produced from rabbit manure, four samples were collected from vermicomposting bins (Avery Islands, LA) for Nanopore long-read sequencing: one unprocessed manure samples, and samples which had been composting for 1-, 6-, and 12-months. About 135Gb of sequence data with a median quality of Q19 was produced. Relative taxonomic abundance of the microbial community was assessed using Kraken2 and Braken. Manure samples differed in microbiome composition, but were both much less diverse than vermicomposted samples, which had much greater bacterial diversity and were rich in nitrogen-fixing bacteria such as Mesorhizobium and Bradyrhizobium. 1-month old vermicompost more closely resembled 12-month old vermicompost than unprocessed manure, suggesting that a majority of the benefits of vermicomposting are realized within a relatively short period of time.

Speakers

June Labbancz

Texas A

Co-authors

Amanda Birnbaum

Texas A&M

Amit Dhingra

Texas A

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

Poster presentation (individual talk), Genetics and Germplasm 2

SUBJECT Genetics and Germplasm

1:44pm HST

Viticulture and Small Fruits 4 (VSF 4)

Thursday September 26, 2024 1:44pm - 2:45pm HST

Nautilus 1

First They’re Sweet, Then They’re Sour: The Impact of Cultivar, Berry Maturity, and Phytohormones on Blueberry Quality Uniformity - Michael Gasdick
Phytohormone and Plant Growth Regulator Use in Blueberry Production – A Review - Daniel Dick
Postharvest Quality of ‘Calypso’ Blueberry After Hand and Machine Harvest - Wei Yang
Preliminary Findings from the Evaluation of New Cranberry Cultivars in Massachusetts - Giverson Mupambi

Moderator

Wei Yang

North Willamette Res

Thursday September 26, 2024 1:44pm - 2:45pm HST
Nautilus 1

Oral Sessions, Viticulture and Small Fruits 4

SUBJECT Viticulture

1:45pm HST

VSF 4 - First They’re Sweet, Then They’re Sour: The Impact of Cultivar, Berry Maturity, and Phytohormones on Blueberry Quality U

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

Nautilus 1

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

Speakers

Michael Gasdick

Michigan State University

Co-authors

Daniel Dick

Michigan State University

Josh VanderWeide

Michigan State University

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

Oral presentation (Individual talk), Viticulture and Small Fruits 4

SUBJECT Viticulture

2:00pm HST

VSF 4 - Phytohormone and Plant Growth Regulator Use in Blueberry Production – A Review

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

Nautilus 1

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

Speakers

Daniel Dick

Michigan State University

Co-authors

Josh VanderWeide

Michigan State University

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

Oral presentation (Individual talk), Viticulture and Small Fruits 4

SUBJECT Viticulture

2:15pm HST

VSF 4 - Postharvest Quality of ‘Calypso’ Blueberry After Hand and Machine Harvest

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

Nautilus 1

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

Speakers

Wei Yang

North Willamette Res

Co-authors

Sarah Doane

North Willamette Res

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

Oral presentation (Individual talk), Viticulture and Small Fruits 4

SUBJECT Viticulture

2:30pm HST

VSF 4 - Preliminary Findings from the Evaluation of New Cranberry Cultivars in Massachusetts

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

Nautilus 1

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

Speakers

Giverson Mupambi

University of Massachusetts Amherst

Co-authors

Hilary Sandler

University of Massachusetts Amherst

Leela Uppala

University of Massachusetts Amherst

Peter Jeranyama

University of Massachusetts Amherst

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

Oral presentation (Individual talk), Viticulture and Small Fruits 4

SUBJECT Viticulture

2:59pm HST

Propagation (PROP)

Thursday September 26, 2024 2:59pm - 3:40pm HST

Nautilus 1

K-IBA Promotes Adventitious Rooting of Bog Birch Stem Cuttings - Jessica Hutchinson
Propagating Pomegranate Through Hardwood and Softwood Cuttings - PRAKRITI NEPAL
Identifying Patterns of Clone Degeneration to Improve Diagnostics - Thomas Gradziel
Evaluating Leaf Cutting Success for Achimenes Propagation - Chad Miller

Moderator

Chad T. Miller

Assistant Professor; Department of Horticulture and Landscape, Colorado State University

Thursday September 26, 2024 2:59pm - 3:40pm HST
Nautilus 1

Poster Session, Propagation

SUBJECT Propagation

3:00pm HST

PROP - K-IBA Promotes Adventitious Rooting of Bog Birch Stem Cuttings

Thursday September 26, 2024 3:00pm - 3:10pm HST

Nautilus 1

Native ornamental plants, which are growing in demand in the U.S. horticulture industry, may promote biodiversity and wildlife habitat, and improve landscape resilience. To succeed in the horticulture industry, novel introductions must be aesthetically pleasing and amenable to commercial propagation and production. Bog birch (Betula pumila) is a shrub native to the United States with pubescent, ovate leaves with rounded margins that have tones of red, orange, and burgundy in autumn. In addition, young pubescent stems are brown to reddish-brown and become deep in color with a glossy finish at maturity. These qualities would make bog birch attractive within managed landscapes. We investigated the effects of auxin concentration and wounding during propagation of bog birch by softwood stem cuttings under intermittent mist. Cuttings collected in late July in northern Maine and treated with the potassium salt of indole-3-butyric acid (K-IBA) in solutions of 1,000 to 5,000 mg⋅L-1 produced greater root counts and root ratings, and longer root lengths, than cuttings treated with water alone. Cambial wounding increased root counts modestly, but was unnecessary to produce quality clones. Nearly 75% of all cuttings produced roots rated 3 or higher, the threshold at which they are transplantable. Only low concentrations of K-IBA are needed to produce root systems that meet this threshold, as transplantability increased from 55% in cuttings treated with water to 73% when 1000 mg⋅L-1 K-IBA was applied. During one season in

Speakers

Jessica Hutchinson

University of Maine

Co-authors

Bryan Peterson

University of Maine

Thursday September 26, 2024 3:00pm - 3:10pm HST
Nautilus 1

Poster presentation (individual talk), Propagation

SUBJECT Propagation

3:10pm HST

PROP - Propagating Pomegranate Through Hardwood and Softwood Cuttings

Thursday September 26, 2024 3:10pm - 3:20pm HST

Nautilus 1

Pomegranate (Punica granatum) is a fruit-bearing deciduous shrub or small tree known for its nutritious and medicinal value. Its global demand is high due to rich antioxidant content, health benefits, and culinary versatility. However, the expansion of pomegranate cultivation face challenges due to the need for efficient propagation techniques that can produce high-quality plant material to meet commercial and agricultural demands. The propagation of pomegranate using cuttings is considered an easy and cost-effective method. Hardwood and softwood cuttings were treated with 3000 mg/ L indole-3-butyric acid (Hormodin® 2) and stuck in a rooting medium consisting of perlite and peat moss (4:1, v:v). Hardwood cuttings of 21 pomegranate cultivars, including ‘Al-Sirin-Nar’, ‘Angel Red’, ‘Apseronski’, ‘Arturo Ivey’, ‘Ben Ivey’, ‘Carolina Vernum’, ‘Chiva’, ‘DeAnda’, ‘Early Wonderful’, ‘Kandahar’, ‘Kazake’, ‘Kunduzski’, ‘Larry Ceballos І’, ‘ML’, ‘Mollar’, ‘Purple Heart’, ‘Russian 8’, ‘Salavatski’, ‘Spanish Sweet’, ‘Surh-Anor’ and ‘Wonderful’ were propagated in 2014, 2016, 2018, and 2023. In addition, softwood cuttings of 23 cultivars, which included ‘Al-Sirin-Nar’, ‘Ambrosia’, ‘Apseronski’, ‘Ariana’, ‘Azadi’, ‘Cranberry’, ‘Desertnyi’, ‘Eversweet’, ‘Golden Globe’, ‘Green Globe’, ‘Haku Batan’, ‘Loffani’, ‘Medovji Vahsha’, ‘Molla Nepes’, ‘Palermo’, ‘Parfianka’, ‘Phoenicia’, ‘Purple Heart’, ‘Salavatski’, ‘Sirenevyi’, ‘Surh-Anor’, ‘Vkusnyi’, and ‘Wonderful’ were propagated in 2022. The rooting percentage of hardwood cuttings was higher in ‘AL-Sirin-Nar’, ‘Salavatski’ and ‘Surh-Anor’, whereas ‘DeAnda’ and ‘Early Wonderful’ showed lower rates compared with other cultivars based on cluster analysis. For softwood cuttings, the rooting percentage did not display significant differences across cultivars, however, the number of roots were significantly higher in ‘Cranberry’, ‘Eversweet’, ‘Surh-Anor’ and ‘Wonderful’ compared with ‘Ambrosia’ and ‘Golden Globe’. Further research is needed to identify the most effective propagation technique for pomegranate production.

Speakers

PRAKRITI NEPAL

Utah State Univeristy

Co-authors

Asmita Paudel

Utah State University

Benjamin Scow

Utah State University

Youping Sun

Utah State Univeristy

Zirui Wang

Utah State University

Thursday September 26, 2024 3:10pm - 3:20pm HST
Nautilus 1

Poster presentation (individual talk), Propagation

SUBJECT Propagation

3:20pm HST

PROP - Identifying Patterns of Clone Degeneration to Improve Diagnostics.

Thursday September 26, 2024 3:20pm - 3:30pm HST

Nautilus 1

Plant clones, because they are the product of asexual reproduction, are populations of genetically identical individuals and are important in agriculture, horticulture, and ecology. Although clones can be maintained for hundreds to thousands of years through repeated cycles of vegetative reproduction, degeneration of plant fitness and/or productivity often occurs with increasing age and/or cycles of propagation. While powerful diagnostics allow increasingly accurate identification of the underlying causes for biotic (diseases, pest, etc., and abiotic (nutrient deficiency, inadequate chill, etc.) breakdowns in normal growth and development, genetic/epigenetic failures remain poorly understood, often being generalized as ‘off-types’. A major impediment to the effective deployment of emerging tools for identifying causes of genetic/epigenetic failures is the uncertainty as to where the failure first occurred, which is necessary to identify the most appropriate tissues for testing. Characteristic patterns of clone degeneration can be used to distinguish among different types of failure as well as recommend appropriate methods and tissues for analysis. Clone degeneration from ‘General-aging’ is due to the accumulation of many small-affect deleterious factors making targeted genetic/epigenetic diagnosis difficult though tracking changes in selected methylation profiles could serve as indicators of ‘clone-age’ particularly when ‘slow-to-age’ epicormic meristems are available for reference. ‘Bud-sports’ results from genetic/epigenetic changes in mitotically active cells resulting in distinct sectoral chimeras in subsequent shoot growth and development that can be targeted for molecular and phenotypic analysis. In contrast, ‘epigenetic-imprinting’ seems to be induced at the tissue rather than single cell level making the determination of initial induction time and site difficult to determine. In addition, because most shoot structure in temperate perennials is largely preformed during the previous growing seasons, the time and location between the initial imprinting and its first phenotypic detection can be months to years. Examples, largely from tree crop production, will be presented showing that expression patterns within these major groups can further delineate the specific nature of clone degeneration including the identification of appropriate tissues for testing.

Speakers

Thomas Gradziel

University of California

Thursday September 26, 2024 3:20pm - 3:30pm HST
Nautilus 1

Poster presentation (individual talk), Propagation

SUBJECT Propagation

3:30pm HST

PROP - Evaluating Leaf Cutting Success for Achimenes Propagation

Thursday September 26, 2024 3:30pm - 3:40pm HST

Nautilus 1

The hot water plant (Achimenes hybrids) is a colorful gesneriad plant and can be
used as potted decorative plants indoors. These impatiens-like plants can also
be used outdoors in mixed containers and in hanging baskets. Increased
commercial production of Achimenes is limited for a couple of reasons.
Achimenes are typically propagated by rhizomes and rhizome production is
limited due to poorly understood plant responses to environmental conditions to
develop rhizomes and subsequent dormancy release. Moreover, rhizomes also
randomly develop on stolons and enlarged roots in growing media, making
harvesting challenging. One alternative method to asexually propagate
Achimenes would be from stem tip cuttings or leaf cuttings. This study
investigated three different Achimenes selections and the effects of bottom heat
and three different rooting hormone concentrations [0; 1,000; and 8,000 ppm
indole-3-butryic acid (IBA)] on root and shoot development on Achimenes leaf
petiole cuttings. Generally, leaf cuttings for all three selections developed more
shoots without bottom heat, although not always significant. All leaf cuttings, for
all selections propagated with and without bottom heat, developed roots and
shoots. The percent leaves developing adventitious shoots were lowest for
leaves treated with bottom heat for 0 and 8,000 ppm IBA in ‘A16’ at 80% and for
8,000 ppm IBA in ‘A23’ at 60%. Root ratings, based on a scale of 0 (no
adventitious roots) to 5 (significant number and length), were significantly higher
across all auxin levels for leaves grown without bottom heat in ‘A16’ and ‘A23’.
This study demonstrated that leaf petiole cuttings for Achimenes can be
successful and result in rooted cuttings producing adventitious shoots, which
could be potentially further propagated.

Speakers

Chad T. Miller

Assistant Professor; Department of Horticulture and Landscape, Colorado State University

Thursday September 26, 2024 3:30pm - 3:40pm HST
Nautilus 1

Poster presentation (individual talk), Propagation

SUBJECT Propagation

4:00pm HST

Interest Group Session: Sensing the Plant, for the Farmer's Benefit! A Historical Perspective Reflecting on the Work of Marc van Iersel

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

Nautilus 1

The recent loss of our colleague Marc van Iersel reminds us of the reasons our work in horticulture is so important. Marc's career was devoted to developing processes that judiciously utilized sensors to create efficient strategies to optimize crop quality and production for the grower. By examining the path of van Iersel’s work, we can understand how directed, mindful research can move quickly from the hands of the researcher to the farmer. Marc’s early work centered around developing smart irrigation systems utilizing biofeedback to measure soil moisture, with the goal of reducing water usage. More recently, Marc’s work integrated LED lighting with sensors including light sensors, moisture sensors, and low cost canopy and fluorescence detection to generate strategies for precise, energy efficient control of lighting in greenhouse and vertical growing platforms. Marc frequently consulted with growers to understand their needs and challenges, allowing the grower’s needs to frame his research. Marc also mentored the development of students, fellows, and colleagues in their own research, helping them discover how their programs could unfold in directions which would be most valuable. In this session we will examine the history of Marc’s research and continued work by colleagues, to ensure his lessons in how to provide practical answers for commercial horticulture are not lost. This two-hour session will include presentations from Marc's students and colleagues, and conclude with a 30-minute moderated Q&A/discussion.

Coordinator(s)

Jennifer Boldt, United States Department of Agriculture, Agricultural Research Service, Toledo, OH, United States
Neil Mattson, Cornell University, Ithaca, New York, United States
Melanie Yelton, Grow Big, United States

Bruce Bugbee, Utah State University, Plants, Soils, and Climate, Logan, Utah, United States
A Life Filled with People, Plants, Photons, and Perseverance (15 mins)
Stephanie Burnett, University of Maine, School of Food and Agriculture, Orono, Maine, United States
Impact on Sensor Automated Irrigation and Student Mentoring (15 mins)
Rhuanito Ferrarezi, University of Georgia, Horticulture, Athens, Georgia, United States
The Man Behind the Legend (15 mins)
Andrew Ogden, University of Georgia, Griffin, Georgia, United States
Shuyang Zhen, Texas A&M University, United States
The Light He Shined: Translating Plant Physiology into Smart Lighting Control Strategies (15 mins)
Leonardo Lombardini, University of Georgia, Horticulture, Athens, Georgia, United States
Honoring Marc's Legacy (15 mins)

Moderator

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Neil Mattson

Cornell University

Melanie Yelton

GrowBig Consulting

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

Speakers

Stephanie E. Burnett

University of Maine

Bruce Bugbee

Rhuanito Ferrarezi

Andrew Ogden

Shuyang Zhen

Leonardo Lombardini

ASHS International Division VP

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

Interest Group Session

SUBJECT Growth Chambers and CE

9:59am HST

Growth Chambers and Controlled Environments 7 (CE 7)

Friday September 27, 2024 9:59am - 11:45am HST

Nautilus 1

Foliar Nutrient Concentrations of Strawberry Mother and Daughter Plants Grown in Controlled Environments - Jennifer Boldt
Increasing Nutrient Solution Electrical Conductivity Increases Vegetative Growth of Strawberry - Erin Yafuso
Impact of Artificial Chilling on Yields of Indoor-Propagated Strawberry Plants in California, Florida, and North Carolina - Ibraheem Olamide Olasupo
The Nitrate to Ammonium Ratio Impacts Strawberry Runnering and Daughter Plant Number - Erin Yafuso
Effect of Monosilicic Acid on Growth and Physiology of Lettuce - Seunghyun Choi
Light Intensity and Zinc Biofortification Effect on Yield and Nutritional Quality of Pea and Radish Microgreens - Pradip Poudel
Evaluation of Liquid Organic Fertilizers for Containerized Production of Leafy Greens in a Controlled Environment - Uttara Samarakoon

Moderator

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Friday September 27, 2024 9:59am - 11:45am HST
Nautilus 1

Oral Sessions, Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:00am HST

CE 7 - Foliar Nutrient Concentrations of Strawberry Mother and Daughter Plants Grown in Controlled Environments

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

Nautilus 1

Few published studies provide foliar tissue nutrient concentrations for strawberry (Fragaria × ananassa) mother and daughter plants. Recommendations primarily focus on tissue concentrations for field-grown plants during fruit production. As controlled environment production of strawberry increases, a need exists to define tissue nutrient concentration ranges for healthy foliar tissue, for both vegetative and fruit production. Defining deficient, sufficient, and toxicity ranges will assist growers in selecting nutrient solution recipes and correcting nutritional issues that arise. The objective of this study was to identify nutrient concentration ranges for healthy strawberry mother and daughter plants grown in controlled environments. Foliar tissue samples were collected from two separate experiments: 1) ‘Albion’, ‘Fronteras’, and ‘Monterey’ grown in a peat-based substrate, and 2) ‘Monterey’ grown indoors in deep water culture. Plants received a modified strawberry nutrient solution (Yamazaki) that provided 100 mg·L-1 nitrogen (N). The percent total N provided as ammonium (NH4 ) ranged from 0% to 40% in both experiments. Plants did not exhibit any visual symptoms of foliar nutrient deficiencies or toxicities. Foliar tissue from mother (n=72) and daughter plants (n=144) were collected and analyzed individually. Nutrient concentration ranges comprised the middle 75% of plant samples (12.5% – 87.5% quantiles). Mother plant macronutrient concentrations ranged from 2.12%–2.64% nitrogen (N), 0.53%–1.23% phosphorus (P), 2.05%–3.88% potassium (K), 2.01%–3.36% calcium (Ca), 0.33%–0.56% magnesium (Mg), and 0.14%–0.28% sulfur (S). Daughter plant foliar macronutrient concentrations ranged from 2.18%–3.38% N, 0.49%–0.92% P, 2.20%–4.19% K, 1.01%–3.03% Ca, 0.31%–0.53% Mg, and 0.15%–0.30% S. Mother plant foliar micronutrient concentrations ranged from 158–233 mg·kg-1 boron (B), 1.5–5.6 mg·kg-1 copper (Cu), 57–587 mg·kg-1 iron (Fe), 131–384 mg·kg-1 manganese (Mn), and 11–29 mg·kg-1 zinc (Zn). Daughter plant foliar micronutrient concentrations ranged from 69–212 mg·kg-1 B, 1.2–4.5 mg·kg-1 Cu, 56–347 mg·kg-1 Fe, 78–315 mg·kg-1 Mn, and 18–36 mg·kg-1 Zn. In general, these macro- and micronutrient ranges overlap between mother and daughter plants. These values represent a first step in developing and refining foliar nutrient ranges for strawberry mother and daughter plants in controlled environments.

Speakers

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Co-authors

Erin Yafuso

United States Department of Agriculture

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:15am HST

CE 7 - Increasing Nutrient Solution Electrical Conductivity Increases Vegetative Growth of Strawberry

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

Nautilus 1

Established guidelines for electrical conductivity (EC) for strawberry (Fragaria ×ananassa) fruit production exist for plants grown in soilless substrates. However, EC recommendations for strawberry mother plants may differ when the goal is prolific runnering instead of flowering and fruiting. Our objective was to evaluate the impact of EC concentration strawberry runner and daughter number. Strawberry ‘Monterey’ were grown in a greenhouse in 19.1-cm diameter pots filled with a soilless substrate (50 perlite : 25 coco coir : 25 peat). To formulate the EC treatments, all components of a strawberry nutrient solution (Yamazaki) increased equally, which corresponded to nitrogen (N) concentrations of 50, 100, 150, 200, 300, and 400 mg·L-1 N. After adding 0.8 mM potassium bicarbonate as a buffer and adjusting pH to 5.7, the final nutrient solution EC values were 0.9, 1.6, 2.3, 2.8, 3.9, and 4.9 mS·cm-1. After 12 weeks of treatment, runner and daughter plant number, morphological assessments, and mother plant leaf burn index were evaluated. The qualitative assessment of leaf burn utilized a 1 to 5 scale (1 = no tip burn; 2 = mild, margins of ≥ 3 leaves; 3 = moderate, necrosis on at least half of ≥ 3 leaves; 4 = moderate to severe, complete necrosis on ≥ 3 leaves; and 5 = severe, complete necrosis on ≥ 4 leaves and necrosis of daughter plants). Leaf burn values ranged from 1.6 ± 0.2 (± SE) in the 50 mg·L-1 N treatment to 5.0 ± 0.0 in the 400 mg·L-1 N treatment. Runner number exhibited a quadratic response and ranged from 2 ± 0 at 50 mg·L-1 N to 7 ± 1 at 300 mg·L-1 N. Daughter plant number also exhibited a quadratic response. It increased from 14 ± 3 at 50 mg·L-1 N to 44 ± 4 at 200 mg·L-1 N, then declined to 30 ± 13 at 400 mg·L-1 N. Total plant biomass (mother plant, stolons, and daughter plants) exhibited a quadratic relationship. It increased from 23.5 ± 4.0 g at 50 mg·L-1 N to 65.9 ± 7.9 g at 200 mg·L-1 N, then declined to 40.0 ± 5.2 g at 400 mg·L-1 N. Overall, the optimal nutrient solution EC range for strawberry mother plants was 100 to 200 mg·L-1 N (or 1.6 to 2.8 mS·cm-1). In this range, mother plants produced a high number of runners and daughter plants, with minimal leaf burn due to high substrate EC values.

Speakers

Erin Yafuso

United States Department of Agriculture

Co-authors

Jennifer Boldt

United States Department of Agriculture

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:30am HST

CE 7 - Impact of Artificial Chilling on Yields of Indoor-Propagated Strawberry Plants in California, Florida, and North Carolina

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

Nautilus 1

Unavailability of pathogen-free strawberry propagules in commercial quantities necessitates the development of a novel completely indoor precision propagation technology for the crop, which also seeks to reduce dependence on soil fumigants including methyl bromide. Artificial chilling of plug plants could also enhance transplant vigor, flowering, and yield of strawberry. Under this novel technology, strawberry tips which consisted of five short day (SD) cultivars (Fronteras, Camarosa, Chandler, Sensation and Brilliance) and one long day (LD) cultivar (Monterey) were collected from tissue cultured mother plants. Plants were propagated under completely controlled environment (CE) conditions in a plant factory. Strawberry daughter plants were rooted in 50 cc trays filled with a commercial substrate and were arranged in the controlled environment under 90 – 100 % humidity, 27 °C temperature, 80 – 100 µmol m-2 s-1 light (LED), 18 hours photoperiod, and fertigated using the ebb and flow technique for 28 days. Our hypothesis was that artificial chilling will improve plant vigor and yield of CE-propagated strawberry transplants. We therefore assessed the impact of 350 – 450 hours of artificial chilling on the plant performance and yield of the transplants in four different locations in the US. Monterey, Brilliance, and Sensation cultivars received 350 hours of chilling while Fronteras, Chandler, and Camarosa cultivars were chilled for 450 hours. Strawberry plug plants (chilled and no-chill) were planted in replicated field trials in California, Florida, and North Carolina. Camarosa and Chandler cultivars were transplanted in North Carolina, Fronteras in Southern California, Monterey in Central California, while Brilliance and Sensation were transplanted in Florida. Preliminary results show improved vigor and yield from chilled plants in Florida and North Carolina field trials, while no differences were observed in California. Final results of the study will be shared during the conference.

Speakers

Ibraheem Olamide Olasupo

Postdoctoral Research Scholar, North Carolina State University

Co-authors

Calyssa Stevenson

North Carolina State University

Gerald Holmes

Cal Poly San Luis Obispo

Gina Fernandez

North Carolina State University

Mark Hoffmann

North Carolina State University

Oleg Daugovish

University of California Cooperative Extension

Ricardo Hernandez

North Carolina State University

Samantha Simard

Cal Poly- San Luis Obispo

Shinsuke Agehara

University of Florida

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

10:45am HST

CE 7 - The Nitrate to Ammonium Ratio Impacts Strawberry Runnering and Daughter Plant Number

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

Nautilus 1

The use of controlled environments to produce disease-free vegetative clones of strawberry (Fragaria ×ananassa) is increasing. However, protocols for mother plant management that optimize runner and daughter plant number need to be developed. Studies have shown that decreasing the fraction of nitrogen (N) supplied as nitrate (NO3-) can encourage vegetative growth in other crops. Our objective was to identify the %NO3--N that maximized runner and daughter plant number. Strawberry ‘Albion’, ‘Fronteras’, and ‘Monterey’ were grown in 19.1-cm pots filled with a peat-based substrate. Plants were irrigated with a modified strawberry nutrient solution (Yamazaki) that provided a total of 100 mg·L-1 N. The percent of total N supplied as NO3- ranged from 0% to 100%, with the remainder supplied as ammonium (NH4 ). Runners and daughter plants were harvested after eight and 16 weeks of treatment. The impact of %NO3- on cumulative runner number was cultivar specific. ‘Albion’ was not impacted, and the overall mean was 9 ± 1 (± SE).‘Fronteras’ exhibited a quadratic response. It increased from 10 ± 2 at 0% NO3- to 17 ± 2 at 60% NO3-; the calculated maximum runner number was with 64% NO3-. ‘Monterey’ exhibited a linear increase, from 14 ± 1 at 0% NO3- to 22 ± 1 at 100% NO3-. The impact of %NO3- on cumulative daughter plant number was also cultivar specific. ‘Abion’ exhibited a linear increase, from 28 ± 2 at 0% NO3- to 37 ± 10 at 100% NO3- . ‘Fronteras’ exhibited a quadratic response and increased from 19 ± 2 at 0% NO3- to 45 ± 7 at 60% NO3-. ‘Monterey’ also exhibited a quadratic response and increased from 49 ± 4 at 0% NO3- to 90 ± 7 at 80% NO3-. Calculated maximum daughter plant number occurred at 66% and 81% NO3- in ‘Fronteras’ and ‘Monterey’, respectively. Overall, at least 60% NO3- provided robust runner and daughter plant number, but the response depended on cultivar evaluated. ‘Monterey’ and ‘Albion’ appear to prefer a higher %NO3- than ‘Fronteras’ for maximum runner and daughter plant number.

Speakers

Erin Yafuso

United States Department of Agriculture

Co-authors

Jennifer Boldt

United States Department of Agriculture

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:00am HST

CE 7 - Effect of Monosilicic Acid on Growth and Physiology of Lettuce

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

Nautilus 1

Due to the high operation costs of indoor crop production, improving resource use efficiency to reduce costs has gained importance for sustainability in recent years. Silicon (Si) is not an essential plant nutrient since it is not a component of any structural or metabolic molecule, and plants do not suffer from Si deficiency. However, Si applications have shown beneficial effects on various crops, including improved growth, quality, stress tolerance, and water use efficiency (WUE). This study evaluated the effects of Si on indoor lettuce production to enhance lettuce growth and WUE. Two-week-old lettuce seedlings (Lactuca sativa cv. ‘Green Forest’ and ‘Rouxai’) were transplanted into 5-L deep water culture systems and grown for four weeks in a custom growth chamber with an average temperature/relative humidity of 22.4°C/58.8% and light intensity of 230 µmol/m²/s PPFD. The nutrient solution was weighed and replenished weekly. Si (DUNE™ stabilized monosilicic acid) was applied weekly to plants following two application methods (RA=root application and FS=foliar spray) and three concentrations (Control=0 ppm, C1=264 ppm, and C2=528 ppm). RA C1 significantly improved the shoot fresh weights (FW) and dry weights (DW) of both lettuce cultivars, while FS C1 was less effective than RA. Root growth showed the opposite trend, with FS C1 having the highest root FW and DW of both cultivars. However, root morphology showed cultivar-specific responses, with RA C1 producing the highest root length and surface area in ‘Green Forest’ and FS C1 the highest root surface area and volume in ‘Rouxai.’ WUE was significantly improved by RA C1, RA C2, and FS C2 in ‘Green Forest’ and RA C1 in ‘Rouxai’ compared to the control. Taken together, root application of Si at C1-264 ppm concentration most effectively improved the indoor lettuce growth and WUE.

Speakers

Seunghyun Choi

Postdoctoral research associate, Texas A&M Agrilife Research

Co-authors

Daniel Leskovar

Texas A

Joshua Harvey

Texas A

Vijay Joshi

Texas A

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:15am HST

CE 7 - Light Intensity and Zinc Biofortification Effect on Yield and Nutritional Quality of Pea and Radish Microgreens

Friday September 27, 2024 11:15am - 11:30am HST

Nautilus 1

Zinc (Zn) is a micronutrient crucial for human health, impacting gene expression, cell division, and immune system development. Zinc deficiency affects about 17% of the global population, particularly children, pregnant women, and elderly people, and can lead to disorders and even death. Agronomic biofortification implemented by applying Zn-enriched solutions via fertigation to increase crops Zn content may be a valuable strategy to combat Zn deficiencies. Microgreens, known for their nutrient density, rapid growth cycle, and low phytic acid content, are emerging as promising candidates for Zn agronomic biofortification. However, research is needed to evaluate the effect of factors like light intensity and genotype which can affect Zn accumulation in microgreens. To this purpose, a study was conducted to examine the effect of Zn application rate (0, 5, 10, and 15 mg/L) and light intensity (100, 200, 300, and 400 µmol/m2/s) on yield components, mineral content, and phytochemical profile of pea and radish microgreens. The study revealed that Zn concentration increased with increasing concentration of Zn applied in both species. In peas, a 4-fold increase was observed when applying 15 mg/L of Zn without affecting fresh and dry biomass, while an almost 13-fold increase of Zn content was observed in radish, associated with a 7.8% reduction of fresh biomass and no effects on radish microgreens dry biomass. However, with the increase of Zn content, there was a reduction in Fe concentration in both peas and radish microgreens. The light intensity did not affect Zn content in both species; however, it affected the concentration of macro and other microelements and influenced yield, but the result varied by species. In pea microgreens, low light intensity determined higher fresh biomass but did not affect dry biomass. Instead, the opposite result was observed in radish microgreens; light intensity did not affect fresh yield but increased dry biomass with increasing the level of light intensity applied. Regarding the nutritional profile, total phenols, total antioxidants, and flavonoids increased with increasing Zn concentration and light intensity in both pea and radish microgreens. In conclusion, Zn fertigation effectively enhanced Zn in pea and radish microgreens, and although light intensity had no effect on Zn content, contributed to improve their nutritional profile. These findings provide valuable insights into the production technique of Zn biofortified microgreens and the potential enhancement of their overall nutritional profile using agronomic biofortification techniques.

Speakers

Pradip Poudel

The Penn State University

Pradip

Co-authors

Francesco Di Gioia

The Penn State University

Friday September 27, 2024 11:15am - 11:30am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:30am HST

CE 7 - Evaluation of Liquid Organic Fertilizers for Containerized Production of Leafy Greens in a Controlled Environment

Friday September 27, 2024 11:30am - 11:45am HST

Nautilus 1

Organic farming practices, such as the use of organic substrates, fertilizers, pesticides, and biological control, are gaining popularity in controlled environment agriculture (CEA) since soilless production was approved for organic certification in the US. Our past study showed that liquid organic fertilizers are more effective than substrate-incorporated compost fertilizers. Although many liquid organic fertilizers are commercially available, they vary widely in their nutritional composition. Therefore, selection of a suitable fertilizer can be complicated and confusing for CEA growers. The current study aimed to evaluate the effectiveness of different liquid organic fertilizers and compare their performance with that of a synthetic fertilizer for growing lettuce in two different containerized hydroponic systems. Two greenhouse experiments were conducted in a randomized block design with five replicates. In Experiment 1, two types of container (regular container and Dutch bucket) and three fertilizers (earthworm castings and kelp (ECK), molasses with other natural plant extracts (MPE), and hydrolyzed fish protein (HFP)) were considered. The fertilizers were selected from the Organic Materials Review Institute (OMRI) list based on their nutrient profile and reports from other studies. In Experiment 2, selected liquid organic fertilizers (ECK, MPE) were compared with a commercial synthetic fertilizer (CSF). In Experiment 1, ECK performed better, resulting in 28% greater fresh weight, 20% greater dry weight, 48% greater leaf area, 26% greater shoot width, 126% greater average root fresh weight, and 47% greater root length in containerized production compared to the Dutch bucket system. No significant growth difference was observed between MPE and HFP. In Experiment 2, there was no significant growth difference between ECK and CSF; however, the shoot width, leaf area, and dry weight of lettuce were significantly lower with MPE treatments compared to ECK. Results show that ECK performed similarly or better than synthetic fertilizer for growing lettuce in these container hydroponic systems. The findings of this study indicate that a single organic fertilizer could be used instead of several for organic leafy green production in soilless substrate.

Speakers

Uttara Samarakoon

The Ohio State University

Co-authors

James Altland

USDA-ARS

Joanna Moine

The Ohio State University

Milon Chowdhury

The Ohio State University

Oliver Watson

The Ohio State University

Friday September 27, 2024 11:30am - 11:45am HST
Nautilus 1

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 7

SUBJECT Growth Chambers and CE

11:59am HST

Water Utilization and Management (WUM)

Friday September 27, 2024 11:59am - 12:30pm HST

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Evaluating Saline Irrigation Management Strategies Under Drip Irrigated Pistachio - Mukesh Mehata
Lysimetric Determination of Crop Water Requirements for Sorghum - Florence Cassel
Evaluating the distribution uniformity of spray-stakes using pressure compensating emitters - Chris Shogren

Moderator

Chris Shogren

UCCE Los Angeles

Friday September 27, 2024 11:59am - 12:30pm HST
Nautilus 1

Poster Session, Water Utilization and Management

SUBJECT Water Utilization and Management

12:00pm HST

WUM - Evaluating Saline Irrigation Management Strategies Under Drip Irrigated Pistachio

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

Nautilus 1

Over 85% of California's bearing pistachio acreage is located in soils with moderate (4 dS/m) to extremely high (16 dS/m) saline. Several previous studies have demonstrated that pistachios can be grown profitably even in moderately saline soils, with optimal soil salinity (ECe) maintained at approximately 4.5 - 6 dS/m. One common practice to reduce the salinity level in rootzone is to apply good quality water during dormant season. As the availability of good quality canal water for in-season irrigation and dormant season leaching declines, growers are relying more on semi-saline pumped groundwater, particularly in the San Joaquin Valley Westside. It would be beneficial to understand if the volume of dormant season leaching could be reduced, if in-season methods of leaching could be effective, and how to use moderately saline water most efficiently for both dormant and in-season leaching. Current methods for managing salinity through dormant leaching rely on one-dimensional models assuming complete surface wetting. We are exploring alternative approaches, investigating the effectiveness of single and double drip lines in managing root zone salinity using in-row, in-season leaching fractions and small volume pulsed dormant leaching. Preliminary results showed that generally, all leaching treatments, (in-season leaching, dormant leaching and the combination of both, applied with both single and double hose lines, significantly decreased soil ECe relative to the control, reducing ECe values of 13-22% relative to their respective controls. All the leaching treatments also effectively prevented boron from accumulating in the soil relative to the control. No clear effects of line configuration, double versus single line, were detected in soil levels. These findings indicate that treatments are effectively reducing salinity or at least preventing the increases observed in the control. Leaf analysis showed that in-season leaching, with/without dormant leaching, significantly increased leaf nitrogen and phosphorus, and reduced leaf boron accumulation.

Speakers

Mukesh Mehata

University of California, Davis

Co-authors

Blake Mccullough Sanden

University of California Davis

Clay Beck

Maricopa Orchard

Donald Williams III

CSU Fresno

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

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

Poster presentation (individual talk), Water Utilization and Management

SUBJECT Water Utilization and Management

12:10pm HST

WUM - Lysimetric Determination of Crop Water Requirements for Sorghum

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

Nautilus 1

Accurate estimation of crop water requirements (CWR) is essential to optimize water use efficiency and develop efficient irrigation scheduling practices. This is particularly important in California where frequent droughts have accentuated the need to conserve water and improve on-farm water management. The most accurate method to determine CWR is with precision weighing lysimeters, which measure actual crop evapotranspiration (ETa). Thus, the objectives of this study were to determine ETa data, develop new crop coefficients (Kc), and evaluate the relationship between Kc and crop fractional ground cover (Fc) for forage sorghum grown under drip irrigation. Being drought and salt tolerant, sorghum has been considered as an alternative crop to corn in regions of water scarcity and marginal soils. Daily ETa measurements were collected over three years on a clay loam soil using the precision weighing lysimeter available at the University of California Westside Research and Extension Center in Five Points, CA. Crop coefficient (Kc) estimates were derived from the ETa measurements and reference ETo data were obtained from a CIMIS weather station located at the study site. Weekly Fc measurements were also performed to derive relationships between Kc and fractional ground cover. Results from our study indicated that the seasonal ETc ranged from 665 to 870 mm, with average peak ET of 7.0 mm/day and midseason Kc spanning from 0.90 to 1.1. A strong correlation (r2 > 0.95) was also observed between crop Kc and Fc. This study represents the first experiment determining ETc and Kc for forage sorghum grown under drip irrigation in California. Findings also demonstrated the variability of CWR due to seasonal differences.

Speakers

Florence Cassel

California State University, Fresno

Co-authors

Dave Goorahoo

California State University, Fresno

Idalia Navarro

California State University, Fresno

Rafael Solorio

California State University, Fresno

Shawn Ashkan

California State University, Fresno

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

Poster presentation (individual talk), Water Utilization and Management

SUBJECT Water Utilization and Management

12:20pm HST

WUM - Evaluating the distribution uniformity of spray-stakes using pressure compensating emitters

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

Nautilus 1

Spray-stakes technology is common in nursery production systems, yet their distribution uniformity has been poorly studied. Recent innovations have the potential to increase distribution uniformity, but may be cost prohibitive. We analyzed the distribution uniformity of two brands of spray-stakes with and without pressure compensating emitters. We then conducted an economic analysis of switching from non-pressure compensating emitters to pressure compensating emitters. The average distribution uniformity measured was: 0.85 for non-pressure compensating Netafim Spray Stakes, 0.82 for the non-pressure compensating Primerus Spot Spitters, 0.95 for pressure compensating Netafim spray stakes, and 0.95 for pressure compensating Primerus Spot Spitters. While pressure compensating emitters do increase distribution uniformity, it would take 4-6 years based on water savings for the investment in pressure compensating emitters to break even, based on Southern California water prices.

Speakers

Chris Shogren

UCCE Los Angeles

Co-authors

Gerry Spinelli

University of California Cooperative Extension

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

Poster presentation (individual talk), Water Utilization and Management

SUBJECT Water Utilization and Management

12:44pm HST

Growth Chambers and Controlled Environments 8 (CE 8)

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

Nautilus 1

Greenhouse supplemental lighting of lettuce and tomatoes to a target light intensity and daily light integral using dimmable LEDs - Neil Mattson
Hybrid Model for Forecasting Lettuce Yield in Indoor Vertical Farming - MD SHAMIM AHAMED
Rapid Controlled Environmental Propagation of Virus-Indexed Sweetpotato and Field Performance - Phillip Wadl
Development of a pH Management Protocol for Strawberry Mother Plants Grown in Deep Water Culture - Jennifer Boldt
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
Adjusting dissolved oxygen in nutrient solution for optimized kale and arugula growth in hydroponics - Kuan Qin
Developing Cardinal Temperatures for Leafy Green Growth and Development Parameters from Constant and Positive Day-Night Temperatures - Sean Tarr
Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite - Sangjun Jeong

Moderator

Neil Mattson

Cornell University

Friday September 27, 2024 12:44pm - 2:15pm HST
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Oral Sessions, Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

12:45pm HST

CE 8 - Greenhouse supplemental lighting of lettuce and tomatoes to a target light intensity and daily light integral using dimmable LEDs

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

Nautilus 1

A previously developed algorithm controls on/off decisions for greenhouse supplemental light fixtures and retractable shade curtains to achieve a target daily light integral (DLI). The algorithm, termed LASSI (Light and Shade System Implementation) originally used high pressure sodium (HPS) lights with a 1-hour time step to avoid the warm-up time and reduced lifespan of HPS bulbs when they are frequently turned on/off. We have updated the algorithm accounting for dimmability of light emitting diodes (LEDs) for which light intensity can be adjusted in near real-time (RT LASSI). The objective of this study was to compare performance of lettuce ‘Rex’ and Rouxai’ and tomato ‘Sweetelle’ in response to the LASSI algorithm with HPS fixtures vs. RT LASSI with dimmable white LEDs. Experiments were conducted in adjacent greenhouses and DLI setpoints were 17 mol·m-2·d-1 for lettuce and 25 mol·m-2·d-1 for tomatoes. RT LASSI greenhouses had white LEDs (TSR Grow TG-600 HVR) and LASSI greenhouses had HPS fixtures (PL Light 1000 W). For treatments with RT LASSI, when supplemental lighting was called for, LED treatments were adjusted to complement sunlight to achieve a target instantaneous light intensity of 300 and 400 µmol·m-2·d-1 for lettuce and tomatoes, respective, averaged over a 10 minute interval. For tomatoes a minimum 4-hour dark period was imposed while for lettuce, supplemental lighting could occur anytime within the 24-hr period. For lettuce there were three replicate, 35 d crop cycles and for tomatoes plants received 15 weeks of treatment after reaching the fruiting stage with no replication. Both algorithms controlled DLI close to target. For lettuce, LASSI with HPS led to larger plant height and volume and increased fresh weight (but not dry weight) vs. RT LASSI with LED. For tomatoes, RT-LASSI with LED led to about a 30% greater tomato yield vs. LASSI with HPS. Increased yield was associated with increased fruit size but not increased fruit or truss number. Brix of HPS grown fruit was higher than LED fruit. While air temperature was very similar between both treatments, HPS fixtures may have increased plant temperature of LED. More research is needed to determine if plant impacts were due to type of lighting fixture and associated plant temperature and light spectrum or to the control algorithm itself (spreading supplemental lighting across greater hours per day).

Co-authors

Nicholas Kaczmar

Cornell University

Timothy Shelford

Cornell University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:00pm HST

CE 8 - Hybrid Model for Forecasting Lettuce Yield in Indoor Vertical Farming

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

Nautilus 1

The surging demand for sustainable agriculture has accelerated the adoption of indoor vertical farming as a pragmatic solution. Lettuce, a cornerstone crop in this context, assumes significant importance. Accurate forecasting of lettuce yield is indispensable for optimizing resource allocation and ensuring a steady supply. Most existing models used either environmental data or images to predict yield predictions, which could be erroneous for complex systems. This study aims to improve the accuracy of yield prediction in indoor farming settings with a hybrid model. First, we applied the feedforward neural network and random forest models for yield prediction, leveraging data from environmental sensors, cultivation practices, and historical yield records. Then, a convolutional neural network model is tailored to forecast yield using image data captured by RGBD cameras. Based on our results, we found reasonable accuracy in terms of RMSE and MAE, which range between 10-25 gm and 28-49 g, respectively. By amalgamating these diverse models, we aim to elevate yield prediction accuracy. It’s hypothesized that the proposed hybrid model would outperform individual approaches, offering invaluable insights for indoor vertical farming operations decision-making.

Speakers

MD SHAMIM AHAMED

University of California, Davis

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:15pm HST

CE 8 - Rapid Controlled Environment Propagation of Virus-Indexed Sweetpotato and Field Performance

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

Nautilus 1

Sweetpotato (Ipomoea batatas) production relies on clonal propagation of either sprouted storage roots grown in plant beds or from cuttings from greenhouse grown plants. In the USA, the Sweetpotato National Clean Plant Network Centers (SP-NCPN) provide virus-free planting stock of important cultivars for sweetpotato growers. However, most of the virus-indexed materials can be rapidly re-infected by one or more viruses within one growing season via insect vectors. Production of enough virus-indexed propagules is a major challenge and annually shortages exist. We have developed a controlled environment agriculture (CEA) technology that provides rapid propagation of virus-indexed propagules from SP-NCPN foundation stocks within 6 – 12 months. From a single virus-indexed in vitro plantlet, 500 rooted plants were obtained in 3 months compared to 3 plants via tissue culture micropropagation. Within 3 months the 500 rooted plants generated about 250,000 plants. Field performance (establishment and yield) of slips and rooted transplants from the CEA technology were compared with traditional plant bed derived slips. No significant differences were detected for establishment and canner and cull yield, whereas differences were found for total, marketable, jumbo, and US no. 1 yield. Our results offer a potential solution for providing growers a readily available source of virus-indexed propagule source that are comparable to field grown slips.

Speakers

Phillip Wadl

USDA, ARS, U.S. Vegetable Laboratory

Co-authors

Augustine Gubba

University of KwaZulu Natal

Bazgha Zia

USDA, ARS, U.S. Vegetable Laboratory

Christie Almeyda

North Carolina State University

Christopher Clark

Louisiana State University

John Coffey

USDA, ARS, U.S. Vegetable Laboratory

Joni McGuire

USDA, ARS, U.S. Vegetable Laboratory

Kai-Shu Ling

USDA, ARS, U.S. Vegetable Laboratory

Matthew Cutulle

Clemson

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:30pm HST

CE 8 - Development of a pH Management Protocol for Strawberry Mother Plants Grown in Deep Water Culture

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

Nautilus 1

Maintaining a target pH range is important for root zone management and overall plant growth and quality. Commercial soilless substrates often contain liming amendments to increase initial substrate pH to between 5.5 and 6.2. Hydroponic nutrient solutions are less-well buffered than soilless substrates and can experience pH drift in the absence of frequent monitoring and adjustment. Hydroponic deep water culture (DWC) was explored for strawberry (Fragaria × ananassa) research studies, to more-easily collect root growth parameters and root samples for elemental analysis, compared to soilless substrate culture. However, an effective strategy for pH management needed to be developed. The objective of this study was to develop a protocol for growing strawberry mother plants hydroponically. First, three hydroponic systems (drip-irrigated coarse perlite, drip-irrigated sand, and DWC) were compared to a peat-based soilless substrate control. Plants received a modified strawberry nutrient solution (Yamazaki) at a nitrogen (N) concentration of 100 mg·L-1. Plants grew similarly across the four growing systems. Deep water culture provided the easiest access to clean roots; however, root zone pH decreased

Speakers

Jennifer Boldt

Research Horticulturist, United States Department of Agriculture

Co-authors

Erin Yafuso

United States Department of Agriculture

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

1:45pm HST

CE 8 - Adjusting dissolved oxygen in nutrient solution for optimized kale and arugula growth in hydroponics

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

Nautilus 1

Dissolved oxygen (DO) level in hydroponic solution is an important factor affecting plant root development and water and nutrient uptake. However, precisely controlling the DO level in hydroponics has always been difficult due to the direct linkage of solution temperature and oxygen concentrations, especially under different aeration methods. Besides potentially controlling solution temperature, using liquid oxygen fertilization such as hydrogen peroxide (H2O2) has been shown to burst increase DO concentration in the solution, and ozonation, which is a sanitization treatment, has the potential to adjust DO level by supplying oxygen in nutrient solution. Our objective was to evaluate the effects of different DO levels and oxygenation strategies in a hydroponic system for the optimal growth of kale (Brassica oleracea) and arugula (Eruca vesicaria). In this study, we used ozone generators and hydrogen peroxide (H2O2) as a DO enrichment method in addition to the air pump-based aeration system to test the effects of different DO levels – low, medium, high as 6, 9, 12 mg/L, respectively – on kale ‘KX-1’ and ‘Red Russian’, and arugula ‘Astro’ and ‘Esmee’ grown in a deep water culture system. Treatment without using ozone generators or H2O2 was assigned as control. The study was arranged as a completely randomized design with three replications. DO and temperature probes were connected to a datalogger to trigger ozone generators and H2O2 injection using a relay once the DO levels were below the set thresholds. Weekly measurements were taken for plant height, leaf and anthocyanin chlorophyll content. The final harvest additionally measured leaf area, shoot and root biomass the leaf soluble solids content, titratable acidity, and leaf nutrient concentration. Plants grown under a high DO level had a higher root-to-shoot ratio, but the overall higher plant yield was achieved under the medium DO level. This system demonstrated that precise DO level control could be achieved using a sensor-based system.

Speakers

Kuan Qin

University of Georgia

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

2:00pm HST

CE 8 - Developing Cardinal Temperatures for Leafy Green Growth and Development Parameters from Constant and Positive Day-Night Temperatures

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

Nautilus 1

In the evolving landscape of controlled environment agriculture (CEA), precise temperature management remains a pivotal factor in enhancing the growth, development, productivity, and quality of high-value leafy greens. Our research identifies the cardinal temperatures — base (Tb), optimum (Topt), and maximum (Tmax) — for red-leaf and green butterhead lettuce (Lactuca sativa), arugula (Eruca sativa), and kale (Brassica oleracea), comparing how both constant mean daily temperature (MDT) within a greenhouse and positive day-night temperature differences (DIF) in a growth chamber influence plant growth and development. In the greenhouse, we had a constant MDT of 8, 13, 18, 23, 28, and 33 °C under a photosynthetic photon flux density (PPFD) of 220 µmol∙m‒2∙s‒1 for 12 h∙d–1, while in the growth chamber we targeted the same MDTs with air day/night (12 h/12 h) set points of 11/5 °C, 16/10 °C, 21/15 °C, 26/20 °C, 31/25 °C, or 36/30 °C under a PPFD of 300 µmol∙m‒2∙s‒1. Both arugula and kale had greater biomass accumulation at lower Tb and Topt compared to lettuce, suggesting a propensity for growth under a cooler MDT. Specifically, the Topt for fresh mass accumulation was found to be at 24.7 °C for arugula, 22.9 °C for kale, and higher for lettuce cultivars 'Rex' and 'Rouxaï RZ' at 24.7 and 26.2 °C, respectively. We found that DIF exerted minimal influence on these crops, emphasizing the critical role of MDT in influencing their developmental outcomes. Additionally, our research provides insight into the impact of temperature on various physiological and morphological parameters, such as leaf unfolding rate, biomass accumulation, and susceptibility to physiological disorders such as bolting or tipburn. This study underscores the importance of precise temperature management in CEA, offering guidance for producers seeking to optimize energy use while maximizing crop yield and quality.

Speakers

SEAN TARR

Michigan State University

Co-authors

Roberto Lopez

Michigan State University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 8

SUBJECT Growth Chambers and CE

2:29pm HST

Growth Chambers and Controlled Environments 9 (CE 9)

Friday September 27, 2024 2:29pm - 4:00pm HST

Nautilus 1

Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite - Sangjun Jeong
Lighting Around the Clock: Greenhouse Production with 24h Lighting - Jason Lanoue
Explore a Cost-friendly Way for Plant Nitrogen Stress Identification - Ping Yu
Optimization of Irrigation Based on Substrate Type for Tomato Production in the Dutch Bucket Hydroponic System - Milon Chowdhury
The Secondary Metabolite Production and Growth Responses of Cannabis to Thigmomorphogenesis in a Controlled Environment - Jose Franco Da Cunha Leme Filho
Simulated Climate-change-related Environmental Stressors Can Alter the Yield and Metabolomics of Tomato - Marlo Vandiver

Moderator

Ping Yu

University of Georgia

Friday September 27, 2024 2:29pm - 4:00pm HST
Nautilus 1

Oral Sessions, Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

2:30pm HST

CE 9 - Light Intensity Regulates the Interactive Effects between Far-red light and Temperature on Lettuce Growth, Morphology, Photosynthesis, and Secondary Metabolite

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

Nautilus 1

Phytochromes (PHYs) play a dual role in sensing light spectral quality and temperature. PHYs can interconvert between their active and inactive forms upon absorption of red and far-red light (Photoconversion). In addition, the active form can be converted to the inactive form in a temperature-dependent manner (Thermal Reversion). Our recent research found that while far-red (FR; 700-800 nm) light promoted leaf expansion and biomass of lettuce (Lactuca sativa) ‘Rex’ under cooler temperatures (20-24 °C), it reduced plant biomass and leaf area under warm temperature (28 °C). Considering that PHY activity would be driven mainly by photoconversion, not thermal reversion, under higher light intensity (HL), we hypothesized that the magnitude of the interaction between FR light and temperature on plant growth and morphology decreases with increasing light intensity. Lettuce ‘Rex’ was grown under three temperature regimes (20, 24, and 28 oC) x two spectral treatments [0 and 20% of FR light in total photon flux density (TPFD; 400-800 nm)] x two light intensities [150 (lower light intensity; LL) and 300 (HL) μmol·m-2·s- 1 of TPFD]. Our results showed that the effects of FR light on leaf expansion and stem elongation depended on temperature under LL. Specifically, FR light significantly promotes leaf expansion under cooler temperatures (20 oC), while decreasing total leaf area under warmer temperatures (24 and 28 oC). However, the magnitude of the interactive effects between FR light and temperature on plant morphology decreased under HL, leading to a consistent increase in total leaf area by FR light under HL. Similarly, FR light promoted plant growth under HL regardless of temperature, while reducing plant biomass under warm temperature under LL. Crop yield was primarily dependent on photon capture rather than photosynthetic efficiency per unit leaf area. FR light generally decreased the production of secondary metabolites (e.g., phenolics and flavonoids), while warm temperature and HL treatments increased the production of secondary metabolites. We concluded that the interactive effects between FR light and temperature on plant growth and morphology are further dependent on light intensity. The combination of FR light, warm temperature, and HL could maximize crop yield without reducing nutritional quality in terms of antioxidant capacity.

Speakers

Sangjun Jeong

Texas A

Co-authors

Genhua Niu

Texas A

Shuyang Zhen

Texas A

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

2:45pm HST

CE 9 - Lighting Around the Clock: Greenhouse Production with 24h Lighting

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

Nautilus 1

Photoperiod extension in controlled environment agriculture - including the use of 24h continuous light - can be used to reduce light fixture and electricity costs in regions with lower night electricity rates. However, many plant species develop photoperiodic injury characterized by leaf chlorosis and yield reduction at a critical species-specific photoperiod threshold. Here we will discuss the response of different plant species to continuous lighting strategies. We will first challenge the conventional notion that dark adapted chlorophyll fluorescence (Fv/Fm) measurements are the most appropriate when assessing photoperiodic injury. We provide evidence that light adapted (φPSII) measurements allow for a more in-depth understanding of the light capture process at photosystem II. Through RNA-sequencing in tomato, we determined that the use of a dynamic 24h lighting treatment (i.e., red light during the day and blue light during the night) lead to normal gene expression of chlorophyll a/b binding (CAB) proteins. However when tomato plants were grown under a static continuous lighting strategy (i.e., red blue lighting for 24h) at the same daily light integral, gene expression of CAB proteins were drastically reduced, resulting in chlorosis and yield reduction. In comparison to tomatoes, cucumbers tend to be more tolerant to long photoperiods and therefore continuous lighting can have an immediate impact in commercial production. Initial results in cucumbers show that a continuous lighting strategy can decrease the lighting electricity costs by 26% and greenhouse gas emissions by 38.9% per unit of produce compared to a 16h control treatment. Using the knowledge gained throughout our studies, we propose a lighting strategy which gamifies the electricity market to further reduce costs and greenhouse gas emissions.

Speakers

Jason Lanoue

Agriculture

Co-authors

Quade Digweed

Agriculture

Xiuming Hao

Agriculture

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:00pm HST

CE 9 - Explore a Cost-friendly Way for Plant Nitrogen Stress Identification

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

Nautilus 1

Plant stress can cause economic loss for plant production and is hard and expensive to identify at times. Thus, a greenhouse experiment was conducted to find an easy and cost-friendly way to identify plant stress, set up thresholds and values for the initiation of plant nitrogen stresses. Four different crops (basil, pepper, marigold, and sage) were included and treated with five different nitrogen levels (0%, 25%, 50%, 75%, and 100%). Plant height, width and leave greenless (indicated by SPAD) were measured weekly. Pictures were taken weekly. Software Image J was used to process pictures and R was used for data analysis. We found that plants with higher nitrogen treatments (75%-100%) all grow better and have higher SPAD than other treatments, except for bail. Also, RGB value could indicate plant nitrogen status with high accuracy. Plants become nitrogen stressed when SPAD falls to 25. Red and green values in RGB have negative correlations directly with SPAD and indirectly with nitrogen stress status. When the R and G values are higher than 150 and 185, respectively, we can safely predict that the plant is nitrogen stressed. In conclusion, using RBG value can be a cost-friendly way for plant stress identification.

Speakers

Ping Yu

University of Georgia

Co-authors

Kuan Qin

University of Georgia

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:15pm HST

CE 9 - Optimization of Irrigation Based on Substrate Type for Tomato Production in the Dutch Bucket Hydroponic System

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

Nautilus 1

Dutch bucket hydroponic systems are used for high-wire crop production such as tomatoes, cucumbers, or peppers, and are typically filled with perlite as a substrate. Through past research, our group identified pine bark and wood fiber as sustainable alternative substrates for high-wire tomato production. Typically, greenhouse tomato growers utilize leachate-based or timed irrigation; however, the use of a water content sensor could precisely identify the irrigation set-point for different substrates, potentially saving water and fertilizers. This study aimed to optimize the irrigation rate for greenhouse tomato ('Favorita F1') production in the Dutch bucket hydroponic system using a soil water content sensor. Three types of substrates (perlite, pine bark, and wood fiber-coir mix (60:40)) and four different gravimetric water contents (100%, 120%, 140%, and 160%) were considered. The experiment was conducted with three replications in a completely randomized design, with the irrigation treatments under the perlite substrate serving as the control. Physical parameters, such as the number of leaves and plant height, were significantly higher in the wood fiber-coir mix and pine bark at 160% irrigation, and lowest under perlite at 100% water content. However, there was no significant difference among the treatments for the number of flower (fruit) clusters. The plant leaf area measurements indicated better vegetative growth with wood fiber-coir mix at 160% water content, whereas pine bark at 160% water content resulted in a higher yield and better fruit quality. In contrast, phytochemicals such as Brix, vitamin C, titratable acidity, lycopene, beta-carotene, and phenolic compounds were significantly higher in the organic substrates (pine bark and wood fiber) with low water content (100% to 120%) and lower in perlite with high water content (140% to 160%). The highest and lowest concentrations of phytochemicals varied between 13% to 67%. There was no significant difference among the treatments (substrates and water contents) in terms of tissue mineral analysis. In general, plants grown in wood fiber-coir mix treatments required 28% and 51% less irrigation compared to those in pine bark and perlite treatments, respectively. Plants grown in organic substrates require less water, and the yield quantity and quality are either similar to or higher than those in perlite. Out of the organic substrates, wood fiber-coir mix can be used in Dutch bucket systems to conserve water and nutrients, enhancing yield quantity and quality, and thereby achieving environmental sustainability.

Speakers

Milon Chowdhury

The Ohio State University

Co-authors

James Altland

USDA-ARS

Joanna Moine

The Ohio State University

Uttara Samarakoon

The Ohio State University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:30pm HST

CE 9 - The Secondary Metabolite Production and Growth Responses of Cannabis to Thigmomorphogenesis in a Controlled Environment

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

Nautilus 1

As legalization continues to change the cannabis industry, we see an influx of creative innovation, funding, and research as more entities enter the field. The two innovative growing management investigated in this study were Mechanical Vibration Training (MVT) and High Stress Training (HST). MVT was carried out using a grid exposing the plants to 200 Hz vibration, and HST is a practice that involves damaging the vascular bundles, pith, and cortex of the main stem while leaving the epidermis intact. MVT is a newer technique still in development, as Thigmo-priming has been shown to change plant morphology and chemistry and even increase the speed and magnitude of future stress responses. Many industry leaders claim that the advantages of using HST include higher canopy, increased biomass and cannabinoid concentrations, and more effective IPM strategies. However, studies validating these claims are still being determined. This study aims to compare each growing management under the overall category of Thigmomorphogenesis or mechanostimulation against control (no artificial mechanical stimulation) and tease out any synergism between the treatments. We hypothesize that applying mechanostimulation to cannabis plants will enhance their growth and increase secondary metabolite production. The environment-controlled growth units housed the treatments consisted of 1-Control, 2-MVT, 3-HST, and 4-MVT HST. Each growth unit contained five-gallon fabric pots with a single Suver Haze plant. An amended coco coir substrate was used with a water-soluble nutrient solution, and optimal growing conditions, including lighting, were maintained equally in all environment-controlled growth units. Weekly plant parameters included stem diameter, plant height, NDVI, chlorophyll concentration, and photosynthetic efficiency. After-harvest parameters included above/below ground biomass, yield mass, bucked biomass, trichome density, and cannabinoid levels. Morphological and numerical differences between treatments indicated the potential for a shorter, more efficient growth cycle with higher cannabinoid levels. Further testing is currently underway.

Speakers

Jose Franco Da Cunha Leme Filho

Southern Illinois University

Co-authors

Aldwin Anterola

Southern Illinois University

Dila Ozev

Southern Illinois University

Gorman Saunders

Southern Illinois University

Jennifer Weber

Southern Illinois University

Karla Gage

Southern Illinois University

Shiksha Sharma

Southern Illinois University

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

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE

3:45pm HST

CE 9 - Simulated Climate-change-related Environmental Stressors Can Alter the Yield and Metabolomics of Tomato

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

Nautilus 1

Climate change challenges all aspects of food production, including standard greenhouse products, such as tomatoes. The cause of climate change can be directly attributed to the rise in carbon dioxide (CO2) levels, leading to increased temperatures and drought severity. Tomatoes are the most produced fruit crop globally, and in addition to their economic benefits contain several vitamins and minerals essential for human health. The objective of this study was to assess the multi-variable effects of simulated climate change on tomato plants by investigating the combination of elevated CO2 (800 ppm vs 400 ppm), increased temperature (28℃ vs 21℃), and water deficit stress (20% decrease from control) across three development stages: juvenile, anthesis, and fully mature tomato. ‘Sweet ‘N’ Neat Scarlet’ tomatoes (Solanum lycopersicum) were grown in four plant growth chambers in a 2 x 2 x 2 factorial design with four replications. Quality parameters included photosynthetic efficiency, growth index, dry weight, flower number, fruit number, and fruit size. Inductively coupled plasma mass spectrometry (ICP-MS) and oxygen radical absorbance capacity (ORAC) analyses were measured at each of the three stages when applicable. Preliminary data suggests that higher temperatures and CO2 increase (p

Speakers

Oral presentation (Individual talk), Growth Chambers and Controlled Environments 9

SUBJECT Growth Chambers and CE