ASHS 2024 Conference

A comprehensive analysis of Vidalia Onions transplanting and its impacts - Regimar do Santos
Is Winter Squash a Potential Alternative Cucurbit Vegetable Crop to Combat Whitefly and Whitefly-Transmitted Viruses for Fall Production in Southern Georgia? - Nirmala Acharya
Evaluating Onsite Nitrate and Potassium Sensors - Destany Westlake
Filling the Gaps for Informed Adoption of Carolina Strong Back Grafted Nursery: Transplanting Time and Spacing Optimization - Sukhman Kaur
Substrate Hydro-Physical Properties in Soilless Agriculture: Investigating the Role of Container Geometry on Substrate Air and Water Profiles - Brandan Shur
Kenaf (Hibiscus cannabinus) Compost As An Alternative To Peat - Shawn Steed

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

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

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

Grafting is an effective management strategy in watermelon crop against soil borne pathogens. Carolina strongback (SB) rootstock used for grafting, is resistant to both fusarium wilt and root knot nematodes which are devastating soil borne pest of watermelon. In addition, recent studies have shown higher vigour of SB grafted plants than regular nursery plants. However, grafted watermelon nursery is 4-5 times more expensive than regular nursery which leads to reluctance among farmers for adoption of this effective management strategy. Further, recent trials showed that grafted plant bear fruits 7-10 days later than regulate plants leading to farmers losing early profitable watermelon market. To fill these gaps for informed adoption of SB grafted nursery, a field experiment was conducted at Blackville SC with the objective to evaluate the optimum transplanting time and density of SB grafted watermelons nursery to have equivalent fruit yield and harvesting window to that of regular nursery. The experiment comprised of three transplanting times and four transplant densities in a split plot design. We will evaluate the impact of transplanting time and transplanting density on watermelon fruit yield, fruit quality, number of fruits per plant, periodic fruit harvesting yield and plant vigour.

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

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

Chromosome Level Assemblies of Phoenix dactylifera L. 'Medjool' and 'Deglet Noor' - Yoko Hiraoka
Development of Haplotype-Phased, Chromosome-scale Genomes for Pomegranate - Alexander Schaller
In Planta Transformation Efficiency Assessment of Different Agrobacterium Strains and Explant Types in Catharanthus rose - Ting Hsuan Huang
Native Southern Red Aroniaberry (Aronia arbutifolia) Response to Chill Hours in Georgia - Leynar Leyton
Enhancing Ornamental Traits through Induced Polyploidy in Hibiscus hamabo: A Cytomolecular Analysis - Hamidou Sakhanokho
Insights into the Genetic Diversity and Population Structure of Wild and Cultivated Spinach - Gehendra Bhattarai
Population Analysis of Wild-type Venezuelan Sabadilla - Luke Czerwinski

Date palm (Phoenix dactylifera L.) is one of the oldest cultivated perennial woody plant species with significant agricultural and economic importance. Date has its center of origin in the Middle East, spreading in ancient times to North Africa and South Asia and later to other hot, arid areas. Dates are a strict dioecious evergreen, obligate outcrossing, and highly heterozygous monocot species that are typically vegetatively propagated. ‘Medjool’ and ‘Deglet Noor’ are the most widely grown date cultivars in the United States and are also important at the global level. Despite their economic values, genomic studies have been hampered due to lack of available assembled genomes. To facilitate future genomic studies, genomes for ‘Medjool’ and ‘Deglet Noor’ were assembled using Dovetail® HiFi and Omni-C® technologies. ‘Medjool’ had a total length of 757 Mb comprising 899 scaffolds (L50 : 7, N50 : 37 Mb) with a BUSCO completeness score of 97.65 %, and ‘Deglet Noor’ had a total length of 772 Mb comprising 1287 scaffolds (L50 : 9, N50 : 33 Mb) with a BUSCO completeness score of 97.65 %.

Pomegranates (Punica granatum L.) are a significant fruit crop globally, gaining traction due to their high nutritional value and many uses outside of consumption. Despite increasing interest, genetic resources for pomegranates lag behind other crops. Developing these resources can enhance breeding efficiency and deepen genomic understanding. To address this, we sequenced the genomes of two cultivars: 'Azadi', known for its robust fruit rot resistance, and 'Peppy Le Pom', a dwarf variety with short juvenility. Using the PacBio Revio Platform, we generated HiFi reads with 30x coverage and employed Hi-C for sequencing. Leveraging hifiasm's Hi-C integrated assembly method, we assembled two haplotypes for the genome of each cultivar. For 'Peppy Le Pom', we utilized 10.03 Gb of PacBio HiFi reads and 30 Gb of Hi-C data and constructed two haplotypes with eight chromosome-length scaffolds each, totaling 304.9 Mb and 318.7 Mb, with a BUSCO score of 90.3% and 92.3%, respectively. For 'Azadi', we utilized 10.08 Gb of Pacbio HiFi reads and 30 Gb of Hi-C data and assembled two haplotypes with eight chromosome-length scaffolds, measuring 305.5 Mb and 318.1 Mb, with a BUSCO score of 91.0% and 92.6%, respectively. Chromosome sizes of these pomegranate cultivars range from 27.1 Mb to 62.4 Mb. Notably, these results closely align with the previously published draft genome of the 'Tunisia' cultivar. These phased, chromosome-scale genomes will facilitate further exploration of traits of interest for pomegranate breeding, such as disease resistance, dwarfing, and short juvenility. The genomic resources established here pave the way for accelerated advancements in pomegranate research and breeding.

Catharanthus roseus (L.) G. Don is a common ornamental crop worldwide due to its high tolerance to drought and heat. The researches on Agrobacterium-mediated transformation of C. roseus are few, and mostly focus on the production of secondary metabolites in roots. Furthermore, the organogenesis from callus to plantlet is frequently unstable which limits the study on entire plant, especially on flowering. The objective of this study is to evaluate the in planta transformation survival rate in different explants and Agrobacterium strains. C. roseus ‘Cora XDR White’ seeds were cultivated in vitro till the cotyledon expanded. Plantlets and cotyledonary nodes were respectively inoculated with two Agrobacterium strains, GV3101 or LBA4404 harboring the binary vector pHEE401E. Explants were co-cultivated in 1/2 MS medium for three days. After washing with sterile water and cefotaxime, the explants were first placed in a medium containing cefotaxime, then were transferred to a same medium that was further added hygromycin. During the elimination and selection, each cotyledonary node turned brown. In the process of subculture, necrotic parts were removed. Result showed that the survival rate of plantlets was 5% in GV3101 treatment. However, LBA4404 ones eventually got brown.

Aroniaberry or chokeberry (Aronia sp., Rosaceae) is an attractive deciduous tree-like shrub. Native to eastern and central United States, red aroniaberry (A. arbutifolia) is more predominant in the southern part of the distribution. Bright red fruits, proliferous white flowers in spring, and attractive fall color, make A. arbutifolia a native shrub with ornamental potential. Most of the aroniaberry ornamental varieties available in the market are selections or hybrids of black aroniaberry (A. melanocarpa), they produce black fruit, and do not perform well in sub-tropical climates. We collected triploid and tetraploid A. arbutifolia from five different locations in South Georgia and evaluated their flowering period, fruit production, and response to chill hours in Griffin, GA (Zone 8a, Piedmont region). Plants were exposed to 1000, 800, 600, 400, or 0 chill hours and planted in the field in April of 2023. Flowering timing had a strong correlation with chill hours; plants with chill hours below 600 hrs. presented less flowers and flowering was not uniform.

The Hibiscus genus, encompassing roughly 300 species across 10 sections, presents a diverse and economically significant range of industrial, ornamental, and medicinal properties. Polyploidy, whether occurring spontaneously or induced through external agents, such as chemicals like colchicine and oryzalin, plays a crucial role in plant breeding. It enhances various attributes including flower size, resilience, and metabolite production. Among the species in this genus, Hibiscus hamabo is noted for its salt tolerance and its attractive yellow flowers in summer and golden-yellow or burnt orange leaves in fall. However, H. hamabo typically has small and sparse flowers, which led to our efforts to enhance its ornamental value through induced polyploidy. In our study, we treated germinating seeds of H. hamabo with three concentrations of colchicine (0, 0.125, and 0.25% v/v) for varying durations (6, 12, or 24 hours). The most effective conversion was achieved with seeds treated with 0.25% v/v colchicine for 24 hours. This treatment produced solid polyploids (4n = 184) and mixed-polyploids (2n 4n). The 4n plants exhibited a 2C-DNA content of 8.50 pg, compared to 4.23 pg in the untreated (2n = 92) plants. We evaluated the impact of induced polyploidy on several morphological traits including leaf color, shape, size, trichome density, and plant height. Significant differences were observed between the polyploid plants and the control plants. Additionally, we explored the cytomolecular analysis of induced polyploidy, particularly focusing on the distribution and organization of rDNA. In 2n plants, one locus of 5S and four loci of 35S rDNA (two major and two minor) were identified. The 5S site is pericentromeric, while one of the major 35S sites is sub-terminal, and the others are at terminal locations. In 4n plants, the number of 5S and 35S sites was exactly duplicated, confirming the polyploidization at the genetic level. Our results proved that colchicine can be used to induce polyploidy in germinating H. hamabo seeds, paving the way for the improvement of this species through this method.

The wealth of genetic and phenotypic diversity in plant species serves as the primary source of novel traits in plant breeding and crop improvement efforts. Spinach (Spinacia oleracea) has a long cultivation history across diverse environments and geographic regions, which has resulted in adaptation to diverse conditions. This adaptation has been influenced further by human preferences for distinct leaf shapes, tastes, flavors, and nutrition, constituting a rich reserve of genetic and phenotypic diversity within Spinacia germplasm. Moreover, wild species (S. tetrandra and S. turkestanica) offer valuable resources, particularly for traits of commercial significance, such as resistance to prevalent pathogens and pests. Therefore, understanding the genetic variations that underlie phenotypic traits is crucial to enable effective gene introgression and the development of novel spinach varieties. We recently investigated the genetic diversity and population structure of a panel of over 500 cultivated and wild germplasm obtained from the Centre for Genetic Resources, the Netherlands (CGN) at Wageningen University and Research (WUR). This panel, complemented with material from other sources, comprised 49 S. tetrandra and 86 S. turkestanica accessions. Our findings revealed the presence of significant genetic diversity within these panels of accessions, which were categorized into multiple distinct population groups. We evaluate this Spinacia panel for several horticulturally important traits to identify SNP markers and candidate gene regions associated with commercially important traits. Our objectives are to share novel insights into the genetic diversity of spinach and provide valuable molecular markers for improving cultivated spinach production.

Schoenocaulon officinale or sabadilla (Melianthiaceae) is endemic to the Americas with Mexico as the Center of Origin and Diversity. Sabadilla is a subtropical geophytic perennial, producing tunicate bulbs. It reproduces by seed and asexually (daughter bulbs), producing apetalous floral inflorescences. Flowering occurs >1.5 years from seed with annual flowering occurring up to eight years. Sabadilla seeds contain two insecticidally active lipophilic alkaloid compounds: veratridine and cevadine, in concentrations of 0.5-6.0%. These compounds are used as “green pesticides” with a mode of action that is similar to pyrethrins; attachment to sodium channels in insects, causing continuous overactivation. Sabadilla has been used by Native American cultures for thousands of years for its insecticidal properties and medicinal uses. However, about sabadilla, little is known about this species as a crop plant. The purpose of this research was to examine population differences of extant, wild collections in Venezuela. In 2019, seeds (24 subsample seed lots from sympatric plants, bulked by site) were collected from seven locations in The Ávila National Park and the vicinity of Colonia Tovar across three different states (Vargas, Miranda, Aragua). Seed lots were germinated to determine % germination and genetic variation. Dried leaf samples (n=333 genotypes) were used for DNA extraction for genotype by sequencing (GBS) for low-density single nucleotide polymorphic (SNP) marker generation (DArT-seq). Genetic variation within and among populations was determined using principle component, Admixture, AMOVA, and IBS analyses (RStudio).

Create Novel Interspecific Hybrids between Tuberous Begonia and B. semperflorens by Using Embryo Rescue Technique - Yen Ming Chen
Breeding the Unbreedable: Innovating the Generation of Sterile Triploid Lantana through Open-Pollinated Interploidy Crosses - Brooks Parrish
Tetraploid plants of Samanea (Albizia) saman on diploid roots grew similarly to mixoploid and diploid plants on diploid roots while tetraploid plants on tetraploid roots were inferior to triploid plants on triploid roots - Alberto Ricordi

Genus Begonia is prominent ornamental bedding and potted flower crop, encompassing types such as Rieger Begonia (Begonia × hiemalis), Tuberous Begonia (Begonia tuberhybrida), and B. semperflorens, which are extensively cultivated. Building upon the breeding methodology of Rieger Begonia, this study endeavors to utilize Tuberous Begonia as the maternal parent and integrate the attributes of B. semperflorens to develop innovative interspecific hybrid varieties. Interspecific hybridization was accomplished by using Tuberous Begonia 'Fortunate' as the female parent and B. semperflorens as pollen donor through embryo rescue techniques, resulting in successful interspecific offsprings. Flow cytometry analysis revealed the expected DNA content combination in the hybrids. Furthermore, Random Amplified Polymorphic DNA (RAPD) analysis confirmed the authenticity of the interspecific hybrids by exhibiting specific bands of both parents. The plant type, basal branching habit, and leaf shape of the hybrids resembled those of the male parent, B. semperflorens, while the double flower characteristic inherited from the female parent. Additionally, the hybrids exhibited year-round flowering without requiring photoperiod treatment and showed no apparent dormancy, rendering them suitable for continuous production. These hybrids are also exhibiting robust branching habits and possess distinctive plant traits compared to commercially available Rieger Begonias. They are particularly suited for cultivation in hot and humid regions. Evaluation of production and growth advantages indicated their capability for year-round supply and commercial production. Applications for Plant Variety Rights have been submitted for these hybrids in Taiwan.

This study presents a groundbreaking field breeding strategy for Lantana camara, a plant celebrated for its ornamental value yet criticized for its invasive tendencies. Traditional hand pollination techniques for lantana are labor-intensive, as each flower produces only one seed, making the generation of significant populations time-consuming. Although open pollination represents an alternative for seed production, the reliability of generating sterile triploids through interploidy crosses has been questionable. Addressing these challenges, this research innovatively employs open-pollinated breeding between diploid and tetraploid populations to efficiently produce sterile triploid cultivars. The method leverages male-sterile tetraploids for open pollination with female-sterile, male-fertile diploids, yielding 544 triploid seeds within five weeks and proving the effectiveness of interploidy hybridization. Moreover, diploid populations in an all-by-all cross setup produced over 2,000 seeds in the same period, eliminating the need for hand pollinations. Nonetheless, the development of tetraploid breeding lines encountered obstacles due to insufficient pollen transfer, likely resulting from low pollen production, although selfing within hybrid lines remained feasible in an open-pollinated field setting. These findings significantly advance the fields of ornamental breeding and invasive species management, providing fresh perspectives on the cultivation and control of Lantana camara. Demonstrating the capability to rapidly produce large volumes of sterile triploid lines with minimal labor, this study lays the groundwork for the broader availability of non-invasive Lantana camara alternatives in the future.

Many legume trees are notorious for their prolific production of seedpods, which are usually large and in many cases stink when cracked open. Such pods affect both the beauty and sensory perception of the tree, and may be slippery and hazardous on walking surfaces. For example, Samanea (Albizia) saman, which has naturalized in many tropical and subtropical places and is commonly known in Hawaii as monkey pod tree, is a favorite landscape tree in Hawaii for its large canopy, especially in parking lots and parks. Unfortunately, this species produces a large amount of sticky pods that stick to shoes and tires, and can create an objectionable mess, a high volume of green waste and high maintenance of parking lots. The seedpods are heavy to rake and can cause damage to lawn mower blades. Seedless cultivars would have no potential to become invasive and their maintenance cost would be much lower. Seed-bearing ornamental plants can be converted to triploid, non-seed-bearing forms, and thereby eliminate their invasiveness and reduce their maintenance. Triploid plants rarely produce functional gametes, because they do not undergo normal meiosis, and the resulting sterility accounts for the economically valuable seedlessness of triploid bananas, limes, and seedless watermelons. Sterile nursery plants can be used for landscaping virtually without any possibility to become invasive. In a field trial at the University of Hawaii Waimanalo Research Station, it was observed that tetraploid plants of Samanea (Albizia) saman on diploid roots grew similarly to mixoploid and diploid plants on diploid roots. These tetraploid plants were developed by treating the apical meristem of diploid seedlings with 0.1% colchicine for 48h. Therefore, the root system remained diploid, while the above ground portion of the plants were tetraploid. However, tetraploid plants on tetraploid roots, grown from seeds harvested from tetraploid induced plants, were inferior to triploid plants on triploid roots. Triploid plants were almost double in size (67% taller, had 109% wider canopy, and 90% larger DAB, n=8). This is the first time that this phenomenon has been documented in Samanea spp.

Ethylene Degreening: A Technique to Enhance Peel Color of Georgia-Grown Satsuma (Citrus reticulata) Citrus Fruit - Taiwo Owolanke
Postharvest Storage Temperatures to Promote Anthocyanin Accumulation and Antioxidant Activity in Blood Orange cv. Moro - Fariborz Habibi
Preserving Flavor in Grapefruit Juice: Continuous Flow High-Pressure Homogenization Versus Conventional Treatment - Jayashan Adhikari
Effects of Alternative Atmosphere Storage on the Postharvest Quality of Georgia-grown Blackberries - Ramsey Corn
Examining the Effect of Storage Temperatures on Chilling Injury Incidence of Georgia-Grown Peaches - Orestis Giannopoulos
Postharvest melatonin application maintains quality of jackfruit bulbs by alleviating enzymatic browning and oxidative stress under low temperature storage - Jashanpreet Kaur
Catalysis of 1-Methylcyclopropene Degradation By Non-Target Materials: Metals and Metal Salts - Ozge Horzum

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

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

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

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

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

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

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

Growth-promoting Bacteria in Improving the Biophysical Parameters of Cherry Tomatoes (Solanum lycopersicum L.)  - Henrique Oliveira
Promoting Controlled Environment Agriculture Activities At Campus-Wide Events - Kent Kobayashi
Rapid Detection of Herbicide-Resistant Weeds Utilizing Novel Full-Spectrum Imaging and a Hyperparameter-Tuned Convolutional Neural Network (CNN) - Pauline Victoria Estrada
Puʻuhonua Kauluwehi: Maui Wildfire Rapid Response Strategies for Agroecosystem Resilience and Community Well-Being - Nicolette van der Lee
Enhancing Hot Pepper Quality and Yield through Smart Irrigation Strategies - Harmandeep Sharma
Spraying Drone Efficiency: A Comparative Study of Application Rate and Surfactant Addition - Lucas Sales

How can we help students, the public, and stakeholders become familiar and engaged with controlled environment agriculture (CEA) and its benefits? Besides offering undergraduate courses such as TPSS 300 Tropical Production Systems and TPSS 491 Experimental Topics "Controlled Environment Agriculture" we sought other ways to accomplish this. The objective is to describe how we use displays about our CEA lab at campus-wide events to help inform audiences about CEA and its technology. Various events at the University of Hawaii at Manoa (UHM) enable colleges, departments, units, and individual laboratories the opportunity to showcase their programs, curricula, and research. At these campus-wide events, we set up table displays that explain CEA and highlight our CEA research. Our displays exhibit various aspects of the technology used in CEA such as LED (light-emitting diodes) lights, hydroponics, and greenhouse materials. We display high tech acrylic greenhouse coverings and walls, smart glass, photoselective shadecloths, and light spectrum control plastic films to show recent developments in greenhouse coverings. Hydroponic principles are explained through the use of micro-hydroponics, dwarf vegetables grown under LED lights, and hydroponic kits. A display using simulated Martian soils and LEGO® figures shows a Martian landscape with a plastic dome greenhouse with plastic vegetables growing inside. The audience gets to experience a hands-on working miniature grow tent, a replica of actual grow tents, to demonstrate how CEA experiments are conducted using grow tents with manually controlled red, blue, and white LED lights and fans. We have a shadecloth covered PVC pipe box with red and blue photoselective shadecloths and LED light placements on top, sides, and intracanopy to explain light spectrum and light placement. The Lunar/Martian greenhouse model displays an example of how plants could be grown on extraterrestrial bodies such as the moon and Mars. The display shows a cutaway view of a greenhouse installed below the soil surface for protection from radiation. Natural light is supplied with light pipes and artificial light is supplied with LEDs. Our lab’s table displays have been well received by people stopping by our tables. The campus events provide the opportunity for students to assist in staffing the tables and talking about CEA and their research. We also discuss CEA research opportunities provided by the UHM Undergraduate Research Opportunities Program (UROP) and the UHM Hawaii Space Grant Consortium Program.

Every year, farmers around the world lose more than $95 billion from uncontrolled weed infestation. Herbicide-resistant weeds, also known as “superweeds”, are fast becoming a significant part of this weed problem and are a significant threat to crop production and food security. Late detection of resistant weeds leads to increasing economic losses and severe environmental damage. Traditionally, genetic sequencing and herbicide dose-response studies are used to detect herbicide-resistant weeds, but these are expensive and slow processes. To address this problem, an AI-based superweed identifier program (SIP) was developed to quickly and accurately distinguish herbicide-resistant from susceptible chickweed (Stellaria media). A regular camera was converted to capture light wavelengths from 300 to 1,100 nm. These full spectrum images were used to develop a hyperparameter-tuned convolutional neural network (CNN) model utilizing a “train from scratch” approach. This novel approach exploits the subtle differences in the spectral signature of resistant and susceptible chickweed plants as they react differently to herbicide treatments. The SIP was able to identify resistant chickweed to acetolactate synthetase (ALS) inhibitor herbicides as early as 72 hours post treatment at an impressive accuracy of 85%. It has broad applicability due to its ability to distinguish resistant from susceptible chickweed plants regardless of the type of ALS herbicide or dosage rate used. Utilizing the superweed identifier program will allow farmers to make timely interventions and develop more effective and safer weed management practices. This can optimize yield, reduce herbicide use, minimize environmental harm, prevent herbicide-resistant weed proliferation, and improve overall public health.

The Puʻuhonua Kauluwehi project aims to develop a rapid response to the recent Maui wildfires by collaboratively establishing a network of biocultural refuges supporting the cultivation of native plants to accelerate landscape-scale agroecological resilience, food security and community well-being strategies. Puʻuhonua Kauluwehi is a Hawaiian phrase describing regenerative agroecosystem areas that provide shelter for native vegetation, attract native birds and insects, and serve as a source of thriving launching points to revegetate the landscape through community engagement. In Hawaiʻi, establishing biocultural refuges is even more critical as the unique ecosystems of the islands continue to come under threat from invasive species, drought, commercial development, lack of ecosystem management and are more at risk due to the dependence on imported response and aid resources from the mainland as demonstrated by the devastating impact of the Maui wildfires in August 2023. The project’s specific objectives are to: (1) Provide applied research and GIS mapping services that integrate water quality testing, soil testing and native plant and tree cataloging in one accessible database for the growing coalition of local agricultural and conservation organizations responding to the wildfires; (2) Develop strategies to ensure all children, youth, and adults have access to abundant local food during and after wildfire disasters through a network of seed orchard, seed bank, nursery and food hub partners; and (3) Design extension and non-formal community education initiatives to address the health and well-being of children, youth, and adults affected by wildfire disasters through work-based agroecosystem and stewardship training in the Kauluwehi Biocultural Garden for 300 participants. The Puʻuhonua Kauluwehi restoration project, led by University of Hawaii Maui College, will share initial outcomes of launching a technology platform to connect critical nodes of the Maui wildfire response into a thriving network that will serve as a social-ecological incubator for the positive impact of vibrant and culturally authentic landscapes and redefine the value of agroecosystems in Maui’s unique context for disaster recovery.

Hot peppers (Capsicum chinense) are attracting increasing attention due to their rich reservoirs of secondary metabolites, notably capsaicinoids, which are in high demand across various industries such as culinary, cosmetic, and pharmaceutical. Consequently, there has been a surge in the number of new pepper growers emerging throughout the United States. Despite ranking fifth in pepper production, North Carolina’s pepper cultivation remains smaller compared to other states known for hot pepper production. Additionally, the southern U.S. anticipates an increase in extreme weather events such as droughts and floods. Thus, there is a pressing need to identify the most suitable pepper cultivars and implement efficient production management practices tailored to local climatic conditions to maximize both crop production and quality. To address this need, the current study was conducted at Reid Greenhouse, North Carolina Agricultural

Current agricultural practices are facing several challenges because of the use of large and heavy machinery used in the fields. The benefits of covering large areas to meet the time of spraying crops is becoming questionable because the heavy machinery (large self-propelled boom sprayers) also can cause soil compaction and require large amounts of fuel and technical labor to be operated. Moreover, spraying drones are emerging as a pivotal technology in modern agriculture. They serve multiple purposes, from measuring and understanding fields using sensor and camera-captured images to acting as spray applicators for a wide range of products e.g.,including herbicides, pesticides, fungicides, and fertilizers. As a novel technology, spraying drones overcome some of the challenges faced by traditional methods. For instance, they can initiate applications in specific areas that require treatment, thereby avoiding issues like soil compression and unnecessary use of cultivated areas. This enhances precision while reduces losses in the field. However, defining application rate and the impact of adjuvant products is still scarce in previous studies. Therefore, in this study, we analyzed whether the coverage area is influenced by application rates and surfactant addition. The study was conducted in a carrot crop field. Water-sensitive papers were placed on the top leaf and at the bottom of the plants to quantify the coverage area. The measured area comprised a swath of 40 feet and a drone route of 100 feet. Measurements were performed in 9 crop-rows, each row with three hydrosensitive papers spaced in 33 feet apart. A multirotor spraying drone XAG P100Pro with Atomized Nozzles was used to apply spraying rates of 5 and 10 gallons per acre, both with and without surfactant addition. Results showed more coverage area on the top leaf than at the bottom of the plants. Similarly, when 10 gallons per acre were applied, it produced a higher covered area. However, there was a difference when applied 10 gallons with and without adjuvant. By applying adjuvant, the trial proved more efficient in reaching the plants. Conversely, when 5 gallons were applied, the surfactant did not contribute to either the top leaves or bottom part. Therefore, our results are promising and contribute to the enhancement of technology in agricultural production. The insights allow from farms to research centers to improve the spraying drone application, guaranteeing a more sustainable environment.