ASHS 2024 Conference

Biostimulants Promoted Onion Plant Growth and Helped Mitigate Drought Stress During the Seedling Stage - Qianwen Zhang
Effluent of the Anaerobic Digestion of Food Waste as a Biofertilizer for Red Cabbage - Roland Ebel
Optimizing the Application of Anaerobic Soil Disinfestation in Organic High Tunnel Vegetable Production Systems - Francesco Di Gioia
Cover Crops Potential for Regulating Soil Moisture and Temperature in Drive-row of an Irrigated Organic Vineyard - Mehdi Sharifi
Apple Rootstocks Affect Soil Rhizosphere Microbial Communities and Root Exudate Composition - Julie Cardon
No-till planting organic dry bean into rolled-crimped cover crops - Matthew Ryan

Climate change and global warming are increasing the frequency of drought incidents, which negatively impact crop production. Onion is one of the major vegetable crops produced in Texas, which requires a long growth period and prone to drought stress as it has shallow roots and needs frequent irrigation. Plant biostimulants may offer a potential solution to mitigate drought stress in onion production. This study investigated the effect of different biostimulants (no application as control, Kelpak, Spectrum DS, MycoApply, and Tribus Continuum) on onion seedling growth under well-watered and drought stressed (50-60% field capacity) conditions. Results showed that there was no significant interaction between biostimulants and drought stress on most of the parameters we collected. All biostimulants significantly increased shoot weight, leaf area, plant height, and root weight compared to the control. Notably, Spectrum DS, MycoApply, and Kelpak specifically enhanced root morphology by increasing root length, root area, and root volume compared to the control. But the application of biostimulants didn’t significantly affect average root diameter or the number of root tips. Drought stress significantly reduced the growth of onion seedlings across all measured parameters, except for the number of root tips, compared to the well-watered group. While drought stress caused a 36.9% decrease in shoot fresh weight, application of Kelpak, Spectrum DS, MycoApply, and Tribus Continuum increased shoot fresh weight by 29.8 to 34.9%, partly offsetting the growth reduction and alleviating the stress experienced by the seedlings. In conclusion, the application of the investigated biostimulants shows promise for enhancing drought tolerance in onion seedlings.

Food and farm waste processed by anaerobic digestion (AD) generates a nutrient-rich digestate suitable for use as a biofertilizer. Small-scale AD systems production of biofertilizer offer an on-site solution accessible to individual households and small horticultural producers. Unlike common and more complex AD solutions, small-scale systems do not require extensive management or infrastructure investments. In 2022, we investigated the nutrient content and usability of digestate from two small-scale biodigester models: A commercially built digester with a 1,200 L digester tank, and a prototype we designed with a 114 L capacity. Locally sourced fresh raw cow milk served as inoculum. Over a span of 16 weeks, 12 randomly selected households in Bozeman, Montana, tested the two digester models, feeding them with the food waste they generated. Six of the households received the commercial model, and six tested the prototype. Digestate samples were collected biweekly to analyze their chemical properties and potential as a biofertilizer. After 16 weeks, we blended all digestate, taking equal parts from all household samples, and tested it in a greenhouse study as a fertilizer for red cabbage (Brassica oleracea L. Capitata Group) seedlings. In addition to a control treatment where no biofertilizer was used, we applied 40 ml of biofertilizer per plant in a “high dose treatment” and 20 ml biofertilizer per plant in a “low dose treatment.” Each treatment involved 50 cabbage plants growing individually in trays of 10 cm diameter. On a weekly interval, the biofertilizer was sprayed on the substrate, with amounts varying by treatment. The substrate consisted of loam soil, washed sand, Canadian sphagnum peat moss, perlite, vermiculite, and dolomitic lime. Seedlings were irrigated manually every second day. To ensure sufficient nitrogen supply, all three treatments received an initial application of 40 mL of fish emulsion per cabbage plant. No pest or disease management practices were implemented. After 30 days, all plants were harvested, and their aboveground dry biomass was measured. A trend towards higher aboveground dry biomass in the "high biofertilizer dose" treatment compared to the "low biofertilizer dose" and control treatments was observed. Additionally, the aboveground biomass underwent nutrient content analysis, revealing a tendency towards the highest potassium content in the "high dose treatment." This study showed that household food waste processed through small-scale AD systems generates valuable biofertilizer that can help manage crops’ nutrient needs.

The growth of the U.S. organic vegetable industry is currently limited by the availability of viable and effective solutions for the management of soilborne pests and pathogens. Anaerobic soil disinfestation (ASD) is a pre-planting biological method proposed for the management of a range of soilborne pests and pathogens affecting horticultural crops. As an organic amendment-based approach, ASD is implemented incorporating in the soil an easily degradable carbon (C) source, tarping the soil with plastic mulch, and irrigating the soil to field capacity. The selection of organic amendments suitable as C sources is critical for the efficacy of the treatment and its sustainability. Understanding how the physicochemical properties of alternative amendments may affect the efficacy of the ASD treatment, the soil fertility during and post ASD, and consequently the crop performance is critical. Therefore, a study was conducted on organic-certified land at the Penn State High Tunnel Facility to compare wheat middlings (WM), molasses (M), and soybean meal (SM) and their combination as C sources. Treatments tested included WM, M, SM, WM SM, and M SM applied at the standard rate of 6 Mg/ha of total C, SM0.5 applied to reach the equivalent of 3 Mg/ha of total C, and the untreated controls with (UTC W) and without (UTC) initial irrigation. Three weeks after the ASD treatment, Romaine lettuce was planted as a test crop. Organic amendments tested as C source were characterized by different C:N ratio, ranging between 6.3 (SM) and 57.2 (M). All the amendments tested ensured the achievement of good soil anaerobicity levels. The C:N ratio of the amendments significantly influenced the availability of nitrate-N during and post-ASD, thereby influencing the lettuce crop yield and quality performance. Having the highest C:N ratio, M applied by itself decreased the availability of nitrate-N during and post-ASD. Instead, SM characterized by the lowest C:N ratio, increased the availability of nitrate-N. The availability of N during the growing cycle, determined by the characteristics of the organic amendment and by the ASD treatment influenced the crop yield and nutritional profile. The results of the present study provide new insight for the selection of alternative C sources and the optimization of the ASD treatment in organic protected culture systems.

The utilization of cover crops in vineyards has been promoted for their role in moderating soil climate, thus enhancing vineyard resilience to extreme weather conditions. This study evaluated the effectiveness of three drive-row cover crop treatments in regulating soil moisture and temperature within an irrigated organic vineyard characterized by loamy sand soil, located in the semiarid Okanagan Valley, Canada, over the period from 2021 to 2023. Selection of cover crop species was informed by prior greenhouse and field screening experiments. The implemented treatments, established in May 2021, included a mixture of perennial ryegrass, tillage radish, and white clover (PRTRWC); a fescue mixture with white clover (FWC); cereal rye with hairy vetch (CRHV); and a Control (existing vegetation/weeds). The vineyard was equipped with drip lines and undercanopy sprinklers. Soil moisture and temperature were monitored every four hours using Teros 11 sensors at a 10 cm depth in the drive-row. Seasonal observations revealed the highest soil volumetric water content (Ɵv) from November to April, aligning with cooler temperatures and increased precipitation. The Ɵv ranged from 0.10 to 0.14 and significant differences in average Ɵv were noted among the all treatments over the three growing seasons (May to Oct), with CRHV displaying the highest levels, followed by FWC, Control, and PRTRWC. Notably, substantial differences in Ɵv (

The plant rhizosphere plays a key role in plant function and immunity. Apple Replant Disease (ARD) is a dysbiosis in apple rhizosphere environments that have a history of apple cultivation. Due to increased intensification of apple growing systems and land scarcity, ARD incidence is on the rise and can result in a 50% loss of profitability to growers. Soil fumigation is a common practice for mitigating ARD, but has limited efficacy and is not allowed in some areas because of potential for environmental damage and human harm. Using resistant rootstocks is a key strategy in overcoming ARD. To understand rootstock resistance, it is important to describe and characterize the microbial communities of various rootstocks in an environment conducive to microbial health. We planted an organically managed apple orchard with 5 randomized repetitions of 15 different rootstocks. In both 2022 and 2023, we sampled the soil adhering to the roots of these trees for DNA extraction in order to characterize both bacterial and fungal microorganisms in the rhizosphere of the rootstocks in our research. We also established an aeroponic greenhouse trial (randomized with three repetitions) to sample rhizodeposits from 6 of the rootstocks used in the orchard trial, with the aim of characterizing metabolites with untargeted HPLC/LCMS. Bacterial phyla and genera differed in relative abundance between the rootstocks. A sparse PLS (partial least squares) discriminant analysis of rootstock exudates revealed differential sorting of some rootstocks. Neither study revealed clear biological indicators for ARD resistance, but the results evince that rootstock genotype does influence both microbial community and tree root exudation patterns.

Consumer demand for organic and locally sourced plant-based protein has created an opportunity for farmers in the Northeast and Upper Midwest who are interested in organic dry bean (Phaseolus vulgaris) production. However, standard practices for organic dry bean production can degrade soil health because of the soil tillage and cultivation used for weed management and harvesting. Such soil disturbance is not only labor and fuel intensive, but it also makes soil vulnerable to extreme weather, which is a major concern given the increased frequency of heavy rain events. Building on success with no-till planting soybean into mechanically terminated cereal rye, a team of researchers and stakeholders from Wisconsin, New York, Maine, and Vermont developed a project to assess dry beans for cover crop-based, organic no-till production. In addition to crop yield and profitability, field experiments focused on assessing weed and disease management. Findings from several experiments show that dry beans can successfully emerge through mulch from cover crops and produce yields that are comparable to standard tillage based organic production. In an experiment conducted at two sites in 2020-2021 and 2021-2022, a cover crop mixture of hairy vetch and cereal rye produced relatively high biomass (>7000 kg/ha), which suppressed weeds (< 500 kg/ha) and resulted in relatively high (2500 kg/ha) organic black bean (cv. ‘Zorro’) yield. Results are congruent with previous research showing that mulch from cover crops can suppress weeds, particularly small seeded annual weeds. In an experiment conducted in 2016-2017 and 2017-2018, we showed that mulch from mechanically terminated cereal rye (Secale cereale) can also reduce the incidence of the fungal disease white mold (Sclerotinia sclerotiorum) in organic no-till planted dry bean. Although mulch from cover crops can suppress weeds and soil borne diseases, achieving the high cover crop biomass production that is necessary for suppression can be challenging. A field experiment was conducted in Wisconsin, New York, Vermont, and Maine in 2022-2023 to test the efficacy of interrow mowing weeds that break through the mulch in the space between crop rows. Preliminary results show that interrow mowing has potential to reduce yield loss from weeds and weed seed production in organic no-till planted dry bean production. Additional research is needed to develop management guidelines for no-till planting organic dry beans into rolled-crimped cover crops.

PoDRM2: Unveiling a Key Regulator of Biomass Production and Starch Accumulation in Arabidopsis thaliana - JianHuang
Efficient high molecular weight DNA isolation and whole genome sequencing of papaya for molecular applications - Jon Suzuki
Tissue Culture Regeneration of Miscanthus Sinensis ’Gracillimus’ - Kedong Da
In Vitro Shoot Regeneration Protocol For Southern Highbush Blueberry (SHB) Cultivars - Anandi Karn

Starch, a vital dietary component and crucial for bio-ethanol generation, is synthesized by plants during photosynthesis. Augmenting starch output holds promise for human and animal nutrition, as well as bioenergy. Our previous work involved cloning the homolog gene DRM2 from Purslane and subsequently overexpressing PoDRM2 in Arabidopsis. Comparative analysis between wild-type Columbia and homozygous PoDRM2 transgenic lines revealed a substantial increase in plant size and nearly a 90% rise in fresh biomass per plant in PoDRM2 lines, indicating a potentially heightened efficiency in photosynthesis. We conducted further investigations into starch synthesis and accumulation in leaves. Iodine staining revealed that PoDRM2 transgenic Arabidopsis lines accumulated significantly more starch than the control under both dark and light conditions. Additionally, total carbohydrates in the leaves of transgenic lines more than doubled that of the wild type. Furthermore, PoDRM2 lines exhibited higher chlorophyll content compared to the control. These findings strongly indicate that PoDRM2 serves as a crucial regulator of starch accumulation. PoDRM2, encoding a methyltransferase, was implicated in altering the methylation status of over 2,500 genes through genome-wide bisulfite sequencing. Notably, 55 out of 61 genes involved in the photosynthesis pathway were affected, underscoring the significant role of DNA methylation in regulating starch accumulation and photosynthesis in plants.

Plant whole genome sequencing provides detailed information on gene content, genome organization, and evolutionary relationships as well as supports biotechnological applications such as gene editing. The first 3X draft genome sequence of papaya based on whole genome shotgun reads from the transgenic ‘SunUp’ papaya cultivar was published in 2008. Since then, advancements in sequencing and whole genome assembly enabled a near complete sequence of ‘SunUp’ and a detailed picture of events resulting from particle gun-mediated transformation. With current technology, the 372 Mb genome size of papaya makes it tractable for routine whole genome sequencing to characterize different cultivars and molecular events. In this study, we improved ease and speed of preparation, efficiency of recovery, and DNA quality through a combination of classical and contemporary plant nuclei or high molecular weight DNA isolation methods. Leveraging Hi-Fi sequencing and Hi-C technology, we achieved rapid chromosome-level sequence assembly of two local Hawaiian cultivars, Kapoho and Waimanalo. The assembled genomes of Kapoho and Waimanalo spanned 341.6 Mb and 337.4 Mb, respectively, with a total of 20,343 and 20,165 annotated protein-coding genes.

The genus Miscanthus is considered an ideal choice for both ornamental and biofuel purposes, owing to its appealing aesthetics and significant potential for high-energy biomass production. Traditional breeding efforts in Miscanthus have predominantly focused on enhancing nutrient efficiency and tolerance to both biotic and abiotic stresses. However, these endeavors are often time-consuming. The emergence of plant genome editing technologies has opened up a new and efficient avenue for Miscanthus breeding. These innovative techniques hold promise for accelerating the breeding process, allowing for more rapid and targeted improvements in desired traits. The development of an efficient plant regeneration system is crucial for the application of modern genome editing technologies in Miscanthus breeding and for achieving large-scale biomass production. Among the Miscanthus species, Miscanthus sinensis poses a particular challenge in tissue culture regeneration. In this report, we present an effective system for callus induction and regeneration in Miscanthus sinensis. Callus was induced from the stems of in vitro-cultured Miscanthus sinensis 'Gracillimus' using a modified MS media supplemented with varying levels of 2,4-D. Regeneration-competent callus was achieved through continuous selection on the callus maintenance/selection medium over a period of 6 months. Remarkably, 100% of the callus successfully regenerated new shoots on a modified MS medium containing Benzylaminopurine (6-BA) and α-Naphthaleneacetic acid (NAA). This marks the first efficient 'Gracillimus' regeneration system using in vitro culture as the starting material. The established system demonstrates a high potential for the micropropagation of Miscanthus sinensis 'Gracillimus' with a propagation rate of 3.5. Currently, efforts are underway for genome editing of Miscanthus sinensis utilizing this established system.

Blueberry (Vaccinium sp. L.) is one of the most important fruit crops from the Ericaceae family and the highbush blueberry (Vaccinium corymbosum) is the most widely grown species. It's popularity is increasing day-by-day because of their unique flavor and rich nutritional content. Consequently, significant efforts have been made to develop superior cultivars with high yield, biotic and abiotic stress resistance using conventional breeding. However, due to high heterozygosity, polyploidy and long juvenile period, traditional breeding approaches can often be tedious and time consuming. Therefore, there is need to integrate modern precision breeding tools with traditional ones, to accelerate blueberry crop improvement. However, the success of novel biotechnological tools like gene editing and conventional transformation relies on successful shoot regeneration system. Many studies in blueberry show a lack of reliable regeneration protocols and their genotype-dependency. Furthermore, most of the reported regeneration studies have been conducted on northern highbush blueberry (NHB) cultivars. Therefore, the current study aims to develop shoot regeneration protocol for seven important southern highbush blueberry (SHB) cultivars (Colossus, Optimus, Albus, Arcadia, Keecrsip, FL 14-242

Assessing the Viability of Olive Trees as an Alternative Fruit Crop for Cultivation in Florida  - Lorenzo Rossi
A Comparative Study of Ripening Timelines in Haskap (Lonicera caerulea L.) Cultivars. - Venkateswara Rao Kadium
Biostimulants Did Not Influence Strawberry Yield but Increased Fruit Sugar Content - Jayesh Samtani
Assessment of Botrytis Fruit Rot Susceptibility in Selected Strawberry Cultivars under Field Conditions - Jayesh Samtani
Evaluation of Cordon Training System in Blackberry Production - Jayesh Samtani
Effects of Chitosan and Ultraviolet A (UVA) Light on Postharvest of Blackcurrant Fruit - Venkateswara Rao Kadium
Updates on the Genome Database for Vaccinium (GDV): How GDV supports Vaccinium Research and Breeding - Roohollah Abdolshahi

Over the past decade, the cultivation of olive trees (Olea europaea) in Florida has experienced remarkable growth, expanding tenfold. Currently, there are more than 60 growers tending to approximately 800 acres spread across 26 counties in Florida. Despite this significant expansion in Florida’s olive tree cultivation, accompanied by a surge in global olive oil demand, research in this area has been lacking. To address this gap, comprehensive data collection commenced in the summer of 2023 through three distinct trials located in Jay, Wauchula, and Fort Pierce, Florida. These trials aim to determine the most productive olive tree varieties and optimal cultivation techniques tailored to Florida’s diverse climate and soil compositions. Given variations in grove management approaches and tree maturity levels, a range of cultivars representing different genotypes were being tested across various locations. The cultivar ‘Arbequina’ was consistent across all trials. In addition to ‘Arbequina’, other cultivars such as ‘Koroneiki’ and ‘Sikitita’ were assessed in Wauchula, while ‘Lecciana’ and ‘Sikitita’ were examined in Fort Pierce. Throughout the trials, parameters including soil fertility, temperature, soil moisture levels, as well as leaf nutrient status and phenological observations were quantified twice a year. No nutrient deficiencies were detected in either soil or leaf samples, but also no consistent patterns regarding flowering or production were observed. The ongoing data collection is expected to shed light on critical aspects regarding the feasibility of olive tree cultivation within the Florida environment and provide valuable insights for growers and stakeholders.

Haskap (Lonicera caerulea L.), also known as edible blue honeysuckle or honeyberry, is a new and emerging berry crop in North America. Its resilience to cold temperatures, adaptability to various soil pH levels, distinctive flavor, and health benefits make it suitable for cultivation in colder climates. The period from flowering to fruit ripeness is remarkably brief in haskap, typically ranging from six to eight weeks, offering an advantageous alternative in shorter-growing regions. Yet, detailed guidance on its cultivation and fruit quality is scarce. To aid growers, a two-year study at the Western Agricultural Research Center assessed the ripening timelines of 15 haskap varieties, providing critical data to optimize harvest timing and management practices. Throughout the growing seasons of 2022 and 2023, from May through August, fruit quality and ripening stages were closely monitored two to three times a week by collecting berry samples. From these samples, traits such as total soluble solids content (Brix), pH, total acidity (TA), single berry mass, and berry color changes were measured. Assessment of this phenotypic data revealed distinct patterns for each trait across the different varieties studied. Cultivars such as 'Blue Goose', 'Boreal Beauty', and 'Sugar Mountain Blue' reached their harvest readiness sooner, around approximately 650 growing degree days (GDD) for the year, followed by a reduction in berry size due to water loss and a rise in sugar concentration. In contrast, Aurora, Tana, and Kawai matured more slowly, achieving peak ripeness near ~1000 GDD. Yet, they preserved their mature fruit characteristics (consistent berry weight and sugar levels) through the sampling period’s end. These insights into the ripening patterns of haskap varieties from prominent breeding programs in North America can inform growers as they choose specific cultivars and decide on optimal harvest times.

Botrytis fruit rot (BFR) or grey mold disease, caused by Botrytis cinerea Pers., poses a significant threat to strawberry crop production in the mid-Atlantic region of the U.S. The extensive use of fungicides to combat this fungal disease has resulted in listing the strawberries in the Dirty Dozen fruits and the evolution of fungal strain resistance to fungicides. Hence, exploring potential alternative strategies is crucial to reducing pesticide use and minimizing BFR; as such, utilizing resistant plant cultivars is a potential strategy. With this, the current study aimed to assess the susceptibility of two cultivars to Botrytis, Flavorfest, and Honeoye, which showed resistance to gray mold under in vitro conditions, and compare them with grower standard cultivars, Chandler and Sweet Charlie, under field conditions. The field evaluations were conducted at two locations during the 2022-2023 growing season: Hampton Roads Agriculture Research and Extension Center in Virginia Beach, VA, and a grower farm in Fredericksburg, VA. Transplanting of plants was done on October 12, 2022, in Fredericksburg and October 17, 2022, in Virginia Beach. A randomized complete block design was used in the experiments with four replicates per cultivar in Virginia Beach and three replicates in Fredericksburg, and each replicate had 12 plants. Fruits were harvested twice a week throughout the season to assess BFR occurrence and marketable crop yield. The main effect of the cultivar was significant for Botrytis fruit rot and marketable yield for the season. 'Honeoye' showed the lowest BFR-infested fruits (~6.5 g of fruits/plant), compared to 'Chandler' (22.5 g). However, 'Chandler' showed the highest marketable yield (713 g/plant), followed by 'Sweet Charlie' (473 g), while 'Flavorfest' (261 g) and 'Honeoye' (216 g) produced the lowest yields. Additionally, marketable yield differed by location, with higher yields recorded in Virginia Beach. Post harvest parameters including fruit firmness, total soluble solids (TSS), and pH that were measured on a subsample of fruits in Virginia Beach showed significant cultivar effect . ‘Honeoye’ had the least firm fruit but had the highest TSS for the season, not different than ‘Sweet Charlie’. The fruit pH of ‘Sweet Charlie’ was the highest. Information on resistant cultivars could assist growers in choosing appropriate cultivars to meet their farm production practices.

Blackcurrant (Ribes nigrum L.) is a small fruit known for its health benefits, but treatment effects on postharvest storage for fresh markets remains understudied compared to other berries, such as blueberry (Vaccinium spp.). This work aims to identify the effect of chitosan coating, ultraviolet a (UVA) light, and combined UVA-Chitosan treatments on blackcurrant postharvest storage. Physical (weight loss and firmness) and physiochemical analyses (soluble solid content, pH, citric acid content, and ascorbic acid content) were combined with microbial population quantification, phenolic compound characterization, and antioxidant capacity assessment. Samples were evaluated every three days of storage throughout this experiment. The results indicated that chitosan treatments have positive effects on reducing berry weight loss, maintaining berry firmness, and reducing mold populations. UVA influenced certain bioactive compounds, such as cyanidin-3-galactoside and rutin. The interaction effects from these two treatments were minimal. This study provides important information for blackcurrant postharvest storage and further small fruit storage work, considering both UVA and chitosan had differential beneficial effects on blackcurrant berries’ physical and chemical attributes.

In the past few years, there has been an increased interest in the use of biostimulants for improved crop production. Biostimulants are products that can promote plant growth when applied in amounts so small that they do not provide much nutrition. These are composed of different organisms, compounds or plant extracts; they include beneficial fungi and bacteria, humic and fulvic acid, seaweed extracts, and protein hydrolysates. During the 2022-23 growing season we evaluated three different biostimulant products in annual hill strawberry plasticulture production. ‘Ruby June’ plants were transplanted on 24 Oct, 2022 on non-fumigated beds and were maintained as per grower standard practices. Treatments were as follows (i) no biostimulant (ii) preplant AminoSalmon (247 kg/ha) applied during bed making (3) plugs dipped for 20 seconds in TerraGrow Liquid (TGL, 3ml/38 L) prior to transplanting followed by a foliar spray and a drip application (1.5L/ha) at one, fourteen, and thirty days after transplanting, resuming monthly during spring; and (iv) EZ-GRO 16-0-0 (3.9 kg/ha) drip application 14 days after transplanting and every 14 days during fall, resuming during spring. All non-treatment irrigation valves were closed during treatment injection through the drip lines. Ripe fruit was harvested beginning 31 March and continued twice a week until 16 June. Harvested fruit was categorized into marketable and non-marketable yield by replicate and fruits were weighed for each category. Yields were cumulated for the season and expressed as g/plant for data analysis. For total yield and marketable yield, no treatment differences were found. Fruit size was estimated as g/fruit by weighing 10 marketable fruits weekly. Five marketable fruits were measured weekly for firmness using a texture analyzer then stored at -20 °C for later analysis of pH and total soluble solids (°Brix) using a digital refractometer. While fruit firmness and pH were not influenced by treatments, the application of both the amino salmon and EZ-GRO biostimulants significantly improved total soluble solids values compared to the untreated control.

The Genome Database for Vaccinium (www.vaccinium.org) is a valuable resource for genomics, genetics, and breeding research related to blueberries, cranberries, bilberries, and lingonberries. It provides a wide range of genetic data, including genetic markers, linkage maps, and GWAS/QTL alongside genome data. GDV has the MapViewer tool to dynamically view genetic maps as well as genetic data associated with genomes and powerful search interfaces to query and download genetics data in table formats. For Vaccinium breeders, The Breeding Information Management System (BIMS) is a useful tool for storing, managing, archiving, and analyzing breeding data. Additionally, BIMS can be synchronized with the Field Book App to allow efficient phenotypic data collection and management. This poster will provide an update on new data and tools such as BIMS and MapViewer incorporated in GDV. We will demonstrate how these data and tools can be used for research and breeding activities.

Six -year Performance of Semi-dwarfing Peach Rootstocks From the NC-140 'Cresthaven' Trial in Western Colorado - Jeff Pieper
Nutritional Dynamics and Horticultural Performance of Peach Orchard in the United States in Response to Different Soil Amendment Programs. - Ayodeji Idowu
Influence of Low-, Medium-, and High-Chill Requirement Rootstocks on the Metabolomic Profile of Low-Chill Peaches - Jonathan Clavijo Herrera
Effects of plum tree architecture on canopy light environments and fruit quality - Lisa Tang
Does the Utah Model Still Work in Utah? Evaluation of Existing Phenological Models for Tart Cherry in a Changing Climate - Josette Moon
A Mobile Cartographer System to Measure Tree Growth Within Tart Cherry Orchards - Brent Black
Enhancing Uniformity in Tart Cherry Orchards Through Precision Management and Variable Rate Fertilization - Kurt Wedegaertner
Tree temperature prediction to improve chill accumulation estimation in cherry under climate change - Giulia Marino

Eight rootstock cultivars were planted in 2017 as part of the NC-140 semi-dwarfing peach [Prunus persica (L.) Batsch] rootstock trial. The eight rootstock cultivars were budded to ‘Cresthaven’ and examined for their potential use in Western Colorado high density production systems. Listed in order of declining vigor the rootstocks included ‘Guardian®’, ‘Rootpac® 20’, ‘Lovell’, ‘ControllerTM 8’, ‘ControllerTM 6’, ‘Rootpac® 40’, ‘ControllerTM 7’, and ‘MP-29’. One rootstock, ‘ControllerTM 7’, was unable to perform in alkaline soils, showing extreme iron chlorosis and diminutive fruit size. Deemed unsuitable for use in Colorado, this rootstock was removed from analysis in the 3rd leaf. Six years of data showed that all remaining rootstocks, except ‘MP-29,’ had vigor profiles within 14% of ‘Lovell’, a known standard, making them attractive candidates for use in high density production. The two ‘Rootpac®’ rootstocks performed contrary to previous reports. ‘Rootpac® 20’ was the second most vigorous and ‘Rootpac® 40’ was the third least vigorous, slightly larger than ‘ControllerTM 6’. Additional physiological traits showing distinct differences between the rootstocks were yield, proleptic shoot formation, light interception, fruit size, and internal fruit quality. In the six years since planting there have been three harvests. Cumulative yield showed a strong linear relationship to vigor (TCSA). ‘ControllerTM 6’ had early precocity and high yields given its vigor class. Observance of gummosis was also positively associated with vigor. Both vigor and proleptic shoot formation manipulated the canopy light environment. ‘ControllerTM’ series rootstocks had increased proleptic shoot formation. Vigor-limiting rootstocks had increased light availability in the canopy leading to enhanced dry matter content and soluble solid concentration. Cumulative fruit size and weight showed ‘Rootpac® 20’ had the heaviest, and ‘ControllerTM 6’ the largest, fruit size. ‘MP-29’, the most dwarfing rootstock produced smaller fruit on average; however, fruit size was still commercially acceptable.

Compost, mulch and manures have been reported as a potential substitute for synthetic fertilizer in fruit orchards, can improve soil health as well as increase the sustainability of orchard systems. In this study, we compared two rates (10 tons/acre as compost 1x and 20tons/acre as compost 2x) of pre-plant incorporation of food waste compost (FWC) and growers’ standard rate of inorganic/chemical fertilizer (control) of a replanted and virgin peach orchards in South Carolina. Measurement includes soil health indicators such as soil nutritional status and macronutrient dynamics, yield, and fruit quality (specifically on the incidence of diseases and physiological disorders). We hypothesized that the pre-plant incorporation of organic matter with subsequent topical application would improve soil moisture and nutrient availability, increase yield, and enhance the quality of marketable fruits. Higher cation exchange capacity and buffering capacity was recorded in soil treated with FWC than in the control treatment. In the replanted orchard, the 2x treatment resulted in improving soil health indicators such as SOM, cation exchange capacity, phosphorus, soil infiltration, and soil moisture, but not in the virgin orchard compared to the control treatment. Soil extractable P was higher in the FWC treatment as compared to the control treatment, while the soil extractable K ranges from high to excessive K across all treatments. No significant difference between the yields from both orchards. However, we observed numerical differences in the yields of the 2x treatment compared to the 1x and control treatments. Our results show that the yearly application of compost provides the orchard’s nutritional requirement, increases yield, and lower disease pressure in both orchards compared to the control treatments.

Rootstocks are widely used for commercial orchard establishments throughout the world, as they facilitate scion adaptation to challenging edaphic and environmental conditions, as well as mitigate the impact of pests and diseases. Furthermore, rootstocks may influence physiological, biochemical, or phenological processes in the scion. Nevertheless, little is known about the influence of rootstocks on metabolomic profiles of Prunus scions, particularly in low-chill cultivars. This study aimed to determine the influence of rootstocks with varied chilling requirements on the metabolomic profiles of low-chill peaches. Scion ‘UFSun’ was grafted on low-(Flordaguard), medium-(P-22), and high-(MP-29, Guardian, and Nemaguard) chill requirement rootstocks, and grown in a greenhouse in Gainesville, Florida. Vegetative tissue samples were collected for extraction of metabolites. Untargeted compounds were analyzed using an Orbitrap Fusion Tribrid mass spectrometer system, interfaced with an automated A VanquishTM UHPLC system, and a total of 152 metabolites were detected. Potential differences in metabolomes associated with the rootstocks were analyzed by performing a partial least square–discriminant analysis (PLS-DA), although it was not possible to determine group differences when comparing all treatments. An orthogonal PLS-DA approach supported by permutational MANOVA test was implemented for paired comparison of plants grafted on Flordaguard (rootstock recommended for commercial production in Florida) vs. all other rootstocks, and differences were observed for all comparisons. For further confirmation of these results, and determination of the metabolites potentially differentially expressed due to rootstock influence, the Empirical Bayesian Analysis of Microarrays (EBAM) approach was implemented, as adjusted for analysis of metabolites in MetaboAnalyst 6.0. A total of 85, 52, 0, and 61 metabolites were dimmed as potentially differentially expressed when comparing trees grafted on Flordaguard vs. P-22, MP-29, Guardian, and Nemaguard, respectively. Most of these metabolites may be flavonoids, phenylpropanoids, and polyketides. According to our observations, low-, medium-, and high-chill rootstocks can influence the metabolomic profile of low-chill scions.

In the orchard production system, upright or pillar trees with vertical branch orientations have narrow architecture profiles and therefore can be suited to high-density planting to increase productivity. In plum (Prunus domestica), there are natural variations of tree forms that range from upright to more horizontal growth habit. Recently, researchers at the USDA-ARS Appalachian Fruit Research Station demonstrated that silencing TILLER ANGLE CONTROL 1 (TAC1) via RNA interference (RNAi) in ‘President’ plum led to pillar tree forms with upright lateral shoot growth, whereas silencing LAZY1 in ‘Stanley’ plum resulted in outward shoot orientations and weeping tree shape. The objective of this study was to assess the effects of tree architectures on canopy light availability and fruit quality using field-grown mature (7-year-old) TAC1 and LAZY1 silenced plum trees in comparison with their respective non-transgenic counterparts as controls. Our results indicated that slender canopy profiles due to silencing of TAC1 allowed significantly greater light availability without negative impacts on fruit size, soluble solids contents, or titratable acidity compared to non-transgenic plum with the same genetic background. Additionally, skin color of fruit was more uniform in TAC1-RNAi lines than in standard-shaped control trees, suggesting a positive correlation between canopy light distribution and fruit coloration in association with upright branch orientations. In contrast, light availability in LAZY1-RNAi tree was reduced significantly by over 50% compared to the control. Although there is no difference in fruit size, soluble solids content in fruit of the LAZY1-RNAi plum than that of the non-transgenic counterpart.

Phenological models use local temperature data to predict spring flower bud development and guide management decisions in temperate fruit crops. In high elevation continental regions such as the U.S. Intermountain West, changing climate brings more extreme temperature variability resulting in increased risk of spring freeze damage. We evaluated bloom dates of tart cherry (Prunus cerasus L. ‘Montmorency’) in a high elevation continental climate (1327 to 1484 m elevation, Utah) to test the validity of 50-year-old phenological models under current climatic conditions. Mature commercial tart cherry blocks were selected in proximity to existing weather stations (climate.usu.edu, FGNet). Bud stages were observed weekly in April and May of 2019 through 2023 with 3 to 8 locations monitored per year. Observed stages were compared to Utah Standard and Modified prediction models. Prediction error varied with year and stage of development, where 2023 bloom was on average 3 days earlier than predicted, compared to 2020 when bloom was 6 days later than predicted. Modern weather stations provide more detailed climatic data (hourly temperature, light, humidity, wind speed), and the opportunity to refine and improve existing models. Improved model reliability would provide better decision support for increasingly expensive freeze protection measures.

Temperate orchard sites have highly variable soils that contribute to uneven tree growth, providing a unique setting for precision management efforts. Precision management seeks to map spatial variability and implement variable rate management to optimize inputs. The objective of this study was to develop a platform for simultaneous measurement of tree growth and size to facilitate the enhancement of precision management practices in tart cherry (Prunus cerasus) orchards. Measurements included: canopy light interception; canopy height, volume, and width; and trunk cross sectional area (TCSA). Light interception (ceptometry) was by 15 30-cm line quantum sensors recording PAR at 0.6-second intervals, positioned on a UTV-mounted boom that passed under the canopy. Light interception was calculated based on data from a reference PAR sensor placed outside the orchard. Canopy height, width and volume of individual trees were measured using a side-scan LiDAR system mounted to the same UTV that generated point-cloud maps of each orchard row. These canopy measurements were then compared to point-cloud maps generated from aerial visual imaging (UAV). TCSA was estimated using a stereovision depth camera that captured paired visual spectrum (RGB) and point-cloud images, that were then aligned and segmented for individual tree trunks. Using pixel depth data, trunk widths for individual trees were estimated. The platform and associated sensors were used to map four commercial tart cherry orchard blocks (8-10 ha) located near Santaquin, Utah, USA, during the 2023 (ceptometry and UAV, only) and 2024 seasons at 2-week intervals. During the 2023 season, 8 ceptometry maps were generated with corresponding UAV-based maps. Side scan lidar data for 1 map of canopy height, width, and volume were collected in each of the 4 orchards, along with data for 1 TCSA map. Preliminary analysis shows strong spatial agreement among mapping techniques, indicating that the technologies are well suited to precision orchard management. Data for 2024 will also be presented, with multi-season tree growth analysis.

Tart cherry (Prunus cerasus) orchard sites are often chosen for favorable microclimates, and consequently exhibit highly diverse soil conditions that result in non-uniform tree growth and yield potential. There is increasing interest in utilizing precision management techniques to map tree vigor and implement variable rate management to optimize inputs and enhance uniformity. The objective of this study was to assess the variability of soil and canopy characteristics and implement prescription fertilizer rates based on the mapped variability. The study was conducted on four mature (18-22 years) commercial tart cherry orchard blocks (8-10 ha) located near Santaquin, Utah, USA. Soil variability maps for each orchard were generated through soil sampling, guided by surveying apparent electrical conductivity (ECa) using an electromagnetic induction meter. Spatial variability in tree vigor was quantified using satellite imagery provided by Simplot Smart Farm® Permanent Crop Analysis. Prescription fertilizer rates, derived from the variability maps, were applied to each block in the spring/summer of 2023 and 2024, which included granular fertilizer applied as a single application or as split applications based on each prescription map. Tree response to the prescription treatments were monitored every two weeks using a novel platform capable of mapping plant growth parameters including canopy height, volume, width, and density; and trunk cross sectional area (TCSA). By monitoring growth parameters within this timeframe, we were able to comprehensively evaluate within-seasonal fluctuations in growth. Soil sampling revealed significant correlations between ECa and soil texture. Preliminary results indicate significant within-orchard variations in mid-season tree vigor, that are also correlated with long-term growth characteristics (canopy size and density). Both long-term and short-term growth measures are also closely correlated with soil ECa (i.e. texture). The effect of variable fertilizer application within this soil texture variability will be discussed, offering insight into the effectiveness of precision management techniques in mitigating variability within tart cherry orchards.

Timing application of dormancy breaking products is essential for adequate bloom and yield in cherry. Available temperature-based chill accumulation models often fail to predict correct spray timing, particularly during years with unusual temperature patterns recently driven by climate change. One potential cause for the unreliability of the current models is their dependence on a single climatic variable, air temperature, to estimate the impact of weather on tree physiological processes. We hypothesized that using tree temperature, rather than air temperature, will increase the accuracy in predicting chill accumulation, especially in warm and sunny winters. Hence, our objective was to develop a framework to predict cherry tree temperature based on easily available environmental data. For three consecutive seasons and in three commercial cherry orchards across California, including the southernmost US cherry production region, we measured main climatic parameters at half hour intervals. At the same time, we monitored tree temperature with T-type thermocouples inserted below the bark of main branches. We developed predictions of tree temperature as a function of meteorological variables obtained from public weather stations using generalized additive models. Trees were, on average, 10 ºF warmer than the air during clear days, with differences being up to 20-25 ºF. Tree chill accumulation was about 8-12 chill portions lower than air chill accumulation. The difference was year- and site-specific, reflecting the importance of including diverse environmental parameters to estimate chill accumulation precisely. The ‘TreeChill model’ predicts tree temperature based only on environmental parameters easily achievable from public weather stations with a coefficient of determination of 0.956 resulting in only 0.4 chill portions difference between measured and predicted tree chill. This model will enable growers to implement tree temperature in their management decisions, including dormancy breaking agent applications, cultivar selection, pest control etc, increasing California cherry industry resilience to climate change. In the future, we plan to adapt the model to different crops and locations.