ASHS 2024 Conference

The Climate Ready Landscape Plants Project. Testing Plants For Drought Tolerance Across The Western U.S. - Lorence Oki
Performance of landscape shrubs under three irrigation levels in Arizona - Ursula Schuch
Performance of Landscape Plants in California’s Central Valley Under Three Levels of Deficit Irrigation - Jared Sisneroz
Field Trials of Landscape Plants under Reduced Irrigation Frequency - Zirui Wang
Understanding Hernando County Residents' Perspectives on Fertilizer Use and Regulations - William Lester
Using Different Ratios of Blue and Red Light to Induce Drought Tolerance Morphology in Zinnia - Anju Chaudhary
Techniques to Improve Growth, Heat, and Drought Tolerance in Container Grown Trees - Drew Zwart
Using Marketing Initiatives to Promote the UF/IFAS Extension Florida-Friendly Landscaping Program - Tom Wichman

The Climate Ready Landscape Plants project evaluates the performance of plants exposed to three different deficit irrigation treatments in six climate zones. The experimental fields are completely replicated at all of the sites with plants spaced in a 2m x 2m layout, 8 replicates per treatment, up to 15 taxa tested per site, and irrigation based on reference evapotranspiration (ETo) with treatments of 20%, 50%, and 80% of ETo. Irrigation applications consist of a fixed volume of water depending on soil plant available water as determined by the US Geological Survey maps accessed via SoilWeb. The interval between irrigations was determined by accumulating daily ETo modified by the treatment factor. Irrigation occurred when the trigger value was attained. Plants were installed in the fall and irrigated with sufficient water for establishment during the first irrigation season and treatments were imposed during the second irrigation season. Monthly during treatment, 6 qualitative assessments of each plant were conducted and measurements in three directions were recorded to calculate a Plant Growth Index until the end of the treatment period that typically concluded in October. A substantial effort was made to ensure site-to-site consistency of the qualitative assessments by developing a ratings rubric and conducting frequent site visits with project management to “calibrate” site staff conducting the evaluations. Open House Field Days were conducted during the treatment season to which horticultural professionals and Master Gardeners were invited to evaluate the plants. This provided additional data and introduced the plants to potential users. This project started in 2004 as a graduate student research project, was expanded periodically at UC Davis, and then duplicated in 2017 at the UC South Coast Research and Extension Center in Irvine, CA as the University of California Landscape Plants Irrigation Trials™ (UCLPIT) project. With an award from the USDA Specialty Crops Multistate Program in 2019, the project was expanded to the University of Washington, Oregon State University, Utah State University, and the University of Arizona which facilitates the comparison of plant performance in response to deficit irrigation treatments across the western region of the U.S. The data collected leads to recommendations for irrigating those plants that are used by homeowners and landscape irrigation managers and assists landscape designers and architects designing landscapes that are water conserving and complying with California's landscape water conservation regulation, the Model Water Efficient Landscape Ordinance (MWELO).

Fifteen taxa of shrubs growing in a field in Tucson, Arizona were irrigated with three levels of irrigation based on local reference evapotranspiration (ETo) to assess growth and plant quality. Plants established during 2021 under 80% of ETo and in 2022 were irrigated at 20%, 50% or 80% of ETo. Irrigation was applied 2, 9, and 15 times between April 1 and October 31, 2022 for the low, medium, and high irrigation, respectively. Best performing plants were Asclepias linaria ‘Monarch Magnet’, Dodonaea viscosa ‘Emerald Ice’, Eremophila glabra ssp. carnosa ‘Winter Blaze’, Ericameria laricifolia ‘Aguirre’, Hamelia patens ‘Sierra Red’, Leucophyllum frutescens ‘San Antonio Rose’, Leucophyllum langmaniae ‘Rio Bravo’, Tecoma ‘Red Hot’ and Rosmarinus officinalis 'Arp'. Irrigation did not affect plant growth of these nine taxa from April to October. Monthly visual quality assessment of some taxa was temporarily affected by irrigation, however, all performed acceptable or better at the low irrigation with the exception of Asclepias linaria ‘Monarch Magnet’ which had less than acceptable ratings in July and August for the low and high irrigation treatments. This taxa also had 62% mortality of plants under the high irrigation treatment between July and October. Hamelia patens ‘Sierra Red’ plants had frozen to the ground in winter 2022 and started to regrow in May. Five of the taxa (Dodonaea viscosa ‘Emerald Ice’, Eremophila glabra ssp. carnosa Winter Blaze, Ericameria laricifolia Aguirre, Hamelia patens Sierra Red, and Leucophyllum frutescens ‘San Antonio Rose’) maintained a high overall rating at the lowest irrigation treatment. Two field days were held in August and October 2022 where participants from the green industry and related sectors were invited to rate overall appearance, flowering and foliage of one representative plant from each taxa and irrigation treatment. Ratings from field day participants were similar to those from researchers during that month. Most participants’ favorite plants included the five taxa with consistently high overall ratings, only Dodonaea ‘Emerald Ice’ was among the top four favorites at both field days. All nine taxa tested are low water use shrubs that can grow in the landscape with 20% of ETo in the low desert in Arizona. However, some may benefit from additional irrigation during the hottest time of the year for optimum performance.

To develop landscape irrigation recommendations, 22 taxa of landscape plants were evaluated under three levels of deficit irrigation in a field trial. The taxa consisted of common horticultural perennials and shrubs including multiple cultivars of Hibiscus syriacus, Nandina domestica, Rosa spp., and Salvia spp. Based on anticipated plant size and cultural requirements, taxa were planted in one of three adjoining fields, with each field laid out in a grid pattern with either 2 or 3 meter spacing between rows and between individual plants in each row. All fields were covered with a 2-3” layer of chipped bark mulch. For each taxon, 24 individuals were planted with eight replicates per irrigation treatment in a randomized complete block layout with both taxa and irrigation treatment being randomly assigned. Plants were installed in March as bareroot inputs, with containerized plants installed from April to early June of 2021. Daily reference evapotranspiration (ETo) values from a local weather station were obtained from the California Irrigation Management Information System. The amount of plant available water (PAW) for the trial site was obtained from the US Geological Survey via the Soilweb application. In 2021, plants were irrigated regularly to fully establish their root systems. From April to October 2022, plants were irrigated with one of three deficit irrigation treatments equal to 80%, 50%, or 20% of ETo. The treatments functioned similarly to a crop coefficient to modify daily ETo values. The modified ETo values were used to estimate when 50% of PAW was depleted for each treatment. Irrigations occurred whenever this threshold was reached, with the volume of water applied being equal to 50% of PAW. The volume applied at each irrigation was constant across treatments with the frequency between irrigations varying by treatment. As a result, the 80% treatment was irrigated most frequently with the 20% treatment was irrigated thrice during the deficit period. Monthly during the deficit period, each plant was rated on six categories of aesthetic quality and length, width, and height measurements were collected to develop a plant growth index. Aesthetic performance between the treatments was compared using an ANOVA in conjunction with Tukey’s HSD post-hoc test in R. A majority of the taxa evaluated maintained acceptable aesthetic quality ratings on the lowest irrigation treatment. Two taxa evaluated, Lagerstroemia ‘SMNLCIBF’ Center Stage® Red and Rosa ‘ChewPatout’ Oso Easy® Urban Legend achieved high levels of aesthetic performance on the 20% treatment.

Utah has experienced significant drought conditions, with 99.3% of the land under drought stress from the previous year to the present. In response to this challenge, deficit irrigation landscapes are gaining popularity in arid regions. This study aimed to investigate the overall appearance, plant growth, and physiological response of ten ornamental plants to deficit irrigation. The selected species include Caryopteris ×clandonensis ‘Blauer Splatz’ (Sapphire SurfTM bluebeard), Cercis canadensis (eastern redbud), Cercis occidentalis (western redbud), Cotoneaster ×suesicus ‘OSUCOT2’ (Emerald BeautyTM cotoneaster), Hesperaloe parviflora ‘Straight Up Red’ (‘Straight Up Red’ texas red yucca), Miscanthus sinensis ‘NCMS2B’ (bandwidth maiden grass), Physocarpus opulifolius ‘Diabolo’ (Diabolo® ninebark), Physocarpus opulifolius ‘Little Devil’ (Little DevilTM ninebark), Rosa ×hybrida ‘Meifranjin’ (Blushing Drift® rose), and Vitex agnus-castus ×rotundifolia ‘Helen Froehlich’ (Summertime BluesTM chaste tree). Eight plants per species were randomly assigned to one of three deficit irrigation frequencies, calculated based on 80% reference evapotranspiration (ETo) (high), 50% ETo (medium), and 20% ETo (low) at the Utah Agriculture Experiment Station’s Greenville Research Farm, North Logan, UT, USA. The overall appearance was evaluated biweekly, spanning from 30 Jun to 31 Oct 2023. Plant growth and stomatal conductance were recorded monthly during the growing season. The growth of plants was not significantly affected by reduced irrigation frequency. However, the impact of deficit irrigation on aesthetic performance and stomatal conductance was notable, particularly during August and September. The results highlight variability in plant performance across species, with Caryopteris ×clandonensis and Cotoneaster ×suesicus showing consistent performance across irrigation levels. However, Cercis canadensis and Physocarpus opulifolius ‘Diabolo’ exhibited a more pronounced difference under varying irrigation levels. Funding Source USDA Agricultural Marketing Service Specialty Crop Multi-State Program, USDA NIFA Hatch project UTA01666, 2022 Extension Water Initiative Grants Program, Utah State University’s Center for Water-Efficient Landscaping, and the Utah Agricultural Experiment Station

In response to recent revisions to the fertilizer ordinance in Hernando County, our research endeavors to delve into the attitudes and behaviors of residents towards fertilizer usage. With over 100 counties and municipalities in Florida implementing urban landscape fertilizer ordinances, Hernando County serves as a significant case study in understanding the dynamics of public perception and compliance. Our project employs a multi-faceted approach to gather comprehensive insights into resident perspectives. Tailored surveys have been developed to assess various aspects, including residents' knowledge of lawn care, familiarity with the county's fertilizer ordinances, current landscape conditions, and practices regarding fertilizer application. These surveys are being disseminated through diverse channels, encompassing social media platforms, the Hernando Extension networks, and Hernando County Utilities Department customers. Additionally, forthcoming focus group interviews will provide qualitative insights, offering a deeper understanding of community sentiments and the underlying factors shaping attitudes and behaviors. Through the integration of quantitative and qualitative data analysis, our aim is to gain a holistic understanding of the landscape of fertilizer usage in Hernando County. This entails not only identifying prevalent practices but also discerning the concerns and barriers faced by residents in adhering to the fertilizer ordinances. Such insights are pivotal in informing the development of targeted educational materials aimed at addressing community concerns, dispelling misconceptions, and providing practical guidance on responsible fertilizer usage. Our initial online survey revealed that 31% considered themselves very familiar with the Hernando County Fertilizer Ordinance, but 31% were not familiar with the details at all (n=383). Of these respondents, 73% care for their lawn and landscape themselves, with 11% using a professional service. Most residents responded that their lawn was fertilized at least once per year, with 18% saying that their lawn was never fertilized (n=844). Ultimately, the findings of our research hold significance beyond Hernando County, offering valuable lessons and strategies for promoting sustainable landscape management practices in similar contexts across Florida and potentially beyond. By fostering greater awareness, understanding, and knowledge of proper fertilizing practices, our project contributes to the broader goal of safeguarding water quality and environmental integrity for present and future generations.

Growing population, rapid urbanization and economic expansion have been raising the demand for fresh water. Additionally, climate changes, characterized by warmer temperatures, shifting precipitation patterns, and reduced snowpack are diminishing the water availability presenting new challenges for agricultural water use and conservation, particularly in the arid western states. One approach to addressing water scarcity involves inducing drought tolerance in crops. Plants exhibit physiological, morphological, and biochemical changes upon exposure to different wavelengths of light. This study focuses on determining the optimal ratio of blue to red light for inducing drought tolerance morphology in Zinnia elegans ‘Envy’. Seeds were sowed in Metro-Mix® 820 (SunGro Horticulture, Agawam, MA, USA) and kept on a misting bench. After germination, the plugs were exposed to full spectrum LED grow lights (ScynceLED, Mesa, Arizona) maintained at three ratios of blue and red light, 10:90, 25:75, and 50:50, controlled using a spectrometer (StellarNet Inc., Tampa, Florida, USA) in a covered chamber. The Photosynthetic photon flux density (PPFD) was maintained at 150 µmol.m-2.s-1 and the photoperiod was maintained at 12 hour dark and 12 hour light period. After four weeks of treatment, physiological and morphological parameters were measured in five destructively harvested plugs per treatment. The leaf number, growth index, and leaf area index showed no significant differences among treatments, however, the rate of assimilation and stomatal conductance were found highest under the 50:50 blue and red light ratio, compared to 25:75 but similar to 10:90. The total dry weight, leaf thickness, SPAD, and NDVI values were also higher at the 50:50 ratio, with total dry weight comparable to the 25:75 ratio. Subsequent irrigation treatments at 25% and 35% volumetric water content (VWC) were applied with the help of automated irrigation system using capacitance sensor, ECH2O 10HS (Meter Group, Pullman, WA, USA) to assess water requirements under different ratios of blue and red light suggesting a potential of these light treatments to reduce the Zinnia’s water needs.

Heat and moisture stress are increasing limitations to production of container-grown trees and growth of landscape trees, while reducing water use is an increasingly common goal. In two experiments, we investigated methods for reducing stress caused by limited water and extreme heat in container-grown tree seedlings in Aurora, Oregon. In the first experiment, we evaluated the potential for several ‘biostimulant’ or stress-tolerance inducing, soil-applied materials to improve growth of tree seedlings (Betula nigra) under limited water conditions. In the second experiment, we evaluated one of the most promising materials from that study in comparison to several other known or potential stress-reducing materials or techniques. In the first study, B. nigra seedlings were grown in pots with full water (determined by site evapotranspiration rate), one-half water, or one-half water with four different commercially available ‘biostimulant’ products that are marketed as inducing tolerance to moisture and heat stress in plants. Caliper growth, visual rating, and chlorophyll fluorescence values all showed that in the low-water groups, the plants treated with a mannitol plus calcium chelate product or a potassium phosphite product performed best and significantly better than the low-water control group. In the second experiment, over the course of two seasons we compared the effects of soil-applied potassium phosphite with other methods previously shown to reduce heat and/or drought stress. Abnormal extreme heat events, or ‘heat domes’, occurred during both growing seasons. Container-grown red maple (Acer rubrum) saplings were grown with moderate water and subjected to one of six treatments: untreated control, fresh-water misters triggered by preset ET value, kaolin foliar treatment, potassium phosphite soil application, propiconazole foliar treatment, and paclobutrazol foliar treatment. After two growing seasons, the mist treatment significantly improved growth compared to control plants while the potassium phosphite and kaolin treatments showed non-significant trends of improved growth. Based on these two studies, it is concluded that where possible, mist treatments during hot and dry conditions can improve container-grown tree seedling growth and condition, while potassium phosphite soil treatment and kaolin foliar treatments are likely to improve growth and condition in landscapes or where installation of misting apparatus is not feasible.

The UF/IFAS Florida-Friendly LandscapingTM (FFL) Program is Florida's premier Extension program for ecologically sustainable, science-based landscape practices that conserve water, protect water quality, and promote biodiversity. Since 1993, the FFL program has promoted water resource protection through both water conservation (water savings) and reducing non-point source pollutants (fertilizer nitrogen and phosphorus; pesticides) that may otherwise be carried into the state’s water bodies via runoff and/or leaching into groundwater. Despite longstanding promotion of FFL through Florida’s 67 county Extension offices, most Florida residents remain unaware of the program and its benefits. To promote public awareness of FFL, the program has undertaken a variety of marketing initiatives involving radio, television, social media, webinars, and online educational opportunities. On the radio, FFL produced a series of one-minute-long spots providing sustainable gardening tips. Called Florida-Friendly Landscaping in a Minute, the episodes aired twice each weekday on two NPR stations covering 19 northeast Florida counties. The daily listening audience was estimated at 4,600 for each airing, with 2.4 million total listeners each year. Webpage links to additional information back-up each episode. A wider audience was reached through the subsequent production of the Flip My Florida Yard television series. Produced in partnership with Crawford Entertainment with funding from the Florida Department of Environmental Protection, each 30-minute episode chronicles the complete makeover, or flip, of a homeowner’s typical Florida landscape into a more sustainable Florida-friendly landscape. All accomplished in eight hours, each episode features local designers and contractors and the local Extension agent, as well as a Maintenance Moment tip and a Yard Science segment featuring experts from UF/IFAS and other state entities. New shows air statewide on PBS and past episodes are streamed online. The program received a regional Emmy award in 2023. Flip My Florida Yard has been viewed more than 9.9 million times in the past year. FFL also recently hired a social media manager to increase FFL’s visibility on Facebook, Pinterest, Instagram, YouTube, and Linked-In. FFL’s social media reach is now growing exponentially. FFL also offers monthly webinars for both commercial and homeowner audiences. These webinars are archived to the FFL website and have accounted for more than 38,000 live and recorded views in the past year. Finally, the program has developed numerous online trainings and certification programs to help reach audiences at their convenience. As FFL begins its 32nd year, these marketing initiatives are helping it grow and reach new audiences.

Validation of Diagnostic Markers for Stenospermocarpic Seedlessness and Flower Sex in Diverse Muscadinia and Vitis Grape - Isabella Vaughn
High-Density Linkage Mapping and Identification of Quantitative Trait Loci Associated with Leaf-Scab Resistance in Pecan - Gaurab Bhattarai
Genome Wide Association Studies Unmasks Loci Associated With Fruit Size and Sugar Content in Mango - Vincent Njung'e Michael
A Genome-Wide Association Study To Identify Loci Underlying Fruit Color In Red Raspberry - Claudia Baldassi
Relatedness of Luther Burbank’s Plum (Prunus sp.) Introductions based on Genotyping by Sequencing (GBS) - Rachel Spaeth
A Deep Learning‐based Smartphone App for Blueberry Yield Prediction - Sushan Ru
Utilizing Optical Sorting Technology for High-Throughput Phenotyping in Sweet Cherry Breeding - Per McCord

Muscadine grapes (Muscadinia rotundifolia) are perennial vines grown commercially in the Southeast United States for the fresh market and as wine and juice grapes. Two highly sought-after traits in fresh market muscadine cultivars are stenospermocarpic seedlessness and perfect-flowered vines. However, the genetic disparity between Vitis and Muscadinia subgenera, coupled with differing chromosome numbers (Vitis=38 chromosomes, Muscadinia=40 chromosomes), presents challenges in introgression of stenospermocarpy from V. vinifera to M. rotundifolia. Although conventional breeding has introduced stenospermocarpy into M. rotundifolia, no molecular markers for this trait have been validated in muscadines. Recently, two Kompetitive Allele Specific PCR (KASP) markers targeting candidate genes for male sterility (VviINP1) and stenospermocarpy (VviAGL11) in V. vinifera have shown promise. Sequence comparisons with published V. rotundifolia genomes suggest that these markers might be effective across diverse Vitis, Muscadinia, and wide hybrid germplasm. In this study, we validated the predictive ability of KASP markers for flower sex and stenospermocarpy across thirteen Vitis x Muscadinia hybrid seedling populations and 191 diverse genotypes. In 2023, 891 seedlings were evaluated for seedlessness, with an additional 214 seedlings assessed for flower sex. Furthermore, 191 diverse accessions underwent evaluation for both flower sex and seedlessness. Of the 891 seedlings, 66 were seedless, 490 were seeded, and 335 could not be phenotyped due to fruit absence. Among the 214 seedlings assessed for flower sex, 88 were perfect, 106 were female, and 20 could not be phenotyped due to flower absence. The stenospermocarpy marker accurately predicted 771 of 783 seedlings and diverse material, while the flower sex marker matched 366 of 383 seedlings and diverse accessions. Discrepancies between marker predictions and observed phenotypes may be due to human error or pollen sterility. Notably, most fruitless seedlings were predicted to be stenospermocarpic, indicating potential issues with partial sterility or cold hardiness in seedless hybrids. We intend to reevaluate the populations for flower sex and seedlessness in summer 2024 to address discrepancies. Overall, the KASP markers developed in V. vinifera exhibited excellent predictive ability across diverse germplasm, offering valuable insights for muscadine breeding programs.

Genetic maps are essential tools for gene positional cloning and marker-assisted breeding. A pecan mapping population of 119 F 1 trees was derived from a cross of the widely planted cultivars Pawnee and Elliott. Whereas ‘Pawnee’ is susceptible, ‘Elliott’ has long- standing resistance to pecan scab caused by the fungal pathogen Venturia effusa. Molecular markers were developed using genotyping-by-sequencing, and linkage maps were constructed for each parent following the two-way pseudo-test-cross strategy used for cross-pollinated species. The ‘Pawnee’ and ‘Elliott’ maps contain 1,347 and 1,050 single nucleotide polymorphism markers spanning a genetic distance of 4,493.0 and 3,758.4 cM, respectively. While these map lengths are likely inflated due to genotyping errors, a high level of synteny between genetic and physical distances of the markers in both parental maps was achieved. Scab resistance was evaluated through controlled inoculations in the greenhouse using two scab isolates, and a significant quantitative trait locus (QTL) for scab resistance was identified on chromosome 5 in ‘Elliott’. Candidate gene searches within the 2-logarithm of the odds interval of the scab-resistant QTL identified a number of disease resistance related genes, including genes encoding wall-associated receptor kinases, cytochrome P450s, leucine-rich repeats receptor-like serine/threonine-protein kinases, a pectinesterase inhibitor, a cellulose synthase, a flavonol synthase, a 4-coumarate-CoA ligase, a caffeic acid 3-O-methyltransferase, and a MYB domain transcription factor.

Mango (Mangifera indica L.) is a popular fruit produced widely along tropical climates for fresh consumption. In this study, mature fruits from a collection of 189 mango cultivars were evaluated for fruit weight and sugar content at horticultural maturity. Subsequently, a total of 10958 single nucleotide polymorphisms (SNPs) generated through genotyping by sequencing (GBS) were used to identify quantitative trait nucleotides (QTNs) associated with fruit weight and sugar content through genome wide association studies (GWAS). Fruit weight over three seasons averaged 454 g. ‘Lancetilla’ and ‘Webber’ cultivars produced the heaviest fruits averaging 1127.5 g and 1108.5 g respectively and the lowest average fruit weights (166.16 g, 184.5 g, and 189.5 g) were observed in ‘Itamaraca’, ‘13-1' and ‘Fralan’ cultivars respectively. The mango cultivars had a mean degrees Brix (°Bx) value of 14.8 with ‘Venus,’ ‘Peach Cobbler’ and ‘Julie’ displaying the highest degrees Brix (°Bx) values of 25.6, 22.4 and 20.6 respectively. Three QTNs in chromosomes 5, 8 and 10 were significantly associated with fruit weight using Fixed and random model Circulating Probability Unification (FarmCPU) association model, while two QTNs in chromosome 2 and chromosome 20 were significantly associated with sugar content using Bayesian-information, Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model. Genetic characterization of loci associated with these two traits in mango provides a solid foundation for SNP marker assisted selection (MAS) to accelerate molecular screening of segregating populations and germplasm in a mango breeding program.

Red raspberry (Rubus idaeus L.) is a high-value crop, acclaimed for its fruit quality characteristics and putative health benefits. Among fruit quality characteristics, color is a critical trait in determining market acceptability and consumer preference. Red raspberry fruit encompasses a wide array of colors, notably yellow, orange, and red. Red fruited cultivars are the most common in commercial settings and market selection is dependent on the color intensity: while the processing industry needs dark berries for most applications, the fresh market requires bright red and non-darkening fruit. Anthocyanins, a group of water-soluble phenolic compounds, are regarded as the major contributors to raspberry red fruit color. Knowledge on the genetics of raspberry fruit pigmentation would be valuable for breeding programs, but to date the genetic control of the different red intensities of raspberries remains elusive. This research aims to map the genetic regions underlying the red shades of raspberry fruit through a genome-wide association study (GWAS). Fruits from 765 red raspberry cultivars and selections – including red-, orange-, and yellow-fruited genotypes – were harvested over four seasons (2018-2021) and analyzed for total anthocyanin content and color. Total anthocyanins were measured through the pH differential methods and color was assessed using a high-throughput digital phenotyping protocol. Leaves from all genotypes were harvested in summer 2022 and used for genomic DNA extraction. Whole-genome sequencing of DNA samples was achieved through Illumina NovaSeq6000, with an average coverage of 30×. Sequences were aligned to the ‘Malling Jewel’ reference genome using BWA-MEM and single nucleotide polymorphisms (SNPs) were identified following the GATK pipeline. Total anthocyanin content ranged between zero (yellow genotypes) and 113.21 mg/100 g fresh weight (FW) of peonidin-3-O-glucoside equivalents (P3OG eq.) and averaged 42.09 mg/100 g FW P3OG eq. Color coordinates L* (lightness) varied between 11.99 and 48.21 and averaged 21.21, a* (red-green) spanned -1.18 and 38.38 and averaged 26.85, b* (yellow-blue) ranged between 4.57 and 30.04 and averaged 18.05. The association between the detected genetic variants and the phenotypic data (fruit color and total anthocyanins) will enable the identification of SNP markers that explain the variation in observed red shades of berries. Such markers will be used in raspberry breeding programs to facilitate the development of cultivars with desired fruit color.

The renowned horticultural artist and plant breeder Luther Burbank worked with many different species of plants. During his 50-year career, he introduced over 800 cultivars, including more than 150 accessions of plums (Prunus spp.) in the late 1800’s and early 1900’s. Burbank preferred utilizing wide, interspecific crosses to create a vast range of phenotypic variation and then artificially select from the extremes. While a very great artist, Burbank was a substandard scientist because he was derelict in pedigree note-taking. Though many of his introductions are extinct, hobbyists, enthusiasts, and international collections retain nearly a third of the economically viable cultivars he bred. For a century, many of his hybridizations remained inscrutable mysteries until modern genomic and computational tools developed their resolution and statistical power. Today, genotyping by sequencing (GBS) is a useful tool for pedigree reconstruction in the absence of reliable records. GBS can inform principal component analyses (PCA), identity by descent (IBD) kinship, and phylogenetic admixture, revealing complex relationships among taxa. In this study, whole genome sequencing was performed on 53 Prunus taxa used by Luther Burbank in his breeding experiments in the most comprehensive genetic survey of his work to date. Exact parent-offspring relationships between this population may be impossible to discern due to years of back crossing, sibling mating, and open pollination. However, the proportion of genomic similarity amongst these taxa provides information on the relatedness of the genotypes in Burbank’s Prunus experiments, defining four primary lineages within his breeding population. These lineages are comprised primarily of P. salicina and P. simonii, but also have influences from P. americana, P. cerasifera, P. domestica, and P. rivularis. The prevalence of P. simonii in Burbank’s Prunus introductions appears to have been vastly underreported, indicating that some of the seedstock founders of his breeding population could have been P. salicina x P. simonii hybrids at the inception of his career. This research has implications for pedigree reconstruction and prioritizing conservation in collections curation for future studies.

The global blueberry market has been expanding vastly driven by consumer demand for healthier food. As a top blueberry producer, United States generated a revenue of $932 million in 2020. A profitable blueberry industry relies on continued cultivar improvement. One challenge faced by blueberry breeders, researchers, and growers, is yield data collection. Measuring blueberry yield by manual sampling is labor-intensive and time-consuming. We developed a smartphone application leveraging deep learning techniques to automate yield prediction and maturity assessment for different blueberry cultivars under field conditions. State of the art YOLOv8 models were fine-tuned and evaluated using a dataset of side-view images of various southern highbush and rabbiteye blueberry cultivars. The best performing DL model of YOLOv8-x achieved a mean average precision of 0.708 and 0.372 under 0.5 and 0.5-0.95 Intersection over Union thresholds on validation datasets, respectively. Blueberry yield was predicted using non-linear regression-based machine learning models using the image-derived mature berry count multiplied by user-defined average berry weight and cultivar as explanatory variables with satisfactory accuracy. This proposed smartphone app can enable image-based yield prediction for blueberry growers and breeders, which is valuable for management decision making and accelerated selection for high-yielding cultivars.

Phenotyping remains a bottleneck in many breeding programs, including sweet cherry. Current fruit evaluation protocols require extensive manual sorting and visual evaluation, which reduces throughput and is subject to evaluator bias and fatigue. The Washington State University Cherry Breeding Program is seeking more efficient methods of evaluating fruit quality. In 2023, the program acquired an optical fruit sorter. Our objective was to customize the sorter parameters according to breeding program needs and compare the results of the sorter with traditional methods. Our Tomra InVision 2 sorter has the same optics, software and computer hardware as a commercial sorter, but operates on a single lane. Fruit are loaded onto an infeed system which passes fruit in single file into the detection area. A combination of fruit rotation, multiple cameras and mirrors is designed to image the entire surface of individual fruit. Both visual and infrared images are captured, generally > 24 images per fruit at a rate of approximately 15 fruit per second. The sorter software identifies fruit and classifies them according to a set of tunable quality parameters or grades. Air-actuated valves then eject the fruit into one of four grade-determined exits. The sorter generates reports that include the fruit size profile as well as the percentage of fruit sorted into the various exits and/or grades. The sorter shipped with a pre-loaded map (sorting algorithm), which we modified by updating with data from representative images of various quality parameters. We then used the sorter to grade fruit from Phase 2 variety trials. We analyzed 50-fruit subsamples in the traditional manner for size and defects. All remaining fruit from each sample were analyzed via the sorter. Out of 20 samples evaluated, the average number of fruit per sample evaluated by the sorter was 154, vs. 50 for manual evaluation. Overall, the sorter detected a lower percentage of cracking, doubles (polycarpy), and pitting vs. manual evaluation, and a higher percentage of skin blemishes. Continued testing will be required to determine whether these differences are due to the effects of small sample size or bias due to the methods themselves (human evaluator vs. sorter). While the sorter required a similar number of personnel as for manual evaluation, it required less time to evaluate each sample even though more fruit were analyzed. We will expanding the use and testing of the sorter in 2024, including evaluation of postharvest quality.

Aerated Compost Tea Impacts on Soil Parameters and Yield of Tomato, Carrot, and Beet - Charlie Rohwer
The Effect of High Concentrated Liquid Fertilizer at Hydroponic Culture to the Contents of Amino Acids and Mineral in Watermelon Fruits - Sentaro Tomiyama
Changes Of Fruit Profile And Content Of Carotenoids At Different Nutrient Conditions In Hydroponically Grown Watermelon - Xiangyu Cui
Phosphorus Fertilizer Application Strategies to Improve Phosphorus Availability and Utilization in Potatoes. - Samuel Essah
Nitrate Leaching in Processing Tomato Production Subjected to Deficit Irrigation and On-Demand Nitrogen Fertilization - Dave Goorahoo
Greenhouse Nitrogen application rate optimization for optimal bamboo (Dendrocalamus asper) growth and productivity in Florida - Cyrus Januarie
Determining Adequate Nutrient Application Rates for Water Spinach (Ipomoea aquatica) Production in Deep Water Culture - Shelbie Bohensky
The incorporation of black soldier fly larvae to fish feed increased fish and plant growth - Most Tahera Naznin

The intentions of aerated compost tea are to provide nutrients to plants or beneficial microbes to the soil or phyllosphere. Compost tea may also contain organic compounds which alter plant physiology (growth or induced defenses). Compost tea is mainly encountered in organic systems, but there is evidence for improved outcomes when using both organic and conventional nutrient sources. The objective of this study is to understand more about the impacts of aerated compost tea (ACT) on soil microbial activity and nitrogen status and plant responses. ACT was applied weekly or bi-weekly as a drench or as a spray to field-grown tomatoes, carrots, and beets fertilized organically or conventionally at two locations in Minnesota. Results presented here focus on produce yield from year 1 of the 3-year study. We found no difference in any of the yield parameters measured due to compost tea application. We generally observed higher yields in organically-fertilized produce in both locations. One location, with a longer history of organic production, had higher soil microbial activity in the organically-fertilized treatment but the difference in yield between conventional and organic tomatoes was similar at both locations.

We have previously reported the sugar distribution and accumulation in watermelon fruit grown hydroponically (Tomiyama et al. 2023 . Hort Science). In this research, the contents of amino acids and mineral in watermelon fruits grown hydroponically at high concentrated nutrient solution were investigated. Three different hydroponic culture conditions were set by Electric Conductivity: EC 5.0, 3.0, and 1.2 dS-m-¹. Initially watermelon seedlings (Citrullus lanatus (Thunb.) Matsum. Et Nakai ‛Hitorijime-BonBon) were grown at EC 1.2 dS-m-¹ (Control) conditions on deep flow technique in a glasshouse. Treatment was initiated two weeks after pollination. Forty days after pollination, watermelon fruits were harvested and measured its size. Then, mineral and amino acids content were analyzed by HPLC. We measured NH⁴⁺, K⁺, Mg⁺, and Ca²⁺ as cations and PO⁴- and NO³- as anions. Twenty amino acids were measured also. As result, the fruit size and weight decreased under high nutrient conditions. At mineral analysis, the cations NH⁴⁺, Mg⁺, and Ca²⁺ content in the flesh did not increase at the high concentrated treatment, but K⁺ increased in the pericarp at higher treatment. Similarly, the anions PO⁴- and NO³- content increased as K⁺. In control, amino acids was accumulated in the center of flesh, whereas in the higher concentration amino acids was concentrated in the pericarp. When we focused on citrulline and proline, they were accumulated more in pericarp than flesh. In conclusion, mineral (K⁺, PO₄³-, NO₃-)and some amino acids such as citrulline, and proline, which accumulate in the pericarp, accumulated under high concentrated liquid fertilizer at hydroponic culture.

Researches on carotenoid content in hydroponically grown watermelon fruits are rarely conducted. In hydroponic system, nutrient condition can be easily monitored and precisely controlled by regulating the concentration of culture solution. To study the changes of fruit profile and content of carotenoids at different nutrient conditions, we cultured watermelon in hydroponic system and changed the electric conductivity (EC) of solution which can represent the condition of nutrient. Forty seedlings were provided by Hagihara Farm company and replanted in the hydroponic system where the electric conductivity of solution equaled 1.2 dS·m-1. Three branches were remained for one plant and each pistil after 20 nodes were pollinated by hands. The nutrient condition was divided 14 days after pollination into 3 groups which were Control (EC = 1.2 dS·m-1), the regime of solution EC = 3.0 dS·m-1 (group 2) and the regime of solution EC = 5.0 dS·m-1 (group 3). Samples were taken every 10 days interval, and the fruit size, weight as well as Brix of flesh were measured on the sampling day. Carotenoid contents were determined by high performance liquid chromatography. Results showed that compared to the control group, fruit size and weight were promoted in group 2 but restrained in group 3. However, group 3 had the highest Brix among three groups. In terms of β-carotene, the higher the concentration of solution was the earlier its promotive and restraining effects showed out. Lycopene was also promoted in the early stage (10-30 days) in group 2 and group 3 but the total amount on 40 days decreased and dropped to near or below the control group.

Phosphorus (P) is a poorly soluble plant nutrient. Therefore, P uptake by the potato crop is primarily through root interception and short distance diffusion. This limits the percentage of soil supplying P to potato roots. Placement of P fertilizer is a management variable that can influence P uptake and P use efficiency, thereby improving tuber yield and quality. Recent studies conducted at Colorado State University’s San Luis Valley Research Center, USA, has shown that blending orthophosphate fertilizers with 10-34-0 reduces required P fertilizer cost and improves P use efficiency, as well as increase potato tuber yield and quality, compared to using 10-34-0 as sole source of P fertilizer. Information on placement method of blended P fertilizers for maximum use efficiency and tuber performance has not been documented. Studies were conducted at Colorado State University’s San Luis Valley Research Center, USA, with the objective of evaluating the effect of blended liquid P fertilizer placement method on Russet potato performance in the field. Three orthophosphate fertilizers each blended with 10-34-0 were evaluated under three placement methods (banding, in-furrow, and banding in-furrow application). Banding of blended liquid P fertilizers increased medium size (4-10 oz) tuber yield by 22%, compared to in-furrow application. In-furrow application of blended liquid P fertilizers increased production of premium size (> 6 oz and > 10 oz) tuber yield by 8 and 49%, respectively, compared to banding application. Results from this study suggest that appropriate liquid P fertilizer placement method can enhance sustainable potato production.

The information presented in this poster represents the first-year findings of an ongoing two-year study to assess the efficacy of two nitrogen (N) fertilization and irrigation approaches on tomato yield and quality, and the Nitrate (NO3) Leaching Index (NLI) defined as the ratio of the amount of NO3 in 60-120 cm of soil to the amount in 0-120 cm. Water and N use efficiency (WUE and NUE) were determined for processing tomatoes (Solanum lycopersicum) grown on a Handford Sandy Loam soil, with a pH of 6.7, in the San Joaquin Valley (SJV), California, USA. The experiment was a split-plot design with three replications of irrigation rates (I) as the main factor based on evapotranspiration (ET) scheduling amounts of 74% and 100% of crop evapotranspiration (ETc) and two fertilizer (F) application methods as the subplot factor. The Growers Practice (GP) was seven equal applications of CAN-17 for a total of 201 kg N/ha (180 lbs N/ac) over the growing season, whereas the Soil Nitrate Quick Test (SNQT) approach was to apply 17kg N/ha (15lbs N/ac) whenever the NO3 test strip value was less than 20 ppm. A total of 36 beds with a width of 130 cm x length of 2,700 cm were planted so that each subplot comprised three beds, with the two outer beds used as buffer rows. There were no significant differences in the total yield of all tomatoes (reds, breakers, and green) harvested as a function of either the irrigation (p= 0.79) or fertilizer rates (p=0.12). However, for the fully matured marketable red tomatoes, fertilizer practice had a significant effect (p=0.02), with the GP yielding approximately 30% more tomatoes than the plots subjected to SNQT. There was no interaction effect of F x I on the yield of these red tomatoes. With respect to sugar content, I (p

Bamboo, a giant tropical and temperate region grass, is used for food, timber, furniture, building and construction material, and paper making, among others. With the US being the world's number one importer of bamboo shoots, many growers are venturing into bamboo production with little or no knowledge of the best management practices. There is no reliable literature conducted in Florida about the crop. Therefore, this study was conducted to develop site-specific nitrogen (N) requirements for young bamboo plants in a controlled environment. This study was done in a greenhouse at UF/IFAS Citrus REC in Lake Alfred. One-year-old bamboo plants were transplanted into 37.85 L pots and treated with varying rates of N (0,112,224, and 336 kg N ha-1). Growth, photosynthetic rate, and tissue composition were measured biweekly for five months. Initial and final soil analyses were done. The results demonstrated that higher rates of N (up to a certain amount, i.e. 224 kg N ha-1) increased growth rate, number of culms, and dry matter accumulation. Analysis of Variance (ANOVA) test and regression analysis were conducted for the response variables in R software. Chlorophyll content and culm diameter were comparable. It was concluded that 200 kg/ha N was optimal for young bamboo plants since it demonstrated the peak growth rate, number of culms, and dry matter compared to the rest of the treatments. Key words: Dendrocalamus asper, nitrogen fertilization, best management practices

Water Spinach (Ipomoea aquatica) is a novel crop within the U.S. that is widely grown throughout southeast Asia. Although considered a noxious weed by USDA, interest from ethnic communities has led to the restricted permittance of cultivation within Georgia, USA. In order to determine nutrient requirements for hydroponic production of water spinach, a study was conducted using a deep-water culture in a greenhouse located in Watkinsville, Georgia, USA in the summer of 2023. Two selections of water spinach were grown in plastic containers filled either a ¼ or ½ strength Hoagland’s solution arranged in a randomized complete block design with four replications of each selection by nutrient solution combination. Initially, 15 plants of each selection were placed into the tubs. Beginning at 21 days after transplanting, two plants were removed from each tub for determination of biomass and nutrient concentrations. Additional plants were removed at 10-day intervals until a final harvest at 61 days after planting. The trial was then repeated. Results indicated that biomass (root and shoot) and nutrient removal within foliar tissues were significantly greater in the ½ strength solution compared to the ¼ strength solution. Total nutrient accumulation for most macronutrients exhibited a quadratic response, increasing until 51 days after planting and then plateauing. Plants grown in the ½ strength and ¼ strength Hoagland’s solution accumulated similar concentrations of foliar macronutrients though due to differences in biomass accumulation, total nutrient removal was significantly different between the two nutrient solutions. At harvest (day 61), ½ strength plants had an average potassium (K) concentration of 5.24% (dry weight), while those grown in the ¼-strength Hoagland’s solution averaged 4.48% K on a dry weight basis. However, due to significant differences in biomass production, K nutrient removal rates were more than twice as much in the plants grown in the ½ strength Hoagland’s solution compared to those grown in the ¼ strength solution. Our results suggest that although water spinach may grow in river systems in its native environments, that growth benefits from additional levels of fertilizer nutrients when cultivated in greenhouse systems and that a ½ strength Hoagland’s solution should be an appropriate baseline to develop recommendations for hydroponic nutrient solutions for greenhouse production of water spinach.

The economic success of the aquaponics industry and fish farming is mostly dependent on the use of inexpensive, nutritionally adequate meals. Approximately sixty percent of the economic balance is accounted for by fish feeding. The substitution of insect meal for fish meal appears to offer a promising approach to reducing cost and the environmental impact. The black soldier fly larvae (Hermetia illucens) possess 40–45% proteins and a favorable essential amino acid profile. The objective of this experiment was to investigate the effects of commercial and black soldier fly larvae (BSFL)-based diet on Nile tilapia growth, plant growth, and antioxidant accumulation in crops. The results showed that tilapia fish can grow at a higher rate on BSFL-based meals than on commercial diets. On the other hand, a study revealed that BSFL BSFL-based fish feed waste water significantly stimulated plant growth and antioxidant accumulation in aquaponic systems. This study opens up new possibilities for using BSFL as a substitute for fish meal, which could help to reduce the environmental effect of aquaponic production systems while also contributing to a circular economy.

Evaluation of Wireworm Resistant Sweetpotato Cultivars in Western Washington - Laura Schulz
Variation in Toxic Element Presence in Sweetpotato Storage Roots From A Small Plot Trial: Sampling Implications - Arthur Villordon
Striving to stay clean: Production of sweetpotato nuclear stock used for certified seed growers in North Carolina - Christie Almeyda
Effects on yield, quality, sugar content and soil health indicators of foliar and soil applied Chlorella vulgaris in ‘Beauregard’ sweetpotato (Ipomoea batatas [L.] Lam). - Brian Ward
The Effect of Potassium Fertilization on Potato Tuber Nutrition in the Columbia Basin of Oregon - ruijun qin
Predicting Potato Tuber Yield Through Hyperspectral Signals and Machine Learning - Ravinder Singh
Evaluating King Stropharia Mushroom as an Intercrop in Asparagus and Tomato Production - Olalekan Sipasi

Sweetpotato (Ipomoea batatas) is a nutritious, productive, and resilient crop that is grown worldwide and is gaining popularity throughout the U.S. In western Washington, wireworms (Agriotes lineatus, A. obscurus, and Limonius canus) are the primary pest impacting sweetpotato production. Wireworm resistant cultivars can provide an effective and sustainable pest management tool for growers. A field experiment in Mount Vernon, WA included nine sweetpotato cultivars and breeding lines: wireworm-susceptible cultivars Bayou Belle, Beauregard, Covington, and Orleans; wireworm-resistant cultivars Cascade and Monaco; and wireworm-resistant breeding lines USDA-04-136, USDA-04-284, and USDA-04-791. Storage roots were graded according to USDA sweetpotato categories and root weight, number, and wireworm damage [Wireworm-Diabrotica-Systena (WDS) severity index] were measured. Marketable yield ranged from 22 t/ha (USDA-04-136) to 57 t/ha (‘Bayou Belle’) (p

The overarching goal of FDA’s Closer to Zero (C2Z) action plan is to reduce dietary exposure to contaminants, in foods commonly eaten by babies and young children, to as low as possible while maintaining access to nutritious foods. In addition to establishing action levels for specific toxic elements (TEs), C2Z proposes to develop new and improved testing methods to measure lower levels of contaminants in food and monitor levels over time to determine potential adjustments to proposed action levels. These proposed testing and monitoring activities represent potential added costs to the producer. The sweetpotato (Ipomoea batatas L.) is a leading baby food raw product but very little information is available on the appropriate frameworks for optimal sampling procedures to ensure accuracy and precision of surveys, especially at the field scale. A field trial to investigate the role of commonly used soil amendments in reducing storage root accumulation of arsenic (As), cadmium (Cd), and lead (Pb) revealed interesting trends that merits further investigation. Three random U.S. No.1-sized storage roots were sampled from each of three random plants from each of two unamended (control) plots (plot size=12’ x 3.3’) and analyzed for TE presence at a commercial laboratory. The Pb and Cd content of storage roots from cultivars ‘Bayou Belle’ (BB) (SDs: Cd=1.1, Pb=1.3) and ‘Beauregard’ (BX) (SDs; Cd=1.8 Pb=1.3, Cd=) showed more variability relative to As (SDs: BB=0.5, BX=0.6). There were no differences between two cultivars for all TEs measured. A possible follow-up study could investigate plant- or soil-based variables that contribute to variation in Pb and Cd accumulation. Such findings can be used to improve the accuracy and precision of sampling approaches to enable producers to meet C2Z goals, especially as it concerns sampling of storage roots for monitoring and enforcement purposes.

The Micropropagation and Repository Unit (MPRU) produces, maintains and distributes meristemmed-tip culture, virus-tested, indexed, true-to-type sweetpotato nuclear plants to certified seed growers in NC. Under the certification program, seed growers use nuclear plants for production of G0 plants in greenhouses, and subsequently G1 and G2 plants and storage roots (seed) in the field. All these materials are inspected and certified by NC Crop Improvement Association, Inc. (NCCIA). The MPRU is a clean center for sweetpotato under the National Clean Plant Network (NCPN) umbrella. It works closely with the NC State sweetpotato breeding and genetics program to clean advanced selections yearly. The MPRU distributes about 90,000 nuclear plants to NC certified seed growers every year. It is estimated that about 70% of the commercial sweetpotato acreage in NC is planted annually with stocks derived from the MPRU. It is known that the accumulation and perpetuation of viruses in sweetpotato is a major constraint for production of seed and the commercial crop. The aphid-transmitted potyvirus complex is prevalent in NC and comprises Sweet potato feathery mottle virus (SPFMV), Sweet potato virus G (SPVG), Sweet potato virus C (SPVC) and Sweet potato virus 2 (SPV2). In order to evaluate the performance and quality of clean seed after it had been integrated into commercial sweetpotato operations, NCPN field trials were carried out in 2021 and 2023 with Covington and Beauregard as evaluated varieties. Because sweetpotato is vegetatively propagated, viruses and mutations can accumulate readily which can lead to cultivar decline. G1 seed was used as a reference to compare the yield and virus incidence of growers’ generation 2 (G2), generation 3 (G3) and generation 4 (G4) seed roots (grown in the growers’ seed production fields 1, 2 or 3 years following the year of clean seed production). Virus detection data suggested a low incidence of viruses (mainly SPFMV) on G1 material. Potyviruses (mainly SPVG, SPVC and SPFMV) started to be prevalent on G2 and G3 material. In the older generation evaluated (G4), all potyviruses (SPVG, SPVC, SPFMV and SPV2) were detected. In general, the prevalence of four potyviruses was associated to higher seed generations, indicating a buildup over the years on clean seed regardless of the variety. Yield data suggested a negative impact due to virus infections in Beauregard. This study will allow us to understand the impact of clean seed on the economic value of the crop to educate growers and stakeholders.

Commercial sweet potato production has seen a recent surge in both fresh market and processing acreage in South Carolina. Producing quality conventionally and organically grown sweetpotatoes is a challenge in South Carolina due to numerous biotic and abiotic factors. One of the most important deciding factors on sweetpotato yield is germplasm and fertility. In this study we examined effects on yield and quality of foliar and soil applied Chlorella vulgaris (CV) in ‘Beauregard’ sweetpotato (Ipomoea batatas [L.] Lam). Chlorella vulgaris (EnSoil Algae, Enlightened Soil Corp) is marketed under the USDA/APHIS category of soil amendments and Plant Growth Enhancers (PGE). This study was conducted in 2022-2023 in a randomized complete block full factorial design with 4 replications and a total of 17 treatments with a product rate of 250ml/Ac, including the following: 1) Unfertilized Control, 2) 100 % Preplant Granular Fert. (PGF), 3) Soil Algae Application (SAA), 4) Foliar Algae Application (FAA), 5) 100% PGF SAA, 5) 100% PGF SAA, 6) 100% PGF FAA, 7) 100% PGF SAA FAA, 8) SAA FAA, 9) 25% PGF SAA 75% Drip Irrigation Fert.(DIF), 10) 25% PGF FAA 75% DIF, 11) 25% PGF SAA FAA 75% DIF, 12) 25% PGF SAA, 13) 25% PGF FAA, 14) 25% PGF SAA FAA, 15) 25% PGF 75% DIF, 16) 75% DIF, 17) 25% PGF. Results were mixed over time with 2022 being a better growing year. In 2022, USDA grade Jumbo roots were 10% numerically greater in SAA treated plots, than 25% PGF SAA 75% Drip Irrigation Fert. (DIF) and 9% over SAA and FAA. In 2023 there were similar trends, with USDA grade Number

Potato (Solanum tuberosum L.) crops require a high amount of potassium (K) to achieve the ideal yield and quality. However, the effect of K fertilization on potato tuber nutritional value is largely unknown. Based on the tubers from two-year field trials on a Quincy loamy fine sand soil in the Columbia Basin of Oregon, we evaluated yield, specific gravity, nutritional contents (i.e., ascorbic acid, tyrosine, chlorogenic acid, tryptophan, phenylalanine), and nutrient contents (nitrogen [N], phosphorus [P], K, and sulfur [S]) of three potato varieties (Clearwater Russet, Russet Burbank, and Umatilla Russet) under three K rates (0, 448, and 897 kg ha-1). Our results showed that the K application increased the yield of >170 g tubers but had no considerable effect on the total tuber yield. The application of K tended to decrease specific gravity regardless of varieties and years. Russet Burbank had the lowest specific gravity while Clearwater Russet had the highest one. Most of the nutritional contents were higher in 2020 than in 2021. Russet Burbank generally had the highest nutritional contents except for ascorbic acid compared to two other varieties. The application of K generally did not affect tuber nutritional contents but reduced the amounts of tyrosine in Clearwater Russet and Umatilla Russet in 2020. Fertilization of K resulted in an enhanced K content in the tuber, with the highest K application rate exhibiting a 35% increase in K compared to the control. However, it did not have any discernible effects on N, P, and S contents in the tubers. The tuber P and S were lower in Russet Burbank than other varieties. In general, there is no strong relationship between K fertilization and tuber nutritional contents.

Potato production is crucial for global food security, and with an increasing demand for food and a diminishing supply of fertile land, there is a need to boost production. Remote sensing technologies, such as high-resolution hyperspectral sensors, have the potential to provide valuable insights into potato growth, yield, and quality. Narrow spectral bands captured by these sensors are directly linked to biophysical parameters and can accurately estimate crop parameters. Recent studies have utilized hyper-spectral imagery acquired from proximal sensor such as ASD FieldSpec to estimate various crop parameters and yield. The results from these studies are promising, indicating that hyper-spectral sensors have the potential to improve crop management and agricultural practices. Moreover, the integration of remote sensing data with advanced analytical techniques, such as machine learning, helps in accurately estimating yield and yield components. In this study we are testing two machine learning such as PLSR and RF to predict biomass and N uptake in-season. Results from this indicate that PLSR performs better in predicting biomass and N uptake in potatoes. Moreover, yield can be best estimated at tuber bulking stage.

Stropharia rugosoannulata (L.), the King Stropharia or Wine Cap mushroom, is a wood-loving fungus that grows well on organic mulches. Some vegetables can be successfully grown using organic mulches like woodchips or straw. As a result, farmers may be able to enhance their income by intercropping Stropharia mushrooms with their vegetable crops. However, no study has been identified that assesses this strategy's potential or effect on vegetable yields. Thus, a Stropharia-asparagus intercrop was evaluated by applying woodchips at three depths (4, 8, and 12 in), and a Stropharia-tomato intercrop was evaluated using woodchips, wheat straw, and soy straw (all at 6 in depth). Both experiments utilized a randomized complete block design (RCBD) with four replications and included bareground controls. The tomato study also included a positive mulch control using black plastic. In the fall of 2021, black plastic, inoculated wheat straw, and uninoculated soy straw and woodchip mulch provided earlier harvest than unmulched plots, while the soy treatments and bareground and black plastic controls increased total fruit numbers. In 2022, overall tomato production decreased, resulting in no marketable fruit. Across both 2022 and 2023 asparagus harvest began earlier with decreasing depths of mulch, and therefore lasted longer. Inoculated plots also produced more marketable spears than uninoculated plots. And, 12 in woodchip mulch significantly inhibited asparagus emergence and is therefore not recommended. These results suggest that a Stropharia-tomato intercrop may not be feasible without additional work, though a Stropharia-asparagus intercrop shows great promise. In fact, in 2023, mushrooms were observed in uninoculated plots demonstrating the gregarious growth of Stropharia in woodchip mulch on asparagus plots. The relative success in asparagus plots supports a need for further research to evaluate other Stropharia-vegetable [or fruit] intercrop candidates and/or strategies to improve compatibility.