ASHS 2024 Conference

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.