ASHS 2025 Conference

Ranunculus are sensitive to high soil salinity and to high chloride concentrations. A trial was set up in fall 2024 at the Flower Fields in Carlsbad, CA to evaluate the yield and quality parameters of field-grown ranunculus under three irrigation water treatments and corresponding increasing levels of water salinity. The treatments were 1) Municipal water, currently used at the Flower Fields to grow ranunculus and other crops; 2) a 50:50 blend of municipal water and reclaimed municipal water; 3) 100% reclaimed water (called hereafter “recycled”). The objective of the study was to investigate if a blend of municipal and reclaimed water or 100% reclaimed water can be used in the future to grow ranunculus at the flower fields. The expected salinity levels in the water, measured as electrical conductivity before fertilizer injection were

Floriculture supply chains are undergoing a shift toward sustainability, driven by consumer demand and industry initiatives to reduce environmental impacts. While previous research has explored the carbon footprint of some ornamental horticultural products, domestic U.S. cut flower production and distribution remains largely understudied. Understanding the emissions associated with different supply chain models can guide sustainable practices in the domestic floriculture industry. This study examines the carbon emissions from the production and transportation of one representative cut flower species – snapdragon. Two primary distribution models were compared: point-to-point delivery where individual growers supply retailers directly and the hub-and-spoke system where wholesale hubs consolidate and distribute flowers. By evaluating data collected from 188 growers, 330 retailers, and six regional wholesale hubs, the research quantifies carbon emissions at each stage of the supply chain. The life cycle analysis uses openLCA software to standardize emissions data to an "emissions per stem" metric, aligning with horticulture footprinting standards. The results highlight the importance of optimizing supply chain logistics to reduce emissions. Furthermore, applying the social cost of carbon ($185 per metric ton of CO2) provides an economic perspective on the environmental impact of floral supply chains. As businesses move toward more climate-conscious operations, these insights can guide decisions that align with both financial and sustainability business goals.

Caladiums (Caladium x hortulanum) are popular ornamental plants prized for their vibrant foliage and unique patterns. The great majority of caladium tubers used by the U.S. and the world are produced in Florida. The tuber production process typically begins in March, with harvesting taking place between November and February. During this period, plants are exposed to high temperatures, high radiation, high relative humidity, heavy rainfall, and tropical storms, resulting in multiple stresses on the plants. Research in other crops has demonstrated the effectiveness of clay-based products in reducing leaf temperatures and protecting plants from environmental and/or biological stresses. This study aimed to assess the plant growth, quality, and tuber production of five caladium cultivars ('Tapestry', 'Lava Glow', 'Wonderland', 'Pink Panther', and 'Summer Pink') under different kaolin clay treatments. Field-grown plants were sprayed throughout the season with either kaolin, kaolin with red dye, or left untreated (control) to assess their response. An adjuvant was added to prevent excessive washout from rainfall. Data collected over two seasons included plant height, canopy coverage, and volume (per plot) extracted from multispectral images captured by a small uncrewed aerial system, leaf temperature using an infrared thermometer, chlorophyll content using a SPAD meter, and subjective ratings for plant color display, leaf health, and plant fullness using a scale from 1 to 5. At harvest, tuber production was evaluated through fresh weight, dry weight, and production index. Results showed that the growth curves for plant height, canopy coverage, and volume exhibited a bell-shaped curve, with an initial linear growth and a maximum peak in early to mid-September for most cultivars, except 'Summer Pink', which peaked later. Treatment differences were not statistically significant, with cultivar variations being the primary factor. However, kaolin and kaolin red treatments effectively reduced leaf temperatures during the 2023 production season, with kaolin red also receiving a higher rating for color display. Plants under kaolin treatments displayed lower chlorophyll content compared to untreated plants. Tuber production was unaffected by the treatments but showed differences among the cultivars, with 'Tapestry' producing the highest tuber dry weight. The production index, which accounts for tuber grading, number, and relative economic values, revealed that 'Summer Pink' had the highest value compared to 'Tapestry'. This study provides valuable insights into the growth behavior of caladium cultivars and the potential benefits of using kaolin treatments as a crop protection strategy.

Peatmoss, a commonly used substrate component, is facing numerous challenges to remain a sustainable option for horticultural production. Due to mounting factors such as weather-limited harvesting, increasing transport costs, waning public acceptance, and now potential international tariffs, many are searching for alternative materials to replace some of the peatmoss in their operations. Biochar is one such alternative that may present numerous benefits as a peat alternative in container production. Biochar is the product of the pyrolysis of biomass (commonly agricultural residues) in an oxygen limited environment, resulting in a product that has increased porosity, increased water and nutrient retention, and can be produced regionally from a number of sources. Incorporating biochar into container production can reduce peat use and improve nutrient retention. However holistically blending can prove costly and alter the substrate physical properties, requiring major changes to production practices, an obstacle that can be considered a barrier. The use of stratification has been shown to successfully reduce peat use while maintaining highly productive growing conditions. With stratification, growers can incorporate alternative materials strategically in the container while limiting the associated costs. Therefore, this study was designed to evaluate the effect of sugarcane bagasse biochar on nutrient retention in both stratified and non-stratified peat-based container systems. Nine peat-based substrate treatments were utilized in this study, with either the entire container filled with peat-based substrate or stratified above a pine bark or hammermilled wood fiber. Within each substrate, sugarcane bagasse biochar was amended at 0 (control) or 10% of the container volume, by either blending throughout the container or blending at 20% upper strata only (equivalent to 10% by vol. overall). Petunia plugs were planted into 3.8 L containers filled with each of these different substrate treatments. The plants were placed on two different fertilizer regimes, with plants receiving either 100 ppm or 300 ppm fertilizer once a week. Leachate was collected biweekly to assess the impact on nutrient retention. Plant growth and nutrition were assessed. The incorporation of biochar has not significantly impacted plant growth; however, it has improved nutrient retention. Biochar improved nutrient retention in the plants stratified with wood fiber in both the high and low fertilizer regimes, while improving nutrient retention in stratified bark in the high fertilizer regime. The results indicate that strategic inclusion of biochar may reduce fertilizer application frequency.

Our objective was to evaluate the efficacy of benzyladenine or ethephon foliar spray applications to control growth and improve branching of ‘Dragon Wing® Red’ begonia (Begonia interspecific). On 10 Sep 2024, a 288-cell plug tray of ‘Dragon Wing® Red’ begonia was received from a commercial propagator. Plugs were transplanted into 15.2-cm-diameter containers filled with a commercially available soilless peat-based substrate. Plants were grown in a glass-glazed greenhouse under supplemental and day-extension lighting provided by 780-W light-emitting diode lamps from 0600 to 2200 HR (16-h photoperiod) with an air temperature set point of 20 °C. At 7 d after transplant, 10 single-plant replicates were treated with a solution containing benzyladenine or ethephon and a surfactant. Plants received a foliar spray (vol. 0.2 L·m–2) containing deionized water (0 mg·L–1; untreated) or 10, 30, 50, 70, or 90 mg·L–1 benzyladenine or 125, 250, 500, 750, 1,000, or 2,000 mg·L–1 ethephon. Benzyladenine and ethephon foliar spray applications influenced begonia growth and development differently. Benzyladenine concentrations increasing from 10 to 90 mg·L–1 suppressed growth index, an integrated measurement of height and diameter, by 1% to 3%, respectively, compared to untreated plants. Branch number increased by 32% to 64% (3 to 5 branches) as concentrations increased from 30 to 90 mg·L–1 benzyladenine compared to untreated plants. Shoot dry weight (SDW) decreased as benzyladenine concentrations increased, but time to flower (TTF) was unaffected. Ethephon concentrations increasing from 125 to 2,000 mg·L–1 influenced plant height, plant diameter, growth index, branch number, SDW, and TTF. Growth index was suppressed as ethephon concentrations increased from 125 to 2,000 mg·L–1, resulting in plants that were 11% to 30% smaller than untreated plants. Compared to untreated plants, ethephon concentrations increasing from 125 to 1,000 mg·L–1 improve branching with 1 to 2 more branches developed per plant. Ethephon concentrations of 125 to 2,000 mg·L–1 limited SDW by 23% to 49% compared to untreated plants. Time to flower was delayed by 3 to 10 d as concentrations increased from 125 to 2,000 mg·L–1 ethephon. Begonia plants sprayed with ≥750 mg·L–1 ethephon developed phytotoxicity and had reduced ornamental quality. Our results indicate that growers can attain growth control and enhance branching with foliar spray applications of 30 to 90 mg·L–1 benzyladenine or 125 to 500 mg·L–1 ethephon, but these should be used as an initial range for trials during greenhouse production.

Ethephon substrate drenches have been shown to effectively control growth of annual bedding plants and herbaceous perennials. However, research has shown the efficacy of ethephon substrate drenches is impacted by the time of application. Therefore, the objective of our research was to evaluate how ethephon substrate drenches impact growth when applied at varying times post-transplant. Young plants of lobed tickseed (Coreopsis ×hybrida Big BangTM ‘Mercury Rising’) and coleus [Coleus scutellarioides (L.) Benth. ‘Main StreetTM Bourbon Street’] were transplanted into 12.7-cm containers filled with a soilless peat-based substrate. At 3, 7, 10, 14, 17, or 21 d after transplant, 8 single-plant replicates received a single substrate drench of 90 mL aliquots of a solution containing 0, 25, 50, 100, or 200 mg·L–1 ethephon. Plants were grown in a glass-glazed greenhouse for 5 to 7 weeks after initial drench application before growth and morphological data including plant height, plant diameter, shoot dry weight (SDW), and root dry weight (RDW) were determined. In general, increasing concentrations of ethephon influenced plant height, plant diameter, SDW, and RDW of coleus and lobed tickseed. In Expt. 1, plant size (height and diameter) and biomass accumulation (SDW and RDW) of coleus was significantly influenced by increasing concentrations of ethephon, with the effects diminishing as application time was delayed. For example, as concentrations increased from 0 to 200 mg·L–1 ethephon, coleus treated at 3 days after transplant (DAT) were 33% (5.3 cm) shorter, while those treated at 17 DAT were 21% (3.6 cm) shorter. Shoot dry weight of coleus drenched with 200 mg·L–1 ethephon at 3 or 21 DAT were 50% (2.0 g) and 23% (1.0 g) lower, respectively, compared to untreated plants. Compared to untreated plants, RDW of plants drenched with 200 mg·L–1 ethephon 3 or 14 DAT was 65% (2.8 g) and 50% (2.6 g) smaller, respectively. In Expt. 2, plant height was unaffected by increasing concentrations of ethephon, but plant diameter and biomass accumulation of lobed tickseed was significantly affected. For example, as concentrations of ethephon increased from 0 to 200 mg·L–1, lobed tickseed treated 3 and 21 DAT were 8% (2.4 cm) and 9% (2.8 cm) narrower, respectively, compared to untreated plants. Overall, the magnitude of control diminished as application time increased and negative phytotoxic effects were seen in early applications (≤7 d). Therefore, we suggest applying ethephon substrate drenches 7 to 14 d after transplanting.

Despite not well studied within the sustainable agriculture research community, there is evidence that animal traction could be a regenerative power option for small farms. Animals cause minimal compaction, appreciate, and can regenerate. Fuel can be grown on farm, some animals are multi-purpose, and there is social benefit for those that interact with them. However, opportunities for aspiring teamsters to gain knowledge are limited. Extension materials and programming from public Universities are also not widely available. A side-by-side tractor animal traction comparison was established at the Meigs Horticulture Facility in Lafayette IN (Meigs). There were two treatments potato production with animal traction (AT) and potato production with small tractor traction (TT). During the study all field activities related to potato production were performed with animal power or tractor power in the two treatments, respectively. Data collection included: cost of equipment, time for each field, potato yield, and comprehensive soil health assessment including penetration resistance. Potato yield did not differ between AT and TT (P = 0.79213). Yields were 15,266.3 ± 7,523.6 and 12,981.0 ± 9,175.0 lb. 1-acre for AT and TT, respectively. Overall cost of capital equipment used in thus study were 17,050 and 42,147.30 for AT and TT, respectively. Total time in the field for major field events was 4 hours for AT compared to TT. Preliminary results reveal that similar yields to tractor power can be achieved when using animal power. Time in the field may be greater in animal traction, but capital equipment costs can be lower.

Edamame, a vegetable soybean harvested at the immature stage with green pods, has gained popularity in the United States due to its high nutritional value and appealing taste, resulting in growing consumer demand. However, over 70% of the edamame consumed in the U.S. is currently imported from East Asia. To support domestic production and reduce reliance on imports, identifying suitable varieties and production windows is essential—especially in regions like Florida, where subtropical conditions allow for multi-season cropping. This study aimed to evaluate the performance of sixteen commercial edamame varieties (maturity groups 0–V) across South Florida’s two primary bean production seasons: spring (early February to mid-May) and fall (early October to mid-December). The objectives were to (a) identify varieties best suited to South Florida’s subtropical climate, and (b) determine the optimal growing season for each variety. Growth parameters (emergence rate, plant height, canopy diameter, leaf area, and nodes per plant) and agronomic traits (fresh pod yield and 10-pod weight) were measured to assess adaptation and productivity. In the spring, ‘UA-Kirksey’ achieved the highest yield at 5.0 t/ha, while ‘Midori Giant’ had the lowest at 0.8 t/ha. In the fall, ‘Chiba Green’ produced the highest yield at 3.2 t/ha, and ‘Karikachi #3’ the lowest at 0.5 t/ha. Six varieties, i.e., ‘KAS 355-11’, ‘Kahala’, ‘Karikachi #3’, ‘Shirofumi’, ‘UA-Kirksey’, and ‘Young Soybean’ yielded significantly higher (p ≤ 0.05) in spring compared to fall, while no significant seasonal differences were observed for the other varieties. These findings demonstrate the importance of selecting season-appropriate varieties to maximize yield potential and production efficiency in subtropical regions like South Florida, offering a promising strategy to support local edamame cultivation.

Edamame [Glycine max (L.) Merr.] exhibits a promising opportunity for Indiana farmers. Its high nutritional value and nitrogen-fixing capabilities reduce input costs while benefiting crop rotation systems. The crop’s short duration facilitates sustainable practices like cover cropping. Research on edamame cultivation for Midwest local markets remains limited despite increasing sales and consumption. Therefore, this study aimed to explore potential cultivars suited for the fresh and direct consumer market and identify cultural and cultivation practices that minimize weed-crop competition here in Indiana. A field experiment was established at Meigs Horticulture Research Farm, Lafayette, Indiana, which evaluated three different row spacings (7 inch, 15 inch, and 30 inch) on growth and yield of six edamame cultivars (Chiba Green, Sayamusume, BeSweet 292, Midori Giant, Tohya, and Karikachi). This study was designed as an RCBD split-plot design with 4 replications, with different row spacings as main plots, and variety as the split-plot. Leaf area index (LAI), dry weight of weed, total pod count, pod count, and fresh weight of marketable and non-marketable pods were measured. All data were analyzed with R Studio. We hypothesized a) standard row spacing (30 inch) would improve edamame seed yield and productivity compared to narrow row spacings (7 and 15 inch); b) narrow row spacing would reduce the weed growth and density of common weed species compared to standard row spacing; c) standard row spacing may increase yield of edamame but would increase weed-crop competition. Our results from one year are in agreement with our hypotheses. Standard row spacing resulted in the greatest pod yield, but highest weed dry weight. Specifically, 30 inch row spacing produced significantly greater pod count (27) per plant compared to 7, and 15 inch row spacing (9 and 16 pods per plant, respectively). Also, 30 inch row spacing resulted in the greatest marketable pod count (23) per plant compared to 7 and 15 inch row spacing (6 and 12 pods per plant, respectively). 30 inch row spacing led to significantly greater weed dry weight (4.27 g) compared to 7 and 15 inch row spacing (1.01g and 2.81g, respectively). Lowest weed dry weight (1.01 g) at 7-inch row spacing suggests that narrow row spacing might help suppress weed growth. The greatest LAI was measured at 7-inch row spacing (5.26) compared to others (3.77 and 3 for 15 and 30 inch row spacing). BeSweet 292 performed better in terms of yield parameters compared to other varieties.

Plastic mulches are widely used in U.S. vegetable production to cut costs and improve efficiency. However, polyethylene, the principal ingredient of plastic mulches, is a poorly degradable material causing significant pollution. Biodegradable mulches, especially those made from local waste materials such as low-grade cotton, offer a sustainable alternative by reducing pollution, enhancing soil health, and supporting circular economy principles. This study aims to evaluate two different types of low-grade cotton mulches in comparison to commercially available plastic and biodegradable plastic mulches in Jalapeño pepper production. Five mulch treatments, including a no-mulch control, were arranged in a randomized complete block design with four replications. The assessment focuses on mulch decomposition, plant biomass, crop yield, and weed suppression.

High tunnel production is increasingly important on small, diversified farms with more than 1,700 and 700 high tunnels (HTs) in Kentucky and Tennessee, respectively. Weed management in HTs is more challenging than open field production and there are limited options. Soil solarization is one alternative; it heats moist soil to high temperatures by trapping solar radiation under transparent plastic tarps. Heating soil to at least 40°C is beneficial for managing soil-related issues, such as reducing the weed seedbank. Soil solarization was conducted in April, July, and September 2024 in Kentucky and Tennessee in open and closed HTs to assess whether growers could solarize individual beds. The objectives were to evaluate the effect of solarization on soil temperatures, weed biomass and emergence, and lettuce yield. Treatments included 2-week (Sol-2wk) and 4-week (Sol-4wk) solarization and a nonsolarized control (NS). Data loggers recorded soil temperatures hourly. Soil in closed HTs accumulated more hours >40°C versus open HTs. The most hours over 40°C occurred in July, followed by September then April, with more hours in Tennessee than Kentucky. In Kentucky, after April solarization, there was less weed biomass in Sol-4wk compared to NS in the closed HT and less weed emergence in Sol-2wk and Sol-4wk compared to NS. There were no differences in lettuce yield. After July solarization, there was less weed biomass in Sol-2wk and Sol-4wk in the closed HT compared to NS, but no differences among treatments for weed emergence. Lettuce yield was higher in Sol-2wk and Sol-4wk compared to NS regardless of HT. There were no differences in weed biomass or weed emergence in September. Lettuce yield in Sol-4wk was higher than NS regardless of HT. In Tennessee after April solarization, there was less weed emergence in Sol-4wk in the closed HT compared to Sol-2wk and NS. Lettuce yield was higher in Sol-2wk and Sol-4wk compared to NS in the closed HT. In July, there was less weed biomass in Sol-2wk and Sol-4wk in the open HT compared to NS. Lettuce yield in Sol-4wk was higher compared to NS regardless of HT. In July and September, there was less weed emergence in Sol-2wk and Sol-4wk compared to NS regardless of HT. There were no differences in lettuce yield in September. Overall, soil solarization in July in both locations reduced weeds and increased lettuce yields. Results were mixed in April and September. The experiment will be repeated in 2025.

Tepary bean (Phaseolus acutifolius) is a short-lived legume native to the deserts and semi-arid regions of Northwestern Mexico and the Southwestern United States. It is resilient and adaptable to high temperatures and drought stress, ideally suited as a low-input organic cover crop in southern Texas. Tepary beans are prized for their nitrogen-fixing potential and high nutritional value. We explored the effectiveness of tepary beans and common summer legume cover crops, such as cowpea and Sunn hemp, on the productivity of subsequent vegetable crops like spinach. Additionally, we evaluated 207 USDA-GRIN undomesticated tepary bean accessions under organic production systems to assess their seed nutritional profiles. Preliminary findings indicated that spinach grown following tepary beans as a cover crop significantly enhanced biomass and exhibited nitrogen use efficiencies comparable to Sunn hemp and cowpeas. The amino acid profiles of the seeds and the total protein content across tepary bean accessions displayed significant variability. We conducted a genome-wide association study (GWAS) of seed nutritional and physiological traits using SNPs obtained through GBS. The candidate genes and loci associated with these traits could advance breeding efforts to enhance nutritional value. The study's outcomes would help affirm the potential of tepary beans as a promising summer cover crop, identifying high-value accessions with superior yield and nutritional qualities to facilitate the development of improved cultivars through introgression breeding.

In this 2023 undercover tomato study conducted at the New Mexico State University Agricultural Science Center in Los Lunas, New Mexico, treatments included two tomato cultivars, ‘Big Beef Plus’ (indeterminate, hybrid) and ‘San Marzano II’ (indeterminate, heirloom), grown under three types of shade cloth: 1) white 15% shade, 2) white 50% shade, and 3) black 60% shade. Unshaded plants of both cultivars served as controls. Two irrigation methods were also evaluated: drip irrigation and furrow flood irrigation, each applied to half of the plots. Dependent variables included mortality rates attributed to confirmed beet curly top virus (BCTV) infection, as well as plant size, yield, and fruit quality indicators such as the percentage of fruit exhibiting blossom end rot. Preliminary data indicate expected cultivar differences in yield and susceptibility to blossom end rot. Shade treatment and irrigation method appeared to influence blossom end rot incidence, although the effects varied between cultivars. The protective effect of shade cover was pronounced. By July, 79% of the surviving, uncovered control plants tested positive for BCTV; assuming that untested deceased plants were also infected, this rate rises to 89%. In contrast, among the shaded treatments (white 15% shade, white 50% shade, and black 60% shade), 25%, 25%, and 9% of the surviving plants tested positive for BCTV, respectively, with only one untested deceased plant. These findings suggest that the shade cover, wrapped around the tomato cages, effectively limited exposure to the only known vector of BCTV. The plot thickens, however, as some shaded plants that tested positive for BCTV in July still produced over 21.9 kg of fruit per plant before the first frost in late October. These preliminary findings underscore the potential of shade structures as a viable cultural practice for mitigating BCTV impact and warrant more comprehensive investigation.

Sweet potato is grown year-round and is planted on all islands of Hawaii. During the 20th century, sweet potato was a profitable export crop for Hawaii, but production and sales have been declining for decades. Environmental conditions, such as continued droughts or precipitations and poor soil nutrients, contribute to low sweet potato yields. Sweet potato yields can be determined by the number of storage roots (tubers) per plant, and the size of each storage root at harvest. To maximize the marketable yields of sweet potato, it is necessary to achieve the greatest possible number of storage roots. In a field trial at the Kula Agricultural Park in the island of Maui, Okinawan sweet potatoes were grown under different irrigation regimes, both with and without fertilizer application. Control plots were irrigated daily regardless of soil moisture, and irrigation treatments were designed to initiate irrigation events based on soil moisture thresholds as follow: high moisture (irrigated to a soil water tension threshold of -60 kPa), medium moisture (irrigated to a soil water tension threshold of -80kPa), low moisture (irrigated to a soil water tension of -100 kPa). Fertilizer (16-16-16 and potassium sulfate) was applied to half of each plot in a split plot design. Marketable yield was evaluated in the different treatments. The fertilizer treatments were only significantly different in the irrigated control and the lowest moisture treatment. Marketable yield was highest in the irrigated control that received no fertilizer, and lowest in the low moisture treatment that received fertilizer. As irrigation was reduced, yield was also reduced, and the number of off-grade small tubers increased. In the irrigated control, adding fertilizer reduced the number and weight of marketable tubers, especially in the AA grade, and increased the number and weight of large, off-grade tubers. In the lowest moisture treatment, high numbers of “pencil roots” were observed due to inadequate moisture during tuber development, and few marketable tubers in both the fertilized and unfertilized treatments.

Priming seeds with nanoparticles (NPs) has the potential to enhance germination, growth, and resilience against environmental stresses by inducing the biosynthesis of secondary metabolites, which promote plant protection and health. However, the effectiveness of the essential micronutrients iron (Fe) and copper (Cu) as priming agents for crop production and postharvest qualities is largely unexplored. This study examines the impact of seed priming with Fe- and Cu-NPs on the production of onions, a crop of significant economic importance in Texas. NPs were synthesized using a green approach that employs onion juice as a reducing agent. The resulting Fe-NPs and Cu-NPs were characterized, and an optimal dose, determined by the length of root and shoot growth, was employed as a priming agent for two commercial yellow onion varieties (Legends and Pecos) and two Texas A

Sweet potato is a nutritious root crop, rich in fibers, beta-carotene and vitamin C, especially in highly pigmented varieties. The warm climate of Georgia provides ideal conditions for the cultivation of sweet potatoes. Maintaining postharvest quality during long-term storage remains a challenge for sweet potatoes packers and shippers. This study aimed to evaluate the effects of controlled atmosphere (CA) storage on the postharvest quality and shelf life of ‘Covington’ sweet potatoes. Roots from two farms in South Georgia, Herring Farms (HF) and Bland Farms (BF), were cured at 29 °C and 85–90% relative humidity (RH), for three weeks and one week, respectively. After curing, samples were stored at 13 °C and 85–90% RH for up to six months under different atmosphere compositions: (1) Air 21 kPa O2-Control, (2) 7 kPa O2, (3) 7 kPa O2 2 kPa CO2, and (4) 7 kPa O2 10 kPa CO2, using an Oxystat 200 control atmosphere system, which mixed and regulated O2 and CO2 gases under constant pressure, ensuring gas levels within ± 0.5% of the target concentrations. After cold storage, roots were transferred to ambient conditions (21 °C and 85–90% RH) to simulate market and consumer handling. Quality parameters, including firmness, color, weight loss, decay incidence, sprouting, and respiration rates, were assessed at six time points: one month, one month plus two weeks at ambient conditions (AC), three months, three months plus two weeks at AC, six months, and six months plus two weeks at AC. For each location, 1,260 roots were evaluated, with 315 roots assigned to each atmospheric composition (three replicates of 15 roots per evaluation time point). Results demonstrated that storage under low O2 and moderate CO2 levels (7 kPa O2 2 kPa CO2) reduced weight loss and decay while maintaining higher firmness compared to Control (storage in air). In contrast, higher CO2 levels (10 kPa) resulted in increased weight loss and surface decay. These findings suggest that controlled atmosphere storage with low O2 and moderate CO2 levels can improve postharvest quality and extend the shelf life of sweet potatoes, whereas higher CO2 levels negatively affect postharvest quality of Georgia-grown ‘Covington’ sweet potatoes.

Sweet onions (Allium cepa L.) are becoming increasingly popular due to their mild, sweet flavor and low pungency. Consequently, enhancing their pre- and post-harvest quality attributes has emerged as a key area of research. One promising method is seed nanopriming, where seeds are pre-treated with nanoparticles (NPs) to improve germination, overall plant growth, and quality. Zinc (Zn) plays a crucial role in plant metabolism, acting as a cofactor for various enzymes involved in processes like auxin production and chlorophyll synthesis, and onions are particularly sensitive to Zn deficiency. This study investigated seed nanopriming in four onion varieties: two yellow commercial types (Legend Onion and Pecos Onion) and two Texas A

A large and expanding literature about the application of skin coatings to fruits and vegetables has developed. Interest in coatings is being driven in part by concerns about the use of plastic films for packaging. While several major crops are routinely treated with coatings, many research studies do not consider the commercial logistics of applying coatings to the product. The prime example of this issue is strawberry fruit, which are usually field packed into clam shell containers, cooled, and in some cases stored in pallet shrouds that are injected with high carbon dioxide, before being sent to market. Despite claims that strawberry storage is problematic because of its short storage life, the market size continues to grow steadily, e.g., internationally from $15.3 billion in 2023 to $15.88 billion in 2024, success being based on cultivar selection and standard technologies. Despite this, numerous reviews on postharvest handling of strawberries cite technologies and treatments as if they are applied commercially. A Web of Science search with the words ‘strawberry’ and ‘skin coatings’ reveals 760 publications, mostly in the last 25 years. The reality is that almost without exception, no commercial application is viable because they do not fit well with harvest and handling processes that are focused on getting fruit market expeditiously. Breeding programs are critically important strategies to improve strawberry fruit storability. Where postharvest technologies or treatments may have a place for further development it most likely through modified atmosphere packaging either passive or active. The best coating for strawberries is chocolate.

Cornus florida (flowering dogwood) is a valuable tree native to eastern North America and prized for its floral bracts and colorful foliage. However, the tree is highly susceptible to powdery mildew (PM), a common fungal disease that challenges ornamental plant production. There are bioengineering approaches to developing PM resistance that involve the introduction of genes into C. florida cells and the regeneration of plants through somatic embryogenesis (SE). SE is a process by which somatic cells have the capacity to produce embryos without sexual reproduction. In C. florida, the regeneration of transgenic somatic embryos into plants has been problematic. Our work aims to determine the impact of cold treatments on the germination of somatic embryos. We propose that short-term low-temperature treatments will improve embryo germination, considering past research has demonstrated the importance of periodic low temperatures on natural seed germination in woody plant species such as fruit trees. We cultured a transgenic line of C. florida embryogenic callus expressing a visual marker (ß-glucuronidase) and enriched for globular stage embryos. We then introduced these globular embryos into liquid suspension media allowing the embryos to proliferate pro-embryogenic masses (PEMs) needed for mass embryo production. We chose somatic embryos morphologically identical to zygotic embryos of the same stage of development for testing plant regeneration following exposure to four different temperature conditions over four different time periods. The four different temperatures included: (1) 3°C; (2) 4°C; (3) 7°C; and (4) 23°C as the control temperature. The four different time exposures to the different cold periods included 0, 2, 4, and 6 weeks. Following cold exposure for a designated time, we transferred the somatic embryos to germination media, exposing the embryos to fluorescent light at room temperature ( /-) 23°C. Successful germination of the somatic embryos was indicated by taproot elongation with the production of roots, greening of the cotyledons, emergence of the apical shoot, followed by expansion of epicotyl and primary leaves. This research will yield the first transgenic C. florida plants and enable the introduction of PM resistance using bioengineering methods.

Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (FON), remains a major threat to watermelon production worldwide. Effective management depends on accurate race identification, as resistance in commercial cultivars is race-specific. However, current bioassay-based race differentiation is unreliable due to genetic variability within isolates. While molecular identification exists for FON Races 1 and 2, confirming Race 3 has required multiple PCR reactions, making diagnostics cumbersome and inefficient. This study developed and optimized a multiplex PCR assay that simultaneously differentiates FON Races 1, 2, and 3 in a single reaction, significantly improving diagnostic speed and accuracy. FON isolates and related Fusarium species from Georgia, Florida, and South Carolina were tested to assess the assay’s sensitivity (0.5 ng/µL detection limit) and specificity. Results confirmed that the multiplex PCR effectively distinguishes FON from non-pathogenic Fusarium species while accurately identifying all three pathogenic races. This is the first successful multiplex PCR assay for FON race differentiation, providing a rapid, reliable tool for plant pathologists and diagnosticians to track the spread of virulent FON races. Given the increasing prevalence of Race 3, which lacks effective fungicidal control, this tool will support early intervention strategies to mitigate outbreaks and inform resistance breeding programs. Keywords: Fusarium oxysporum f. sp. niveum (FON), multiplex PCR, race differentiation, watermelon wilt.

Dormancy constitutes a critical regulatory mechanism in perennial plants, conferring resilience to winter stress and impacting subsequent reproductive success. While previous investigations have predominantly focused on vegetative and floral buds during the dormancy-regrowth cycle, often neglecting the potential contributions of other plant compartments, this study adopts a comprehensive, whole-tree perspective. Utilizing four-year-old, root-bagged peach (Prunus persica) trees (cv. 'John Boy') we investigated dormancy progression by analyzing carbohydrate metabolism in different tissues relative to accumulated chilling units (CU) and growing degree hours (GDH). Our results demonstrated that roots maintained the highest starch reserves during endodormancy; however, soluble sugar accumulation in roots appeared largely independent of local starch hydrolysis, indicating potential translocation from distal storage tissues. This hypothesis is supported by the concomitant decline in starch content in branches and stems, which coincided with increased soluble sugar accumulation in these tissues. As dormancy progressed, soluble sugars were progressively redistributed, reaching peak concentrations in roots at the onset of ecodormancy and exhibiting a more uniform distribution across tissues during ecodormancy. A significant increase in floral bud soluble sugars preceding budbreak, without a corresponding starch depletion, suggests an enhanced capacity for carbohydrate uptake. Transcriptomic analysis of root tissues across all dormancy stages identified two key gene modules (ME) exhibiting inverse correlations with carbohydrate levels. Genes within ME3, associated with starch accumulation, were significantly enriched in fatty acid metabolism pathways—including SBE2, DBE1, FAD8 and KAS1. Notably, the upregulation of FAD8 during ecodormancy suggests increased membrane fluidity, potentially facilitating carbohydrate transport. Conversely, ME10 genes, associated with soluble sugar levels, displayed enrichment in hormone signaling and carbohydrate metabolism pathways—including SUS3, BAM6, and GH9A1. These findings underscore the coordinated regulation of carbohydrate metabolism and membrane lipid composition during dormancy transitions and bud break. Furthermore, the data indicate that starch catabolism in branches and stems during chilling accumulation serves as a source of soluble sugars for roots, which in turn may sustain metabolic activity and contribute to dormancy release in buds. Future research employing this whole-tree system is warranted to elucidate the comprehensive roles of roots and other storage organs in the regulation of dormancy.

Cucumber (Cucumis sativus L.) is an economically important crop and is widely cultivated throughout the world. Cucumber plants often suffer from biotic and abiotic stresses during the whole development life cycle, which lead to reduction in yield and quality. Improvement of cucumber for disease, insect, or nematode resistance and other horticultural traits with conventional strategy is limited by long breeding cycle, narrow genetic basis, and severe incompatibility barriers in related species. Emerging plant genome editing techniques provide trait specific breeding for enhancement of plant yield, quality, stress tolerance, and disease resistance. Highly efficient regeneration and transformation system is a prerequisite for cucumber genome editing. We report an efficient Agrobacterium mediated cucumber CRISPR-Cas9 transformation system with the aid of GFP visual selection. Cotyledons from 7 days old in vitro seedlings were harvested, and inoculated with Agrobacterium tumefaciens strain GV3101 contains a binary vector with CRISPR-Cas9 gene, GFP visual selection maker and hygromycin resistance genes. Transgenic callus and shoots obtained with GFP visual selection with high efficiency. PCR double check confirmed transgenes in transgenic plants. Transgenic plants are phenotyping in the greenhouse.

Photosynthetic light response (Pn–PAR) curves provide insights into optimizing light use efficiency and plant productivity while supporting decision-making on canopy management, such as plant spacing and pruning. In strawberry (Fragaria ×ananassa), previous Pn–PAR studies have primarily focused on mature leaves but ignored how photosynthetic capacity varies with leaf and plant age. To fill this knowledge gap, we examined leaf and plant age-related changes in Pn–PAR of strawberry plants. A field experiment was conducted with ‘Florida Brilliance’ short-day strawberry during the 2023–2024 growing season in West Central Florida. We determined Pn–PAR at three development stages: early (21 Nov.), mid (12 Dec.), and late (1 Feb.) growth stages. Leaves were classified into three categories based on leaf age: young (first fully expanded leaf), mature (fully developed leaf), and old (senescing leaf). Measurements were made using a portable infrared gas analyzer at ten photosynthetically active radiation (PAR) levels ranging from 0 to 2,000 μmol m⁻² s⁻¹ at a constant CO₂ concentration of 400 μmol m⁻² s⁻¹. During the early growth stage, the light-saturated photosynthetic rate (Pmax) was highest in mature leaves, followed by old and young leaves (18.17, 16.33, and 15.48 µmol CO₂·m⁻²·s⁻¹, respectively). Despite the relatively low Pmax, young leaves showed efficient low-light photosynthesis with a notable quantum yield (QY) of 0.0685 mol·mol⁻¹, trailing just behind mature leaves (0.0768 mol·mol⁻¹). During the mid-growth stage, mature leaves had the highest Pmax, followed by young and old leaves (16.38, 15.06, and 9.86 µmol CO₂·m⁻²·s⁻¹, respectively), with corresponding QY values of 0.0574, 0.0588, and 0.0365 mol·mol⁻¹, respectively. During the late growth stage, Pmax remained highest in the mature leaves, followed by young and old leaves (14.83, 13.43, and 6.80 µmol CO₂·m⁻²·s⁻¹, respectively), with corresponding QY values of 0.0574, 0.0588, and 0.0365, respectively. The results show that young leaves achieve efficient photosynthesis under low light, as indicated by their consistently high QY values across all stages, while old leaves exhibit reduced efficiency with both lower Pmax and QY. These results reveal that light use efficiency is highly dependent on both leaf and plant age, with the greatest senescence-associated decline occurring in old leaves at the late growth stage. Optimizing light use efficiency in strawberry plants, whether through light intensity control in indoor production or canopy management in open fields, must account for the leaf- and plant-age-dependent Pn–PAR relationship.

The water balance of fleshy fruit is heavily influenced by fruit transpiration. Transpiration is driven by the vapor pressure gradient between the fruit and the atmosphere. Stomatal closure is the main form of resistance to water loss. Thus, stomatal density (the number of stomata per unit area) and function are critical for regulating transpiration. In Northern Highbush blueberry (NHB, Vaccinium corymbosum L.), transpiration rates decline as the fruit develops. However, these dynamics remain unknown in Southern Highbush blueberry (SHB, Vaccinium corymbosum L. interspecific hybrids). This study examines the relationship between stomatal density, stomata function, and fruit transpiration rates in SHB. Three SHB cultivars were analyzed: ‘Jewel’, ‘Sweetcrisp’, and ‘Keecrisp’. Fruits were sampled weekly between petal fall and the ripe stage. Stomatal imprints were collected from six fruit regions: calyx basin, calyx, distal (calyx) end, distal middle, proximal middle, and proximal (pedicel) end. Stomatal density and distribution were quantified using StoManager, an artificial intelligence tool that uses convolutional neural networks to count and measure stomata in micrographs. Stomata density varied by genotype and fruit region. Distal regions exhibited the highest stomata densities in all varieties. No stomata were observed in the proximal middle or proximal (pedicel) end for either genotype. Fruit transpiration rates were measured using an infrared gas analyzer equipped with a custom-built chamber. Results indicated a progressive decline in transpiration rates as the fruit matured. The results suggest that SHB and NHB exhibit similar stomata morphology and transpiration patterns during fruit development.

Recent studies show that far-red photons (FR; 700–750 nm), when combined with photosynthetically active radiation (PAR; 400–700 nm), can drive canopy-level photosynthesis as effectively as PAR alone. This has prompted suggestions to redefine PAR as extended PAR (ePAR; 400–750 nm). However, few studies have evaluated whether FR and PAR photons produce equivalent photosynthetic rates at the leaf level. We investigated whether photosynthesis is maintained under increasing FR substitution at equal total photon flux (1000 µmol·m⁻²·s⁻¹). Five crop species (apple, blueberry, corn, strawberry, and tomato) were grown under natural field conditions (tomato in a hoop house) and sampled for leaf gas exchange using A/Ci curves under three light spectra: 0%, 15%, and 30% FR substitution. Leaf transmittance of FR photons was 3–11 times greater than PAR across species, indicating reduced FR absorption compared to PAR photons. Nonetheless, maximum photosynthetic rates were similar across treatments for all species. For most species, FR substitution did not affect Vc,max or Jmax, indicating that rubisco activity and electron transport capacity remained stable. However, blueberry showed declines in both parameters with increasing FR, while corn exhibited increased Jmax under FR substitution. Despite reduced FR absorption, photosynthetic performance was largely unchanged with up to 30% FR substitution. These results support the inclusion of FR photons in the PAR definition and reinforce the relevance of ePAR in both natural and controlled environments.

Light attenuation effects on productivity, yield and fruit quality of Cranberries under Massachusetts conditions. Brian Makeredza, Giverson Mupambi and Peter Jeranyama University of Massachusetts Cranberry Station, 1 State Bog Rd, East Wareham, MA 02538 Cranberry (Vaccinium macrocarpon Ait.) is a fruit of significant commercial importance in North America. The fruit is consumed for its high vitamin C and antioxidants such as phenols, including anthocyanins and quercetin. Radiation stress poses significant challenges to production of high-quality marketable cranberries. Elevated exposure to high visible and ultraviolet (UV) light negatively impacts physiological and stress defensive mechanisms of the fruit, made up of biochemicals such as antioxidants, pigments and organic acids. We investigated the effects of light levels and quality on the productivity of two cranberry cultivars, Stevens’ and ‘Mullica Queen’ at two different sites. A sun exposed control was compared to three light reduction treatments. The treatments were two shade net treatments that filtered 17% and 34% visible light and a particle film spray (Raynox®), that filtered UV light. Sensors were installed to log micro-climatic weather conditions. Net carbon assimilation, stomatal conductance and transpiration were measured at the green, blush and full red stage of fruit development. The ratio of carbon isotopes as described by the δ13C value were assessed to determine carbon discrimination as a stress indicator. Fruit quality parameters measured at harvest were flesh firmness, titratable acidity (TA), total soluble solids (TSS), total anthocyanins (TAcy) and fruit rot. Raynox®, did not have an effect on carbon assimilation, yield and fruit quality. Reducing visible light did not affect stomatal conductance and transpiration but decreased carbon assimilation and yield but the effects were not statistically significant in some cases. Micro-climatic conditions under shade nets were conducive to the development of cranberry fruit rot which consequently contributed to yield reduction of marketable fruit. There were no differences in carbon isotope composition indicating no differences in abiotic stress levels. Fruit firmness decreased with an increase in shading. Trends for TA and TSS were inconsistent and unclear between the cultivars, but TAcy was only impeded by reducing light up to 34% level. Keywords: Cranberry, shade nets, light levels, particle film spray, carbon isotope

The American cranberry (Vaccinium macrocarpon Aiton), commonly known as the large-fruited cranberry, is native to North America. Fruit quality remains a major challenge for cranberry growers, with the cranberry fruit rot (CFR) complex posing a significant threat. Cranberry fruit rot is associated with over a dozen taxonomically diverse fungi. In the northeastern United States, growers typically apply three to five fungicide treatments per growing season to manage CFR. Even with well-timed applications, growers often observe rot levels between 1% and 15%, or sometimes higher. When rot exceeds 12%, growers face financial penalties, and crops with more than 20% rot are often rejected by processors. Managing CFR has become increasingly difficult, particularly in high-yielding and newer cultivars. This challenge is further compounded by regulatory restrictions over the past decade on key fungicides such as chlorothalonil and mancozeb. As conventional control options decline, interest in alternative strategies continues to grow. However, the influence of microclimate, cultural practices, and plant physiological factors on CFR incidence and overall fruit quality remains poorly understood. In this study, we investigated 22 cranberry bogs in Massachusetts over a three-year period (2021–2023) to elucidate the relationships among weather variables (temperature, humidity, growing degree days [GDD], soil moisture), plant traits (fruiting upright-to-total upright ratio, leaf area index [LAI], canopy height), cultural practices (fungicide choice and frequency), and fruit quality metrics (rot incidence, yield, anthocyanin content, and firmness). Statistical analyses included year-to-year comparisons, predictor-response modeling, and time-series evaluations to identify critical periods influencing fruit quality outcomes. Key findings indicate that interannual microclimatic variation significantly affects fruit quality. Temperature influenced anthocyanin accumulation throughout the growing season, while GDD accumulation influenced fruit yield. A higher fruiting upright ratio was associated with increased yield and firmness, while greater LAI correlated with higher anthocyanin content. Although fungicide choice and application frequency varied widely among participating bogs, a marked reduction in fruit rot and an increase in yield were observed with up to four fungicide applications; however, additional applications beyond this threshold did not result in further significant improvements. Notably, bog age did not have a significant effect on fruit quality. These findings highlight the need for integrated, site-specific strategies that combine environmental monitoring with targeted interventions to improve cranberry production and support long-term sustainability.

The balance between photosynthetic carbon fixation and leaf respiration drives our expectations of crop performance. The Laisk method is a technique used to estimate the CO2 concentration in the intercellular air space when Rubisco’s oxygenation velocity is inferred to be twice its carboxylation velocity (Ci*) and leaf respiration in the light (RL). These parameters serve as the basis for understanding leaf carbon dynamics at the physiological level and can also be incorporated into global carbon models. While Ci* and RL estimates have been well characterized in model plant species, there is a paucity of information available for horticultural crops. Further, intraspecies variation in these parameters has not been explored. We used the Laisk method to estimate Ci* and RL in three apple rootstock genotypes—G65, G11 and B10. The Laisk method was conducted in the steady-state along with chlorophyll fluorescence measurements to fit the solar induced fluorescence (SIF) model for estimating rates of net assimilation (An). In addition, the Laisk method was conducted in the nonsteady-state using the Dynamic Assimilation Technique (DAT). We found there were no statistically significant differences between genotypes nor technique used for the Laisk method when estimating Ci* and RL across the three genotypes. The findings of this study suggest that Ci* and RL values are conserved within species, the SIF model accurately predicts An for Laisk method data, and the DAT can be used to reliably estimate Ci* and RL.

Southern highbush blueberry (Vaccinium corymbosum interspecific hybrids) cultivars exhibit diverse canopy architectures. Plant architecture phenes influence light interception in other plant species. However, the relationship between canopy architecture and light interception is still poorly understood in southern highbush blueberry. We evaluated 29 genotypes, including cultivars and breeding selections from the University of Florida Blueberry Breeding and Genomics program. Plants were grown under commercial conditions in Citra, FL. We employed photogrammetry, field measurements, and a plant canopy analyzer to measure canopy density, canopy volume, base angle, and plant height in four plants per genotype. We found that genotypes differed in all measured phenes. Intercepted PAR in the bottom of the canopy varied among genotypes according to their plant architecture. Taller, wider, and denser genotypes received less light in the bottom of the canopy than shorter, narrower, and more sparse ones. We used principal component analysis to assess the relative contributions of each plant architecture phene to intercepted PAR. Canopy density and volume strongly contributed to intercepted PAR. These results suggest that plant architecture could be optimized, through breeding and agronomic practices, to maximize photosynthetic light interception in southern highbush blueberry.