The Boons of Breeding at a Botanic Garden - Justin Lombardoni Mutagenesis of Hardy Hibiscus Using Ethyl Methanesulfonate - Greta Gallina Genetic Sterilization of Four Invasive Ornamental Plant Species to Reduce Their Invasive Potential: Progress and Prospects - Zhanao Deng Inheritance and Genetics of Ornamental Traits in Pomegranates - Alexander Schaller Induction and Characterization of Mutations Related to Dwarf Habit in Hardy Hibiscus (Muenchhusia section) - Conner Austin Compatibility of Cross-hybridizing Lagerstroemia taxa - Yongjun Yue
While many institutions have staff that dabble in plant breeding, the Chicago Botanic Garden is one of the only gardens to administer a breeding program dedicated to introducing ornamental perennials. A botanic garden possesses a wealth of resources not available to hobbyist breeders and other companies, providing key advantages that aid in cultivar development. Among these resources are staff members that support plant breeding with different fields of expertise, such as horticulture, production, propagation, and landscape design. Other resources include well-maintained breeding beds and greenhouses for crossing plants and growing progenies as well as a plant exploration program that conducts both national and global plant collection trips. Various lab facilities are available through the science department, including equipment and staff that can help with seed cleaning and banking, pollen banking, flow cytometry, and more. Because the Chicago Botanic Garden and its plant introduction program Chicagoland Grows® are non-profits, there is more freedom to work on lesser known genera. This contrasts with traditional industry breeding, which often focuses on well-established genera when introducing new cultivars. Using Baptisia (false wild indigo) as an example, we’ll explore some past breeding conducted at the Chicago Botanic Garden by Dr. Jim Ault and how this breeding will continue moving forward. This will illustrate how ornamental cultivar development is possible without modern genotyping methods and high input costs.
Hardy hibiscus (Hibiscus moscheutos) are native herbaceous perennial plants. Due to their ornamental nature, variations in flowers, foliage, color, and variety are important. Mutagenesis is a method to increase variation in hibiscus plants, and ethyl methanesulfonate (EMS) is a common chemical mutagen that causes nucleotide substitutions. It converts guanine-cytosine pairs to adenine-thymine pairs. This study aimed to determine the EMS LD50 value for hardy hibiscus. The cultivar ‘Luna Red’ (Ball Horticulture) seed was used for treatment. An EMS LD50 determination study was performed using a factorial randomized complete block design. Three replications of 15 seeds were used for each treatment. EMS treatments consisted of 0, 0.25, 0.5, 0.75, and 1% EMS solution, each treated for 4, 8, and 12 hours to determine the ideal treatment concentration and time. The germination rate, survival rate, and height of seedlings were measured. The interaction effect for germination was insignificant when measuring concentration and time, so the LD50 values were identified for each time separately. The LD50 values for seedling survival were 0.64% EMS for 4 hours, 0.45% EMS for 8 hours, and 0.38% EMS for 12 hours. Notable phenotypic differences between the treated and control plants were observed. There was 92% greater two-month survival in the control plants compared to those treated with 0.75% EMS solution. The control plants were 90% taller at three months after treatment than the plants treated with 0.75% EMS solution.
Invasive ornamental plants have been considered as a major contributor to the spread of invasive plant species in the United States and many other countries in the world. To mitigate the economic and ecological impacts of invasive ornamental plants, we have focused on genetic sterilization of four invasive ornamental plants that are commonly produced and widely used in Florida to develop sterile, triploid cultivars as alternatives to the invasive types. Toward this goal, we have made progress in (1) artificial induction of tetraploids in nandina, privet, and porterweed, 2) developing and releasing new sterile, non-invasive triploid lantana cultivars, 3) understanding the reproductive biology of lantana, 4) developing and applying new genomic and molecular tools, and 5) testing alternative breeding approaches. By applying the mitotic inhibitor agent colchicine to germinating seeds or seedlings, we have induced tetraploids in nandina, privet, and porterweed. Tetraploid nandina showed significantly reduction in pollen stainability and seed set. Tetraploid privet lines exhibited thicker leaves with darker green color. Induced tetraploid nandina, porterweed, and privet lines have come into flowering, and interploidy crosses are made to produce new triploids. Using existing tetraploids in lantana, we have generated hundreds of new triploids, evaluated their male and female sterility, and released five sterile, non-invasive triploid cultivars, three of which have become popular replacements of the invasive types. Ploidy and molecular marker analyses have revealed the production of unreduced female gametes and apomictic seeds in lantana and natural sexual polyploidization in lantana and several other lantana species. Genome and transcriptome analyses have uncovered candidate genes that are linked or directly involved in the production of unreduced female gametes in Lantana. A number of diploid and tetraploid lantana genotypes with male or female sterility have been identified, which are being used to generate new triploids through open pollination. Additional tools are needed to rescue triploid embryos and screen breeding populations for high female sterility. These new plant materials, genetic and genomic resources, and molecular tools are expected to facilitate the genetic sterilization of lantana, nandina, porterweed, and privet. The findings may guide similar genetic sterilization efforts in other invasive ornamental plants.
Dr. Sandra Wilson is a Professor of Environmental Horticulture at the University of Florida’s main campus in Gainesville. She received B.S. and M.S. degrees from the University of Delaware and a Ph.D. in Plant Physiology from Clemson University. Dr. Wilson completed postdoctoral... Read More →
Thursday September 26, 2024 8:30am - 8:45am HST
South Pacific 4
Pomegranates, renowned for their fruit, also possess ornamental varieties with unique traits such as double flowering, diverse flower colors, and dwarfing characteristics. Despite their appeal, limited information exists on the genetics and inheritance of these ornamental traits. In this study, we investigated the inheritance and genetic controls of these traits through crosses between the dwarfing cultivar Peppy Le Pom and pomegranate cultivars showcasing ornamental traits. By analyzing multiple families and conducting a genome-wide association study (GWAS) using resequencing data from 64 cultivars, we made several key findings. Firstly, the double flower trait exhibited Mendelian inheritance with a single locus controlling its expression, as evidenced by a 1:1 ratio of double to single flower plants in the F1 generation where a double flower individual was crossed onto a single flower individual. Subsequent analysis identified a SNP within an AP2-like gene on chromosome 3 that was able to differentiate between a single and double flower phenotype. Secondly, flower color inheritance revealed the recessive nature of white flowers compared to orange and red hues. SNPs near a PGLOX gene, previously linked to anthocyanin-less pomegranates, distinguished between white and red/orange flowers, suggesting specific genetic loci involved in determining flower color. Lastly, the dwarfing trait was identified as recessive, exhibiting phenotypic diversity among selfed F1 individuals, indicating potential multiple loci control. Further investigation into the genetic mechanisms governing dwarfing is warranted. In conclusion, our study contributes to understanding the genetic underpinnings of ornamental traits in pomegranates, offering insights valuable for breeding programs aimed at developing novel varieties with desirable ornamental characteristics. Further research into the identified genetic loci promises to enhance our understanding and facilitate targeted breeding efforts in this versatile fruit species.
Hybrids originating from different species within the Muenchhusia section of Hibiscus are well-received in commercial markets for their vibrant and abundant blossoms. However, many commercially available varieties prove overly robust for smaller garden spaces, often yielding a limited number of blooming flowers. The cultivation of stable, heritable mutants displaying a dwarf stature and improved branching architecture holds significant promise for enhancing the commercial production of resilient Hibiscus. The objective of this project was to induce point mutations in genes linked to the biosynthesis or signaling of plant growth-related hormones, using ethyl methanesulfonate (EMS). Successful induction of multiple mutations associated with dwarf, compact phenotypes was achieved. Hybridizations were carried out between M2 plants exhibiting a dwarf phenotype and hybrids generated through traditional breeding that lacked the dwarf mutation in their genetic background. This aimed to produce a diverse array of dwarf plant selections. The inheritance patterns of the dwarf genes were elucidated by analyzing the segregation ratios of the dwarf phenotype in the F1 and F2 generations of these hybrids. In comparison to non-dwarf progeny, dwarf progeny exhibited significantly shorter internode lengths and a greater number of primary branches.
Lagerstroemia indica L. is a favored landscape plant in mild-climate regions, cherished for its easy propagation and cultivation, prolonged blooming period, and variety of plant forms. The majority of new cultivars are the result of cross hybridization. However, compatibility issues arise with some cultivars and species. To enhance our understanding of the cross-compatibility of our elite cultivars, we selected four plants (C14-35, C14-39, D03-29, and D03-34) for reciprocal crosses and for crossing with other elite plants, chosen for their clean foliage and extended summer bloom periods. A total of 3126 crosses were made in the summer of 2023. By the season's end, 731 fruits were harvested to assess seed set, and viable seeds were counted in winter 2023. From these efforts, 20,862 seeds were harvested, with 5,470 identified as viable. Interspecific crosses with L. speciosa revealed that C14-35 and C14-39 had significantly better fruit set percentages (40% and 35.2%, respectively) compared to D03-29 and D03-34 (6.3% and 0%, respectively). Thus, C14-35 and C14-39 exhibit greater compatibility with L. speciosa. For reciprocal crosses, C14-39 and D03-34, when used as pollen donors, resulted in much lower fruit set percentages and seed sets than C14-35 and D03-29. Pollen studies of the four cultivars indicated that both C14-39 and D03-34 produced little to no pollen, while C14-35 and D03-29 were prolific pollen producers. Future cross hybridization studies will therefore avoid using C14-39 and D03-34 as pollen donors. A seed germination study is planned for spring 2024 to further assess the various cross combinations and confirm interspecific hybrids.
Digging into Clover Living Mulch Effects on Soil - Connor Ruen Effects of Mulch Type on Day-Neutral Strawberry Yield and Quality in an Organic Production System in the Upper Midwest - Mary Rogers The Nebraska Urban Soil Health Initiative: Combined Effects of Cover Crops, No-till, Compost, and Biochar on Soil Health and Vegetable Crops - Collin Eaton HydroMulcH2O: A Novel, Certifiably Organic, Biodegradable Mulch Technology for Northern Highbush Blueberries - Ben Weiss Effect of Plastic Mulch, Living Mulches and Cover Crops on Soil Characteristics, Weed Pressure and Yield in Organic Globe Artichokes Production - Arianna Bozzolo Eastern South Dakota Early Season Soil Tarping Impacts on Soil Microbiology - Hannah Voye
Ben is from Philadelphia and has been interested in food systems since an early age. He attended his first natural products expo before kindergarten because his parents worked in the natural foods industry. During late adolescence, he started a prolific tomato garden that blossomed... Read More →
Thursday September 26, 2024 9:44am - 11:15am HST
South Pacific 4
Living mulch research has focused on crop health without digging in to the effects on soil health. Soil management influences soil structure, water infiltration, and compaction. The recent drought has affected the Great Plains where precipitation is already limited. This makes it important for the water to infiltrate into the soil instead of running off, taking nutrients along with it. Soil compaction limits plant root’s ability to reach ground water and nutrients deeper in the soil profile which are needed during dry spells. In this study, living mulches of three established clover varieties, ‘Domino’ white clover (WC) (Trifolium repens), ‘Aberlasting’ white x kura clover (KC) (T. repens x ambiguum), and ‘Dynamite’ red clover (RC) (Trifolium pratense), bare ground control (BG), in combination with in-row management of tilled (T), no-tilled (NT), tilled fabric (TF), and no-tilled fabric (NTF) were evaluate for water infiltration, soil compaction, soil temperature and moisture. Water infiltration was measured using a 25.4 cm PVC ring which was pounded in the ground to prevent lateral flow. Water was added every minute to measure the infiltration rate. Soil compaction was measured using a SpotOn soil penetrometer measuring the PSI needed to pass through the soil. Soil moisture and temperature were measured every hour using HOBO MX soil moisture and temperature logger. Water infiltration in NT soil management had a was 67% greater when compared to T soil management. Soil compaction readings from 0-15 cm had a range from 324 PSI in NT to 351 PSI in NTF. After one year of changing the soil management, there was a significant increase in on water infiltration rate in the NT which means the soil can handle much larger volumes of water compared to T. Soil compaction has changed very little between soil managements which can be expected since it takes many years to break compaction layers and improve the soil structure. Soil management can improve water infiltration rates which increases the water added to the soil and decreases the risk of erosion. More time is required to determine how soil management will affect compaction in this study.
Organic, locally produced strawberries are in high demand in the Upper Midwest. Day-neutral cultivars fit well within an annual production system, allow growers an extended harvest period, and previous research shows they can be productive in our region. However, key production challenges limit adoption of organic production of day-neutral strawberries including weed, insect, and disease pressure. To address these challenges, we established controlled experiments investigating the effects of four different mulch types: white-on-black poly (standard), black poly, reflective metallic poly, and biodegradable paper mulch on yield and quality of ‘Cabrillo’ strawberries across two years (2022 and 2023) and two locations (Madison, WI and St. Paul, MN). Our results show that strawberry yield ranged from 5,000 - 18,000 lbs per acre across treatments and years. The highest yields were achieved in 2023 in Wisconsin in the reflective metallic poly treatment, which was significantly different from the white-on-black treatment in the same year. Proportion marketable yield was equal between treatments in both years in Wisconsin and in 2022 in Minnesota, however we observed a significant decline in marketable fruit quality in Minnesota in 2023 under the paper treatment compared to black plastic.The paper mulch broke down before the end of the production season in Minnesota in both years which led to increased weed pressure and reduce fruit quality; however paper mulch retained at least 90% coverage and integrity in Wisconsin across both years. Tarnished plant bugs (TPB) are a key pest in this system and will significantly reduce fruit yield and quality if not managed. In both Minnesota and Wisconsin, TPB damage was higher in our standard white-on-black poly compared to the reflective metallic poly mulch in both years. In addition, thrips counts were significantly higher on white-on-black poly compared to reflective metallic poly in Minnesota in both years. Anthracnose fruit rot was the most common disease observed and was most common in the white-on-black poly treatment. Anthracnose was also a significant problem on row edges where weeds were actively growing and retaining moisture near the fruits. Overall, reflective metallic poly mulch significantly reduces strawberry insect pest pressure while maintaining yield and fruit quality and outperforms the current grower standard white-on-black plastic mulch. Price premiums for organic strawberries marketed direct by growers combined with the longer day-neutral production season, make day-neutral strawberries financially lucrative despite production issues and high labor requirements.
Adoption of soil health management practices like cover crops, no-till, and organic soil amendment is increasing in rural agroecosystems, but less in known about whether urban farmers and gardeners are using these practices and how implementing these practices might influence their soil. To address this knowledge gap, we started the Nebraska Urban Soil Health Initiative to 1) benchmark soil health and current management practices in urban gardens throughout Nebraska, and 2) evaluate the effects of adding new soil health management practices on urban soil health and crop performance. Using a citizen-science approach, we recruited and have retained over 300 participants who collect annual soil samples, complete surveys about their practices and knowledge, and implemented an assigned soil health management practice. Soil health management practice treatment groups ranged from low (e.g., individual practices) to high management intensities (e.g., combinations of practices) and include: 1) a cover crop mixture; 2) no-till with geotextile fabric; 3) compost soil amendment; 4) biochar soil amendment; 5) cover crop mixture no-till; 6) cover crop mixture no-till compost, or 7) cover crop mixture no-till compost biochar. Prior to implementing, most participants (>70%) had positive perceptions about cover crops, no-till, and compost soil amendment, whereas >60% had no opinion or prior knowledge about biochar soil amendment. Over 50% of participants characterized their garden weed pressure as somewhat to very high and over 60% reported very low to low pesticide use, which suggests room for improvement using cover crops and a no-till weed barrier. Baseline soil P across gardens was 186 mg/kg (above a sufficiency level of 25 mg/kg in 98% of gardens) and average soil organic matter was 6.9%, which suggests a legacy of compost amendment to meet crop nitrogen needs. Biochar soil amendment (8 tons/acre) alone reduced zucchini yield by 37%, but yield loss was avoided by pairing biochar with compost and the weed barrier. Initial changes in soil health among participant gardens following implementation of new practices in year one will be analyzed along with year two sweet corn crop response.
Utilizing single-use polyethylene (PE) mulch in agriculture is controversial due to concerns with plastic waste generation and pollution. An alternative option to PE mulch is hydromulch (HM), which is paper-based, biodegradable, and potentially could be certified organic. HMs can be produced from water, recycled paper, and organic-approved tackifier(s). The objective of this experiment was to determine the efficacy of different HM formulations on yield, fruit quality, mulch coverage, and weed suppression in a mature planting of northern highbush blueberry (Vaccinum corymbosum ‘Valor’) grown in eastern Washington. Using a randomized complete block design with four replications, four mulch treatments were tested: (i) HM with 4% guar gum, (ii) HM with no tackifier, (iii) paper mill slurry, and (iv) woven PE mulch (hereafter “weedmat”). The papermill slurry was made by agitating recycled paper with water and sodium hydroxide until the paper was pulped and ink removed. Yield, fruit firmness, titratable acidity as percent citric acid, total soluble solids, and pH were similar across all treatments. Mulch coverage measured as percent soil exposure was greatest for the slurry, followed closely by the 4% tackifier and no tackifier treatments. Weedmat had the lowest percent soil exposure. All treatments mostly suppressed dicot weeds, however, the no tackifier and slurry treatments had the greatest dicot numbers. The 4% tackifier suppressed nearly all dicots. HMs struggled to suppress monocots, with the slurry and no tackifier treatments performing the worst at monocot suppression. The 4% tackifier treatment was better than the other HM formulations, however, it had little-to-no effect on nutsedge (Cyperus esculentus) while weedmat suppressed all monocots. Weed biomass data revealed different patterns with the 4% tackifier treatment having similar weed biomass compared to the slurry and no tackifier treatments. This was likely due to lack of competition, as when weeds penetrated the 4% treatment they did not have other plants to compete with, and thus accrued biomass much faster than weeds in the slurry and no tackifier treatments. Although weed and fruit quality was maintained, future research should focus on increasing HMs ability to suppress nutsedge and other vigorous weed species.
Ben is from Philadelphia and has been interested in food systems since an early age. He attended his first natural products expo before kindergarten because his parents worked in the natural foods industry. During late adolescence, he started a prolific tomato garden that blossomed... Read More →
Standard organic farming production practices for specialty crops frequently involve the use of polyethylene plastic mulch or mechanical soil disturbance to reduce weed competition and enhance crop yields. Although successful, these practices come with environmental consequences, including soil pollution and loss of soil organic matter. As such, alternative methods that prioritize the long-term health of the soil and minimize environmental impact are needed. We performed a field experiment to assess and compare the influence of five soil management systems on soil characteristics, weed pressure and yield in globe artichokes production. Artichoke (Cynara scolymus L.) seedling cvs. Tavor were established on raised beds as: A) intercropped with white clover (Trifolium repens L.) as living mulch, or B) intercropped with crimson clover (Trifolium incarnatum L.) as living mulch, or C) transplanted into mixture of buckwheat (Fagopyrum esculentum M.) and pea (Pisum sativum L.) cover crop residue or D) intercropped with Kurapia (Lippia Nodifera L.) as living mulch, or E) transplanted in PE plastic mulch. Results show that white clover increased soil organic matter (SOM), soil potassium and manganese content, water extractable carbon, soil respiration (CO2), soil nitrate, ammonium and total soil nitrogen compared to plastic mulch at 360 DAS (Days After Seeding). White clover weed suppression ability did not differ from crimson clover and buckwheat/pea mixture. Crimson clover increased SOM at preharvest sampling. Both clovers decreased artichokes yield per plant when compared to plastic mulch. Kurapia increased soil sodium content compared to plastic. Cover crop/reduce tillage system increased SOM at 120 DAS compared to plastic. Due to biomass decomposition, the suppression ability of this mixture decreased over time. Plastic mulch increased copper and iron soil concentration. Artichoke yield from plants grown on plastic mulch had comparable bud weight and yield to buckwheat/pea mixture and Kurapia. The potential to enhance soil nitrogen and carbon levels over a longer period of white clover makes it a valuable choice in systems aiming to improve soil fertility. Crimson clover emerges as the most promising among the clovers, exhibiting less competition compared to white clover, effective weed control, and, although the yield is lower than that achieved with plastic mulch, it maintains a well-balanced crop load. The reduced tillage system has shown promising results, successfully managing weeds adequately and allowing for a satisfactory level of production. No detrimental impact on yield were found intercropping artichokes with Kurapia and, but its effect on soil health was limited.
Solarization and occultation are weed management strategies used by growers across the globe. However, there is not a large amount of literature discussing the impacts of this weed management practice on soil health. This study evaluated the impact of tarp materials and duration of tarp coverage on soil microbiology. Field experiments were conducted in the 2023 growing season in Brookings, South Dakota. Solarization was conducted using clear tarps secured with sandbags and buried edges. Clear tarps were placed early spring for six, four, and two weeks before tarp removal in May. Immediately following tarp removal, each plot was tilled, and rows of onion transplants were planted. Occultation was conducted using white side up and black side up silage tarps, both applied for six, four, and two weeks before removal and planting onions. These treatments were organized in a randomized complete block design with four blocks and ten treatment plots per block including a control with no tarp. Temperature and moisture data were taken in treatment plots using HOBO temperature and moisture sensors during tarping as well as during the growing season. Soil samples were taken before tarp application to observe organic matter and basic nutrients. Samples were also collected in each treatment plot after tarping and at the end of the growing season to determine differences in organic matter, basic nutrients, soil respiration, permanganate oxidizable carbon, and nitrogen. Solarized plots showed trends of higher temperatures during tarping compared to occultation plots. Solarized plots showed higher soil moisture trends during tarping and lower moisture trends during the growing season. Occultation tarp treatments showed trends of lower moisture during tarping and higher moisture during the growing season. No significant differences were seen between tarp treatments for soil respiration, permanganate oxidizable carbon, and nitrogen. While soil tarping can manipulate soil microbiology, more research is needed to determine the full extent of these impacts.
Evaluating Faba Bean (Vicia faba) Performance Using Desalinated Irrigation Water and Compost Amendments in the Southwest - Jannatul Afroze Planning for Success: A Roadmap to Establishing a Certified Naturally Grown Production Plot - Shelby Mendoza Fertility Management in Soilless Growth Media for Beet Crop Production. - Bryce Waugh Adaptation of AgRobotics for Onion Production in High Organic Matter Soils - Mary Ruth McDonald Dual-cropping Sweetpotato for Greens and Root Production - Laura Schulz Effect Of Selenium Fertilization on Beta-carotene Accumulation in Hydroponically Grown Two cress Varieties - Adekunle Adeyeye Effect Of Levels Of Magnesium Fertilization On The Carotenoid Accumulation Among Three Kale Cultivars Grown Hydroponically. - Alex Kofi Red And Blue LED Lighting Effects On Hydroponically Grown 'Koba' Green Onion - Kent D. Kobayashi Plant Health Aerial Mapping Integration In Precision Agriculture Systems - Wael Elwakil Evaluation of Vegetable Soybean Adaptations to South Florida's Tropical Climate- Xiaoying Li Lettuce Cultivar Trials in a Deep-Water Culture (DWC) Hydroponic System - Alireza Rahemi
Water and soil salinity pose a significant challenge to global food production, particularly in semi-arid and arid regions. In many of these areas, the only available irrigation water often has high salinity levels. Utilizing irrigation water with high salinity can lead to salt accumulation in the rhizosphere, causing reduced infiltration rates, yield losses, decreased crop quality, and even potential plant mortality. Two strategies to address water and soil salinity include integrating compost soil amendments and implementing water desalination techniques. In addition to these two strategies, legumes are suitable crops for enhancing bioproductivity and reclaiming marginal lands due to their symbiotic association with rhizobia bacteria that can increase soil nitrogen. The objective of this study was to evaluate how the combined use of saline and desalinated water for irrigation, along with compost amendments, impacts faba bean germination, growth, physiology, and nodulation. Two common faba bean cultivars, Broad Windsor and Aquadulce were planted in fall of 2023 in field plots at the arid Brackish Groundwater National Desalination Facility, Alamogordo, NM, USA. Faba bean cultivars were grown in a combination of treatments of mulched composted wood with soil, bare soil, saline (1.97 dS/m) irrigation water, and desalinated (0.80 dS/m) irrigation water. Germination rates, plant nutrient composition, chlorophyll index, nodulation weight and number, along with root weight were measured. Preliminary results show that compost treatment as a main effect had a significant effect on faba bean germination rates with a 22-26% reduction in germination at 18, 25, and 35 days after planting (DAP) in plots with compost. By 107 days after planting, faba bean plants in the compost-treated plots showed no signs of nodulation, whereas the majority of plots without compost had nodules present. Water treatment significantly influenced the chlorophyll index of faba beans at 107 DAP; plants irrigated with saline water exhibited higher chlorophyll indexes. Compost treatments could have influenced germination rates due to variations in soil temperature, while nodulation might have been affected by adequate nitrogen potentially supplied by the compost. Upon completion of the current season and subsequent second season, we will have a more comprehensive basis to evaluate the relationships between compost application, saline irrigation water treatments, and their impacts on faba bean growth.
In the face of escalating environmental concerns, the horticultural sector is encouraged to pivot towards more sustainable and environmentally friendly production practices. Specifically, Certified Naturally Grown (CNG) emerged in 2002 as a new production system for small-scale producers rooted in organic farming principles and relying on peer-reviewed certification that fosters a community network. However, there is limited literature on the process of achieving CNG certification. Hence, this research strives to provide a detailed roadmap of the different phases of setting up a demonstrational CNG production system at the Oklahoma State University Student Farm including strategic planning and execution phases. The research plot is intended to serve as both an educational tool and a practical guide for growers aiming to transition to CNG practices. The implementation of this project began with familiarizing ourselves with the CNG organization, their inspection processes and planning accordingly. This is crucial to ensure the plot meets CNG criteria, focusing on sustainable practices and ecological balance from the outset. Next, the planning phase encompassed establishing the research plot including site selection, soil analysis, anticipated barriers of CNG certification, plot design and layout, resource assessment, and an implementation timeline. The planning phase aids in physically establishing the CNG demonstration plot and ensuring its role as a research and educational hub. By accurately addressing each planning component, the project aims to lay a solid foundation to demonstrate the viability of CNG practices in Oklahoma, stimulate community engagement, and promote a deeper understanding of sustainable agriculture practices. Ultimately, this project seeks to illustrate the detailed strategic planning and preparation required to develop a CNG production system. The education tools we develop will provide a template for producers aiming for CNG certification. With this initiative, we aim to educate growers on sustainable and resilient production methods and enable a transition towards them.
Greenhouse production is experiencing a rise, with more emphasis being placed on sustainability and efficient resource utilization. Accurate fertilizer applications are now more crucial than ever across various production systems. Soilless growth media possess different physical and chemical properties compared to soil, resulting in differences in nutrient retention capabilities. Because of this, it is imperative to apply precise fertilizer rates. This study evaluated 14 fertilizer blends with varying nitrogen (0-120ppm), phosphorus (0-120ppm), and potassium rates (0-120ppm). ‘Red Ace’ beet seeds were planted into 1-pint pots with Berger BM6 and plants were hand watered weekly with each treatment fertilizer rate to a 10% leaching fraction. Dry shoot weight, fresh root weight, dry root weight, number of leaves, and SPAD were taken as end measurements. This study found that high rate of nitrogen increased fresh shoot weight, while higher rates of potassium increased root weight. More studies should be done to dial in fertilizer rates for different specialty crops grown soilless greenhouse media.
The high organic matter soil (50 -80%) in the Holland Marsh, Ontario, Canada, is ideal for growing root and bulb vegetables but weeds also thrive. There are few registered herbicides and increasing herbicide resistance necessitates hand-weeding, but labor shortages and increased costs increase the interest in alternative methods. The solar-powered FarmDroid FD20 is one option, if adapted to work in vegetables. The FarmDroid was used to seed and weed onions on 2.8 ha of a commercial farm with weed control issues. The robot seeded 21 beds ~800 m long, with 4 single rows in each bed, and seeds 3.4 cm apart within the row, at 225 meters per hour. Seeding took 81 hours. Weeding was done with using a cultivator with metal tines to remove weeds growing between the rows it had seeded, at a speed of 500 m/hr. Weed counts were consistently higher in the robot-weeded than conventional-farmed sections (408 and 186 weeds/m, respectively), largely because of the inability of the robot to weed within the rows. There were no differences in yield. Small scale trials were conducted to compare conventional seeding of four double rows, with single rows as above and clusters of 3 seeds, 12 cm apart in the row. Emergence was 25, 35 and 17 plants/m for single, double and triple cluster seeding, respectively. There were no differences in yield at harvest (73-76 t/ha) but there were significantly more jumbo onions (42%) in those seeded in clusters, compared to the others (9 and 1%). A separate trial assessed seeding accuracy with increased speed. Emergence was highest for onions seeded at 200 m/hr with a significant decrease at speeds of 300 – 500 m/hr. Seeding in clusters shows promise for faster seeding and larger onions. Modifications to improve the configuration of tines for weeding are ongoing.
Research and extension interests include vegetable production and crop protection, with the emphasis on onions, carrots, celery and Brassica crops. Also conducting research on soil health of high organic matter soils and agricultural robots.
Sweetpotato (Ipomoea batatas) is a nutritious crop that produces edible roots, stems, and leaves. The tender vine tips, including both leaves and stems, are consumed as a vegetable in many regions of the world, including the Pacific Islands, Asia, and parts of Africa. A field experiment in Mount Vernon, WA evaluated time of vine tip (15 cm from the end of every vine) harvest on sweetpotato root yield of breeding lines USDA-04-284 (semi-erect growth habit), USDA-04-136 and USDA-04-791 (both with spreading growth habit). Treatments included no harvest during the season (control treatment, 1 harvest at time of root harvest), early harvest (8–12 weeks after transplanting, 4 harvests), late harvest (12–14 weeks after transplanting, 3 harvests), and continuous harvest (8–14 weeks after transplanting, 5 harvests). Vine tips were harvested at 2-week intervals during the harvest period, with an additional harvest for all treatments (including control) immediately before root harvest. Breeding line USDA-04-284 (semi-erect growth habit) produced 330 g of greens (fresh weight) per plant on average for all harvest treatments, which was significantly higher (p<0.0001) than USDA-04-136 and USDA-04-791 (spreading growth habit), which produced 118 and 139 g, respectively. Total greens production was significantly higher for the early and continuous harvest treatments (ca. 219 g/plant) than for the late and control treatments (ca. 173 g/plant) (p<0.01). Marketable root yield was similar for all the greens harvest treatments and was significantly lower for all harvest treatments compared to the control (p<0.0001). Compared to the control treatment, marketable root yield was lowest for early harvest and continuous harvest (ca. 34%), and highest for late harvest (51%). Across all greens harvest treatments, marketable root yield was lower compared to the control in the spreading breeding lines (33% and 40% for USDA-04-791 and USDA-04-136, respectively) than in the semi-erect breeding line (51% for USDA-04-284). While sweetpotato can be dual cropped for both greens and roots, the production of greens as an additional vegetable crop must offset financial losses of decreased root yield. Harvesting sweetpotato greens later in the season or only immediately before root harvest can reduce root yield losses while still producing a substantial crop of greens. Erect cultivars are best suited for greens production due to the lesser impact of greens harvest on root yield and higher production of greens.
EFFECT OF SELENIUM FERTILIZATION ON BETA-CAROTENE ACCUMULATION IN HYDROPONICALLY GROWN TWO CRESS VARIETIES. A.O. Adeyeye*; T. Nzaramyimana, Ph.D.; A. Kofi. College of Agriculture, Community, and the Sciences, Kentucky State University, Frankfort, KY 40601. Advanced plant cultivation techniques such as hydroponic vegetable planting, coupled with targeted soil micronutrient fertilization, exemplify sustainable agriculture's innovative approach to maximizing crop yields, enhancing nutritional quality, and minimizing environmental impact. This study will investigate the effect of selenium fertilization on the accumulation of beta-carotene in two varieties of hydroponically grown watercress. Hydroponic cultivation offers a controlled environment for plant growth, allowing precise manipulation of nutrient levels to optimize desired outcomes. Selenium, an essential micronutrient for both plants and animals, has been shown to influence the synthesis of secondary metabolites in plants, including carotenoids such as beta-carotene, which are important antioxidants and precursors of vitamin A. In this innovative idea, the experiment will be conducted using two cress varieties, (watercress) and (Upland cress), subjected to different levels of selenium fertilization. Selenium treatments will be applied according to a randomized experimental design, with each variety divided into multiple treatment groups receiving varying concentrations of selenium fertilizer. The hydroponic system provided consistent environmental conditions, including nutrient solution composition, pH, temperature, and light intensity, throughout the experiment. The beta-carotene content in watercress leaves will be quantified using High-performance Liquid chromatography (HPLC)analysis which is a technique used in analytical chemistry to separate, identify, and quantify components in mixtures and this allows for accurate measurement of carotenoid levels. Statistical analysis of the data will reveal significant differences in beta-carotene accumulation between selenium-treated and control groups within each watercress variety. Moreover, variations in beta-carotene accumulation will be observed between the two watercress varieties in response to selenium fertilization, indicating potential genotype-specific responses. Overall, the results will demonstrate that selenium fertilization influences beta-carotene accumulation in hydroponically grown watercress, with implications for agricultural practices and human nutrition. Understanding the interactions between selenium supplementation and carotenoid synthesis in watercress can inform strategies to enhance the nutritional quality of crops and promote sustainable agricultural production systems. Keywords; Selenium fertilization, Beta-carotene, Hydroponic, Watercress varieties, Agricultural sustainability, Crop yields, Environmental impact, Spectrophotometric analysis,
Phytonutrients in fruits and vegetables are crucial in promoting human health and preventing various diseases. Among these are carotenoids that are found abundantly in green leafy vegetables like kale, which have garnered significant attention due to their numerous health benefits, including antioxidant and anti-inflammatory properties. Despite kale’s reputation as a nutritional powerhouse, little research has focused on the effect of magnesium fertilization on carotenoid production and accumulation in this vegetable. This study aims to address this gap by investigating the impact of different rates of magnesium fertilization on the carotenoid contents and elemental nutrient levels of three hydroponically grown kale cultivars. The Darkibor, Mamba, and Red Russian kales would be grown hydroponically using Hoagland solution in a greenhouse. Different magnesium rates at 0 mgL-1, 12.3 mgL-1, 24.6 mgL-1 and 59.2 mgL-1 would be used. Carotenoid contents and levels in the three kale varieties will be analyzed using High-performance Liquid Chromatography. Additionally, an Agilent 7500ce inductively coupled plasma-mass spectroscopy (ICP-MS) system will be used to measure their elementary nutrient levels. Data would be analyzed using the PROC GLM analysis of variance (ANOVA) and regression analysis procedure of the SAS v9.1 software package. At the end of the experiment, it is expected that increased rates of magnesium fertilization will lead to a significant increase in the accumulation of carotenoid and elemental nutrient levels in each kale cultivar. Understanding how magnesium fertilization influences carotenoid accumulation and other nutrient levels in kale could improve nutritional quality, thereby reducing reliance on dietary supplements to address nutrient deficiencies. Keywords: Phytonutrients, Magnesium, Carotenoids, Kale, Antioxidants
Food safety, environmental impact, and efficient energy usage are growing concerns in horticultural production systems. In Hawaii, 'Koba' and local strains of green onion can be planted year round. The use of artificial lighting in green onion production could be a solution to help address the above concerns. The objective of this study was to compare the effects of red and blue LED lighting on the growth of 'Koba' green onion plants in a noncirculating hydroponic system. 'Koba' green onion (Allium fistulosum) seeds were germinated in Oasis® cubes under T5 high output fluorescent lighting in the lab. Seedlings were then transferred to 5.1-cm net pots, which were placed in 1.9-liter containers containing a hydroponic nutrient solution of Hydro-Gardens' Chem-Gro lettuce formula 8-15-36 hydroponic fertilizer with added calcium nitrate (19% Ca and 15.5% N) and magnesium sulfate (9.8% Mg and 12.9% SO4). Half of the seedlings were grown under red LED lighting (82 µmol/m2/s, 12-h photoperiod) and half under blue LED lighting (82 µmol/m2/s, 12-h photoperiod). Data was collected at the end of the experiment. At the end of the study, there were significant differences in plant height, number of leaves per plant, stem diameter, total leaf length per plant, leaf dry weight per plant, and root dry weight per plant. For all these variables, red LED lighting resulted in greater values than those for blue LED lighting. In conclusion, different LED lighting could be used to supply artificial lighting for 'Koba' green onion plants. Red LED lighting enhanced the growth of 'Koba' green onions.
Aerial multispectral imaging is a great tool for early detection of plant health stresses. There is a variety of sensing hardware with even more options for data analysis ranging in their ease of use and computing power requirements. These tools have been used very successfully in research settings such as breeding trials, nutrient management evaluations, and pesticide efficacy trials. These technologies have tremendous potential benefits if utilized in commercial production systems. While some agronomic crop producers have been using some of these technologies to some extent, there have been various barriers to adoption in specialty crop production. Data collection, analysis, and computing power limitations are some of the primary challenges. However, we find that there is a serious limitation in integration and data output compatibilities from the analysis side to plugging in precision ag equipment. In this project, we examine multiple systems and platforms from data collections to creating decision maps used in field equipment. This project is conducted in partnership with specialty crop growers and aerial service providers. We are in the process of streamlining the process of data collection, analysis, and creation of decision maps, to optimize the use of ground based or aerial fertility and pesticide precision applicators.
Authors: You's Kertye Myrtil, Vander Lacerda, and Xiaoying Li
Edamame, a vegetable soybean harvested at an immature stage with green pods, has gained popularity in the United States due to its high nutritional value and taste, resulting in rising demand. However, limited information is available on the performance of edamame varieties in South Florida. This study aimed to 1) evaluate the field performance of fourteen commercial edamame varieties in South Florida to determine their adaptability for local production, and 2) explore correlations between yield, pod size, and plant physiological traits to identify key indicators for both fresh yield and pod size. The study assessed various phenotypic and agronomic traits at harvest, including yield, plant height, canopy size, leaf area, chlorophyll content, 10-pod weight, pod size (length, width, and thickness), root nodule count, and biomass (fresh and dry). Principal component analysis (PCA) identified Kahala, Goo, KAS 355-11, UA-Kirksey, and Young Soybean as the best performers, while Envy Soybean, Butterbeans, and Fiskeby were the poorest. Yield varied significantly among varieties (p<0.01). Strong correlations (r>0.70; p<0.01) were found between yield and traits such as biomass (fresh and dry), leaf area, and plant height and canopy size. Positive correlations were also observed between yield and maturity days (r>0.61; p<0.05), suggesting that later-maturing varieties tend to have higher yield potential in South Florida. On the other hand, pod size (length, width, and thickness) showed a positive correlation with 10-pod weight and biomass (both fresh and dry) at an r value of approximately 0.6 (p<0.05), but not with maturity days, chlorophyll content, or other factors. This indicates that biomass contributes to both yield and pod size. Interestingly, no correlation was found between yield and pod size, likely because yield was more closely related to the number of pods per plant. These findings provide valuable insights for selecting suitable edamame varieties for South Florida production.
Lettuce (Lactuca sativa L.) is a leafy vegetable in the Asteraceae family and is classified into various types, such as Romaine, Butterhead, Crisphead (Iceberg and Batavian), Latin, Leaf, and Stem. Lettuce propagates by the seeds. The seedling can grow in soil or a hydroponic system in a controlled environment Agriculture (CEA) system. This study was conducted to study the ability of different types of lettuces to grow in a hydroponic system and to assess the effect of light, humidity, and temperature on the yield. The experiment was conducted twice (2023 and 2024) in the Department of Agricultural Science lab at Morehead State University. Four lettuce cultivars, including 'Gustav's Salad' and 'May Queen' as the Butterhead type, 'Ice Queen' as a Crisphead type, and 'Lollo' as the Leaf type, were planted directly on rock wools (Rockwool Starter Plugs) in 2-inch Garden Net Pot in hydroponic containers. The commercial aquarium pumps constantly aerated the nutrient solution. Plants were fertilized with liquid plant food, and the Standard Hydroponic solution controlled the pH. The artificial light was provided by a mix of different lights (µmol/m2/s), including LEC, LED, and Fluorescent, for 16 hours daily under different temperatures (°C) and humidity (%). Biological control products were used for pest and disease control. Harvesting was done after 60 days, and fresh and dried yields of leaves were calculated. The roots were also collected and weighed. Dried leaves and roots were ground and analyzed. The primary results show significant differences among different cultivars.
Fine-tuning Substrate Stratification Ratios for Shrubs and Flowers - Jeb Fields Engineered Substrates Improve Nitrogen, Phosphorus, and Water Retention in Nursery Container Production - Henry Gonzalez Hernandez A 2-Dimensional Analysis of How Root Architecture and Morphology Are Influenced by Stratified Substrate Systems - Kristopher Criscione Predicted Drought Tolerance of Cephalanthus occidentalis L. for Use in Managed Landscapes - John Larsen Comparative microbial diversity analysis and isolation of plant growth-promoting rhizobacteria from roundleaf buffaloberry (Shepherdia rotudifolia) - Amita Kaundal Navigating the Interplay of Climate Stress and Pest Pressure in Shade Tree Nursery Production: Insights from Oregon and Tennessee - Lloyd Nackley The Effects of Supplemental Nickel on Mouse Ear Disorder of Three Diospyros Species - Alyssa Headley
The ornamental production industry utilizes either controlled greenhouse or open-air nursery production systems. Both rely upon the use of soilless substrates, with regular application of water and mineral nutrients, to maintain profitability and quality crop growth and development. However, the leading base substrates components used, peat moss and bark, present sustainability concerns for producers. Peat moss sustainability concerns surround harvest, supply, and cost (environmental, social, and economic; three tiers of sustainability) of the material. Pine bark sustainability in production is due to inefficiency in water and mineral nutrient retention (environmental, social, and economic). Nevertheless, a solution to help improve the sustainability of both substrates across the greenhouse and nursery industry has developed. Soilless substrate stratification is a practical management strategy that entails layering two unique substrates, either derived from the same substrate or different substrates, atop one another in the container. Stratifying substrates has been shown to reduce peat use and reliance in the greenhouse industry by upwards of 50%. Moreover, stratifying substrates can reduce irrigation and fertilizer applications by 25- and 20%, respectively. To date, stratified substrate research has utilized an even 50:50 stratified depth layer partition. As growers adopt this technique, more understanding of the balance and opportunities is needed. Thus, a series of experiments was developed to explore varying ratios of stratification. In two experiments, popular greenhouse (Petnas) and nursery (Rosa) crops were grown in different stratified depth layer ratios with peat-based (greenhouse) and bark-based (nursery) systems. Ratios included a non-stratified treatment (100% filled), a 75:25 percent by vol. layer partition, a 50:50, and a 25:75. In the greenhouse experiment, peatlite mix was layered over unscreened bark and irrigation was lysimeter-actuated. In the nursery experiment, fine bark particles were layered over coarse particles. Moreover, different fertilizer rates were applied (low, medium, high). The results showed in the greenhouse study, a Pentas crop can be grown with equal growth (and similar quantities of water) as traditional greenhouse crop when ≥50% peatlite is used by vol. In the nursery experiment, low fertilizer application rates can be used to grow a crop similar to a traditional nursery-grown crop when grown in a stratified system. While there are discrete differences, it primary take away is that stratification does not need to be overly technical to generate impact and improve efficiency; however, there is a limit to the ability to use “filler” material which tends to be about 50% of the volume.
Container nursery production is the fastest-growing sector in the nursery industry. High volumes of runoff containing nitrogen (N) and phosphorus (P) from container production result in wasted high-quality fresh water, loss of costly applied fertilizer, and increased risk of nutrient management regulations, especially near receiving waters prone to eutrophication. The authors hypothesize that stratified substrates, in which a fine textured substrate is placed atop a coarse substrate amended with ferrous sulfate (FeSO4), can reduce water use and decrease N and P losses while yielding a high-quality container crop. This research was conducted at the Horticulture Teaching and Research Center in Holt, Michigan on three replicate simulated nursery pads per treatment, each having 45 containers consisting of Buddleja x ‘Miss Violet’, Ilex crenata ‘FARROWSK6’, Hydrangea paniculata ‘Limelight’, Physocarpus opulifolius ‘Seward’, Cornus sericea ‘SMNCSBD’, Cotinus coggygria ‘MINCOJAU3’, Rosa x ‘ChewDelight’. Substrate treatments consisted of an 85:15 (by vol.) pine bark:sphagnum peat uniform profile (Conv), an 85:15 pine bark:sphagnum peat uniform profile fully amended with 3 kg/m3 FeSO4 (Conv Fe), stratified substrate (Strat) in which fine sphagnum peat amended bark substrate was atop a coarse bark substrate, and stratified substrate with the coarse bark layer amended with 3 kg/m3 FeSO4 FeSO4 (Strat Fe). All plants were micro-irrigated with a spray stake. Irrigation water usage, N, and P leaching were quantified and compared. Preliminary results indicate that lower amounts of N leached from Strat (12 mg L-1, p = 0.03) and Strat Fe (13 mg L-1, p = 0.02) compared to Conv (23 mg L-1). Similarly, lower P was found in leachate from Strat (6.33 mg L-1, p = 0.01) and Strat Fe (6.74 mg L-1, p = 0.02) compared to Conv (11.78 mg L-1). These preliminary results, in addition to leaching fraction and growth index, will be discussed in this presentation.
Jim Owens is a USDA-ARS Research Horticulturist located at the Application Technology Research Unit in Wooster, OH. Jim received his B.Sc. in Plant and Soil Science at the University of Kentucky, his M.Sc. in Environmental Science at the University of Rhode Island, and Ph.D. at North... Read More →
Soilless substrates serve an important role in both the sustainability of specialty crop production and supporting healthy containerized root growth. The requirements and tolerance of containerized roots are essentially what dictates the (i) physiochemical limitations of the substrate, (ii) how production practices are managed (i.e., quantity and quality of irrigation / fertilization), and (iii) the performance of high-quality shoot growth and development, emphasizing the importance of both substrates and roots. Nevertheless, most horticultural crop research primarily focuses on shoot growth and dismisses important root growth traits, often only reporting root biomass at study culmination or during destructive harvests. Information regarding how roots grow throughout the substrate matrix is evidently sparse. More research is needed to develop better understandings of spatial and temporal root development, such as root architecture, which describes how (and where) roots invests carbon throughout the 3-Dimentional substrate matrix. Research regarding popular engineered substrate systems, stratified substrates (i.e., layering different media atop each other), has began to dive deeper into how roots grow in time and space, where stratified-grown roots grow differently than traditionally grown (non-stratified) cropping systems. However, no research to date as explored root architecture, temporally or spatially, in stratified systems. The study herein explored root architecture in time and space using clear acrylic-based RhizoBoxes (8-L vol.). Several different types of crops (nursery- hibiscus; greenhouse- basil; representative crop- sunflower) were grown in different non-stratified and stratified substrate systems, including bark- [non-stratified: 100% unscreened bark; stratified- fine bark (< 6.3 mm) layered over coarse bark (> 6.3 mm)] and peat-based [non-stratified: 100% peat-lite (7:3); stratified: peat-lite layered over unscreened bark] substrates. Root growth was traced frequently and analyzed quantitatively for total visible root length and growing angle, and qualitatively for general shape and patterns. The results showed that stratified grown crops, across cropping systems, had a wider root distribution spreading angle, growing wider and more outward than crops grown in non-stratified systems. Moreover, stratified grown crops typically grew in the upper stratified layer longer than crops grown traditionally, growing more sequentially than continuously. In most cases, stratified-grown crops had longer visible roots growing against the acrylic glass in the upper 50% of the profile. Stratified-grown roots were often longer and finer than non-stratified grown crops. In all, this study highlights that stratified grown crops have superior root growth and development and that RhizoBoxes are a useful tool in studying root architecture in soilless substrate systems.
Buttonbush (Cephalanthus occidentalis) is a valuable landscape shrub revered for its prominent white, globe-shaped blooms which can later develop into brilliant red aggregate fruits. This North American native shrub occurs almost exclusively in riparian habitats, typically in standing water in the wild, but it is curiously adaptable to a range of landscape conditions in cultivation. Because this species appears to perform well when grown using average soil-moisture conditions, we questioned where the limits of drought tolerance occur for this riparian-adapted species. The objective of this study was to evaluate USDA-GRIN germplasm of buttonbush to compare unique provenances representing different regions of the native range of the taxon to generate a relative scale of predicted drought tolerance for the species. Utilizing vapor pressure osmometry, this study examined seasonal osmotic adjustment and predicted leaf water potential at the turgor loss point (ᴪpo) among ten Cephalanthus occidentalis populations grown at the Morton Arboretum in Lisle, Illinois. All populations evaluated demonstrated a minor ability to osmotically adjust (Δᴪ𝝿100) throughout the growing season. NA 79917 exhibited the most osmotic adjustment (-0.22 MPa) whereas NA 61271 exhibited the least (-0.08 MPa). Estimated spring ᴪpo and summer ᴪpo across populations was -1.75 MPa and -1.91 MPa, respectively. NA 79705 exhibited the highest ᴪpo in both spring (-1.56 MPa) and summer (-1.68 MPa). NA 82190 exhibited the lowest ᴪpo in spring (-1.92 MPa ), whereas NA 73814 exhibited the lowest in summer (-2.17 MPa). These data indicate that drought tolerance in buttonbush varies across populations, suggesting that this trait can be improved in landscape selections through selective breeding efforts.
John works with winter hardy landscape plants, with a special emphasis on Salix pellita (Satiny Willow). A major interest of John's is looking at the horticultural potential of certain native flora, hoping this could lead to new means of conservation for Minnesota's threatened sp... Read More →
The world is haunted by climate change and global warming, posing critical challenges to plant health and productivity. Hence, it is now imperative to think about ecosystem resilience and conservation. Microbiomes from extreme environments with plant growth-promoting and stress-relieving properties can be used as inoculum for growing plants during stress. Hence, our study aims to explore the root and soil microbiome of native and hardy Shepherdia species available in Utah, USA. The native Shepherdia species, S. rotudifolia was selected for the study. We compared the microbial diversity of S. rotudifolia from three different locations in Utah. The plants' bulk soil, rhizosphere, and root were collected for the study from Torrey, Colorado City, and Cannonville in Utah and brought to the Utah State University, Logan, for further processing. DNA extraction was done from all the samples and sequenced for 16S rRNA region. The bulk soil of roundleaf buffaloberry from Torrey is highest in organic matter, while that from Colorado City is highest in salinity but lowest in NPK and most micro-nutrients. Bulk soil and rhizosphere bacterial alpha diversity differ significantly (p=0.05) among the locations of roundleaf buffaloberry; however, there is no difference in root endosphere alpha diversity among the locations. The bacterial community composition of roundleaf buffaloberry from Torrey is significantly different from the other two locations. Proteobacteria and Actinobacteriota are the dominant phyla in the bulk soil and rhizosphere of roundleaf buffaloberry from all three locations; however, Actinobacteriota dominates in root in all three locations. The genus composition of bulk soil, rhizosphere, and root of roundleaf buffaloberry is very diverse among the three locations. Frankia, the well-known nitrogen-fixing bacteria, is prevalent in the root samples of S. rotundifolia from Cannonville and has lesser abundance in the other two locations. Fifty-seven bacteria were isolated from the rhizosphere of the S. rotudifolia on different nutrient media. These isolates are being tested for eight plant growth-promoting traits, such as the production of indole acetic acid, siderophore, catalase, protease, ACC deaminase activity, nitrogen fixation, phosphate solubilization, and sulfur-oxidizing activity
The plant nursery production industry in Oregon and Tennessee faces escalating challenges from climate change, particularly concerning shade trees like red oak (Quercus rubra) and red maple (Acer rubrum). This research investigated the physiological responses of these species to fluctuations in soil moisture, vapor pressure deficit (VPD), and leaf temperature (Tleaf) through field experiments in Oregon's Willamette Valley and Tennessee's nursery regions. Monitoring stomatal conductance (gs) and stem water potential (Ψs) under varied conditions revealed distinct responses between the two species, with red maple exhibiting greater sensitivity to soil moisture and VPD compared to red oak. Additionally, a novel correlation between VPD and maple gas exchange underscores the significance of atmospheric moisture dynamics in plant water management strategies. Furthermore, assessing the impact of abiotic stressors on flatheaded borer (FB) attacks, we found that drought-stressed red maple trees experienced the highest borer infestations. Plant growth was adversely affected by all stressors, with drought stress exhibiting the most detrimental impact. Our findings underscore the complexity of plant responses to climate stress and highlight the necessity of informed water management practices for sustainable nursery production in diverse regional contexts. Bridging knowledge gaps in plant hydraulic physiology can empower growers to adapt to evolving environmental conditions and ensure the resilience of shade tree production systems. Further research is crucial to deepen our understanding of plant hydraulic physiology and its implications amidst climate change-induced challenges.
Lloyd Nackley is a plant ecologist who applies a systems approach to improve nursery and greenhouse management. Nackley's research program at Oregon State University focuses on addressing four challenges facing nursery and greenhouse production in Oregon: irrigation application, pest... Read More →
American persimmon (Diospyros virginiana L.) is a multipurpose tree endemic to the eastern United States with potential for broader use in managed landscapes or for producing desirable fruits. Whereas most members of this genus originate from tropical and subtropical regions, the American persimmon could expand landscape diversity and fruit production applications in northern climates. Due to purported challenges with transplant success, American persimmon is likely best suited to cultivation in containers. Recent observations of container-nursery crop production indicates American persimmon is susceptible to mouse ear disorder (MED), a function of nickel deficiency. We hypothesized that American and Asian-origin persimmon species are susceptible to MED and that supplementing nickel with a foliar spray will ameliorate the disorder. Our objectives were to characterize symptoms of non-treated MED with American (D. virginiana), Japanese (D. kaki), and dateplum (D. lotus) persimmon as well as to determine if MED could be corrected by foliar application of nickel or other compounds presumed to interact with the urease metabolic pathway, such as urea. In a randomized greenhouse study, seedlings of American, Japanese, and dateplum persimmons were evaluated by comparing a non-treated control (H2O spray), to foliar spray treatments of NickelPlus® (169 ppm), NiCl2 (169 ppm), urea (0.325 g/L), and combined NiCl2 (169 ppm) and urea (0.325g/L). Following treatment, plants were evaluated using a MED severity rating scale, leaf characterization metrics (greenness, count, surface area, dry mass, and specific area), as well as metrics characterizing stem traits (elongation and dry mass). Compared to the non-treated control, leaf surface area increased by ~56%, ~61%, ~25%, and ~52% for the Nickel Plus®, NiCl2, Urea, and combined NiCl2 Urea treatments, respectively, when pooled across species and cultivar. These results suggest nickel supplements are effective at increasing important growth metrics like leaf surface area for Diospyros species displaying MED symptoms. This study offers valuable insights for improving the cultivation of persimmons in container nursery production settings, contributing to the development and advancement of American persimmon as an emerging specialty crop.
Quantifying Growth Control of Ornamental Millet ‘Jester’ with Ancymidol, Ethephon, Flurprimidol, Paclobutrazol, and Uniconazole Substrate Drenches - Lauren Seltsam Controlling growth of Brunnera macrophylla L. ‘Jack Frost’ with Uniconazole Substrate Drenches or Sprays - William Rich Uniconazole Substrate Drenches Control Growth of Buddleia Cultivars - Lark Wuetcher Effects of Weather Conditions on the Efficacy of ACC as a Peach Thinner - Jozsef Racsko Mode of Action and Uptake Investigations of ACC as a Peach Thinner - Jozsef Racsko Physiological Mechanism of Silicon’s Enhancement of Drought and Heat Tolerance in Creeping Bentgrass - Xunzhong Zhang Effect of Light Quality and Intensity on Cannabis Photosynthetic Activity - Philip Wiredu Addo Enhancing the quality of novel greenhouse crops through dynamic LED lighting - Rose Seguin
Plant growth regulators (PGRs) are a valuable tool in the ornamental industry. Whether it is for promoting or controlling growth, PGRs give growers the opportunity to produce high quality crops in the face of their production or shipping challenges. Often, substrate drench applications provide greater growth control, require less labor, and have shortened re-entry intervals than spray applications. Current PGR recommendations for ornamental millet (Pennisetum glaucum ‘Jester’) are for spray applications; therefore, the objectives of this study were to evaluate the efficacy of different PGRs applied as substrate drenches to improve marketability and control growth of ornamental millet ‘Jester.’ Seeds were received from a commercial supplier and sown into 288-cell plug trays (5-mL individual cell vol.) filled with a pre-moistened commercial soilless propagation substrate. After 24 d, young plants of similar heights, basal diameters and culm were transplanted with one plant per 11.4-cm-diameter container filled with a commercially available peat-based substrate. At 7 d after transplant, plants received 59-mL aliquots of solution containing 0 (deionized water control),1, 2, 4, 8, or 16 mg·L–1 ancymidol, flurprimidol, paclobutrazol, or uniconazole or 25, 50, 75, 100, or 200 mg·L–1 ethephon. Plants were grown at bench-level in a glass-glazed greenhouse with an air temperature set point of 23 °C, and supplemental day-extension lighting provided by light-emitting diode lamps from 0600 to 2200 hr (16-h photoperiod) to achieve a daily light integral of ~14 mol·m–2·d–1. Data were collected four weeks after drench. For each chemical, effects of PGR concentration were analyzed independently, and means were separated using Tukey’s honestly significant differences. For all analyses, a P ≤ 0.05 was used to determine significant effects. In general, ancymidol and ethephon provided the best growth control, while flurprimidol and uniconazole were found to be inadequate for drenches at the concentrations investigated due to unmarketable plants. Paclobutrazol resulted in unmarketable plants at concentrations ≥ 1 mg·L–1. Ancymidol substrate drenches containing 1 to 16 mg·L–1 resulted in plants that were 3% to 21% shorter and 3% to 14% smaller plants, respectively, than untreated plants. Similarly, increasing ethephon substrate drench concentrations from 1 to 16 mg·L–1 resulted in plants that were 7% to 36% shorter and 27% to 41% smaller plants compared to the untreated control. Results from this study establish substrate drench recommendations for ornamental millet ‘Jester’; however, further investigations are needed to assess growth control responses of other ornamental millet cultivars.
Heartleaf brunnera (Brunnera macrophylla L.) is a popular herbaceous perennial that is often used in the landscape. With large leaves and a mounding habit, growth control is often needed during greenhouse production. Plant growth regulators (PGR) applied as substrate drenches or foliar sprays can control growth necessary to produce compact, high-quality containerized plants. Our objectives were to evaluate the efficacy and growth control provided by uniconazole substrate drenches or sprays. Rooted liners of heartleaf brunnera ‘Jack Frost’ were transplanted into containers (16.6-cm; 2.8 L) filled with a commercially formulated peat-based substrate. After 10 d, eight single-plant replicates received either a substrate drench or foliar application of uniconazole. For substrate drenches, 296-mL aliquots of solution containing deionized water (0 mg·L–1; control) or 0.25, 0.875, 1.75, 2,5, 5.5, 7.5, or 10.0 mg·L–1 uniconazole were applied across the substrate surface. For foliar sprays, 0, 2.5, 5.0, 7.5, 10.0, or 20.0 mg·L–1 uniconazole were applied at a rate of 1.89 L/ 9.29 m2. Plants were grown in a glass-glazed greenhouse at 23 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈120 µmol·m–2·s–1 delivered from light-emitting diode lamps from 0600 to 2200 HR (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At 7 weeks after treatment, data were collected and plants were destructively harvested. In general, uniconazole significantly controlled plant height, diameter, and dry mass for each uniconazole application method. Plant height and diameter were 15% to 51% (2.2 to 7.6 cm) shorter and 22% to 40% (7.4 to 13.5 cm) smaller, respectively, than untreated plants as uniconazole drench concentration increased from 0.875 to 5.0 mg·L–1, respectively. Plants treated with 0.875 to 5.0 mg·L–1 developed 3 to 7 fewer leaves. Shoot dry mass was 39.5% lower than untreated plants as uniconazole drench concentration increased from 0.875 to 5.0 mg·L–1, respectively. For foliar applications, plant height and diameter were both reduced but to varying degrees. Plant height was reduced by 6% (~1 cm) but the greatest amount of control observed was in plant diameter which was reduced by 15 to 21% (4.8 to 7.2 cm) as concentrations increased from 5.0 to 10.0 mg·L–1. Collectively, these results indicate that drenches of 0.875 to 5.0 mg·L–1 uniconazole or foliar sprays of 5.0 to 10.0 mg·L–1 uniconazole may be used to control growth of ‘Jack Frost’ heartleaf brunnera.
The increasing diversity of butterfly bush (Buddleia × hybrida) cultivars presents new challenges for growers, particularly in adjusting plant growth retardants (PGRs) to manage plant size effectively. Therefore, the objective of this study was to evaluate uniconazole substrate drench concentrations for growth control of two popular cultivars of butterfly bush (Buddleia × hybrida). Liners of ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush were individually transplanted into containers (16.5-cm; 1.7 L) filled with a commercially formulated bark-based substrate. After 10 d, eight single-plant replicates received a substrate drench of 266-mL aliquots of solution containing deionized water (0 mg·L–1; untreated) or 0.25, 0.5, 1, 2, or 4 mg·L–1 uniconazole. Plants were grown in a glass-glazed greenhouse at 20 °C under ambient daylight supplemented with a photosynthetic photo flux density of ≈125 µmol·m–2·s–1 delivered from light-emitting diode arrays from 0600 to 2200 HR (16-h photoperiod) to achieve a daily light integral of 14 mol·m–2·d–1. At 5 weeks after drench, data were collected. Plant height, plant diameter, growth index (GI), and shoot dry weights were unaffected by cultivar or cultivar × uniconazole concentration interaction but varied by uniconazole concentration (P < 0.0001); therefore, all data were pooled and analyzed by uniconazole concentration. Increasing uniconazole substrate drench concentrations effectively controlled ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush plant height, plant diameter, GI, and shoot dry weights. Plant height and diameter were 16% to 32% (6.9 to 13.8 cm) shorter and 10% to 24% (6.9 to 16.9 cm) smaller than untreated plants as uniconazole drench concentration increased from 1 to 4 mg·L–1, respectively. Shoot dry mass was 24% to 34% (5 to 7 g) lower than untreated plants as uniconazole drench concentration increased from 1 to 4 mg·L–1, respectively. Overall, these results indicate that 1 to 4 1 to 4 mg·L–1 uniconazole applied as a substrate drench may be used to control growth of ‘Grand Cascade’ and ‘Prince Charming’ butterfly bush. Time to visible bud and flower was not negatively influenced by increasing uniconazole concentrations; however, growers should trial drench concentration and adjust as needed for desired market dates. Additionally, further investigations with uniconazole are warranted for other butterfly bush cultivar introductions because it is the is the preferred PGR for perennial growth control.
1-aminocyclopropane-1-carboxylic acid (ACC) is the immediate precursor of ethylene in plants. Accede SG containing ACC as active ingredient has been registered as a chemical thinner in the US for stone fruit and apple. The objective of this study was to investigate the effects of weather parameters on Accede SG efficacy. In a series of experiments in Oregon and California in the field and growth chambers, we evaluated the relationship between flower/fruitlet abscission caused by ACC and weather parameters in peaches. In field trials, ACC at 300 mgL-1 and 600 mgL-1 was sprayed on a daily basis to different set of peach trees throughout the bloom period and correlated fruit set data with daily weather parameters. From these field trials, it became apparent that flower/fruitlet abscission caused by ACC is in negative relationship with daily minimum and maximum temperatures. These findings were confirmed by greenhouse studies where increase in nighttime temperature reduced thinning efficacy of ACC. No close relationship between thinning efficacy and relative humidity was found. We created three models to predict ACC thinning efficacy using weather parameters and ACC spray concentration.
1-aminocyclopropane-1-carboxylic acid (ACC) is assumed to cause flower abscission via the ethylene pathway when used as a chemical thinner in peaches. The objectives of this study were to investigate the uptake of ACC via flower parts, and determine if ethylene is the main cause of flower abscission by ACC. In a series of field trials in Oregon, we determined that ACC is a non-mobile compound when applied as a foliar spray to peach trees. ACC does not translocate between branches and movement of externally applied ACC is very limited even between flower parts. When the ACC solution was applied via paintbrush to various parts of the flowers, it became evident that for sufficient flower thinning activity, the presence/uptake of ACC is needed through the pedicel and/or Abscission Zone tissues of the pedicel (AZ1-2). Application of ACC to the petals only, resulted in petal drop only but not in flower abscission. When evaluating the mode of action of ACC, we established a close relationship between ethylene production of the flowers and flower abscission. However, when ethylene production of the flowers was reduced with the addition of ACC oxidase inhibitors (2-picolinic acid, pyrazinecarboxylic acid) in the ACC spray solution, the flower abscission rate remained the same as in the ACC application alone. These results indicate that ethylene might not be the only factor in flower abscission caused by ACC.
Creeping bentgrass is an important cool-season turfgrass species widely used for golf course putting greens, however it experiences summer stress and quality decline in the U.S. transition zone and other regions with similar climates. Silicon (Si) may improve abiotic stress of creeping bentgrass, but mechanism of its impact on plant drought and heat tolerance has not well understood. The objectives of this study were to investigate physiological mechanism of Si on tolerance to drought and heat stress in creeping bentgrass under growth chamber and field conditions. The five treatments from two Si products (Potassium silicate at 0.95 and 1.91 mL m-2, and Ortho-Si at 0.16 and 0.32 mL m-2) were applied biweekly to creeping bentgrass, and treated grass was subjected to heat and drought stress for 56 days and also the treatments were applied to creeping bentgrass putting green in the field conditions. Turfgrass quality, physiological parameters and root growth characteristics were evaluated biweekly. Deficit irrigation was applied to induce drought stress in June and July in the field plots. Foliar application of the Si products improved turf quality, photochemical efficiency, leaf chlorophyll and carotenoid content, antioxidant enzyme activity and endogenous Si content. The Si treatments at the high rates also improved root biomass, length, surface area, volume, and root viability when compared to the control. The results from the field study confirmed the findings in the growth chamber study. The exogenous Si may improve drought and heat tolerance by enhancing root growth and viability, Si uptake by roots, and up-regulation of antioxidant activity, protecting photosynthetic function. The results of this study suggest that foliar application of Si products may be considered as an effective approach to improve turf quality and physiological fitness of creeping bentgrass during the summer months in the U.S. transition zone and other regions with similar climate.
Among numerous abiotic environmental factors, varying light quality and intensity elicit photosynthetic responses that can play vital roles in the optimization of crop production in controlled environment agriculture. Earlier and preliminary studies on photosynthetic activity reported that amber light (595 nm) induces higher photosynthetic rates and quantum yield of plants is a wavelength-dependent response. To resolve the most accurate ePAR curves in cannabis (Cannabis sativa), this study investigated the spectral response of photosynthesis by examining the effects of the leaf versus the whole plant on the impact of photosynthetic activity. A customized CO2 chamber equipped with relative humidity, temperature, and CO2 was used to collect leaf and whole plant photosynthetic data from 5 week old clones with different monochromatic wavelengths (380–750 nm) using the LI-6800 Portable Photosynthesis System (LI-COR) equipped with the Large Leaf and Needle Chamber (LI-COR 6800-13). Differences and correlation between photosynthetic activity at the leaf level and the whole plant were determined. Subsequent studies will involve the combinations of different wavelengths at different ratios. Findings will expand the current understanding of the photosynthetic response of plants to light and provide highly resolved spectral quantum yield curves.
The adoption of supplemental lighting in horticulture has allowed greenhouse growers to increase the yield of multiple crops by at least 10%, with a 300% yield increase documented for cucumbers when transitioning from unlit to lit production. Since then, horticultural lighting has advanced significantly to now include dynamic LED lighting, which provides unparalleled control over the light intensity, spectrum and zoning within the greenhouse. This has allowed greenhouse growers to further maximize crop productivity, but also to target improvements in crop quality and to diversify their production. For example, the greenhouse industry has seen the introduction of multiple berry crops, leafy crops, Asian cucumbers, etc. in recent years, all of which have varying lighting requirements ranging from 12 to 25 mol of light per square meter per day. The ideal spectrum also differs between crops, as do the light saturation points and target intensities. Beyond enhancing photosynthesis and increasing crop productivity, dynamic LED lighting can also be used to improve the nutritional quality and taste of various crops through spectral adjustments during the growth cycle. In a trial comparing the impact of broad and narrow spectra on basil, a broad spectrum produced a flavor profile stronger in eucalyptol whereas a narrow spectrum produced an estragole-dominant crop. This resulted in a milder flavor under a broad spectrum and a stronger flavor under a narrow spectrum. With dynamic lighting, growers can adjust the spectrum to target different flavors and thus different markets. Further, the application of high levels of blue light during the last week of production has been repeatedly shown to enhance the antioxidant capacity of red leafy greens through the bioaccumulation of anthocyanin. The Brix, or sweetness, of fruiting crops has also been improved under dynamic lighting, with commercial trials showing a minimum of 7% increase in Brix in speciality cherry tomatoes compared to fixed spectrum lighting. This increase could potentially be enhanced with end-of-day (EOD) light treatments, which early trials have suggested to enhance the translocation of sugars from leaves to fruit. As such, dynamic LED lighting can improve both the productivity and nutritional quality of greenhouse crops, allowing forward-thinking growers to meet the growing population’s needs in terms of both quality and quantity.
Rose Séguin is an agronomist specializing in controlled environment agriculture, with previous experience in indoor agriculture, agricultural innovation systems, and agricultural development in remote areas of Canada. She holds a bachelor's degree in agro-environmental sciences and... Read More →
Thursday September 26, 2024 5:45pm - 6:00pm HST
South Pacific 4
