FFAR Fellows: Opportunities for Horticulture PhD Students - John Dole Nurturing Knowledge: The Impact of Assuming Professional Role in Achieving Learning Objectives in Upper-Level Horticulture Courses - Shivani Kathi Mid-semester Teaching Evaluations to Enhance Course Communication - Rebekah Maynard Evaluation of Packback - an AI-Assisted Writing Program for Student Assignments in Horticulture Courses - Navreet K Mahal Evolution Of An Undergraduate Tropical Crop Production Systems Course - Kent Kobayashi Service-learning Horticulture Students Growing Food for Themselves and Others - Carl Motsenbocker Hands-on Horticulture Activities for Undergraduate Introduction to Horticulture Courses - Claire Luby
The Foundation for Food and Agriculture (FFAR) Fellows Program was launched in 2018 and has become the premier professional development program for food and agriculture doctoral students. The FFAR Fellows offers leadership and professional development training for PhD students studying food and agriculture-related sciences in the U.S. and Canada. North Carolina State University leads the initiative, which provides Fellows with training, networking opportunities, and peer support. The objectives of the program are to 1) develop leadership competencies that enhance current and future individual productivity and well-being, and enhance Fellows capacity to contribute to the public good, 2) connect young scientists across research domains and geographic areas to promote multi-disciplinary understanding and problem-solving, and 3) broaden students understanding of their career options and create links to sectors beyond academia (industry, government, NGO). Over a 3-year period members of each cohort (25-30 Fellows) attend four in-person meetings plus monthly virtual sessions, create and execute annual professional development plans, and network and establish mentor-mentee relationships with industry scientists and others outside of academia. Eligible students are those who have completed their MS degrees before the program starts or current PhD students with at least three years remaining in the program. FFAR provides 50% of the funds with the rest matched from industry, NGOs, commodity organizations, or other sources of non-federal funds. Deadlines are generally late February for the Stipend Professional Development Category (providing professional development $50,000/year in support) and mid April for the Professional Development Category (providing professional development). Application requirements will be discussed in the presentation. The research program of each Fellow must address one or more of the six FFAR challenge areas, five of which relate to horticulture: Soil Health, Sustainable Water Management, Next Generation Crops, Urban Food Systems, and Health-Agriculture Nexus. Approximately 7% of the 139 Fellows are from horticulture programs. There are opportunities for more horticulture PhD students to take advantage of this program.
Practical experience is invaluable to students majoring in plant-related fields including horticulture. Most times students with no prior practical experience acquire the required knowledge and skills to succeed in horticulture field through college education. However, there is limited literature on the impact of courses implementing experiential learning through students assuming horticulture-related professional roles on achieving learning objectives. Hence, the current study investigated the pedagogical approach of practical learning by incorporating students undertaking management role in achieving learning objectives of upper-level horticulture courses within a classroom setting. The methodology involves implementing this student-centered activity of assuming professional role as greenhouse manager and hydroponics operation manager in two different 3000-level courses (urban horticulture and hydroponics and soilless crop production, respectively) and assessing their impact on learning outcomes. Each student assumed the role of manager for a week and experienced real-world problem solving in greenhouse and hydroponics operation management settings. Quantitative and qualitative data collection methods, including surveys, and observational analysis, are utilized to evaluate the effectiveness of the approach in enhancing students' understanding and attainment of course objectives. Preliminary findings indicate that incorporating assumption of horticulture professional role activities fosters deeper engagement, critical thinking, and practical application of theoretical concepts. Students reported increased confidence in their abilities to apply learned principles in real-world scenarios, as well as a greater appreciation for the complexities of urban horticulture and hydroponics crop production. Overall, this research highlights the potential of experiential learning strategies, such as horticulture professional role simulations, to effectively support the achievement of learning objectives while providing students with valuable insights into professional practice. Finally, the findings contribute to the ongoing discourse on innovative pedagogical approaches and their impact on student learning outcomes in higher education settings.
Effective course communication is critical to foster a positive learning environment. One way communication can be improved is by scheduling a mid-semester teaching evaluation to capture student perspectives on what aspects of the course are going well and what could be improved. By providing students with a platform to express their opinions mid-semester, instructors have access to timely feedback to improve their teaching methods while the course is still ongoing. In this study, a mid-semester evaluation was conducted in an asynchronous, online Fruit Production course with 27 undergraduate students and one graduate student. The students were given a link to an online survey to respond to specific questions about the course structure and an open-ended question for actionable feedback. The evaluations were voluntary, anonymous, and confidential to solicit honest student responses. By having students respond individually, it was possible to capture unique student viewpoints and consensus statements among the class with a 96% response rate. Students responded positively to some aspects of the course such as the use of hands-on assignments; however, course modifications were made only in response to critiques. The most notable feedback was 14.8% of the students responding that the course material did not feel manageable with 44.4% of the class spending more than the expected time on lecture assignments. Additionally, students requested more clarity on the assigned projects. The survey responses were summarized for the students along with specific ways the course would be adjusted to better meet the student's needs and enhance their learning experience. To address the students’ concerns, the course workload was reduced, and students were provided with a clear explanation of their expected level of engagement. Recorded instructions along with detailed written descriptions and templates of the projects were also provided to aid in transparency about course assignments. Overall, students were well receptive of the mid-semester evaluation and reported it improved their satisfaction with the course. Because students found the mid-semester evaluation valuable to their learning, the course modifications will be maintained for future semesters.
The use of Artificial Intelligence (AI)-supported writing tools in higher education has been a hot topic since OpenAI introduced ChatGPT in 2022. These AI-supported writing tools are intended to analyze written materials and provide feedback on the writing , including grammar, vocabulary, content, and structure. Packback (https://www.packback.co/) is one of the AI-supported online platforms that intends to improve student curiosity, communication skills, and critical thinking, and provides ease of assessment for instructors. Two instructors in the Department of Horticultural Sciences at Texas A
TPSS 300 Tropical Production Systems is a four-credit undergraduate crop production course. It has two lectures and one lab period a week. In Spring 2023, there were 16 undergraduate students registered for this every Spring offered course—12 TAE students, one NREM student, one Interdisciplinary Studies student, one Botany student, and one Hawaiian student. In Spring 2024, there were nine undergraduate students—six TAE students, one Botany student, one Journalism student, and one Elementary Education & Special Education student. The objective is to describe the improvements made to TPSS 300 based on student interests and emerging new technologies and disciplines in horticulture. Various teaching techniques were used including flipped classroom, small group discussions, class discussions, in-class activities, lectures, guest speakers, field trips, YouTube videos, and laboratories. With a BYOD format, students could review assigned materials and look up information on the Internet to aid group discussions. New topics were added such as agricultural drone technology and crop sensors and equipment for monitoring plant status. Besides inviting our department graduate students as guest speakers, department extension agents and faculty and faculty and graduate students from other departments were invited. A TPSS faculty with another department’s faculty discussed the regulations for drone use and gave a demonstration of flying drones. The TPSS graduate students spoke on breadfruit tissue culture and industrial production in Hawaii; innovative agroforestry in ancient ways; and taro in aquaponics. Extension agents spoke about food safety. A PEPS graduate student spoke on invasive pests impacts on palm species with a focus on the Pacific and Israel. Two GEO students demonstrated their experimental growth chambers and artificial lighting set up. The manager of our college’s greenhouse facilities provided a tour of the facilities, explaining maintenance and irrigation. The rigor of this course was increased through incorporating more mathematics and quantitative reasoning, growth analysis, yield analysis, crop modeling and simulation, computer applications in horticulture, and high technology in horticulture. Students commented that TPSS 300 was a valuable learning experience. The course provided diverse learning experiences and hands-on activities. The integration of graduate students, extension agents, and the greenhouse manager as guest lecturers into the course worked well, providing benefits to both the speakers and the students.
Organic gardening (Horticulture 2525) is a mandatory class for students in the LSU medicinal plants and sustainable crop production concentrations, where the focus of the lab is for students to intensively grow their own garden plot of vegetables and herbs in the fall semester. Students are mandated to grow at least 10 different crops and to use both direct seeding and using their own transplants to establish, maintain throughout the semester, and then harvest their plot. The course is a service-learning course and over the years the class have worked in establishing and maintaining community and school gardens, harvesting/gleaning vegetables from garden plots, and assisting with a local farmers market. The most recent classes focused on growing food in community plots for the LSU Food Pantry, a local food bank that is used by many students. Each week students are required to work in the community rows from the beginning of working and shaping the beds, applying and incorporating fertilizer, planting seeds directly into the beds, transplanting crops, and setting up trickle and overhead irrigation systems. Students maintain their own plots as well as the community rows by fertilizing, and applying organic pest management measures as needed. The harvest from the individual plots and the produce is left up to the students and all the students harvest, wash, pack and prepare the product from the community rows for donation each week to the campus food pantry. Students are encouraged to participate my transporting the produce at least once, from the field or the cooler at the teaching facility to the food pantry. Many of the students have indicated that the class is the first time they had grown any plants in a garden and they used the garden harvest in their own kitchens. Students also indicated that they learned about the needs of the community and students and several also became aware of the food pantry and its services. In the fall of 2023 over 1,800 pounds of fresh vegetables were donated to the campus food pantry. Data from the students’ perceptions and comments from the semester will be presented.
Professor, Executive Director Louisiana Farm to School Program, Louisiana State University
Dr. Carl Motsenbocker is a professor of horticulture and sustainable agriculture at Louisiana State University. Motsenbocker is Executive Director of the Louisiana Farm to School Program and teaches Organic Gardening, Sustainable Agriculture and Vegetable Crops at LSU. Motsenbocker... Read More →
Two intended learning outcomes of our undergraduate introduction to horticulture courses are for students to be more aware of the horticultural plants and practices that they encounter in their daily lives and to enthusiastically engage in growing and caring for plants. While lectures provide students with a framework on which to hang their expanding knowledge of plant science and horticultural concepts, we have found that including hands-on activities that allow students to reconstruct their own knowledge framework and connect the concepts to their daily lives has successfully engaged students and improved achievement of learning outcomes. In this presentation, we will describe how we have integrated a new introductory horticulture textbook, lectures, and hands-on ‘Seeing Horticulture’ activities, and examine student learning outcomes, in courses at Montana State University, the University of Minnesota, and the University of Wisconsin-Madison.
An ongoing and challenging issue for all administrators who have to assign teaching responsibilities is assessing “effort” associated with different types of courses. While it is abundantly clear that different amounts of effort go into lecture classes versus lab classes, we still frequently talk about teaching responsibilities as the “number of classes taught per semester.” In the department of Horticulture and Landscape Architecture at Purdue University, we faced this challenge across lecture courses, lab courses and Landscape Architecture studio classes. We undertook a year-long effort to assign “effort” values to each of our classes. In this presentation we will discuss our philosophy and approach to this undertaking, including how we engaged the entire department in the process. We ultimately developed a complex spreadsheet (currently being converted to an interactive database) that assigns points to classes based on number of contact hours, preparation work, service learning or experiential experience, grading/management workload, and class size. We then used this information to determine where additional support, in the form of graduate or undergraduate student TAs or staff, was most needed to create equity across teaching loads. This work is ongoing and needs to be updated annually based on changes in course structures and sizes and teaching assignments. In this presentation, we will share the database we created to make annual updates easy and transparent to everyone in the department.
Identification and Prevalence of Grapevine Virus Diseases (GVD) in North Carolina - Kimberly Heagy Learning Sustainable Edible Gardening through Hands-on Approach with Muscadine Grapes - Claude Judy Jean Creating a Practical Approach for Wine Grape Grower to Predict Grapevine Water Status by Precision Viticulture Technologies - Runze Yu Effect of Planting Distance on PD Resistant Predominantly Vitis Vinifera Grape ‘502-20’ During the Years of Establishment - Elina Coneva Genetics of Adventitious Root Formation in Dormant Bud Cuttings of Grapevines - Sadikshya Sharma Evaluation of Cordon Training System in Blackberry Production - Jayesh Samtani
Grapevine virus diseases (GVD) are a leading cause of economic concern in the US grape and wine industry, including in North Carolina (NC). Visual vineyard observations in summer and fall of 2017 revealed GVD-like symptoms across European-style winegrowing regions in NC. These observations prompted a state-wide vineyard survey with two aims, (1) identify and assess the prevalence of common grapevine viruses in NC and (2) develop a GVD testing service for growers in NC. A vineyard survey was conducted after harvest (October
As the growing number of individuals moving to Florida has increased to over 1000 residents on average per day. Also, with the current focus on Florida’s water conservation
quality, alternative crops are a 15) and the second in March 2024 (n=19). Within both two-hour workshops, participants were able to go home with a muscadine grape cultivar of their choosing. The first workshop covered pest management, cultivar selection, and culture. Participants harvested and sampled fruit from different cultivars and then made cuttings of different varieties to propagate their own. The second workshop focused on the maintenance of grape vines. From the first workshop’s exit survey, participants reported intending on make changes to their landscape practices, including Right Plant Right Place (87%), Fertilize Appropriately (93%), Water Efficiently (67%), and Mulching (73%). 100% of participants also reported willingness to attempt to grow muscadines in the home landscape. From the second workshop, Right Plant Right Place (61%), Fertilize Appropriately (67%), Water Efficiently (44%), and Mulching (55%). 94% of participants self-reported that they felt better in managing muscadine vines, including installation
With the water regulations getting stricter in California and the climatic conditions getting warmer and drier during grape growing seasons, grape growers are forced to improve irrigation efficiency and eventually conserve water usage. This study was designed to incorporate soil moisture sensors and local above-ground weather stations to estimate grapevine water status with the goal to potentially replace pressure chamber measurement, which is the most popular plant-based method of measuring grapevine water status but labor-intensive and time-consuming. The study was conducted in a Barbera vineyard in Fresno, CA and there were four different regimes used in this study, including 50%, 75%, 100% crop evapotranspiration (ETc) replacement, and an over-irrigated condition (>150% ETc). Three Sony’s soil moisture sensors were installed at 20cm, 37.5 cm, and 75 cm in the soil paired with four time-domain reflectometry (TDR) sensors at 20cm, 37.5cm, 75cm, and 150cm in the soil to continuously monitor additional soil conditions besides soil moisture content. The above-ground weather conditions were collected from a nearby California Irrigation Management Information System (CIMIS) station (
Presently, Vitis vinifera grape production in Alabama and the southeastern U.S. is extremely limited due to Pierce’s disease (PD), caused by the bacterium Xylella fastidiosa (Xf) and vectored by insects from the family Cicadellidae. In 2019, UC Davis grape breeding program has released five PD resistant predominantly V. vinifera cultivars which can help sustain the vinifera grape cultivation in the region. Although these new cultivars are currently available, no V. vinifera grape production and management recommendations exist for Alabama conditions. An experimental vineyard was planted at the Chilton Research Extension Center, AL in 2017 to determine the effect of planting distance on vegetative growth and productivity of PD resistant, predominantly V. vinifera advanced selection ‘502-20’. The experiment utilizes a randomized complete block design consisting of three blocks with three vines per block. Vines were planted at an in-row distances of 1.8m, 2.1m and 2.4m and a between row distance of 3.7m and trained to a Watson system. Vine phenology, vegetative growth, yield, and fruit quality characteristics data were recorded during the period of vine establishment (2019-2023). Our results suggest there was a significant treatment by year interaction effect on pruning weight with the lowest pruning weight of 0.8 kg/vine found for vines at an in-row spacing of 2.1m during 2021. Treatment by year interaction also resulted in the highest yield per vine (28.0 kg/vine) measured for vines planted at 2.4m in 2021. Planting distance of 2.4m resulted in a significant increase of the number of clusters per vine during 2021 and 2022 seasons, while no vine spacing effect was found to account for differences in cluster weight, berry mass, or total soluble solids (TSS). Current results indicate planting distance of 2.4m x 3.7m can increase the yield of ‘502-20’ during the years of vine establishment and contribute to sustainable production of PD resistant predominantly V. vinifera grapes in Alabama conditions. Further research will be conducted to expand current knowledge and assist in the development of management recommendations for the successful production of V. vinifera grapes in the region.
Grapevine propagation depends on the formation of adventitious root formation. Vitis riparia and V. rupestris, two native species of North America, serve as the progenitors for the majority of commercially available rootstocks, especially due to their resistance to Phylloxera and ease of propagation. Despite the presence of at least 20 other native Vitis species in North America, many possessing strong resistances to biotic and abiotic stresses, their utilization has been limited by either poor rooting capabilities or insufficient understanding of their rooting potential. This study aims to achieve two main objectives. Firstly, to assess the rooting capabilities of 208 accessions across 20 different species through a dual approach combining traditional evaluation methods with AI-enhanced image analysis. Secondly, to pinpoint the genomic regions linked to rooting ability via a genome-wide association study, which will aid breeding efforts through marker-assisted selection. Preliminary analyses indicate that rooting capability is not solely species-dependent, as there is considerable variation in performance among accessions within the same species. Ultimately, this research will facilitate the development of new, better-adapted rootstocks, which will be crucial in the face of climate change and the increasing prevalence of biotic stresses.
I am a PhD candidate working on grape breeding and genomics at the University of California Davis. I am working on developing high-throughput phenotypic and genomic tools for salt and drought tolerance in grapes.
Tuesday September 24, 2024 1:10pm - 1:20pm HST
South Pacific 4
Commercial blackberry producers use various types of trellising systems to support the canes and prevent damage from wind and added fruit weight. The objective of this study was to determine the fruit yield and quality with a new training and pruning strategy (cordon system) in a T-trellis system. The 2022-23 growing season was the first year of a two-year study to evaluate the conventional winter pruning and training strategy against a modified “cordon” training system, with the Prime-Ark® Traveler cultivar, at the Hampton Roads AREC in Virginia Beach, VA. The study was set up as a completely randomized design with two treatments and six replicates. Each replicate had 3 plants. The conventional pruning and training strategy involved leaving 4 to 6 main canes along with their laterals per plant. The cordon system had 2 to 4 canes pruned to the height of each trellis wire allowing two laterals per cane to extend horizontally along the wire in both directions. The intent was to distribute the fruit weight along the wires, making harvest easier. New primocanes were trained to the wires in the same manner after spent floricanes are removed. All winter pruning was done between 10 and 20 March, 2023. Fertigation was done as per standard extension recommendations. Harvesting was done two to three times per week beginning 30 May and ending 28 August 2023. Fruit yield was collected by replicate and fruits were categorized as marketable Grade 1, Grade 2 or nonmarketable. The nonmarketable fruits were recorded as having white drupelet disorder, diseases, and insect or “other” damage. Fruit size, firmness, total soluble solids (TSS) and pH data were collected on ten Grade 1 berries per harvest week and data were averaged for the season. Statistical analysis was done with two-sample t-test at alpha =0.05. The conventional training and pruning strategy had an overall higher total, marketable and nonmarketable yield. Fruit size was slightly smaller in the cordon system and no differences in firmness, TSS or pH were observed.
Comparing Scion and Rootstock Trunk Injection of Oxytetracycline for HLB Management Across Diverse Rootstocks in Florida - Larissa Nunes da Silva Evaluation of Different Oxytetracycline Rates Delivery by Trunk Injections on Mature Valencia Sweet Orange Trees - Gabriel de Castro Marconi Pugina Field Performance of Novel Citrus Rootstocks Grafted with Valencia and Their Response to Systemic Delivery of Oxytetracycline - Caroline de Favari Tardivo Florida-grown 'Hamlin' Sweet Orange Failed to Produce Adequate Pounds-solids Despite Budline, Environment, and Antibiotic Treatment - John Chater Hedging, Thinning, Controlled Release Fertilizer, and Oxytetracycline Trunk Injections to Mitigate Fruit Disorder Incidence in HLB-Affected 'Sugar Belle' Mandarin - Joe Volpe Grove First: A Framework to Find Citrus Greening Treatments that are Safe, Affordable, and Available.- Guilherme Locatelli Can We Improve Growth and Production in HLB- Affected Citrus Trees Using Plant Growth Regulators? - Prudhvi Vulchi Methyl Salicylate and Gibberellic Acid For The Rehabilitation Of HLB- Affected Sweet Oranges. - Gurleen Kaur
The huanglongbing (HLB) associated pathogen Candidatus Liberibacter asiaticus (CLas) inhabits the phloem of infected citrus trees, which impedes the efficacy of foliar-applied chemicals for management of the disease. Trunk injection is an alternate method that allows the targeted delivery of agrochemicals into the vasculature, resulting in their systematic distribution throughout the tree. This study aims to determine the large-scale efficacy of trunk injection of oxytetracycline (OTC) on citrus tree health, fruit quality, and yield in existing rootstock trials in a commercial production site in Florida. The study compares 9-year-old Valencia sweet orange (Citrus sinensis) trees grafted on six different rootstocks in a large field trial in Polk County, Florida. The experimental design is a complete randomized block design, with three injection treatments: 1) no injection (control), 2) injection into the scion trunk, and 3) injection into the rootstock trunk. The injections were performed in May 2023, and injected trees received a commercial formulation of OTC at a rate of 1.1 g per tree using FlexInject injectors. Data collection included HLB status, tree size, yield, fruit/juice quality, fibrous root density, and leaf macro- and micronutrient content once a year, wound phenotype every six months, and bacterial titers before injection and 3 days, 1 week, and 1 month after injection. OTC injections into the scion or the rootstock trunk improved tree health, yield, fruit/juice quality, and the leaf Ca content. Overall, injections increased fruit yield by 24% and juice brix by 9%, increasing the revenue by 36% on a per acre basis. Injection into the scion trunk was slightly superior in terms of tree growth and fibrous root density, while injection into the rootstock trunk reduced the wound size, bark cracking, and HLB symptoms. CLas titers were reduced regardless of the injection site one month after injections. In conclusion, our results suggest that OTC injections have the potential for short-term management of HLB to help with the recovery of the Florida citrus industry in the face of endemic disease conditions. The trial will continue to assess longer-term effects.
In Florida, Huanglongbing (HLB), also known as citrus greening, has severely impacted citrus production, prompting research into alternative treatment methods such as trunk injection of oxytetracycline (OTC) to manage Candidatus Liberibacter asiaticus (CLas) colonization. This study aims to 1) determine the optimal OTC rate administered by injection to improve the health and productivity of HLB-affected mature sweet orange trees and 2) determine the impact of spring versus late summer injections to maximize benefits and the potential for extending the harvest window. The study was initiated in 2023 in a commercial citrus production setting in Polk County, Florida. The trees were 18 years old and composed of ‘Valencia’ (Citrus sinensis) scion on Swingle (C. paradisi × Poncirus trifoliata) rootstock. Four different OTC rates (0.55 g, 0.852 g, 1.1 g, and 1.65 g active ingredient per tree) and two injection times (June and September) were compared against a control receiving no injections. The experimental design was a randomized block design with eight replications, and each replication consisted of four linear trees. A commercial formulation of OTC registered in Florida was used and administered through FlexInject injectors. A volume of 100 ml per tree was used for the 0.55-1.1 g rates and administered with one injector. The highest rate (1.65) was administered using two injectors on opposite sides of the tree in a volume of 75 ml per injector. Tree health was assessed by visual ratings of foliar HLB symptoms and canopy densities, while CLas titers were quantified using real-time PCR. Fruit quality and yield measurements included total soluble solids, titratable acidity, fruit weight, and juice characteristics. Trees were harvested, and fruit/juice quality was determined in March 2024. Overall, injected trees produced significantly more and larger fruit with better juice color, a higher percentage of juice, and more total soluble solids than control trees. The highest rate of OTC produced the highest yield and highest-quality fruits compared to the other rates. We did not observe any difference between spring (June) and summer (September) injections on any measured variables. Bacterial titers were reduced in the injected trees compared to the non-injected trees, and injected trees had fewer HLB symptoms and denser canopies than control trees. This research provides important insights into the best practices for managing HLB using trunk injection of OTC.
Worldwide citrus production faces significant challenges from the devastating disease Huanglongbing (HLB), necessitating innovative management strategies. This study aimed to assess the performance of novel rootstocks under natural HLB-endemic conditions using regular management practices and the recently registered practice of delivering oxytetracycline (OTC) through trunk injection to reduce pathogen load. Nine novel rootstocks, US-1673, US-1676, US-1680, US-1672, US-1687, US-1688, US-2111, US-2132, and US-2137 with different genetic backgrounds, including Citrus maxima, C. tachibana, C. reticulata, and Poncirus trifoliata were included in the study. Also included were two commercial rootstock standards, sour orange (C. aurantium) and Swingle (C. paradisi × P. trifoliata). The rootstocks were grafted with ‘Valencia’ sweet orange (C. sinensis) scion and planted in 2014 in a randomized complete block design and 12 single-tree replications in an open field in St. Lucie County, Florida. In July 2023, half of the trees were injected with ReMedium TI® (95.0% oxytetracycline hydrochloride) dissolved in reverse osmosis water acidified with muriatic acid to a pH of 2.0. Each tree received 0.75 g OTC dissolved in a volume of 75 ml (10,000 ppm) administered using FlexInject injectors. Injections were performed in the scion, approximately 5 cm above the graft union. Tree measurements included tree size, canopy health, pathogen titers, fruit yield, and juice quality. Significant differences among rootstocks were observed in the years before injection. In the 2022-2023 production season, US-1688 induced the highest yield, and US-2132 induced the best juice quality. Preliminary results indicate an overall positive response to the OTC treatment across all rootstocks. Injected trees had a 36% increase in yield, an 11% increase in juice brix, and a significant reduction in leaf and root pathogen titers. As in the previous years, growth and productivity varied significantly among the rootstock cultivars. US-1688, a new release by USDA under the name SuperSour 4, continued to be among the largest, healthiest, and most productive trees. The results from this research demonstrate the importance of rootstock selection for sustainable citrus cultivation. It also highlights the benefits of integrating the systemic delivery of antibacterial therapies to maximize the resilience of citrus trees to HLB.
Huanglongbing (HLB) is a devastating bacterial disease in Florida and has been spreading in citrus-growing regions in Texas, Georgia, and California. HLB threatens the entire US fresh and processed citrus industries. To date, all commercial sweet orange (Citrus sinensis L. Osbeck) cultivars are susceptible, though some are more tolerant than others. The citrus industry has an estimated economic impact nationwide of over $13 billion. The currently applied strategies for mitigating this disease are costly and unsustainable. The development and commercialization of HLB tolerant sweet orange scions is needed for sustainable and profitable citriculture in the US. Citrus Under Protected Screen (CUPS) is a method used in Florida to exclude the Asian Citrus Psyllid (Diaphorina citri Kuwayama, or ACP), which is a phloem-feeding hemipteran insect that is the vector for Candidatus Liberibacter asiaticus CLas the causal agent believed to be responsible for HLB disease in citrus. ‘Hamlin’ sweet orange is the most important early sweet orange for processing in modern history. ‘Hamlin’ has a budline called ‘Hamlin 1-4-1’, which is the predominant budline in the State of Florida. ‘Hamlin 1-4-1’ has high susceptibility to HLB, which causes symptoms such as blotchy mottle, small fruit size, high titratable acidity (TA), low total soluble solids (TSS), and severe fruit drop. ‘Hamlin N13-32’ is a new budline of ‘Hamlin’ sweet orange that appears to have enhanced tolerance to HLB in terms of tree health. ‘Hamlin 1-4-1’ and ‘Hamlin N13-32’ trees were followed for two years in multiple environments with and without treatments of oxytetracycline. Tree size, rootstock, fruit number, fruit size, TSS, TA, TSS:TA ratio, and pounds-solids data were collected to determine the effects of environment (CUPS versus outside grove), antibiotic treatment effects, and budline effects on production. There were some significant differences among groups for fruit quality, but more research is needed to determine effects of oxytetracycline, budline, rootstock and environment on ‘Hamlin’ sweet orange production.
Global citrus production has been severely impacted by huanglongbing (HLB), a disease presumably caused by the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas). While there are not any commercial citrus cultivars currently available that have total resistance to this pathogen, several varieties show some degree of tolerance, including the LB8-9 ‘Sugar Belle’ mandarin. This cultivar was released by the UF/IFAS CREC Plant Improvement Team in 2009 and is known to be one of the most HLB tolerant varieties in HLB-endemic conditions when considering tree health. Fruit from this cultivar can be used for juicing or in the fresh market and with proper cultural care the trees consistently produce relatively high yields with typically an acceptable ratio of total soluble solids (TSS) to titratable acidity and value in pounds-solids per acre. Despite the improved tolerance to HLB in ‘Sugar Belle,’ many growers in Central and South Florida have had increased incidences of fruit disorders with this variety in the past several seasons. Fruit that are misshapen, have a poor peel color, or go soft on the tree are more common making this cultivar often undesirable for packing houses. The objective of this study is to determine if hedging the trees at different times (early summer, middle summer, or late summer), manually removing ~50% of the developing fruit in July (thinning), controlled release fertilizer applications, or oxytetracycline trunk injections will help mitigate some of the incidences of fruit disorders and increase overall fruit and juice quality at harvest. There were two sites used for this experiment (The Citrus Research and Education Center in Lake Alfred, FL, and Tamiami Citrus “Bee Branch Grove” in Avon Park, FL) and it was conducted over two seasons 2022-2024. Significant differences (p-value < 0.05) were discovered among the treatment groups in terms of TSS, titratable acidity, sugar:-acid ratio, pounds-solids per box, fruit size, yield, percent asymptomatic fruit, and peel rupture force. Despite evidence that some treatments may provide benefits to the grower, more research is needed to mitigate the soft fruit problem in ‘Sugar Belle’ mandarin.
Citrus greening (Huanglongbing, HLB) is considered one of the most devastating diseases affecting the global citrus industry. There is an urgent need to provide relief from HLB and restore profitable citrus production. Since 2005, over a billion dollars has been spent on research to find a solution to HLB. Trunk injection with the antibiotic oxytetracycline is the current treatment that Florida growers are using to manage the disease. To broaden the number of molecules available to growers to treat HLB a framework was developed to efficiently screen molecules in citrus groves, selecting those that enhance tree health over a season. The framework is based on the principles of the design-of-experiments (DOE). Utilizing the injection system developed by TJ Biotech (LLC), 88 molecules were injected into 8-year-old ‘Valencia’ sweet orange (Citrus × sinensis) trees grafted on ‘US-812’ (Citrus reticulata × Poncirus trifoliata) rootstock over a six-week period. The injections were divided into nine sets, with varying numbers of molecules injected in each set (12, 10, or 6). The injections were administered into the scion, approximately 5 cm above the graft union. Visual assessments of tree health index and canopy density were collected to evaluate changes in restoring tree horticultural traits. Ratings were recorded before injections and at 90 and180 days post-injections. In addition to health index and canopy density, a series of seven pictures were taken per tree on the injection day and subsequently at 30, 60, 90, and 180 days after injections. Pre-harvest fruit drops were measured by counting and removing any fruits on the ground beneath each tree. The total number of fruits on each tree was tallied at harvest to calculate the percentage of fruit drops for each tree. Yield, fruit, and juice quality were assessed at harvest. In this screening trial, trees injected with oxytetracycline have been used as a positive control to indicate enhancement in tree health. Results from the tree health index obtained at 90 and 180 days after injection showed that 17 molecules performed similarly or better than the oxytetracycline-treated positive control. We are partnering with regulatory consultants to identify those that are safe and affordable. New molecules for injection will require regulatory labeling.
Emerging Pests and Pathogens Research Unit, USDA Agricultural Research Service/ Plant Pathology and Plant Microbe Interactions Section, School of Integrative Plant Science, Cornell University
Huanglongbing (HLB) disease is arguably the biggest concern for citrus growers in Florida causing a drastic more than 75% decline in citrus-bearing acreage since 2005. HLB symptoms include sparse canopy, poor leaf growth and development, ultimately resulting in yield losses. Standalone applications of plant growth regulators (PGRs) and certain antibiotics have been reported to reduce the impact of HLB on tree growth and promote new flush growth. However, very little research has been done on synergistic effect of PGRs and antibiotics on tree growth and yield. The goal of HLB mitigation strategies is to promote a denser canopy, enhancing source to sink ratio as trees with dense canopies are known to produce high fruit yield. Thus, we initiated a field study to evaluate foliar applications of PGRs (auxins, cytokinins, and gibberellins) and trunk injections of Oxytetracycline (OTC) in 9-year-old orchards of Valencia on ‘Swingle’ rootstock in central Florida. This is the first research in citrus where PGRs are being applied according to tree phenology. The experimental design is a split-plot with a completely randomized block design with 8 replications. The antibiotic programs (with and without OTC injections) are assigned to the main plots, while the PGR treatments assigned to the subplots consist of an no PGR control, PGR applications with varying concentrations, and PGR applications with constant concentrations throughout the year. Parameters such as leaf area, fresh weight, dry weight, water content, chlorophyll content, starch content and carbohydrate content from leaf samples are recorded every three months starting from July 2023. Over 9 months no consistent pattern of PGR or OTC treatment was observed for vegetative traits. Nonetheless, Non-OTC trees showed higher leaf water content compared to OTC during the dry season months of October and January. Regarding yield, the study suggests that both PGR treatments, when applied with or without OTC lead to significant improvement in yield. PGR variable treatment showed 30% improvement in yield efficiency compared to both the control and PGR Constant treatments. No difference is observed between OTC and Non-OTC programs in terms of yield efficiency. These findings suggest that use of PGR treatments regardless of use of antibiotics can be beneficial for growers.
Investigating the Effect of Pecan Rootstock on Rhizosphere Soil and Root Microbial Communities - Xinwang Wang Enhancing Urban Food Production: A Multi-Omics Investigation of Microbe-Mediated Soil Improvement and Plant Nutrition in New York City Farms - Yejin Son The Effect of Reclaimed Water on Young Blueberry Seedling Root Architecture Using Rhizotron Technique - Yasmeen Saleem Root Characterization Analysis of Navajo Peach Seedlings - Reagan Wytsalucy Characterizing Root Dynamics and Phenology of Hops in a Subtropical Climate Using an In-situ Root Imaging System - Alvaro J. Bautista Effects of Reclaimed Water on Blueberry Seedling Growth and Root Morphology - Yasmeen Saleem
Pecans (Carya illinoinensis), the most valuable native North American nut crop, are commonly propagated through grafting to maintain desired traits from parent trees. Successful pecan cultivation relies on scion varieties, rootstocks, and soil conditions. This study investigated the microbial abundance and diversity in soils and roots of a southern rootstock (87MX5-1.7) and a northern provenance ('Peruque') in a rootstock test orchard, both grafted with a 'Pawnee' scion cultivar in the USDA ARS Pecan Breeding program. The 16S ribosomal RNA of bacteria and ITS of fungi were sequenced and annotated into trophic and nutrient-related groups to characterize the rhizosphere microbiota. The results showed fungal dominance over bacteria, with Peruque roots having a higher relative abundance of saprotroph fungi compared to 87MX5-1.7, while 87MX5-1.7 exhibited higher levels of nitrogen fixation-related bacteria. Despite no significant difference in diversity index, the presence of symbiotrophs, especially the ectomycorrhizal fungi, exhibited distinct ectomycorrhizal fungi, which may lead to a divergent pathway of nutrient translocation between these two rootstocks. The study suggests rootstocks from different origins shape rhizosphere microbiota differently, affecting nutrient uptake and potentially nut yield. Exploring rootstock-fungi combinations could enhance grafting success and ultimately increase nut yield.
Urban agriculture (UA) is an emerging food production system in which farmers grow crops within cities. However, many urban farmers face challenges with their compost soils, including poor soil structure and low nutrient availability. This study aimed to utilize beneficial microbes, such as arbuscular mycorrhizal fungi (AMF) and phosphorus solubilizing bacteria (PSB), to address soil aggregation and biological phosphorus (P) cycling in UA soils while also assisting urban farmers in generating higher economic returns. We cultivated Bush Champion II Hybrid Tomatoes (an indeterminate tomato cultivar) in three organic urban farms in New York City in 2022 under four different treatments: 1) Control tomatoes, which were not treated with PSB or AMF; 2) Tomatoes treated with PSB; 3) Tomatoes treated with AMF; and 4) tomatoes treated with PSB and AMF. Our hypothesis posited that the positive interactions of PSB and AMF would synergistically enhance soil phosphorus cycling and carbon accumulation and, thereby, promote plant growth and nutrition. Our findings indicate that the combined application of AMF and PSB increased the overall abundance of soil microbiomes, as measured by flow cytometry. There was also an increase in the production of soil-aggregating proteins and soil acid phosphatase activity. Additionally, the nutrient uptake by tomatoes, including calcium (Ca), potassium (K), and phosphorus (P), was enhanced. We also employed omics approaches using deep sequencing metagenomics and metaproteomics to generate meaningful insights into how AMF and PSB interacted with soil native microbial populations and defined soil microbiome functions. Our findings offer novel insights into the characteristics and functions of soil microbiomes in UA soils. This knowledge will contribute to advancing the potential of beneficial microbes in enhancing food production within urban agriculture systems.
Southwest Native American Tribes, such as the Navajo, Hopi, and Pueblo, have grown peaches at least since the early 1600’s, making them a nutritionally and culturally important food source. Historic management practices consisted of reduced irregular irrigation of sandy to sandy loam soils with no fertilizer additions, no pruning, and no fruit thinning. Recent research indicates germinated peach seedlings from seed sourced from a Navajo orchard in Utah are more drought resistant when compared to direct seeded ‘Lovell’ seedlings, and container transplanted ‘Lovell’ seedlings. The purpose of this study was to characterize the Navajo seedlings’ root distribution after direct seeding to better understand their rooting dynamics with regular irrigation and no pruning. All trees were direct seeded in May 2018 and destructively sampled in May 2022. Three trees from each Navajo and ‘Lovell’ treatment were destructively harvested to determine above ground biomass. Root distribution (location relative to the trunk and depth in the soil profile) was determined using a soil core sampling technique. Soil cores were taken in a radial array around the tree, and tree roots (small, medium, large) were separated from the soil cores in the field, before drying and weighing. After the cores were extracted, the remaining root system was excavated, air dried for 10 days, then weighed and photographed. The main effect and interactions of tree type, sampling location, and depth were tested by analysis of variance. The Navajo seedlings had a more extensive root system, including more roots in the grass alleyways, than Lovell seedlings indicating a more competitive root system. There were also qualitative differences in root types between Navajo and ‘Lovell’ in the occurrence of lateral primary roots, sinker roots or fibrous roots. The results of this research will be utilized to determine the Navajo seedlings’ potential for becoming a viable rootstock for the fruit industry.
In Florida's subtropical climate, photoperiod manipulation facilitates a unique production system for hops (Humulus lupulus L.), an important crop for the brewing industry, with two growth cycles per year. The spring season spans from mid-February to early June, immediately followed by the fall season, which concludes in late November. With contrasting climatic conditions, plant phenology, yield, and cone quality differ dramatically between the two growing seasons. To gain insights into the roles of roots in the seasonal differences in plant phenology and performance, we characterized root dynamics and phenology of 'Cascade' hops grown in West Central Florida using an in-situ root imaging system. The soil at the study site was Myakka fine sand with 97% sand. Plants were grown on a 4.5 m V-trellis system, and data were collected over 2 years upon transplanting. Minirhizotron tubes were installed at varying distances (0, 30, and 60 cm) from the planting hill perpendicularly to the row to capture biweekly root images up to a depth of 84 cm. These images were processed using WinRhizo Tron software to measure various root morphological parameters, including total root length, projected area, surface area, volume, and the longest root. Notably, hop roots showed rapid elongation, reaching a depth of 84 cm, and expanding up to 60 cm from the hill center within one month after establishment under subtropical conditions. However, the primary, larger in diameter tap roots exhibited signs of decay after 5 months, culminating in complete mortality within 15 months following their establishment. Interestingly, the phenological stage of cone development induces a proliferation of new root growth, although temporary, with these ephemeral roots having a lifespan limited to approximately 3 months. These results can provide insights into the shoot-root interactions and help improve fertilizer, water, and ground cover recommendations, ultimately optimizing hop production in Florida's unique subtropical system.
A high percentage of agricultural production depends highly on groundwater irrigation. Groundwater depletion has been putting significant pressure on global water resources and food production. Using reclaimed water (RW) as an alternative source of irrigation water for crop production can mitigate the huge demand on groundwater resources. Blueberry plants are characterized by their preference for acidic soil conditions with a shallow, salt-sensitive root system. The alkaline and saline nature of RW necessitates an understanding of its suitability as irrigation water for blueberry production. We conducted a greenhouse rhizotron experiment to characterize root morphological responses of ‘Arcadia’ blueberry seedlings to RW. Four irrigation water treatments were implemented: 100% well water (WW), 100% deionized water (DW), a blend of 50% DW/50% RW, and 100% RW. These treatments were applied to rhizotron boxes filled with 50% sand and 50% pine bark mixed uniformly by volume. Root morphological variables, stem diameter, plant height, canopy projected area, and plant physiological variables were examined biweekly. Soil and plant tissue nutrient contents and plant biomass were examined at the end of the experiment. Water quality was slightly alkaline with pH values of 7.8 for 100% WW and 100% DW, and 7.7 for 100% RW. Electrical Conductivity (EC) values varied among the treatments, with 0.428 dS/m for 100% WW, 0.338 dS/m for 100% DW, and 0.769 dS/m for 100% RW. Initial soil mix pH at the beginning of the experiment was 6.8. Our preliminary findings indicate no significant difference in root elongation, plant above-ground biomass and leaf chlorophyll index among the four irrigation treatments (p > 0.05). A significant difference was observed between DW and WW for plant stem diameter and height (p > 0.05), possibly attributed to blueberry plants’ sensitivity to salt. The soil mix pH had risen to 7.8 for all the treatments at the end of the experiment. Our preliminary interpretation suggests that 100% RW does not adversely affect young blueberry plants growth parameter over the short-time period of the experiment. That indicates that RW can be a promising alternative of irrigation. Existing literature indicates that blueberry plants have the ability to adopt to irrigation water EC level of up to 2 dS/m, while the measured EC of 100% RW was 0.77 dS/m, it appears that the blueberry plants didn’t reach to the stress level that could significantly affect their growth parameters. We believe the experiment duration was insufficient to observe the high pH symptoms.
Optimizing Tomato Crop Production: Fertility Management in Soilless Media - Bryce Waugh Improving the Growth and Yield of Tomato through new Integrated Pest Management Strategies - Rosemary Gutierrez Coarite Assessment of Novel, Interspecific Hybrid Tomato Rootstocks for Production under Environmental Stress - Joshua Harvey Evaluation of Biostimulant on Nutrient Use Efficiency in Tomato - Weining Wang Alternative Carbon Sources Effects on the Soil-plant Nutrient Dynamics During and Post ASD in a High Tunnel Tomato Crop System - Francesco Di Gioia Advancing Pepper Production Beyond Seasonal Limits: Findings from a High Tunnel System Integrated with Biostimulant Applications - Asmita Nagila Optimizing Nitrogen Fertilizer Rate and Planting Density of Vidalia Onion Yield and Bulb Size Distributions - Elvis Pulici Assessing the Efficacy of Plant Biostimulants on Onion Growth and Production in Greenhouse Trials and Field Conditions - Prakriti Nepal
Tomatoes are one of the most important greenhouse produced crops and the number of producers using greenhouse to grow them has risen in recent years. Sustainable development and effective resource management are becoming more and more important to the agricultural industries as well. Applying fertilizer precisely is becoming more and more important in different agricultural systems. Different physical and chemical characteristics of soilless growing substrate result in varying capacities for retaining nutrients. As a result, precise fertilizer rates are essential. This study investigated 14 fertilizer blends with varying proportions of nitrogen (0-400ppm), phosphorus (0-100ppm), and potassium (0-425). Six-cell seedling starter trays were filled with Berger BM6, and 'Big Beef' tomato seeds were planted. After four weeks, the seedlings were transplanted into five-gallon aeration fabric grow bags. Plants were hand-watered once a week with each treatment fertilizer rate to maintain a 10% leaching fraction. End measurements included the number of leaves, dry shoot weight, fresh root weight, dried root weight, and SPAD readings. The study revealed that a higher rate of nitrogen increased fresh shoot weight and lower rates of phosphorous increased number of non-harvestable fruits, increasing the need for further investigation to determine optimal fertilizer rates for various specialty crops grown in soilless greenhouse environments. Such endeavors are crucial for maximizing agricultural productivity while minimizing resource wastage and environmental impact.
Tomato (Solanum lycopersicum L.) is the number one vegetable crop in Hawaii in terms of popularity and market value. Of the total tomatoes consumed in Hawaii only 23% is produced locally. Local production has decreased substantially over the past few years due to crop losses caused primarily by the Tomato Yellow Leaf Curl Virus (TYLCV), which is vectored by whiteflies Bemisia tabaci and Bemisia argentifolii. Crop losses by TYLCV in tomato crops on Maui range between 60 to 100%. Efforts to keep plants from becoming infected, manage the rate of infection, timing, or severity of the infection are needed to protect crop health. Therefore, a new integrated pest management approach was conducted integrating the use of reflective ground cover, companion plants, insecticides, and tomato varieties resistant to TYLCV. The highest total weight (4.4 lb/pl per harvest time) was observed in the variety PS01522935 in the treatment combining reflective ground cover and companion plants and the highest marketable weight was observed in the same treatment in the varieties PS01522935 and Mesquite (3.5 lb/pl per harvest time), and the highest TYLCV infection was observed in the conventional treatment in the varieties Paisano followed by Healani, Celebrity Plus and Kewalo, and the varieties with no TYLCV infection were PS01522935, SVTD8601 and Mesquite. The use of reflective ground cover and companion plants may reduce TYLCV infections in tomato crops by reducing whitefly populations.
A growing global population and worsening global environmental change necessitate the development of improved crop varieties and cultivation techniques. In tomatoes, the world’s most popular vegetable crop, grafting has emerged as a cultivation technique for addressing these challenges through improving tomato crop vigor and stress resistance, especially to abiotic stresses that are becoming more widespread including heat, salinity, and drought stress. In order to expand the offerings of tomato rootstocks, we have conducted multiple trials to assess the beneficial impact of 10 novel tomato rootstocks on ‘Celebrity’ scion vigor and stress resistance. The rootstocks, developed by colleagues at the King Abdullah University of Science and Technology (KAUST) consist of interspecific Solanum spp. hybrids including two tetraploid hybrids. We conducted three trials to assess the impact of grafting with the novel rootstocks, including a greenhouse pot trial to quantify growth and vigor and two controlled environment trials to assess stress resistance. In each trial, ‘Celebrity ’ scions were grafted with either the novel rootstocks, ‘Maxifort’, ‘Multifort’, or left ungrafted. In the greenhouse trial, measurements of stem diameter, shoot height, shoot canopy projection area, and fresh and dry weights at harvest were used to determine overall vigor. We identified five and eight of the novel rootstock grafting combinations that outperformed the ungrafted and ‘Maxifort’-grafted plants, respectively. Additionally, measurements of SPAD and observations of foliage coloration provided initial evidence of differential nutritive requirements between the novel rootstocks. In our controlled environment trials, chlorophyll fluorescence, SPAD, and porometer data demonstrated differential susceptibility to salinity, heat, and drought stress between the rootstocks. This presentation will highlight key differences in morphological and physiological traits that assisted us in selecting a narrow set of rootstocks for a forthcoming evaluation in a passive high tunnel to demonstrate the utility of these new rootstocks.
To evaluate the efficacy of a commercial available biostimulant (a product containing friendly microorganisms like N2 fixing bacteria) on the improvement of nitrogen (N) and phosphorus (P) use efficiency in tomato, two independent field experiments were conducted in West Central Florida in the fall production season of year 2023. For both experiments, treatments included a factorial combination of two biostimulant rates (0 or 0.247 kg/ha) and four fertilizer rates (N or P2O5) (0, 67, 135, 202 or 269 kg/ha) that were arranged in a split-plot design. Biostimulant was applied as a solution drenched in soil following transplanting, and fertilizer treatments were applied as pre-plant application in soil and/or through drip injection during the season. Commercial tomato cultivar ‘HM1823’ was chosen as plant material. Analysis of variance (ANOVA) revealed that biostimulant did not have statistically significant influence on fruit marketable yield, fruit quality (Brix) and plant biomass, regardless of application rates of P2O5. By contrast, however, application of N had statistically (P
Dr. Lakesh Sharma is an assistant professor of soil fertility and sustainable agriculture at the University of Florida in Gainesville, FL. Lakesh has been farming since he was a child on his own farm. His academic school journey started in 2000. He is currently working on nutrient... Read More →
Anaerobic soil disinfestation (ASD) is a microbial-driven soil disinfestation approach for the management of soilborne pests and pathogens of horticultural crops including protected vegetable production systems increasingly affected by emerging soilborne issues. ASD is implemented by incorporating in the soil an easily labile carbon (C) source, mulching the soil with an impermeable film, and irrigating the soil to field capacity. Organic amendments used as C source also provide N and other nutrients, and research is needed to assess if and how crop fertilization should be adjusted accounting for such nutrients. A study was conducted to evaluate the effect of alternative C sources on soil nutrient availability during and post-ASD in a high tunnel tomato production system. Carbon sources tested included sugarcane molasses, wheat middlings, and soybean meal mixed with wheat middlings. Each C source was applied at the standard rate of 6 Mg/ha of total C. The same C sources were also applied at half rate (3 Mg/ha of total C) balancing the total nitrogen (N) applied to 350 kg/ha of N using composted chicken manure as a source of N. The selected C source treatments were compared with untreated soil amended only with composted chicken manure and an untreated control to estimate the amount of nutrients provided by the untreated soil or by the composted chicken manure. Post ASD, fresh-market tomato cv Red Deuce was planted and used as a test crop evaluating plant growth, nutrient uptake, and yield and quality performance in response to soil treatments. Post-ASD, soil redox potential (Eh) was monitored revealing that all C sources tested determined a significant decrease of soil Eh, suggesting a good efficacy of the ASD treatment. During and post-ASD soil pH, EC, nitrate-N and ammonium-N levels were monitored using soil-water extracts (obtained with the 1:2 v:v method). Significant variation of soil pH, EC and mineral-N content were observed during and post-ASD, which influenced tomato marketable yield. Among the treatment tested WM applied at half rate and balanced for the N which had an intermediate C:N ratio (11.65) provided the highest seasonal marketable yield (10.4 kg/plant), while the untreated control amended with chicken manure provided the lowest yield. Overall, this study suggests that C application rate and the C:N ratio of the organic amendments used to apply ASD have significant effects on the efficacy of the ASD treatment as well as on the availability of nutrients and the crop performance post-ASD.
Pepper is an important specialty crop in the Southwest U.S., cherished for its economic importance, cultural history, and high nutritional values. Despite being a leading pepper producer in the U.S., challenges such as high temperatures, erratic weather patterns, and imports from Mexico have hindered both production and profitability of growers in this region. In response, alternative systems like high tunnels have emerged as viable solutions. The mild winter climate in Southwest Texas offers an ideal setting for winter pepper cultivation in high tunnels, potentially boosting growers' profitability with off-season market opportunities. Application of biostimulants, such as seaweed extracts, holds promise in enhancing cold tolerance and transplant success within high tunnel systems. This study investigates the feasibility of winter pepper production in high tunnels established in the Wintergarden region, assessing various cultivars based on yield and quality. The high tunnel maintained a range of 8-10°C higher temperatures than the open-field on chilly days without additional heating. Seven pepper cultivars were evaluated, with and without seaweed extracts. Seaweed-treated plants exhibited an overall higher stomatal conductance and leaf transpiration rates along with reduced leaf electrolyte leakage. Rio de Oro; a Santa Fe type pepper had the highest PSII efficiency and total fruit yield. Seaweed application also increased total yield and individual fruit weight in cultivar-specific manner. The total phenolic content of fruits was increased by seaweed application at the early maturity stage whereas total flavonoid content varied by cultivar and maturity stage. Despite facing freeze challenges at the early transplant stage, this first-year experiment demonstrated promising potential for off-season pepper production in high tunnels in our region.
This study was carried out at the University of Georgia (UGA) Vidalia Research Center during the 2022/2023 winter season and is being repeated in 2023/2024. The objectives of this experiment were to identify the relationship between planting density, nitrogen fertilizer rates, and the effects on yields and bulb size distribution. The variety “Sweet Magnolia” was tested at three planting densities (116,000; 87,000; and 58,000 plants per acre) and three nitrogen rates (120, 100, and 80 lbs. per acre). Results indicated there is no interaction between planting density and nitrogen rates on onion bulb size distribution or total production. However, the effect of planting density was significant. Higher densities (116,000 plants/acre) yielded a total weight of 1788 40 lbs. bags/acre with a significant proportion of jumbo-sized bulbs 62%, while lower densities (58,000 plants/acre) resulted in larger colossal bulbs 290 40 lbs. bags/acre with a reduced total yield 1370 40 lbs. bags/acre. Nitrogen application also had a significant impact on both yield and size of the bulb. The highest nitrogen rate (120 lbs./acre) produced a higher total yield (1670 40 lbs. bag/acre), with a significant portion of jumbo at 50% and colossal bulbs at 15%. There was no significant difference between the nitrogen rates of 100 and 120 lbs./acre, but the lowest nitrogen rate (80 lbs./acre) had the worst yield with 1434 40 lbs. bags/acre resulting in a 15% decreased yield compared with the higher rate. These results suggest that optimal planting density and nitrogen application are decisive for reaching the desired bulb size distribution and maximizing yield.
The escalating impacts of climate change on agriculture necessitate the exploration of sustainable crop enhancement methods. This research integrates greenhouse screening and field application to evaluate the efficacy of biostimulants in promoting the growth of onion (Allium cepa L.) under variable environmental conditions. In the initial greenhouse experiment, seven biostimulants were tested, including three bacterial products (Continuum, Spectrum DS, and Tribus Original), two mycorrhizal products (Mighty Mycorrhizae and Myco Apply), one seaweed extract product (Seaweed), and one product containing humic acid (Huma Pro 16). These were applied to assess their impact on seedling emergence and growth in a peat-based soilless substrate. Huma Pro 16 and Spectrum DS were identified as the most effective in increasing seedling emergence, leaf area, and biomass. Based on these findings, field trials were conducted with four onion cultivars (red, sweet, white, and yellow), subjected to conditions simulating drought and normal watering (75 % and 100 % evapotranspiration) or with nitrogen levels adjusted to low and high (75 % and 100 % of optimal 168 kilograms per hectare). The field trials assessed bulb diameter, weight, and leaf metrics. Results indicated that cultivars responded differently to varying conditions, with red and white onions showing consistent growth patterns, while sweet onions displayed more variability. Yellow onions benefited from the biostimulants, exhibiting improved growth under both drought and low nitrogen conditions. This study demonstrates that the application of certain biostimulants can significantly enhance crop growth and resilience. Huma Pro 16 and Spectrum DS show promise for improving onion yield in the face of climatic challenges. Keywords: biostimulants, drought stress, nitrogen availability, onion, and sustainable agriculture.
Developing Irrigation Tools and Information for Effective Irrigation Management of California’s Avocado Orchards - Ali Montazar Comparative Assessment of Satellite-Derived Crop Evapotranspiration and Estimated Evapotranspiration in Almond and Walnut Orchards for Precision Irrigation Management - Abdelmoneim Mohamed Physiological Thresholds Provide Targets for Climate-Resilient Irrigation Management in Hazelnut - Steven Bristow Determination of Crop Coefficient and its Inter-annual Variability in Pecan Orchard in Georgia - Kriti Poudel Assessing Water Status in Citrus Plants Using Thermal Imaging in Greenhouses - Gustavo Haddad Souza Vieira The Impact of Irrigation Rates Based on Crop Water Requirement on Tree Growth and Water Relations in Commercial Citrus Groves - Alisheikh Atta
In California, avocado is primarily grown in Southern and Central parts of the state, typically in regions tempered by coastal climates and fine or course sandy loam soils. These regions face uncertain water supplies, mandatory reductions of water use, and the rising cost of water, while efficient use of irrigation water is one of the highest conservation priorities. Moreover, due to increasing salinity in water sources, effective irrigation is more critical to ensure optimal yield and high-quality avocado fruits. A two-year study was conducted in 12 mature avocado sites in California. Extensive field measurements and surveys were conducted to better understand the current water management practices, to acquire and develop relevant information on crop water use (ET) and crop coefficients, and to assess the performance of satellite-based OpenET tool for irrigation management in avocados. Surface renewal and eddy covariance equipment was used to measure actual evapotranspiration (ETa) in each site. The results illustrated considerable variability in avocado crop water consumption both spatially and temporally. The crop coefficients curves were developed for each site. Across the avocado research sites, the average seasonal crop coefficient values varied from 0.6 to 0.76. The findings demonstrated that canopy features, soil types and conditions, pruning practices, soil surface cover, and row orientations need to be considered to perform effective water management in avocado orchards. Ground shading percentage and row orientations provide a good estimation of canopy size/volume and the amount of light that it can intercept are likely the most important drivers influence crop water needs. The RMSE of the measured ETa from eddy covariance equipment and estimated ETa from Ensemble OpenET varied from 0.53 to 1.37 mm d-1. The preliminarily findings indicated that the Ensemble OpenET estimates ETa relatively well in some sites and could be an effective irrigation management tool in the future for avocado orchards, however more evaluations are required.
Almond and Walnut are the major irrigated crops in the Northern San Joaquin Valley (NSJV) of California. The recurring droughts and climate change in California will likely increase the uncertainty in water supply to almond, walnut, and other specialty crops. Site-specific irrigation is critical to cope with these challenges. Knowing the water consumption of these water use intensive crops is imperative for optimizing irrigation management since it affects nut quality, productivity, and composition. This requires accurate estimates of crop water use (Evapotranspiration, ET). Traditional methods for estimating crop water use are spatially limited, whereas satellite remote sensing of ET offers the advantage of large-scale coverage and is increasingly adopted in irrigated agriculture. This study compares OpenET models, an open-source database providing ET estimates, against calculated ET from weather stations that are commonly used by growers in their irrigation management. Evaluation of OpenET against estimated ET might provide a good opportunity for growers to improve water use efficiency. Such improvements could lead to the adoption of publicly available irrigation management tools and ensure healthier tree development, better resource utilization, and more resilient orchards in the face of climate change. This presentation delves into the preliminary findings of the OpenET evaluation against calculated ET from weather stations in estimating water use for almonds and walnuts, while also examining the potential and challenges associated with each approach for implementation in growers' fields.
The rapidly changing climate is creating challenges for the selection and management of woody perennial crops. For North American (NA) cultivars of hazelnut (Corylus avellana), there is insufficient information on water stress management to maintain physiological performance and optimize productivity under limited soil water availability. Current plantings of NA hazelnuts are predominantly comprised of cultivars resistant to biotic stress (e.g., Eastern Filbert Blight) such as ‘Jefferson’ and ‘Yamhill’ cultivars, but their responses to abiotic stressors exacerbated by climate change is unknown. Our research objectives were to: 1. identify cultivar-specific physiological thresholds in response to water stress such as negligible leaf gas exchange (i.e., stomatal closure) and onset of leaf wilting (i.e., cell turgor loss) for phenotyping in greenhouse conditions; and 2. relate vapor pressure deficit to plant water status in order to generate a water-potential baseline capable of differentiating between atmospheric and soil moisture impacts on water stress in field conditions. Using the water potential (Ψ) curve (WPC) method, stomatal closure was initiated at less negative Ψ in ‘Jefferson’ (-0.85 MPa) compared to ‘Yamhill’ (-1.1 MPa). Similarly, turgor loss was found to occur at less negative Ψ in ‘Jefferson’ (-1.26 MPa) compared to ‘Yamhill’ (-1.48 MPa). These cultivar-specific differences were confirmed with direct measurements of stomatal conductance using a porometer and an evaluation of turgor loss point using the pressure-volume curve method. In the field, we established a water potential baseline to distinguish between the effects of soil moisture and vapor pressure deficit on Ψ. Our field results found a deviation from baseline of -1.0 MPa resulted in stomatal closure in Yamhill, which was consistent with our prediction from the WPC. ‘Yamhill’ trees that had Ψ on average -0.68 MPa below baseline over the growing season were also observed to have 34% smaller nuts, 46% higher shell-to-kernel ratio, and an estimated 50% of total in-shell yield. Upcoming research will seek to replicate results experimentally with both cultivars. In summary, our results indicate that the WPC is a valid tool for physiological phenotyping and preliminary results suggest that thresholds from the WPC provide viable cultivar-specific targets for improving irrigation management in hazelnuts. These results highlight methods to help determine sustainable irrigation management targets that can help conserve water resources strained by climate change while also maintaining plant productivity.
Pecans have high economic importance in the US. Nonetheless, as one of the top pecan producers, there is little research on water use of pecan trees in the Southeast of the US. The water status of the tree impacts the yield, mostly during the kernel filling period (August and September). The knowledge gap of pecan water requirements stems largely from the Southwest. There, pecan tree needs in the hot and arid climate of the Southwest contrast sharply with those of the long, hot and humid Southeastern climate. Furthermore, the Southwest management practices use flood irrigation in contrast with most Georgia orchards which use micro-irrigation. This paper reports on the development of a crop coefficient specifically addressing the pecan tree needs in the Southeastern US. This study uses an eddy-covariance system and micro-lysimeter to determine the actual evapotranspiration of pecans. The potential evapotranspiration is determined using nearest local weather station data. This paper discusses the behavior of the crop coefficient throughout the different physiological stages of the tree from budbreak to harvest. Results of the crop coefficient obtained throughout the season differs from the Southwest, where the actual evapotranspiration during the growing season is significantly higher than the one observed in the Southeast. The daily and monthly crop coefficient throughout the growing period from 2019 through 2023 respectively are discussed. The year-to-year variability is also discussed. These results should support pecan growers and researchers alike to more tailored irrigation schedule in Southeast pecan orchards.
Thermal cameras can easily determine plant canopy temperature, and the resulting data can be used for irrigation scheduling in addition to other water management tools. This study aimed to develop a method to use thermal imaging for canopy temperature measurements in one-year-old citrus plants to assess citrus water status. We evaluated the influence of five water levels (25%, 50%, 75%, 100%, and 125%) based on the crop evapotranspiration replacement of two citrus species [‘Red Ruby’ grapefruit (Citrus paradisi) and ‘Valencia’ sweet orange (Citrus sinensis)] for 48 days in a greenhouse. To determine the irrigation requirements for the treatment 100%, we estimated the water loss from pots by calculating the difference in soil moisture between the day before and the day of the measurement. We irrigated the pots when the soil moisture was close to the maximum allowable water depletion, keeping the soil moisture between the field capacity and the maximum allowable depletion. A portable thermal camera was used to take images that were later analyzed using open-source software. We determined the canopy temperature, leaf photosynthesis and transpiration, and plant biomass. A positive relationship between the amount of water applied and the temperature response of plants exposed to different water levels was observed. Grapefruit and sweet orange plants that received less water presented water restrictions and reached 6 °C higher canopy temperatures than the air. The thermal images easily identified water-stressed plants. This study allowed quick measuring of the canopy temperature using readily available equipment and can be used as a tool to assess water status in citrus plants in greenhouses. An automated routine to process the thermal images in real-time and remove the background weeds to determine the canopy temperature can potentially allow using it for irrigation management.
The growing demand for affordable and healthy food to feed the growing population necessitates multilayered strategies to meet food demand and supply features: excessive irrigation application to overcome the impact of erratic rainfall, which imposes pressure on groundwater withdrawals, adversely affecting crop failure and sustainability. The objective of the study was to determine the impact of varying irrigation levels on tree growth, leaf nutrient concentrations, and water relations at selected citrus tree densities. The experiment was carried out on Malabar fine sand (sandy, siliceous, hyperthermic Arenic Alaquods) in a commercial citrus grove near Immokalee, FL, USA from 2019 to 2022. Mature thirteen-year-old ‘Valencia’ (Citrus sinensis) citrus trees grafted on Carrizo (a hybrid of Washington Navel orange and Poncirus trifoliata) planted in tree densities of 360, 485, and US-897 (Citrus reticulata Blanco x Poncirus trifoliata (L.) Raf.) citrus rootstock with 920 trees ha-1. Significant water distribution and movement were detected along the soil profile in response to the irrigation rates with higher volumetric water content on the grower standard highest irrigation. As a result, significant fibrous root length densities (FRLD) and median lifespan were observed in the three-row and two-row experiments with the deficit (50%-crop evapotranspiration, ETc) and moderate (78%-ETc) as compared with the grower standard highest (100%-ETc) irrigation regimes, respectively. Stomata conductance and stem water potential ( manifested less tree water stress when trees received moderate irrigation in the low and moderate tree densities than the highest tree density. This significantly impacted the FRLD in the soil and leaf area index (LAI) above the ground tree growth. Moderate irrigation triggered FRLD and improved root survival probability and lifespan. Meanwhile, nutrient uptake from the soil significantly affected leaf nutrient concentration when trees received moderate irrigation than deficit or highest irrigation rates. As a result, irrigation management improved water relations, leaf nutrient concentration, and tree growth across the varying irrigation regimes.
Alisheikh Atta currently works at the Department of Soil, Water, and Ecosystem Science, University of Florida. Alisheikh does research on HLB-affected citrus nutrient and water management. He studies the impact of plant nutrients on the performance of citrus trees, irrigation water... Read More →
New insights into the Yellow2 locus and its role in beta-carotene accumulation in carrots (Daucus carota) - Michael Paulsmeyer Overexpression of the Coding Sequence of Ma1 Leads to Enhanced Anthocyanin Biosynthesis in Apple via MYB73. - Mengxia Zhang Rapid Detection and Coinfection Analysis of Aspergillus flavus in Peanut SeedsRapid Detection and Coinfection Analysis of Aspergillus flavus in Peanut Seeds - Emran Ali RNA-seq Analysis Reveals Differentially Expressed Genes in Sweetpotato cv. Beauregard under Lead Stress - Mary Ann Munda RNASeq Analysis Reveals Key Pathways Involved in Low Nitrogen Tolerance at the Onset of Storage Root Formation in Sweetpotato cv Bayou Belle - Lisa Arce Introducing CHiDO – a No Code Genomic Prediction Software implementation for the Characterization & Integration of Driven Omics - Diego Jarquin
Carrots (Daucus carota) are a unique model for the accumulation of carotenoids. Beta-carotene accumulates in large amounts in the taproot if the proper alleles of the following three loci are present: OR, Y, and Y2. These three loci are not carotenoid biosynthetic genes but rather post-transcriptional regulation of carotenoid accumulation. The genes underlying the OR and Y loci have been characterized, but the gene underlying the Y2 locus is unknown. Through genomic and transcriptomic analyses, a single candidate that may interact with light signaling was found. To determine the function of this gene, the functional transcript from wild carrot was overexpressed in orange carrots and used in a transient infiltration assay with a GFP fusion tag in tobacco. The orange allele of this gene has a large transposon insertion that theoretically inactivates the gene. However, full length transcript can still be detected in orange carrots. This begs the question of whether the transposon is still active in certain accessions. In this study, the proportion properly assembled Y2 transcript was analyzed via qRT-PCR. A KASP marker was also developed to assist plant breeders in selection for the Y2 locus.
Anthocyanins, a group of secondary metabolites synthesized in the phenylpropanoid pathway, largely determine fruit peel color of fleshy fruits, but it is not known if its synthesis is linked to vacuolar malate accumulation that determines fruit acidity. Here, we show that when the coding sequence of Ma1, the major gene controlling apple fruit acidity, is overexpressed in ‘Royal Gala’ (RG), anthocyanin biosynthesis in the fruit peel is enhanced, corresponding to the downregulation of the expression of MYB73, an R2R3-MYB transcription factor. RNAi suppression of MYB73 expression via virus-induced gene silencing increases anthocyanin biosynthesis whereas its transient overexpression decreases anthocyanin biosynthesis in apple fruit peel. MYB73 binds to the promoter of the gene encoding UDP-glycose: flavonoid-3-O-glycosyltransferase (UFGT), the enzyme that catalyzes the last step in anthocyanin synthesis, to repress its expression. When MYB73 expression is suppressed by RNAi, UFGT expression is enhanced, leading to more anthocyanin synthesis, but this effect is blocked by RNAi suppression of UFGT expression. RNAi suppression of MYB73 enhances anthocyanin synthesis in wild-type RG apples whereas its overexpression decreases anthocyanin synthesis in Ma1-OE fruit. In the meantime, MYB73 competes with MYB1, one of the key activators of anthocyanin biosynthesis, binding to the promoter of UFGT and regulating its expression. These results indicate that MYB73 negatively regulates anthocyanin biosynthesis via repressing UFGT expression in apple peel. In Ma1-OE fruit, down-regulation of MYB73 releases UFGT from MYB73 repression and allows more MYB1 binding to UFGT promoter, leading to enhanced anthocyanin biosynthesis.
Aspergillus flavus is a widespread pathogen affecting crops like peanuts, contributing significantly to mycotoxin contamination and subsequent crop losses. Discriminating between toxigenic and non-toxigenic strains is crucial, yet conventional methods are often cumbersome and time-consuming. In this study, we developed rapid molecular tools to differentiate between these strains. Using morphological characteristics and species-specific PCR-sequencing, we identified isolates collected from peanut seeds in southern Georgia. Through primer optimization and qPCR targeting aflatoxin regulatory genes, we successfully distinguished aflatoxin-producing and non-producing isolates. Additional genes involved in aflatoxin biosynthesis were also analyzed, showing clear expression distinctions. Our findings demonstrate the specificity and efficiency of these primer sets, providing a valuable tool for managing A. flavus contamination in peanut seed lots. Additionally, research on the seed microbiome's impact on mycotoxin production remains limited. In this study, we assessed microbial communities in peanut seeds collected over various years using ITS gene sequencing. Our results revealed a diverse microbial population, including A. flavus and other fungal pathogens, highlighting the complexity of seed microbiota. This approach offers novel insights into peanut seed-associated microbiomes and aflatoxin contamination, shedding light on the correlation between microbial communities and aflatoxin pollution.
Lead (Pb) is a widespread toxic element in agricultural soils and Pb accumulation in plant roots represents a potential health risk for human beings. The sweetpotato (Ipomoea batatas L.) is a globally important root crop and one of the leading raw products for baby food processing. Limited information is available about the mechanism by which sweetpotato responds to Pb stress at the molecular level. Understanding the genetic mechanism of Pb uptake is essential for developing management approaches to mitigate Pb uptake in this crop. To address this knowledge gap, RNA-seq was used to characterize the transcriptome and identify differentially expressed genes from Pb-treated and untreated sweetpotato cv. Beauregard. Samples were taken from adventitious root tips at 5, 10, and 15 days after planting (DAP). Transcriptomic analysis revealed 4,077, 5,159, and 3,206 differentially expressed genes at 5, 10, and 15 DAP respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis shows that ABC transporters and sulfur metabolism pathways are upregulated at 5 DAP but are downregulated at 15 DAP, indicating that there may be a threshold in sweetpotato Pb tolerance. The results provide a deeper insight into the species-specific response of sweetpotato to Pb stress which can lead to the development of screening methods and evaluation of management strategies that reduce Pb uptake in this crop.
Nitrogen (N) is a key limiting macronutrient for crop growth and development and affects sweetpotato storage root formation and yield potential. In high-input production areas, excessive N application can suppress storage root formation and results in environmental pollution. The crop is also grown in low-input production systems with little or no N applications. In this study, sweetpotato cv Bayou Belle response to N deprivation during the establishment and storage root formation stages was investigated through a transcriptomic approach. RNA-seq data revealed a number of differentially expressed genes (DEGs) between N sufficient ( N) and N deficient (–N) conditions at 5, 10, and 15 days after planting (DAP). The number of significantly upregulated genes varied between timepoints. DEGs were further classified into functional categories and pathways to reveal putative functions. Gene Ontology annotation together with KEGG analysis revealed that majority of the DEGs are involved in sulfur compound metabolic process at 5 DAP and in ammonium transport for both 10 DAP and 15 DAP. These results provide valuable insights about the molecular mechanism of N regulation in sweetpotato adventitious roots undergoing storage root formation. These findings can lead to the development of tools and processes for improving N use efficiency and consistent storage root yields while reducing environmental impact in this globally important crop.
Climate change represents a significant challenge to global food security by altering environmental conditions critical to crop growth. Plant breeders can play a key role in mitigating these challenges by developing more resilient crop varieties; however, these efforts require significant investments in resources and time. In response, it is imperative to use current technologies that assimilate large biological and environmental datasets into predictive models to accelerate the research, development, and release of new improved varieties. Leveraging large and diverse data sets can improve the characterization of phenotypic responses due to environmental stimuli and genomic pulses. A better characterization of these signals holds the potential to enhance our ability to predict trait performance under changes in weather and/or soil conditions with high precision. This presentation introduces CHiDO, an easy-to-use, no-code platform designed to integrate diverse omics datasets and effectively model their interactions. With its flexibility to integrate and process data sets, CHiDO's intuitive interface allows users to explore historical data, formulate hypotheses, and optimize data collection strategies for future scenarios. The platform's mission emphasizes global accessibility, democratizing statistical solutions for situations where professional ability in data processing and data analysis is not available.
Phenotypic landscape of the photosynthetic performance and seed productivity of spinach germplasm under organic conditions - Vijay Joshi The Southern Cover Crop Variety Trial Program - Assessing Regional Adaptation of Cover Crop Varieties Across the Southern US (Year 2) - Virginia Sykes Production of short, medium and long season specialty crops in high-residue, no-till farming systems - Arianna Bozzolo Comparison of Plastic Mulch and Cover Crops - Roller Crimper Systems on Weed Pressure Soil Moisture and Yield in Organic Strawberry Production - Arianna Bozzolo Impacts of Organic Soil Amendments on Hemp Production - Arnab Bhowmik Biomass Source of Biochar and Genetic Background of Tomato Influence Plant Growth and Development and Fruit Quality - Rishikesh Ghogare Nitrogen Utilization from Compost in Organic Strawberries - Mark Kindred Interactions between photoselective plastics and insect pest dynamics in an organic brassica vegetable system -Dilip Nandwani Anaerobic Soil Disinfestation: A Non-chemical Approach to Managing Weeds and Nematodes in Sweetpotato - Simardeep Singh Potential Establishment of Entomopathogenic Fungi as an Endophyte in Citrus Trees Over Time - Joseph Paoli Impact of Biosolid Compost - Madeleine Tenny
Identifying suitable genetics for low-input organic spinach production and ensuring an adequate supply of organic seeds are critical challenges for organic spinach breeders. This study comprehensively assessed 300 spinach accessions sourced from the USDA National Germplasm Repository and commercial checks. The field trials were conducted at Uvalde, TX, during the 2022-23 and 2023-24 growing seasons, focusing on biomass and nitrogen use efficiency. During the 2023-24 field trial, natural variations in leaf photosynthetic performance, including carbon assimilation, stomatal conductance, photosynthetic electron transport rate (ETR), and PSII actual photochemical quantum yield (PhiPS2), were analyzed utilizing an LI-6800 gas analyzer. The seed productivity traits, such as yield per plant and 100-seed weight, were evaluated at the Organic Seed Alliance Washington field site. The processed data were employed for Genome-Wide Association Analysis (GWAS) to identify underlying genetics associated with organic productivity and photosynthetic traits. Over 88k Single Nucleotide Polymorphisms (SNPs) dispersed across six chromosomes were utilized in the GWAS after stringent filtering criteria. Significantly associated SNPs and candidate genes were delineated for the targeted photosynthetic traits and seed productivity, shedding light on potential genetic factors influencing these crucial traits in organic spinach breeding programs.
Dr. Ainong Shi is a faculty member in the Department of Horticulture at the University of Arkansas. His research laboratory specializes in plant breeding and genetics, particularly focusing on vegetable crops such as arugula, cowpea, and spinach for cultivar and germplasm development... Read More →
Cover crops provide numerous ecological benefits to production systems. Maximizing these benefits requires identifying species and varieties that are the best fit both geographically and for the planting/termination time frame dictated by the accompanying cash crop system. In 2019, the University of Tennessee began a cover crop variety trial to help growers make better informed decisions on which of a broad range of cover crop species and varieties worked best in their specific region and production system. In fall 2022, in collaboration with the Southern Cover Crops Council, this trial was expanded to cover a 10-state region of the Southern US (TN, FL, NC, KY, VA, SC, TX, GA, AR, and AL) and became known as the Southern Cover Crop Variety Trial. This trial program is currently in its second year, with each trial year running from fall through the following spring. Trial sites were planted in mid-October each year. Cover crop cover, weed suppression, height, biomass, and estimated nitrogen release were measured in early and late spring. Twenty entries each were evaluated in the 22-23 and 23-24 trial years. However, as a fee-based program, entries were submitted by public and private institutions and varied from year to year. Eleven of the twenty entries were evaluated in both trial years. In year one, top-performers by rank were largely uniform across sites, consisting primarily of cereal rye and hairy vetch varieties. Many clover species, particularly crimson clover, exhibited greater variation in performance ranking among locations. Performance values varied significantly among and within locations, species, and evaluation period. Data collection for year two will be completed in Spring 2023 and will be presented.
Dr. Lakesh Sharma is an assistant professor of soil fertility and sustainable agriculture at the University of Florida in Gainesville, FL. Lakesh has been farming since he was a child on his own farm. His academic school journey started in 2000. He is currently working on nutrient... Read More →
When speaking to diversified vegetable crop growers, one of the most often cited challenges is the management of weeds. This issue is even more prevalent for organic growers who lack any effective chemical weed control method and rely on crews to mechanically remove weeds from the fields. One possible alternative is the use of terminated cover crops as mulch on the soil surface to act as a physical barrier to prevent weed emergence. This cover crop mulch can be advantageous for a grower in addition to cover crops improving soil health and providing a habitat for beneficial insects. This experiment compared vegetable beds with cover crops terminated with a roller crimper to bare soil beds on short (squash), intermediate (pepper), and long (eggplant) growing vegetable crops and assessed crop performance. In both 2023 and 2024 a cover crop mix of rye and field peas was successfully terminated and provided ample biomass on the soil surface at the time of vegetable transplanting and throughout their grower and harvest. We found that cover cropped treatments led to improvements in soil fertility, higher numbers of soil-dwelling beneficial insects, and lower weed pressure that led to significantly higher yields. These results demonstrate a potential system for organic growers to integrate into their operation as a practice that can reduce time and labor costs for weed management along with improving the soil fertility and creating a system requiring fewer inputs.
While organic production of specialty crops has been highly successful in southern California, it relies heavily on the use of plastic mulch and intensive tillage for weed management. A two-year study conducted from 2022 to 2023 aimed to evaluate the impact of plastic mulch and a cover crop based reduced tillage system using a -roller crimper to terminate cover crops on weed pressure and yield in organic strawberry production. Bare root strawberry crowns of the Albion variety were transplanted into four treatments: 1) Sorghum-sudangrass (S. bicolor x S. sudanense) seeded at 100 kg/ha (Sorghum 1), 2) Sorghum-sudangrass seeded at 200 kg/ha (Sorghum 2), 3) buckwheat seeded at 67 kg/ha, or 4) plastic mulch as standard practice. Cover crops were broadcasted on 1.5 m wide raised beds in May and terminated with a roller crimper in August. Both seeding rates of Sorghum-sudangrass effectively suppressed weed growth before and after termination compared to buckwheat. The significantly lower biomass of buckwheat after termination, relative to the Sorghum-sudangrass treatments, indicates variations in weed suppression efficacy among cover crops. Total differences in soil moisture, calculated based on data collected weekly from after cover crop termination to end of harvest, indicate that all treatments resulted in lower soil moisture levels compared to the plastic control, with the buckwheat treatment showing the most significant decrease. At harvest there were no significant differences between plastic mulch and Sorghum-sudangrass 1 and 2 treatments, indicating comparable yields. Buckwheat resulted in the lowest yield, experiencing a 50% reduction compared to plastic mulch. Based on the findings, plastic mulch and Sorghum-sudangrass planted at different seeding rates can be considered effective alternatives for weed suppression and maintaining yields comparable to conventional plastic mulching. The choice between Sorghum-sudangrass seeding rates may depend on factors such as cost, availability, and specific field conditions. The reduced biomass production of buckwheat compared to Sorghum-sudangrass, coupled with its rapid decomposition rate, resulted in diminished efficacy of buckwheat in weed suppression. Consequently, reduced weed control was observed, leading to significantly lower yields in buckwheat-treated plots compared to Sorghum-sudangrass and control treatments. These findings suggest that buckwheat may not be a viable option for organic strawberry production under comparable conditions, emphasizing the importance of selecting cover crops with longer-lasting weed-suppressive qualities.
Hemp (Cannabis sativa L.) is a highly versatile crop that has attracted considerable attention among farmers due to its diverse applications. Recent studies have sought to establish a fundamental understanding and baseline of the nutritional requirements of hemp, opening up possibilities for organic hemp production. Our research focuses specifically on evaluating the productivity of a floral hemp variety using different regenerative practices, with a particular emphasis on organic soil amendments that promote soil health in Piedmont area of North Carolina. The field experiment was conducted at North Carolina A
The evolving effects of climate change and intensive agricultural practices have adversely affected soil health and crop yields. This necessitates the need to maintain and improve soil health for sustainable food production. Biochar, a carbon-rich material produced from pyrolysis of biomass is being considered as a novel soil amendment that can potentially restore soil health and improve crop yields. Several studies have reported both positive and negative effects of biochar on crop yields while focusing mainly on one type of biochar and a single plant cultivar. However, the effects of different types of biochar and its interaction with plants with different genetic backgrounds has remained unexplored. In this study, we evaluated the impact of six different biochars on the growth performance and fruit quality of three tomato (Solanum lycopersicum) cultivars. The hypotheses that (1) biochars derived from different feedstock sources would produce unique phenotypes in a single cultivar of tomato, and (2) single feedstock-derived biochar would produce different phenotypes in each of the three tomato cultivars were supported by obtained results. This study demonstrated that plant genetic background and biomass source are important variables to consider for using biochar as a soil amendment.
Strawberries are typically grown in high tunnels in the Intermountain West region to protect the flowers and buds from early and late-season frosts and extend the growing season. Organic farmers rely on N mineralization from organic sources to supply plant-available N which can be inadequate for plant needs, especially when temperatures are low. To support cultivar selection for organic strawberry production in high tunnels, greenhouse cultivar trials were conducted to determine if some strawberries grow better on compost than others. Plants were grown for six weeks in a mixture of turface and peat moss with and without compost. A complete liquid fertilizer with and without added N was supplied daily. Leaf, crown, and root dry weights, tissue, and compost N at the beginning and end of each trial were measured and leachate was collected daily and analyzed for nitrate and ammonium. Plant chlorophyll was determined at the end of the experiment. Plants that received liquid N fertilizer grew more, absorbed more N, and had a higher chlorophyll reading compared to plants that received the compost and N-free fertilizer treatment. Ammonium was leached out of the compost-treated pots in the first two weeks while little nitrate was lost. Some cultivars performed better than others on the compost treatment. This suggests that some strawberry cultivars are better able to grow on organic nitrogen sources than others but, additional N fertilization may be needed.
I am a graduate student at Utah State University working on my master's degree in Dr Jennifer Reeve's lab. I got my bachelor's in plant science and Asian studies from Utah State University. While I was an undergrad, I worked in Jennifer Reeve's lab. When I graduated, I was offered... Read More →
Brassica crops are susceptible to a variety of insect pests of particular significance in organic production systems, including flea beetles, aphids, and lepidopteran caterpillar pests. These pests are abundant on brassicaceous vegetable crops throughout the U.S. and populations frequently are high enough to significantly reduce crop quality. There is an increased interest among small and mid-size vegetable growers to adopt poly-covered tunnels to protect high value horticultural crops. Tunnel production allows for season extension, can protect crops from adverse weather conditions, improve the quality of horticultural crops, and may also influence plant-insect dynamics. Photoselective poly coverings influence light wavelength and transmission in tunnel environments and may affect plant physiological responses as well as incidence of disease and herbivory by insect pests. Here, we explored the impact of UV light blocking and UV light transmitting poly coverings on Lacinato kale (Brassica oleracea var. acephala) production and the effects on pest and beneficial insect populations in a tunnel environment compared to an open field system on certified organic land in Morris, MN. Our results showed that total kale harvestable yield was similar between the poly covered tunnels and open field plot treatments. No differences in yield or insect pest pressure were observed between UV light blocking or transmitting poly covered tunnels but were observed between tunnels and the open field environment. Imported cabbageworm populations were 75% higher in tunnels versus open field plots (P=.0023), however the inverse was observed for cabbage loopers, which were 60% higher in open field plots (P=.0072). No flea beetles were found in tunnels, and an average of 1 beetle/plant was observed in open field plots. Diamond back moth and aphid populations were not different between the tunnel and the open field plots. Overall, insect pest populations did not reach economically damaging thresholds during the study period, likely due to the field plot location which did not have a history of brassica production. Our results showed that light transmission and ambient air temperatures were similar under the photoselective poly coverings. We observed that pest pressure increases rapidly in tunnel environments as the season progressed regardless of poly covering. Although our study did not observe differences in the yield or quality of kale across production systems, there were differences in insect pest populations across systems, indicating a different management approach may be needed to prevent crop damage in tunnel environments.
Anaerobic soil disinfestation (ASD) is a promising organic pest management strategy and is an alternative to chemical-led approaches that has shown potential to manage weeds and soil-borne pathogens in organic vegetable production systems. ASD is facilitated by incorporating carbon sources into the soil, tarping the soil with plastic mulch, and irrigating to the soil saturation point. To evaluate the impact of ASD on weed and nematode management in organic-grown sweetpotato, greenhouse studies were conducted at Clemson University, Clemson, South Carolina. Experiments were laid out in a randomized complete block design in 2-gallon microcosms with two carbon sources [ASD (soil amended with chicken manure molasses as carbon source) and non-ASD (non-amended control)] in the main plot and twenty sweetpotato genotypes in subplots. Three-week-old seedlings of tomato (cv. Rutgers) were planted in each microcosm followed by inoculation with 10,000 eggs of the southern root-knot nematode (Meloidogyne incognita). ASD was initiated one month post inoculation to allow nematodes to complete one life cycle. At the time of the ASD initiation, each microcosm was also inoculated with weed seeds [yellow nutsedge (10 tubers) and carpet weed (100 seeds)]. ASD was conducted for three weeks, followed by the transplantation of sweetpotato slips after one week of ASD termination. Weed counts, abundance of nematode second stage juveniles (J2) in soil, and sweetpotato above ground biomass data were collected. Our results suggested that the microcosms receiving the carbon amendment spent the most time under anaerobic conditions (
Entomopathogenic fungi offer an alternative strategy for citrus growers seeking environmentally friendly pest management solutions. This study aimed to assess the ability of a commercial strain of the fungus Beauveria bassiana to become endophytic in citrus plants after a single foliar application. A completely randomized block design, consisting of ‘Valencia’ sweet orange trees (Citrus × sinensis) grafted on ‘US-942’ (Citrus reticulata × Poncirus trifoliata) rootstock, was established under greenhouse conditions. Treatments comprised 6 replications of treated plants in two separate greenhouses (n = 16 per greenhouse), along with one control (water only). Treated plants were foliar sprayed asynchronously with the fungus at the beginning of each experimental trial per treatment. To assess endophytism over time, a series of cohorts were destructively sampled every two months. Spore deposition was assessed using cover slips post-spray application of all treatments. Additionally, detached leaves collected post-spray were imprinted on potato dextrose agar (PDA), amended with dodine and bactericides, to determine spore coverage of the leaf surface by counting colony forming units. To assess endophytism, sterile samples of plant organs (i.e., leaves, stems, and roots) were placed onto PDA-dodine plates to allow detection of phenotypic mycelia. Results from the first cohorts indicated successful application of the fungi on the citrus leaves, and endophytism was assessed after two months. Additionally, no statistically significant changes were recorded in terms of plant height, root, stem, and leaf biomass, as well as stem girth. This project contributed to a clearer understanding of the long-term endophytic persistence of commercially available entomopathogenic fungi and their effect on plant growth in citrus trees. The trial will continue in the field for additional screening.
I am a Master's student at the University of Florida based at the Indian River Research and Education Center (IRREC). I am a long-time Florida resident, having gone to Middle and High School in Central Florida before enrolling at the University of Florida. During my four years of... Read More →
Biosolids, derived from treated sewage sludge, represent a significant resource in sustainable agricultural production, with approximately 70 percent being utilized for land application in the United States. Recognized for their potential as organic fertilizers, biosolids undergo meticulous processing to meet grade AA standards before being blended with locally sourced organic materials, such as woody yard debris, in preparation for municipal distribution. This study delves into the effects of biosolids on soil and seed germination rates using various concentrations ranging from 1% to 7%. Findings reveal that higher concentrations of biosolids in soil significantly delay the germination of lettuce seeds. Through replicated mesocosm experiments at the Southwest Florida Research and Extension Center (SWFREC), UF/IFAS, Immokalee, we evaluate the effects of biosolids on lettuce (Lactuca sativa) growth and physiology. Lettuce was cultivated in 17cm tall pots filled with the soil amendments of biosolids compost in concentrations of 1%, 3%, 5%, and 7% (v/v) over a 60-day period. Comprehensive data collection includes measurements of plant height, leaf chlorophyll content, photosynthetic gas exchange, leaf area index (LAI), fresh and dry plant biomass, visual ratings, and spectral reflectance data at 340-2500 (nm) with a portable spectroradiometer. Data analysis of weekly and post-harvest collected data analyzed the implications of biosolid usage in agriculture, shedding light on significant effects on crop productivity, soil health, and agricultural sustainability. Keywords: Biosolids, Organic Fertilizer, Soil Contaminants, Lettuce (Lactuca sativa), Plant Physiology, Agricultural Systems
This competition is open to graduate students that have a poster presentation scheduled during the ASHS conference AND have also signed up to participate in this competition (Note: This is separate of the assigned time to present your abstract during the conference program).
Please note that if you do not also present your poster during the regularly scheduled Poster session, you will be disqualified from the Poster Competition.
Competition participants will be assigned to a room to present for the competition (this information will be emailed to you the week prior to the conference). You will be responsible for bringing your poster on a thumb drive to your assigned room in order to participate.
Wednesday September 25, 2024 6:00pm - 7:00pm HST
South Pacific 4
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 Investigating Microclimate Conditions and Vegetable Yield under Agrivoltaics Systems in Grafton, MA”. - Mamata Bashyal 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 Effect of Mineral Nitrogen and Foliar Spraying of Humic Acid on Fresh and Dry Leaves and Roots Weights, and Root Length - Ali Omar 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.
Agrivoltaics is the simultaneous production of both solar energy and crops on the same land. The success of crops grown underneath the panels depends on the crop type, soil composition, regional climate conditions, and panel configuration (height, row spacing, tilt angle, and tracking system). There is a need for more research-based guidance on the trade-offs between energy and crop production in agrivoltaics systems. The objective of this study was to compare the microclimate conditions and crop performance within a solar array to the control (without a solar array). The on-farm agrivoltaics study was conducted from July to September 2023 in Grafton, MA, using two contrasting crops: butternut squash (sun-loving) and Boston lettuce (shade tolerant). Microclimate variables such as photosynthetically active radiation (PAR), air temperatures, soil temperatures, soil moisture, and relative humidity were monitored at different transect positions within the solar array [BP 1 (under leading panels), BP 2 and BP 3 (between two panels), and BP 4 (under the back panel)] and control. Data were analyzed in R statistical software using an independent sample t-test to compare control to array and test and one-way ANOVA to compare each bed position within the array only. Preliminary findings showed higher mean and maximum PAR in control than in BP 1, BP 2, and BP 4 within the array. Air temperature (mean and maximum) was found to be higher in control than in the array. Mean and maximum soil temperature was highest in control when compared to BP 1 and BP 2 under the array. Similarly, mean relative humidity was found to be significantly higher in the control than in the array. The chlorophyll index of butternut squash showed a positive correlation with decreasing PAR, suggesting potential adaptive responses to varying light conditions. Butternut squash fruit yield was similar across the four different bed positions under the array, and lettuce yield under the array was similar to that of the control area. Further continuation of this study in 2024 provides insights for growers about the successful production of butternut squash and lettuce production under the agrivoltaics system.
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.
Lactuca sativa L., commonly known as lettuce, represents a vital winter leafy vegetable crop cultivated globally, including Libya, owing to its rich nutritional content and rapid growth characteristics. Enhancing the vegetative growth of lettuce and similar leafy crops often involves employing various horticultural practices, with fertilization being a key component utilizing diverse nutrient sources. Two field experiments conducted at the Department of Horticulture Farm, Omar Al-Mukhtar University, situated in Al-Jabal Al-Akhdar region of Libya in 2021 and 2022 aimed to evaluate the effects of ground-applied urea fertilizer (46% nitrogen) at rates of 0, 60, 120, and 180 kg.ha⁻¹, combined with foliar applications of different concentrations of humic acid (0, 1, 1.5, and 3 ml.L⁻¹), on the fresh and dry weights of leaves and roots, as well as root length of lettuce cv. Nickerson-Zwaan plants under local environmental conditions. Each experiment comprised 16 treatments representing all possible combinations of the two factors and followed a randomized complete block split-plot design with four replications per treatment. Results revealed that increasing levels of mineral nitrogen and humic acid resulted in a significant increase of fresh and dry weights of lettuce leaves and roots across both growing seasons as compared to the control treatment, with consistent effects observed for the interaction between nitrogen fertilization sources and their respective rates. While no significant impact was observed on root length due to urea fertilizer or humic acid spray in either growing season, application of 180 kg.ha⁻¹ urea fertilizer in the second season showed a tendency towards greater root length compared to other treatments. Thus, the findings suggest that the application of mineral nitrogen fertilizer and humic acid spray holds promise for enhancing the vegetative growth of lettuce plants in Al-Jabal Al-Akhdar region of Libya.
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
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.
Vegetable soybean, also known as edamame, is a specialty crop harvested at an immature stage and consumed as pods. It has become increasingly popular in the United States due to its high nutritional value and good taste. Currently, most edamame consumed in the U.S. is imported as a frozen product. States such as Arkansas and Kentucky have started to grow this crop locally on a small scale to meet the high demand. South Florida, known for producing fresh vegetables sold nationwide, especially in the winter and spring markets, also has a highly diverse and growing ethnic population with significant local market potential. These factors make growers in South Florida highly interested in cultivating edamame to meet the demand in both national and local markets. Sixteen commercial edamame varieties were selected and assessed for differences in phenotypic performance, including emergence, yield, plant height, plant width, 10-pod weight, and pod size, to evaluate their production potential in South Florida. Varieties showed significant effects on most traits studied. Emergence rates ranged from 0 to 85%, and fresh pod yield ranged from 4.41 to 14.34 t/ha among all 16 varieties. Varieties like Goo, Karikachi #3, and Midori Giant, despite having moderate emergence rates, produced higher fresh pod yields due to their larger plants, resulting in bigger pods. There were variations in average pod length (35.61 – 51.21 mm), width (9 - 14 mm), and thickness (5.46 - 8.74 mm) among the varieties, with Goo standing out significantly in size. Overall, Goo, Karikachi #3, and Midori Giant demonstrated particularly favorable yield and good pod quality, showing potential for commercial edamame production in South Florida. This research highlighted the potential to grow edamame in higher hardness zone, providing foundational knowledge on edamame production in the US.
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
Can Multi-species Cover Crops and Beneficial Microbes be Utilized for Soil Borne Pathogen Management in Watermelon? - Sukhman Kaur Evaluation of Celery Breeding Lines and Commercial Cultivars for Resistance to Fusarium oxysporum f.sp. apii Race 2 and Race 4 - Christopher Greer Directed Energy System: A Non-chemical Approach for the Management of Nematodes, Pathogens, and Weeds in Nurseries - Tatiana Benedetti Sweetpotato-associated Virome in Mississippi - Sead Sabanadzovic Evaluation of Insecticide Application Plan to Manage Thrips for Sweet Onions in Texas - Subas Malla Are selective insecticides compatible with Bemisia tabaci biocontrol efforts in controlled environments? - Arash Kheirodin Plants Under Regulation; A North Carolina Perspective - Jarred Driscoll
Watermelon is highly susceptible to soil borne pathogens, typically Fusarium oxysporum sp. Niveum (FON) that can lead to a yield loss of upto 60-80%. Out of the four pathogenic races of FON, race 2 is more prevalent in the Southeastern US on more than 60% of watermelon fields. Cover crops are known for improving soil health, diversity, and abundance of microorganisms, and reported to decrease Fusarium wilt (FW) disease severity by up to 20-60%. However, previous studies have only evaluated single species cover crops for its impact on FW in watermelon whereas for ecosystems services, multi-species cover crops are recommended. A greenhouse and field study were conducted with aims to determine the effects of multi-species cover crops and beneficial microbes in controlling FW in watermelon. The cover crop mixtures included in the studies were, mixture A: rye, oat, Austrian winter pea, crimson clover, hairy vetch; mixture B: oat, wheat, crimson clover, radish, turnip. The field study was conducted at two locations in upper coastal region of South Carolina. Periodic cover crop biomass was taken. At location one cover crop mixture A accumulated a fresh biomass of 1017.50 tons/ha as compared to mixture B (907.16 tons/ha), at 97 days after planting. On the other hand, at second field site, mixture A accumulated fresh biomass of (349.6.4 tons/ha) and fresh biomass weight of mixture B was (153.59 tons/ha) at 120 days after planting. This could be due to more sandy and poor soil conditions at second field site. Further we will evaluate the impact of different treatments on FW disease severity index, watermelon fruit yield and fruit quality parameters.
Fusarium wilt of celery, caused by the soil-borne pathogen Fusarium oxysporum f. sp. apii (Foa), has been a persistent challenge for celery growers in California. Two races of the pathogen are documented in California. Foa race 2 was described in the 1970s and is widespread throughout celery-growing regions of California, typically causing yellowing and stunting of established plants, resulting in failure to produce marketable heads. Foa race 4 was identified in Ventura County in 2013 and by 2022 had displaced race 2 as the predominant race causing celery losses in Ventura County. Foa race 4 is more aggressive than race 2, often causing plant stunting and death within weeks after planting, particularly if soil temperature is 22ºC or higher. In support of celery breeding programs, USDA and University of California developed a collaboration to conduct resistance evaluation field trials. Trials were conducted in two coastal California locations naturally infested with Foa in 2022 and 2023: Santa Maria (race 2) and Camarillo (race 4). Cultivars and breeding lines from private companies and public germplasm collections were evaluated in replicated field plots. Plant mortality was assessed, and soil temperature was recorded during the growing season. At harvest, disease severity of internal symptoms of Fusarium wilt were scored from 0 (no visible symptoms) to 5 (severe crown decay) for a subset of plants from each plot. Each celery entry was assessed for petiole length, weight, petiole greenness, cracking, bolting, ribbiness, pithiness, and suckering for a subset of plants from each plot. At Santa Maria in 2022, there was minimal plant mortality, but most entries appeared susceptible with disease severity scores ranging from 2.0-3.6, indicating vascular symptoms in roots and crowns. Many entries did not produce marketable celery due to stunting. Entries exhibiting the most tolerance to Foa race 2 had disease severity scores of 0.1-0.7 and produced the heaviest stalks with the longest petioles. At Camarillo in 2022, daily mean air temperatures during the two weeks after planting were 24 to 27ºC, likely promoting rapid disease development of Foa race 4 and severe early decline in susceptible entries. Six weeks after planting, 23 of 42 entrees exhibited 80-100% plant mortality. However, five entries had disease severity scores of 1.0-1.5 and less than 15% mortality. These more tolerant lines produced marketable celery. These results contribute to the development of Foa-resistant breeding lines and inform growers about the performance of cultivars in local conditions.
Oregon leads the United States in the production of several ornamental nursery products including shade trees, conifers, and flowering trees. Soilborne pathogens and weeds are major constraints to the production of tree seedlings for the ornamental industry. Failure to control pathogens can result in seedling death or unintentional distribution of infected nursery stock while failure to control weeds can lead to competition with seedlings for water and nutrients. One of the primary ways to control soilborne pathogens and weeds is through pre-plant fumigation with methyl bromide. The use of this chemical is detrimental to the environment and human health, making it urgent to develop safer alternatives. Our long-term goal is to discover new ways to manage nematodes, soilborne pathogens, and weeds that will reduce reliance on pesticides and soil fumigants and be safer for the environment. Directed Energy System (DES) has been developed as a novel application technique, which generates pulses of electricity capable of killing nematodes, pathogens, and weeds. Controlled experiments were conducted against Meloidogyne chitwoodi, Phytophthora cinnamomi, and Cyperus esculentus to determine the electrical parameters required to kill each organism. Preliminary data demonstrated that the energy required to kill 90% of M. chitwoodi eggs was 23.4 J/cm3 of soil and for C. esculentus nutlets the energy for reduce weed growth by 50% ranged from 55 to 116 J/cm3 of soil.
Sweetpotato (Ipomoea batatas; Convolvulaceae) is an economically important specialty crop with an overall U.S. production valued at more than $720 million (2020 data, USDA-NASS). Even though virus infections are a major constraint to the sweetpotato industry across the United States and around the globe, organized studies have not been conducted to understand virus diversity and incidence. Therefore, an objective of a transdisciplinary multistate, Specialty Crop Research Initiative (SCRI), CleanSEED Project is to characterize viruses associated with sweetpotato production in major producing states. To that aim, 25 different locations/production fields in Mississippi were surveyed during the 2023 production season to collect symptomatic foliar tissue for total RNA extraction. The detection and identification of viruses of sweetpotatoes was based on a high-throughput sequencing approach on an Illumina platform utilizing 2x150 nt pair-end methodology, followed by computational analyses of billions of raw sequence reads. The four potyviruses, considered of major economic importance for the crop, were prevalent in the state and frequently occurred in mix infections. Furthermore, a few other viruses with possible hosts different than plant, were associated with plants analyzed in this study. This research was supported by the intramural research program of the U.S. Department of Agriculture, National Institute of Food and Agriculture, Specialty Crop Research Initiative, accession no. 1029242.
Thrips is an important pest of onions that not only reduces yield and quality but also transmit Iris Yellow Spot Virus. The study’s objective was to evaluate different chemical application plans to manage the thrips population in onions. The study was conducted in a split plot design with variety as a main plot and chemical plan as a sub-plot with four replications at Texas A&M AgriLife Research and Extension Center, Uvalde, TX during the 2022-23 season. The variety factor had three levels – Hornet, Mata Hari, and Don Victor. The chemical plan factor also had three levels – weekly application, action threshold (1 thrips per leaf), and control. Although the insect population was low, in general, for the season, the weekly application and action threshold treatments had a lower number of thrips per leaf than the control treatment. The numbers of chemical applications for the weekly application and action threshold were six and three, respectively. The results indicate that growers would save input costs if followed by the action threshold chemical plan. The trial will be evaluated in the 2023-24 season to validate results from the first season.
Generalist predators are known for their significant contribution to suppression of major crop pests in controlled environments and beyond. Given that insecticides are one pillar of many Integrated Pest Management (IPM) programs, their compatibility with biocontrol efforts is essential for developing a successful IPM program. Knowledge gaps persist regarding selective insecticides' non-target impacts on whitefly natural enemies that can jeopardize its biocontrol efforts. In this study, we exposed adult predators to commercially available insecticides (Cyantraniliprole and Pyriproxyfen) using multiple laboratory approaches to assess their effects on survivorship, predation, and changes in prey selection in response to insecticides. Two major whitefly predators were evaluated including, Hippodamia convergens (Coleoptera: Coccinellidae) and Geocoris punctipes (Hemiptera: Geocoridae), to estimate survivorship and consumption of whitefly nymph, Bemisia tabaci (Hemiptera: Aleyrodidae). Our result indicates that while pyriproxyfen had a negligible effect on the predators, cyantraniliprole exposure directly affected H. convergence by reducing survivorship duration and indirectly influenced both predators by reducing prey consumption and altering prey preference. Overall, pyriproxyfen demonstrated minimal impact on predators, while cyantraniliprole adversely influenced mortality and indirect foraging effects under controlled laboratory conditions. Hence, our findings highlight that even highly selective insecticides could have a sub-lethal impact on natural enemies, jeopardizing their contribution to pest control, and warranting future efforts to better integrate them into IPM programs.
State and federally regulated weeds pose significant challenges to agricultural economies worldwide, impacting crop yields, production costs, and overall farm profitability. Some estimates have their economic impact upwards of $30 billion dollars annually. Regulated plants can encroach upon public and private property, and cultural and recreational areas, which not only diminishes their aesthetic appeal and usability, but also displaces other native plants and animals. State and federal regulatory agencies operate within a legal framework for setting rules that allow for the control of regulated plants. Regulatory rules apply measures that help preserve these public and private spaces by addressing infestations of noxious plants. Management strategies of active infestations can range from controlling future or current spread to full on eradication. While eradication of a noxious plant may be the gold standard to strive for, it is also the most time consuming and costliest strategy. Often, two commonly employed solutions, aside from eradication, are; either managing or controlling an infestation. Managing is where the infestation isn’t increasing in geographic area. The periphery is fought to limit further spread. Controlling an infestation goes beyond managing, where a push is made to reduce the geographic area and steers the infested area toward an eradication track. The more stringent (eradication) a strategy becomes, the higher the cost and the longer it will take. The classic invasion curve describes this situation perfectly where the longer an infestation goes before it is identified, the more expensive and longer it will take to eradicate, if at all. Chemical applications, IPM and cultural control mechanisms are used to fight active infestations. Other tools in the regulatory tool bag include inspection of agricultural commodities and issuance of phytosanitary certificates, nursery inspections and certification, active survey and the use of quarantines and limited research permits. North Carolina has multiple active projects working towards eradication and control. Witchweed (Striga asiatica) populations have been present in NC and SC since its introduction in 1955. Witchweed, if left unchecked, has the potential to devastate the midwestern corn belt, which was the primary reason for its regulation. At that time North Carolina had approximately 400,000 infested acres. Today we have 2,000 infested acres. Other noxious weeds on the eradication path are wooly frogsmouth (Philydrum lanuginosum) and yellow floating heart (Nymphoides peltata). Both species have been aggressively treated in their limited distribution within the state.
Evaluation of Vegetable Soybean Breeding Lines for Yield and Related Traits - GuoLiang Jiang Could Broccoli's Ancestral Lineage Hold the Key to Increased Fatty Acid Content? - Alaina Kleine Characterization of A Novel Locus for Fruit Flavor Aroma in Tomato - Qian Feng Identification and Validation of Novel Resistance Loci to Fusarium oxysporum f.sp. lycopersici Race 3 in Tomatoes - Samuel Ipinyomi Enhancing Fusarium Wilt Race 2-Resistance and Brix Content in Watermelon through Genomic Selection - Anju Biswas Introgressing QTL from a Wild Relative to Improve Gummy Stem Blight Resistance in Watermelon - Cecilia McGregor Genome-wide association study reveals potential loci for powdery mildew resistance in the USDA core collection of Cucurbita pepo - Prerna Sabharwal BreedwithBIMS (Breeding Information Management System) for Crop Breeders - Ksenija Gasic
Vegetable soybean (Glycine max), also known as edamame, is a specialty soybean that is harvested at R6 growth stage. Vegetable soybean has steadily increased in acreage and market demand although it is relatively new to North America. It is of significance to develop new cultivars that are more adapted to local environment and crop management system to promote specialty crop production and meet the market requirements. In this study, 14 genotypes of vegetable soybean, including 10 breeding lines and 4 check cultivars, were evaluated during 2020-2023 for potential uses as edamame. There were significant differences among genotypes in both fresh pod and mature seed yields, agronomic and seed composition traits investigated. The year effects and genotype x year interactions were also significant in most cases. Fresh pod yield averaged 11,227.5 kg ha-1, ranging 9,800.1 – 13,154.3 kg ha-1, and mature seed yield averaged 2,814.7 kg ha-1, ranging 2,029.2 – 3,175.2 kg ha-1. The average 100-seed weight of 14 genotypes was 26.9 g, ranging 23.1 – 30.1 g. Maturity averaged 153.3 days after planting, ranging 147.1 – 159.5 days. On a dry weight basis, seed protein, oil and sucrose contents averaged 43.5%, 18.7% and 5.0%, respectively. The estimates of broad-sense heritability were medium to high (66.82 – 94.90%) for most of the traits, while the heritability estimates for fresh pod yield and duration from flowering to maturity were relatively low (23.44% and 42.29%). Several breeding lines exhibited good yield, larger seed size, higher contents of protein, oil, oleic acid and sulfur-containing amino acids, suggesting the potential of release and commercial production.
In the pursuit of agricultural productivity, generations of breeding have often prioritized yield-related traits, inadvertently leading to the loss of desirable genetic traits linked to nutritional content. This phenomenon, known as the genetic lag effect, has implications for human health, particularly concerning the availability of essential nutrients such as omega-3 fatty acids. As omega-3 fatty acids are crucial for various aspects of human health, including heart health, cognitive function, and hormone regulation, it is imperative to explore alternative sources beyond traditional fish-derived options. The demand for plant-based alternatives is rising due to dietary preferences and concerns over fish oil production, emphasizing the need to investigate alternative sources of omega-3 fatty acids. Broccoli, with its rising consumption and rich nutritional profile, presents a promising avenue for addressing this need. For humans, the ideal ratio of omega 6 to omega 3, is 1:1. Yet, the American diet offers an astonishing 30:1 ratio! Broccoli has a ratio of 1:3 ratio. This is comparable to fish ranging from 1:1 to 1:7. Despite its potential, most broccoli breeding programs have focused primarily on grower-oriented traits rather than those beneficial to human health. Thus, there is an opportunity to enhance the nutritional content of broccoli, particularly its omega-3 fatty acid profile, to offer greater health benefits to consumers. This study investigates the omega-3 fatty acid profiles of 35 lines, 9 elite and 26 landrace broccoli cultivars, to address the pressing need for nutrient-rich foods. Our research employs lipid extraction from various tissues of broccoli plants, including bouquets, stems, and leaves. The lipid sample is screened using Gas Chromatography-Mass Spectrometry (GC-MS) for precise quantification and identification of fatty acids. Preliminary results reveal significant variation in omega-3 fatty acid content, specifically levels of alpha-linolenic acid (ALA) among the broccoli lines studied, highlighting the potential for breeding programs to select and develop varieties with enhanced nutritional profiles. By prioritizing consumer-oriented traits in crop breeding, such as omega-3 fatty acid content, we aim to contribute to developing biofortified broccoli varieties that offer sustainable and health-promoting dietary options. This research underscores the importance of diversifying food sources and prioritizing human health outcomes in agricultural practices to address evolving dietary needs and promote overall well-being.
Tomato flavor has become an important trait for targeted crop improvement. Because of the historical emphasis on yield and other agronomically important traits, many modern tomato varieties have lost their rich flavor, leading to consumer dissatisfaction. While volatile compounds play an important role in defining the distinct tomato flavor, little is known about their biochemical pathways, making it difficult to build a desirable volatile profile. Identifying the genes involved in volatile production can help us better understand the biochemistry as well as accelerate the breeding process. This study focuses on two consumer-desired volatiles, 1-nitro-2-phenylethane and phenylacetaldehyde, and has mapped a novel QTL on chromosome 8 by combining results from linkage mapping and GWAS (genome-wide association study). A cluster of Amino Acid Decarboxylases (AADCs) were identified as the candidate genes underlying this QTL and a total of four SV haplotypes of the AADC cluster were found in the Varitome collection. Among these haplotypes, Type III was lost during domestication and is a likely beneficial allele to increase the concentrations of phenylacetaldehyde and 1-nitro-2-phenylethane in tomato fruits. Preliminary data of transgenic plants created by CRISPR/Cas9 suggested a positive involvement of this AADC locus in volatile production. Enzymatic analysis of the AADC proteins and incorporation of the beneficial allele into modern tomato varieties is in progress. The outcome of this study will provide breeders valuable tools to facilitate the selection process for better tomato flavor. Characterization of volatile pathways will also give us insights on plant secondary metabolite biosynthesis and the evolution history during adaption and domestication. This research is funded by NSF IOS 2151032.
Fusarium wilt disease caused by the soil-borne pathogen Fusarium oxysporum f. sp. lycopersici (Fol) is a major threat in tomato-producing regions that can lead to acute yield losses. Host resistance as compared to other control strategies provides an effective and reliable means to contain the spread of the pathogen. Given that genes that confer resistance to all the three known Fol races are single dominant genes, there is a risk of resistance breakdown by the mutating pathogen. Furthermore, in the face of imminent race 4 emergence, building a quantitative and durable resistance shield by pyramiding novel resistant genes in commercial cultivars becomes pertinent. S. pennellii has been previously identified as a repository for resistant genes to Fol3 and recently, two novel loci mapped at chromosomes 3 and 10 were identified from two accessions- LA 1522 and LA 750 respectively using bulk segregant analysis QTL seq. Preliminary analysis was conducted to develop molecular markers for both chromosomes and validate their co-segregation with the region of introgression associated with resistance. We found co-segregating markers for resistance harbored by chromosome 3 and designated the locus as I8. This marker therefore constitutes additional genomic resources for marker-assisted selection of this trait. Although we found markers that co-segregate with resistance on chromosome 10, we provide initial evidence that this resistance is the same with the I6 locus previously identified on chromosome 10 and derived from LA 716 while complementary phenotypic screens showed partial penetrance of this locus. Together, these resistance loci (I6 and I8) could constitute a qualitative shield against the pathogen in commercial cultivars. Efforts are underway to fine map these loci and characterize them under field conditions and against other previously known races.
Complex traits in plants are influenced by many genes, each having a small impact. Using marker-assisted selection (MAS) alone is not sufficient to improve these traits in elite cultivars. Genomic selection (GS) is a promising breeding approach for enhancing complex traits like resistance to Fusarium oxysporum f. sp. niveum (Fon) race 2 and increasing sugar levels (brix content) in watermelon. In our study, we wanted to see how well GS can predict disease resistance and sugar levels in an interspecific citron melon (Citrullus amarus) by cultivated watermelon (Citrullus lanatus) population. We created an F2:3 population by crossing USVL252-FR2 (resistant to Fon race 2, low brix; C. amarus) with ‘Sugar Baby’ (susceptible to Fon race 2, high brix; C. lanatus). We tested disease resistance in a growth chamber and measured sugar levels in a field trial using a randomized complete block design of the F3 families. We resequenced the DNA of 150 F2 plants to identify genetic differences. Disease response was assessed 28 days after inoculation, and sugar levels were measured with a brix meter to gauge sweetness. To predict disease resistance, we used two genomic models - Random Forest and GBLUP - which we found to be effective in previous studies. We compared the performance of univariate models (looking at disease and sugar levels separately) and bivariate models (looking at disease and sugar levels together) to identify the best approach for selecting superior cultivars based on these traits. We assessed model performance using ten-fold cross-validation. Our goal is to focus on these important polygenic traits and select superior genotypes early in breeding to develop watermelon cultivars with improved disease resistance and high sugar content.
Watermelon (Citrullus lanatus) is an economically important horticultural crop known for its sweet red flesh and is a popular summer snack. The southeastern US is an important production region for watermelon, but the hot and humid weather is conducive for the development of fungal diseases. Gummy stem blight (GSB), caused by three species of Stagonosporopsis; S. citrulli, S. caricae and S. cucurbitacearum, is an important disease that can cause severe yield losses worldwide under these favorable conditions. Currently, no resistant cultivars are available for this disease and management depends on preventative fungicide spay programs. Host resistance has been previously identified in C. amarus, an inedible crop wild relative of watermelon. However, different Stagonosporopsis spp. isolates elicit different responses in different resistant host genotypes which complicated resistance breeding. To address these issues, we (i) developed a point-of-care assay that can differentiate S. citrulli from the other two species and (ii) introgressed resistance QTL from wild C. amarus into cultivated watermelon. A dipstick-based DNA extraction method was coupled with an S. citrulli specific loop-mediated isothermal amplification (LAMP) assay to detect as little as 1 pg of DNA with real time fluorescence quantification and endpoint colorimetric detection formats. To address host resistance, we developed high throughput KASP markers spanning the QTL regions, and used marker assisted backcrossing to introgress QTL into the cultivar Crimson Sweet. Eight BC2F3 intogression lines were evaluated in the field for resistance to GSB. Two of the lines showed high levels of resistance to GSB under field conditions. KASP assays were also developed for background selection for known domestication alleles to accelerate selection for fruit quality traits. The developed detection assays, KASP markers and introgression lines can contribute to accelerated breeding for host resistance and general breeding efforts for GSB in watermelon.
Summer squash (Cucurbita pepo) is a significant vegetable crop in the United States with an annual value exceeding $216 million. The production of summer squash is significantly hindered by powdery mildew (PM), a fungal disease caused by Podosphaera xanthii. Management of PM relies on costly and routine application of fungicides. Moderate resistance to PM (designated PM0) in C. okechobeensis is widely deployed in commercial summer squash cultivars. However, it is important to expand the repertoire of alleles against PM in squash to complement and reduce the risk of PM0 resistance breakdown. In the current study, the USDA core collection of C. pepo (n= 207) was evaluated for PM resistance in Florida (greenhouse), New York (greenhouse), and Michigan (field) using a randomized complete block design across three reps, each with five plants. ‘Success PM’ (carrying PM0) and ‘Early Prolific’ Straightneck cultivars were used as resistant and susceptible checks, respectively. Pathogen inoculum was provided through naturally infected plants. At the 6th true-leaf stage, symptom severity data were collected on a scale of 0-100% based on visible pathogen sporulation on the surface of ‘top 4th leaf’, ‘bottom 4th leaf’, ‘stem above 4th leaf’, ‘stem below 4th leaf’, and ‘whole plant’. Across locations, ‘Success PM’ and ‘Early Prolific’ were consistently tolerant and susceptible, respectively. On the other hand, wide phenotypic variation was observed across the C. pepo core collection with accession 189 showing resistance across locations. The multi-location phenotype data was combined with genome-resequencing data (4 million SNPs) for the core collection to conduct a genome-wide association study using three statistical models (MLM, FarmCPU, and Blink). GWAS analysis for the FL dataset revealed significant genomic loci associated with PM resistance for ‘top 4th leaf’ (Chr 11 and 20), ‘stem above 4th leaf’ (Chr 4, 14 and 16), and ‘whole plant’ (Chr 13, 15, 18 and 20). Resistance loci for ‘top 4th leaf’ and ‘whole plant’ co-located on Chr 20, suggesting potential linkage/ pleiotropy for the two traits. For NY, significant hits for PM resistance were detected for the ‘top 4th leaf’ (FarmCPU: Chr 2, 4, 7, 13 and 19; Blink: Chr 3, 4, 5 and 19) and ‘bottom 4th leaf’ (Chr 6, 14 and 19). However, no significant GWAS hits were observed using MI data. The significant loci detected in this study will be validated and deployed in marker-assisted selection to improve PM resistance in squash.
With the continuous development of new scientific technology and methodology, breeding programs are both producing and utilizing a large amount of big data. This requires efficient management systems to keep track of various types of data such as performance, pedigree, geographical and image-based data as well as genotype data. Access to integrated breeding data in a database enhances genetic understanding of important traits and maximizes the marker-assisted breeding utility by breeders. The Breeding Information Management System (BIMS) is a free, open-source, secure and online breeding management system which allows breeders to store, manage, archive, and analyze their private breeding program data that has been available in several crop databases. But what about the crops that do not have a database? We report the utility of a new BIMS website (www.breedwithbims.org) that allows any crop breeders can use BIMS. One of the key features of BIMS is that users can import new trait data via an Android App called Field Book as well as historical data via templates. Field Book app allows breeders to collect phenotype data with less possibility of transcription errors. BIMS is also BrAPI compliant so that breeders can send and receive data from other BrAPI compliant resources including the Field Book App. Potential for streamlining data collection and management for vegetable crops will be presented.
Cultural IPM: Developing a Bilingual Landscaping Basics Booklet - Hannah Wooten Learning Outcomes in Floral Design - Melinda Knuth Mentor-Mentee Perspectives And Experiences In A Graduate Scientific Communications Course - Kent Kobayaski Student Engagement and Learning: Evaluating the Effectiveness of Digital Discussion Tools - Remi Ham Training the Next Generation of Leaders to Facilitate Successful and Resilient Urban Food Systems - Eleni Pliakoni Students’ Knowledge of Landscape Sustainability, Soil Quality and Climate Change Across Experiential Learning Courses in Agriculture - I I N Handayani Evaluating In-person and Online Video Teaching Methods to Introduce Landscape Equipment Operation and Safety - Levi Dreiling Evaluating Student Understanding of Plant Physiological Processes After Class Presentations - Levi Dreiling Development of an Agricultural Biotechnology Core Capstone Course - Adrienne Kleintop
Assistant Teaching Professor, North Carolina State University
Remi HamAsst Teaching Professor and Distance Education CoordinatorKilgore Hall NA919-515-5373raham@ncsu.eduRemi’s body of work ranges from city planning, university planning, and project management. Her recent work has focused on designing edible teaching gardens and developing an environmental curriculum for K-12 schools. Additionally, Remi has focused on reducing food insecurity through com... Read More →
Friday September 27, 2024 2:29pm - 4:00pm HST
South Pacific 4
The USDA NIFA has funds for Extension that support more complex projects than typical programs. Since 2021, a multi-county Extension team has developed a UF/IFAS Bookstore publication titled “Basics of Landscaping in Florida, Conceptos Básicos de Paisajismo en Florida”. This pocket-sized, waterproof guide enables multi-lingual landscape teams to effectively communicate essential landscaping best management practices (BMPs). These BMPs promote long term landscape resilience while reducing reliance on chemical inputs. The environmental horticulture industry in Florida is worth over $10 billion annually, employs over 100,000 people, of which, 33% identify as Hispanic/Latino origin. Most horticulture jobs are focused on landscaping for aesthetics which leads to reactionary pest management focused on quick chemical solutions rather than long term economic, environmental, and social sustainability. In Florida, the use of pesticides and fertilizers requires training and professional licensure, yet chemical control and fertilization represent only a fraction of landscape integrated pest management (IPM). Cultural IPM, on the other hand, offers a key advantage: it allows for effective pest management while significantly reducing pesticide use. However, not all industry professionals require a license to perform their duties, and thus, many lack adequate training on the basics of IPM and BMPs. While quality training programs do exist, they may be cost prohibitive or too advanced for landscape professionals early in their careers or for employees performing basic tasks that fall within cultural IPM foundations. Research shows that people typically add more information and overlook subtractive approaches that may actually improve outcomes (Adams, et. al, 2021). The approach to teaching landscape basics is rooted in age old wisdom, from Occam’s Razor, Einstein’s famous quote, “Everything should be made as simple as possible, but not simpler”, and Lockheed Martin’s “Keep It Simple, Stupid (KISS)” methodologies. Thus, a more basic bilingual training on landscape best practices and IPM was needed and developed as part of the USDA, NIFA Award No. 2021-70006-35560. This booklet uses heuristic techniques designed to effectively communicate fundamental cultural IPM principles to a broader audience in English and Spanish, avoiding intricate and technical facets of horticulture. The team will disseminate booklets to clientele in 2024 and subsequently offer them for sale in the UF/IFAS Bookstore. This presentation will focus on simplifying horticultural science educational technologies, making them accessible, actionable, and agreeable for Floridians working with landscapes. Funding options, considerations, and experiences developing bilingual training materials will also be shared.
Learning objectives are put into place to measure student conceptualization in classroom activities. However, how effective are these learning outcomes in individualized student activities? Our research will explore how well students expressed learning concepts through in-class floral design construction. The target group is the students in HS 275 Floral Design. To study student understanding, we analyzed each week’s learning objectives by evaluating each student's submitted floral design project photograph. This was done through analyzing our review comments and student reflections of their final project. We will discuss the results of our study about applying teaching strategies that promote conceptualization that can potentially be applied broadly in higher education courses.
Julieta Trevino Sherk is a distinguished Professor and professional landscape architect known for her expertise in teaching and community design. At North Carolina State University (NCSU) since 2003, she holds a position in the College of Agriculture and Life Sciences within the Department... Read More →
Friday September 27, 2024 2:40pm - 2:50pm HST
South Pacific 4
Peer-to-peer engagement is an impactful way to enrich student learning and the teaching experience, especially in an asynchronous course. Varied online discussion platforms are more readily available to increase engagement, participation, and student learning. However, more information is needed to evaluate whether these discussion platforms enhance engaged learning. This study compares the use of online discussion platforms Packback and Yellowdig, used in sequential years for HS 205 (Sec. 601): Home Food Production - quantifying students' recorded level of participation, engagement with their classmates, and effort put into student posts. In the spring of 2022, Packback was evaluated as an effective class discussion tool for HS 205 (Sec. 601): Home Food Production. Students used Packback as the course discussion forum tool. Each week, they were given instructor-led lead discussion prompts during scheduled weeks and asked to respond to two of their peers. Packback tracked student participation each week and gave students a “curiosity” score. This curiosity score algorithm assessed the effort put into each student’s post. The Packback discussion group had lower full student participation, peer-to-peer engagement, and curiosity/effort scores. In the first week, most students fully participated. But as weeks progressed, the effort put into discussion posting and engagement significantly declined – as low as 65% participation. Beyond answering the discussion prompt, students did not develop their line of inquiry, and engagement was modest – most weeks, students did not fully participate, and the average curiosity score was 66% (the highest participation was 81 and the lowest 40). In the spring of 2023, Yellowdig was used as a digital tool to help create more vibrant, connected learning communities and give students the agency to discuss course topics that are important to them. Using Yellowdig, evidence showed that students became more active participants in the learning process, often exceeding the minimal participation requirement, and played a critical role in constructing knowledge. Crafted course topics provided course relevance and helped students talk about subjects related to the course, but no longer relied on instructor prompts for their discussions each week. With Yellowdig, students in this course performed above average in the number of student connections, the number of discussion posts, the number of reactions and responses given to discussion posts, the total word count average, and the number of multimedia shared (i.e.pictures, videos, weblinks). Furthermore, several students echoed their value of Yellowdig in their end -of-year evaluations.
Assistant Teaching Professor, North Carolina State University
Remi HamAsst Teaching Professor and Distance Education CoordinatorKilgore Hall NA919-515-5373raham@ncsu.eduRemi’s body of work ranges from city planning, university planning, and project management. Her recent work has focused on designing edible teaching gardens and developing an environmental curriculum for K-12 schools. Additionally, Remi has focused on reducing food insecurity through com... Read More →
Friday September 27, 2024 3:00pm - 3:10pm HST
South Pacific 4
Kansas State University formally began working in Urban Food Systems (UFS) with the launch of an UFS specialization in the Horticulture graduate program in 2011. In 2013 it expanded to the KSU-Olathe campus in order to be closer partners and other stakeholders in the Kansas City area. This program provides interdisciplinary training that focuses on sustainable urban food production, local food accessibility, food systems project management, grant writing, public and farmer education, and safe food production in an urban environment. Students gain a foundation in horticultural science while studying how the urban food system impacts social and economic development. There are a number of working urban agriculture professionals that do not have formal education or accreditation in these important topics. Therefore, the MS specialization has a thesis and a professional track (report) option that is intended for working professionals. Based on stakeholder feedback and marketing study performed by KSU, it became clear that there is a strong need for this type of education nationally and for working professionals. An online graduate certificate in urban food systems in January 2022 to address this need. The certificate consist of 6 required credits and 6 elective credits from approved courses in plant and agricultural science, leadership and management, sociology, economics and health. Fall 2023, the professional track MS is available 100% online. Graduates of the program are well prepared to work as director/program managers in not-for-profit organizations, city governments, and extension programs in urban districts, facilitating community gardens, urban farming, farmers’ markets, and farm-to-school programs. Details about the curriculum of the MS specialization and the interdisciplinary graduate certificate will be presented. As urban food systems continue to expand across the US and internationally, it will take a diverse group of professionals to address the complex issues that are relevant to this growing discipline.
Higher education institutions play a crucial role in shaping the future by preparing students to address global sustainability challenges. As we incorporate sustainability principles into teaching and research, faculty members are increasingly adopting an interdisciplinary approach. In particular, colleges of agriculture recognize the urgency of addressing soil degradation, climate change, and land management practices—the very threats that jeopardize global sustainability. However, teaching sustainability is no simple task. Students often grapple with the complexities of land degradation, soil health issues, and the impact of global warming on agriculture. Balancing the need to cover sustainability comprehensively while empowering students to find solutions can be challenging. In response to this challenge, a collaborative effort emerged across five different agriculture college courses. These courses leveraged experiential-learning projects focused on soil quality indicators and climate change mitigation as tools for teaching sustainability concepts. Despite varying levels (ranging from 300 to 400), these courses intentionally shared common components and included research projects, shared readings and reflections, student presentations and a symposium for research competition. The study analyzed over 40 research projects on soil quality and 85 student reflections. The results revealed that students not only acquired a deeper understanding of soil quality variations but also recognized how changes in soil health serve as indicators of land degradation or improvement. Moreover, they appreciated the vital role soil health plays in mitigating climate change. This collaborative approach demonstrates the effectiveness of experiential learning in teaching sustainability. By integrating real-world challenges and fostering interdisciplinary connections, higher education institutions can empower students to become informed stewards of our planet’s future.
Universities are adapting their teaching methods to progress with changes in technology. With these shifts in teaching, researchers are interested in which methods are best for certain applications. In the agriculture/horticulture realm, there are many studies describing the effects of online vs traditional in-class learning. Most of these studies focus on plant identification and generic species knowledge of plants. This study's purpose is to determine the efficacy of online vs traditional hands-on learning with eight types of landscaping equipment. The study was completed in the fall semester of 2023 at Kansas State University during the Sustainable Landscape Maintenance class. The class was randomly divided into two groups and exposed to one of two teaching methods (hands-on and online videos). Eight commonly used landscape equipment were taught to the students: power hedge trimmer, rotary push mower, de-thatcher, over seeder, ride-on zero-turn mower, sod cutter, string trimmer, and core aerifier). Both the videos and the in-person teaching covered proper operation and safety for each piece of equipment. One group was given in-person, hands- on learning the first week, while the other group watched online videos over the same four pieces of equipment. The following week, the groups switched teaching method delivery and learned the other four pieces of equipment. The students were given a pre- and post-test to assess their comprehension of the equipment. They also participated in a survey after the experiment to show prior experience on the equipment and comfortability after the labs. Results showed that students learn landscape equipment better in person through hands- on learning, rather than relying only on videos. The survey also showed students prefer hands-on demonstrations to become more comfortable operating these pieces of equipment.
Concepts of plant water use, photosynthesis, and respiration have historically been challenging for undergraduates in introductory horticulture courses. To increase student understanding of these concepts, we conducted a study in a principles of horticultural science course with two lab sections and a total enrollment of 51 students. After traditional lectures of these plant physiological processes concluded, we used a flipped classroom approach with the learners as teachers to increase student learning. Each lab section was divided into six groups, with 12 groups in total. Groups were assigned one of the three topics and presented their topic to two other groups of students. Five knowledge-based questions on each physiological process, 15 questions total, were included on a pre-test prior to hearing lectures. The same 15 questions were given on a post-test following the lectures, but prior to the student presentations. Those 15 questions were also included on the unit exam following the presentations. No significant differences were found between pre-test and exam scores when evaluated for specific topics students presented. However, an 80% overall score increase from the pre-test to the unit exam was reported. This correlates with student responses to a post-survey in which 80% of the students indicated they understood the other physiological processes better after hearing the group presentations. Our results show that a flipped classroom approach of students teaching students can be effective at increasing student understanding of difficult horticultural concepts.
The undergraduate core curriculum is an opportunity introduce students from diverse majors to topics in agriculture. Agricultural Biotechnology is an interdisciplinary undergraduate course at Delaware Valley University which combines the disciplines of Plant and Animal Science. It has run every spring semester since 2020, with enrollment made up of students from different majors. The course was recently approved as a core capstone course, an upper-level course intended to assess the university’s core curriculum, and it and was run as a core capstone course for the first time in 2024. The objectives of this project were to: 1) create two final course projects including a poster and case study designed to assess the core curriculum outcomes and 2) to provide students with the opportunity to develop their skills in public education and outreach. A final poster project was incorporated into the course in which students were instructed to develop a new Biotech trait in any plant or animal species. The poster project needed to address core curriculum outcomes such as global contexts, using relevant information, quantitative methods, appropriate technology, and required professional communication. The second case study project was used to assess multicultural competency. The posters were on display at events for both the campus community and the outside public. Student feedback was collected via pre-and post-tests and surveys.
