Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Target Audiences: Beneficiaries of results from this work will be local producers of lettuce and spinach who will be able to grow their products in-ground, or in low or high tunnels for out-of-season production. Most of these targeted growers will be small-scale farmers including under-represented groups. Consumers of local produce as well as the outlets for locally produced vegetables will also benefit by having available lettuce and spinach for a longer period of time. Results from this work could also be used by large scale producers of vegetables in the S.E region of the US, especially in the Piedmont regions. Target audiences for this work also include the scientific communities where breeding locally produced vegetables for improved resilience to temperature fluctuations and extremes is a priority for many funding agencies. Efforts: To reach target audiences, papers and posters will be presented at local, regional, national and international scientific and interest group meetings. Workshops and presentations will be made at experiment station field-days including small-farms field days at the A&T Farm in Greensboro, NC. Data for improved resilience of plants to temperature fluctuations and extremes will be included in our courses including "Plant Propagation", where the process of plant breeding is covered; and in the "Science of Plants" course where plant responses to the environment are outlined and discussed. Internships to undergraduate students will be offered during the summer and winter periods where students will get first-hand experience in evaluating the diversity in leafy vegetables for resistance/susceptibility to temperature extremes. Unfortunately, Covid-19 restrictions limited any opportunity to make presentations our high undergraduate students. Finally, research will be published in peer reviewed scientific journals where the information will be shared with the scientific community. Two publication are in preparation. Changes/Problems:1. Project timeline: Because of a delay in purchasing our freezing chambers, the project is approximately 1.5 years behind our timeline in the Evans-Allen proposal. We also had difficulty hiring a research technician which is also causing a 1.5-year delay in our timeline. I have also not been allowed to release my teaching time for the first two years of this Evans-Allen project, so I continue to teach a full load of 4 classes each semester. A lack of time devoted to research has also retarded our progress on the project. After recruiting a foreign graduate student, the student was unable to get the proper visa to enter the United States. This has delayed our progress by a year. 2. Facility issues: We attempted to secure evaluation sites at the A&T Farm, which took time anddelayed our progress on field screening for cold tolerance in lettuce. We have now obtained access, but Covid-19 restriction prevented us from developing the site of in vivo studies. 3. Equipment/instrumentation issues: We had a delay in purchasing our freeze chambers resulting from improper process of purchase documents. Then we had a delay in equipment installation as a result of facilities and Covid-19. Proper ventilation of the room which houses the freeze chambers continues to be a challenge. 4. Personnel issues: Delays in hiring a technical and graduate student have hampered progress. We now have a technician and a domestic graduate research student. 5. Student issues. Covid-19 has made it very difficult to involve undergraduate research students in our studies. What opportunities for training and professional development has the project provided?Our group has developed our knowledge in improving mineral nutrition for the crops we research. We have also developed the skills and equipment necessary to evaluate plants for cold stress tolerance. In addition, we have developed a good understanding of the mating systems of spinach so new varieties can be developed. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? Potassium, calcium, and selenium will be investigated to determine levels of enhanced cold tolerance in leafy vegetable crops. Spinach will be exposed to high temperatures during germination, seedling growth and for mature plants so new spinach varieties can be developed. We will also begin to look at the mechanism responsible for enhanced high temperature germination and resistance to high temperatures in mature plants. A broad base of lettuce germplasm will be evaluated for difference in cold-stress tolerance. We have accumulated approximately 100 lettuce varieties.
Impacts
What was accomplished under these goals?
a. Potassium/magnesium/calcium fertility experiments: Lettuce, spinach and basil were grown in nutrient solutions. Plants were grown for 6 weeks and in two environments to determine nutrient usage, accumulation, and plant productivity. Data is being analyzed and a draft publication is being developed. b. Spinach heat tolerance: A large difference was found among spinach varieties for the ability to germinate at high temperatures. There was an interaction between varieties and increasing temperature indicating that some varieties responded differently to increasing temperatures. Seeds that germinated at 31 ° C were transferred to media and grown to mature plants that flowered. High temperature germinating plants were pollinated and seed collected (First generation population). This seed was germinated and compared to the parental population. Germination trended towards the female parent. Second generation seed is currently being produced. Spinach varieties varied in response to heat stress tolerance at the seedling stage. Some varieties elongated and produced flowers while other resisted elongation and flowering. Tolerance to high germination temperatures did not correlate with resistance to seedling stem elongation and flowering, indicating different resistance mechanism at these plant developmental stages. Mature plants tolerance to heat stress varied among spinach varieties and could be grouped into three categories: no heat tolerance, moderate heat tolerance, and high level heat tolerance. Data of these experiments has been analyzed and a publication is being developed. c. Establishing cold tolerance in lettuce: We developed the technique by which lettuce can be evaluated to cold-stress damage. Lettuce varieties were evaluated and differentiated using both a visual assess and conductivity measurements from electrolyte leakage from damaged cells. The tests were consistent among varieties and between treatments. We are preparing a publication. Plants among three lettuce varieties increased in cold stress tolerance with increasing exposure to 5 °C and 2.5 C hardening temperatures, although varieties different in the rate at which they accumulated cold stress tolerance. A publication is being developed. Once hardened, plants among three lettuce varieties lost cold stress tolerance the longer they grew in 22 °C. Little difference was found among varieties for loss of cold stress tolerance. A publication is being developed.
Publications
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Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Target Audiences: Beneficiaries of results from this work will be local producers of lettuce and spinach who will be able to grow their products in-ground, or in low or high tunnels for out-of-season production. Most of these targeted growers will be small-scale farmers including under-represented groups. Consumers of local produce as well as the outlets for locally produced vegetables will also benefit by having available lettuce and spinach for a longer period of time. Results from this work could also be used by large scale producers of vegetables in the S.E region of the US, especially in the Piedmont regions. Target audiences for this work also include the scientific communities where breeding locally produced vegetables for improved resilience to temperature fluctuations and extremes is a priority for many funding agencies. Efforts: To reach target audiences, papers and posters will be presented at local, regional, national and international scientific and interest group meetings. Workshops and presentations will be made at experiment station field-days including small-farms field days at the A&T Farm in Greensboro, NC. Data for improved resilience of plants to temperature fluctuations and extremes will be included in our courses including "Plant Propagation", where the process of plant breeding is covered; and in the "Science of Plants" course where plant responses to the environment are outlined and discussed. Internships to undergraduate students will be offered during the summer and winter periods where students will get first-hand experience in evaluating the diversity in leafy vegetables for resistance/susceptibility to temperature extremes. Finally, research will be published in peer reviewed scientific journals where the information will be shared with the scientific community. Changes/Problems:Major Problem: A major problem occurred with the delay of ordering and delay of delivery of our freezing chambers. Due to problems in the business office, our attempted order in November 2018 did not get done until April of 2019. Production delays at the manufacturer resulted in a delay in delivery until November 2019. Since the bulk of our proposed work depended on the use of the freezing chambers, the majority of our work has been delayed one year. We attempted to hire a graduate student for Fall 2019, but because of Visa issues, the student was unable to obtain a Visa and could not meet his commitment. We have recruited a domestic graduate student who will start in Summer, 2020. Deviation in goal: We will continue to focus our work with lettuce on better understanding cold tolerance and how to improve lettuce for surviving cold temperatures. Our discovery of genetic diversity for heat tolerance in spinach has provided us an opportunity to research this trait with the overall goal to develop heat tolerant spinach varieties. This is probably a more important trait for spinach than improving cold tolerance. While we are looking at heat and not cold tolerance in spinach, our overall focus will be on improving resilience in vegetable to temperature extremes and fluctuating temperatures, our original goal. The growth chamber we obtain have great versatility and can be used for both high and low temperature testing. What opportunities for training and professional development has the project provided?Training activities: Two undergraduate students were mentored to conduct replicated research. Data obtained from these activities can result in peer-reviewed publications. How have the results been disseminated to communities of interest?A poster presentation was made on our work with leafy vegetables and cold temperatures at the International Allium Research Conference held in Madison, WI July 24-27, 2019. An oral presentation will be made at the Urban Food Conference in Kansas City, MO describing our work with heat tolerance spinach. What do you plan to do during the next reporting period to accomplish the goals?Cold temperature tolerance in lettuce. Having received our freeze chamber in late November 2019, we will begin a series of experiment under controlled low temperatures to determine the range of tolerance in lettuce to cold. We will also look at how preconditioning plants to cold affects low temperature tolerance among lettuce varieties, and work out protocols for measuring resistance to freezing damage in lettuce. Finally, we will look at biochemical changes in plants that differ in cold tolerance to determine key metabolites involved in cold temperature tolerance. We will also do field plantings of the lettuce varieties to determine any relationships between the chamber results and field results. Heat tolerance in spinach. We will continue to evaluate responses among spinach varieties to heat susceptibility/resistance and develop genetic population of heat tolerant and heat susceptible population to determine genetic control of these characteristics. The ultimate goal is to produce heat tolerant spinach varieties for the S.E. Piedmont.
Impacts
What was accomplished under these goals?
Cold tolerant lettuce from in situ evaluation. Viable seed was obtained from the selected plants confirmed by germination testing.Seed is being stored and will be evaluated for improved cold tolerance in freezing chambers in the coming months. Potassium effects on plant growth in lettuce. Data was collected on biomass yield, nutrient utilization from the hydroponic solutions, and nutrient accumulation in plant tissues. This experiment was carried out by an undergraduate research assistant. The experiment is being repeated in a second environment to verify results and produce publishable data. Potassium effects on plant growth of spinach. Data was collected on biomass yield, nutrient utilization from the hydroponic solutions, and nutrient accumulation in plant tissues. This experiment was carried out by an undergraduate research assistant. The experiment is being repeated in a second environment to verify results and produce publishable data. Potassium effects on plant growth of basil. Data was collected on biomass yield, nutrient utilization from the hydroponic solutions, and nutrient accumulation in plant tissues. The experiment is being repeated in a second environment to verify results and produce publishable data. Heat tolerance of spinach varieties.Significant variation was recorded among spinach varieties with some varieties flowering almost immediately following transplanting outside, while others remained vegetative into June and 33 °C temperatures. High temperature tolerance to germination in spinach. Most seeds germinated at 22 °C and the number of seeds germinating as temperatures increased. Some varieties stopped germinating at 28 °C while some continued to germinate even at 34 °C, albeit few seeds. Seed of those varieties that germinated at high temperatures were transplanted to artificial media and place in the greenhouse. Seed will be obtained with the objective of selecting spinach varieties that exhibit low thermo-dormancy at temperatures up to 31 °C making the crop more resilient to extreme temperatures. Resistance to bolting did not correlate well with reduced thermo-dormancy.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Randle, W.M. and Huchette, O. 2019. Improving Intermediate-day Onions for Regional Adaptation and Resistance to Abiotic Stresses. International Allium Research Conference, Madison, WI July 24-27, 2019. Poster presentation.
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