Objective 1: Identify and characterize genetic diversity in economically important agricultural crop plants for biochemical, physiological, and metabolic processes that condition plants for tolerance to drought and heat extremes. Subobjective 1A: Identify the range of drought tolerance that exists within a diverse core reference set of entries from the National Cotton Germplasm Collection. Subobjective 1B: Contribute to the broadening of the genetic base of cotton for improved drought tolerance by developing Recombinant Inbred populations, breeding lines, and mutant populations using fast-neutron and ethyl methanesulfonate (EMS) mutagenesis. Subobjective 1C: Identify the range of heat stress tolerance in corn germplasm. Subobjective 1D: Evaluate the usefulness of a stress visualization computer software platform that can present and compare environmental and plant stress information in an interactive and manipulative environment to provide novel insights into the relationships between environmental cues and plant responses. Objective 2: Determine genetic mechanisms controlling biochemical and physiological processes that contribute to water-deficit and thermal stress avoidance and/or tolerance in agricultural crops. Subobjective 2A: Evaluate the differential onset of water stress in pre- and post-flowering sorghums via metabolite changes. Subobjective 2B: Characterize genetic and molecular mechanisms contributing to contrasting stress tolerance responses in peanuts. Subobjective 2C: Identification of major QTLs and/or genomic loci that are associated with heat tolerance/sensitive traits in maize and characterization of genetic and molecular mechanisms contributing to heat tolerant traits in maize. Subobjective 2D: Identify plant genes associated with improved abiotic stress tolerance in Arabidopsis; and functionally characterize crop ftsh11 protease homologs in maintaining chloroplast thermostability and photosynthesis at elevated temperatures. Subobjective 2E: Investigate small RNA regulation of plant stress responses and impact on transgene activity in genetically engineered plants. Objective 3: Use integrated marker-assisted breeding methods to develop stress-tolerant cotton germplasm or cultivars with high fiber quality and resistance to Fusarium oxysporium f. sp. Vasinfectum (FOV).
A multidisciplinary research approach will be utilized because of the complexity of the problems to be addressed. Genetic diversity will be identified for biochemical, physiological, and metabolic processes that condition plants for tolerance to drought and heat extremes. Genetic mechanisms controlling biochemical and physiological processes that contribute to water-deficit and thermal stress avoidance and/or tolerance will be determined. Marker-assisted breeding methods will be used to develop stress-tolerant cotton germplasm with high fiber quality and resistance to Fusarium oxysporium f. sp. Vasinfectum (FOV).
Soil samplings from different producer sites that represent transitioning from irrigated to dryland conditions and Conservation Reserve Program (CRP) land continue to determine soil microbial changes and new assessments on changes in water availability in soil to establish linkages of the microbial communities responsive to improvements in soil organic matter and water availability (Sub-objective 1A). Wind eroded sediment collection continues on the watersheds at the Sevilleta National Wildlife Refuge (Sub objective 1B). We have decided to abandon the water erosion part of this objective and continue to collect the wind-eroded sediment on the watersheds. Lack of insulation and insufficient vented heating prevent the maintenance of a nearly constant vapor pressure deficit at the Big Spring, Texas Field Station (Sub objective 2C). We have located some vented unit heaters and are investigating the feasibility of segregating 30% of the building interior with the heater and wind tunnel using a reinforced polyethylene membrane, limiting the amount of heat required to maintain the vapor pressure deficit. We compared the timing of irrigation application of the Stress Time (ST) method of irrigation scheduling with the Crop Water Stress Index (CWSI) method on deficit irrigated cotton (Gossypium hirsutum L.) where each irrigation event delivered 5 mm of water through subsurface drip tape. A well-watered (WW) control and a dryland (DL) treatment were also part of the experimental design. Data analyzed, manuscript written and accepted for publication in a Special Issue of the journal Agronomy (Sub objective 2A). The Agro-Climate Monitor (ACM) was linked to the USDA Southern Plains Climate Hub web site (Sub objective 2B and 3A). This application was designed to satisfy sub-objective 3A: Develop informational web sites to inform producers of the Ogallala region and other agricultural regions of recent climate trends. Over the course of the current project cycle the goals of sub-objectives 2B and 3A were substantially met with the development and deployment of the Cotton Irrigation Web Tool, http://www.csrl.ars.usda.gov/wewc/CottonIrrigTool/index.php and the West Texas Mesonet ACM, http://www.csrl.ars.usda.gov/wewc/WestTXClimMonitor/index.php. Although sub-objective 2B’s decision support web site for the management of irrigated corn and cotton was not realized, a similar application focusing on dryland cotton and sorghum management will be attempted during the upcoming research cycle.
1. Alternative genetic source for improving fiber quality of cotton. Cotton produces the most important natural fiber worldwide. And the quality of this fiber is a key factor for determining end-gain for producers, and price and quality of cotton textile products. As yield, fiber quality is significantly affected by different environmental factors/stress conditions, and genetic improvement some times is a challenge due to the narrow genetic base of modern cotton cultivars. The Agricultural Research Service in Lubbock, Texas, and Cotton Incorporated announced the joint release of seven Upland cotton germplasm lines that possess competitive lint yield, superior fiber strength, length, and uniformity when grown on the High Plains of Texas. The lines can be used as parental sources for improving fiber quality traits, such as, fiber strength, length, and uniformity under reduced irrigation levels. For public and private breeders, PSLC-U01-U07 germplasm lines provide an alternative source for improving fiber quality of High Plains' cotton because of their good yield, and superior and stable fiber properties under different irrigation conditions.
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Hinze, L.L., Hulse-Kemp, A., Wilson, I., Zhu, Q., Llewellyn, D., Taylor, J., Spriggs, A., Fang, D.D., Ulloa, M., Burke, J.J., Giband, M., Lacape, J., Van Deynze, A., Udall, J., Scheffler, J.A., Hague, S., Pepper, A., Frelichowski, J.E., Lawley, C., Jones, D., Percy, R.G., Stelly, D. 2017. Diversity analysis of cotton (Gossypium hirsutum L.) germplasm using the CottonSNP63K Array. Biomed Central (BMC) Plant Biology. 17:37.
Adeyanju, A., Yu, J., Little, C., Rooney, W., Klein, P., Burke, J.J., Tesso, T. 2016. Sorghum recombinant inbred lines segregating for stay-green QTL's and leaf dhurrin content show differential reaction to stalk rot diseases. Crop Science. doi:10.2135/cropsci2015.10.0628.
Emendack, Y., Chopra, R., Hayes, C.M., Sanchez, J., Burow, G.B., Xin, Z., Burke, J.J. 2016. Early seedling growth characteristics relates to the stay-green traits and dhurrin levels in sorghum. Crop Science. 57:1-12.
Chopra, R., Burow, G.B., Burke, J.J., Xin, Z., Gladman, N. 2017. Genome wide association analysis for seedling response traits to thermal stress in sorghum germplasm. Biomed Central (BMC) Plant Biology. 17:12. doi:10.1186/s12870-016-0966-2.
Burow, G.B., Franks, C., Burke, J.J., Xin, Z., Pederson, G.A. 2016. Registration of RTx430/gaigaoliang sorghum [sorghum bicolor (L.) moench recombinant inbred line mapping population. Journal of Plant Registrations. 10:206-209.