Objective 1. Use national collections of germplasm to identify, characterize, and exploit superior physiological traits that enhance stress tolerance and increase yield in row crops, such as cotton, maize, peanut, and sorghum, to optimize crop production strategies in water-limited management systems. • Sub-objective 1A: Evaluate a previously selected, diverse core-collection of cotton lines from the USDA germplasm collection and map developed populations for yield and fiber quality under mid- and late-season water-deficit stress and/or disease pressure. • Sub-objective 1B: Identify cotton and peanut germplasm with physiological and morphological traits important to stress tolerance and stress acclimation. • Sub-objective 1C: Characterize agro-morphological and physiological traits controlling water-deficit stress tolerance in diverse grain sorghum germplasm collections to broaden the genetic donor sources for sorghum breeding. • Sub-objective 1D: Characterize genotypic plasticity and identify genetic components of heat tolerance in maize and sorghum. • Sub-objective 1E: Isolation and genetic characterization of sorghum mutants with altered heat tolerance for major traits. Mapping and cloning the causal mutation in sorghum hs mutants and functional characterization of identified genes. • Sub-objective 1F: Physiological characterization of maize core lines for their diversity in heat stress responses. Dissection of cellular and physiological mechanisms in heat stress response in maize. (Chen) Objective 2. Develop and implement crop management systems that are most appropriate for exploiting the uniqueness or strengths of superior new varieties combined with diverse regional production practices. • Sub-objective 2A: Implementation of crop simulation models to explore the GxExM interactions in rainfed cotton and sorghum production systems. • Sub-objective 2B: Evaluation of new genetic sources of cold temperature tolerance in and development of new production schemes from planting date and in-season management to expand current season lengths and regional boundaries for sorghum production. Objective 3. Determine variability in plant environmental stress responses, and exploit the diversity by designing and evaluating genotype-specific production schemes that include assessments of environmental limitations and management interactions. • Sub-objective 3A: Advance new high-throughput, thermographic technologies for estimation of plant responses to abiotic stresses under relevant production conditions in the field. • Sub-Objective 3B: Utilize existing gene mapping technologies/tools to identify and develop new single nucleotide polymorphism markers, biomarker-trait associations, and functional genes associated with tolerance and susceptibility to abiotic and biotic stress.
Unpredictable weather patterns and insect and disease pressures continually threaten yields and quality of virtually all cropping systems. These threats, coupled with accelerating global declines in water available for irrigation and increasing reliance on production from marginal lands present substantial obstacles to achieving the goal of the ARS Grand Challenge to deliver a 20% increase in quality production at 20% lower environmental impact by 2025. The long-term goals of this research are to improve understanding of plant resilience to biotic and abiotic stresses and to develop stress-tolerant cultivars that can be used in existing and future cropping systems. The elucidation of how biological mechanisms control plant stress responses and how the environment, both natural and managed, defines and restricts crop productivity, provide the foundation for the ability to improve agricultural production in low-input systems. Significant changes in management strategies, improved selection methods, and improved germplasm will be required to meet future production demands. Genetic improvements will be derived from active, targeted selection of traits in diverse germplasm grown under relevant production scenarios. Investigations of the interactions among genetic resources, environments, and management systems provide a way to fit technologies from this research to various regional climatic zones. The proposed research is relevant to the NP 301 Action Plan, Component 1 - Crop Genetic Improvement: Problem Statement 1A, Trait discovery, analysis, and superior breeding methods and 1B, New crops, new varieties, and enhanced germplasm with superior traits; Component 2 - Plant and microbial genetic resource and information management: Problem Statement 2A, Plant and microbial genetic resource and information management; Component 3 - Crop Biological and Molecular Processes: Problem Statement 3A: Fundamental knowledge of plant biological and molecular processes; and Component 4 - Information resources and tools for crop genetics, genomics, and genetic improvement: Problem Statement 4A, Information resources and tools for crop genetics, genomics, and genetic improvement.
This research project began in May 2018. The research continues the objectives and milestones of the previous project 3096-21000-019-00D, Enhancing Plant Resistance to Water-Deficit and Thermal Stresses in Economically Important Crops, which expired in FY2018. Research progress will be documented in the annual report for FY2019.