DROUGHT REDUCES PEANUT YIELD BY GREATER THAN $50M ANNUALLY. DESPITE THE CURRENT CROP LOSSES TO DROUGHT, THERE IS GREAT POTENTIAL TO IMPROVE PEANUT YIELD UNDER LIMITED SOIL MOISTURE AND PROLONGED DROUGHT CONDITIONS -- WE ARE BEGINNING TO UNDERSTAND THAT TREMENDOUS HERITABLE VARIATION EXISTS IN BOTH DROUGHT-RESPONSIVE PHYSIOLOGY AND YIELD AMONG PEANUT CULTIVARS.HERE WE PROPOSE TO DEVELOP MOLECULAR TARGETS THAT WILL ENHANCE EFFORTS TO BREED DROUGHT TOLERANT PEANUT VARIETIES THROUGH AN INTEGRATED TEST OF MOLECULAR AND PHYSIOLOGICAL RESPONSES TO DROUGHT. COMBINED WE WILL NOT ONLY DISSECT THE GENETIC BASIS OF IMPROVED YIELD IN DRY CONDITIONS, BUT ALSO DEVELOP A GENOME SEQUENCE FOR THE MOST DROUGHT TOLERANT CULTIVAR AND PRODUCE MAPPING POPULATIONS FOR FUTURE PEANUT BREEDING EFFORTS. SPECIFICALLY, OUR PROPOSED WORK WILL ACCOMPLISH THE FOLLOWING THREE OBJECTIVES: I) DOCUMENT THE DNA VARIANTS THAT DISTINGUISH THE MOST DROUGHT-TOLERANT AND SUSCEPTIBLE PEANUT, II) DISSECT THE MOLECULAR BASIS OF GENE EXPRESSION AND PHYSIOLOGICAL RESPONSES TO DROUGHT, AND III) DEVELOP MOLECULAR MARKERS FOR ALLELES THAT IMPROVE YIELD UNDER DROUGHT CONDITIONS. TO ACCOMPLISH THESE GOALS, WE WILL LEVERAGE OUR COMBINED EXPERTISE IN THESE FIELDS, OUR OPTIMIZATION OF EXPERIMENTAL CONDITIONS IN THE FIELD, AND THE KNOWLEDGE BUILT UNDER OUR CURRENTLY FUNDED NIFA PROJECT. THIS RESEARCH WILL BE A CRUCIAL STEP TOWARDS ACHIEVING AFRI PRIORITIES IN PLANT HEALTH AND PRODUCTION OF PLANT PRODUCTS AND ESPECIALLY CRITICAL AGRICULTURAL RESEARCH AND EXTENSION AS RELATED TO BOTH PEANUT CROPPING SYSTEMS AND THE DEVELOPMENT OF KNOWLEDGE SYSTEMS SURROUNDING THE MOST CRUCIAL PLANT ABIOTIC STRESSOR, SOIL WATER LIMITATION.