**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** DROUGHT TOLERANCE IN PLANTS INVOLVES SIGNALING BETWEEN THE SHOOT AND ROOT SYSTEMS THAT IN COMBINATION DETERMINES THE RESPONSE OF THE PLANT. THE SPECIFIC AIM OF THE PROPOSED RESEARCH IS TO IDENTIFY GOSSYPIUM HIRSUTUM GENOTYPES AND GOSSYPIUM SPECIES THAT HAVE A ROOT SYSTEM CAPABLE OF RESPONDING TO LOW SOIL MOISTURE IN SUCH A WAY THAT THE SHOOT SUFFERS MINIMAL DAMAGE, RETAINS THE ABILITY TO GROW AND DEVELOPS TO MAINTAIN FIBER/SEED YIELD AND QUALITY. WE PROPOSE TO USE GRAFTING AS A TOOL TO ISOLATE AND STUDY THE IMPACT OF NOVEL ROOT GERMPLASM ON COMMERCIAL VARIETY PERFORMANCE AS A MEANS FOR CROP IMPROVEMENT FOR DROUGHT TOLERANCE. GRAFTING STUDIES WILL DISSECT VARIOUS ASPECTS OF ROOT/SHOOT INTERACTIONS UNDER DROUGHT STRESS AND AID IN IDENTIFYING GENOTYPES OR SPECIES THAT HAVE ROOT SYSTEMS WITH THE ABILITY TO PROTECT THE SHOOT UNDER WATER STRESS. VARIOUS MORPHOLOGICAL, PHYSIOLOGICAL, BIOCHEMICAL, AND MOLECULAR RESPONSES OF THE SCION LEAVES AS WELL AS GROWTH, DEVELOPMENT AND YIELD CHARACTERISTICS OF THE GRAFT UNIONS WILL BE EXAMINED. THE RESULTS WILL ALLOW US TO ASSESS THE DEGREE OF PROTECTION PROVIDED BY THE ROOTSTOCK TO THE SCION. THE ABILITY TO IDENTIFY A STRONG ROOT SYSTEM PROVIDES A TOOL TO RECOGNIZE GENETIC MARKERS FOR BREEDING FOR IMPROVED ROOT CHARACTERISTICS AND TO CREATE GERMPLASM WITH THE DESIRED ROOT AND SHOOT RELATED TRAITS. THE SELECTED LINES CAN BE USED IN BREEDING PROGRAMS FOR DROUGHT TOLERANCE WITH IMPROVED EFFICIENCY COMPARED TO THE CURRENT PRACTICE OF SCREENING GERMPLASM LINES IN A DROUGHT NURSERY IN AN ATTEMPT TO EMULATE FUTURE CLIMATIC IMPACTS.