** 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 AND SALINITY STRESS ARE THE MAJOR ABIOTIC STRESSES LIMITING CROP PRODUCTIVITY WORLDWIDE. FURTHERMORE, CLIMATE CHANGE AND RISING SEA LEVELS WILL EXACERBATE THE EFFECTS OF WATER SCARCITY AND SOIL SALINITY ON CROP PRODUCTIVITY. THERE IS THEREFORE A NEED TO BETTER UNDERSTAND THE MECHANISMS THAT CONTROL DROUGHT AND SALT TOLERANCE, PARTICULARLY IN CEREAL CROPS THAT ARE THE FOUNDATION OF OUR FOOD SUPPLY. IN THIS PROJECT, THE ROLE THE PLANT HORMONE CYTOKININ PLAYS IN REGULATING RESISTANCE TO DROUGHT AND SALT STRESS WILL BE CHARACTERIZED. THE STUDIES WILL BE PERFORMED IN RICE, WHICH IS AN IMPORTANT CROP WORLDWIDE, AND WHICH SHARES SIMILAR CHARACTERISTICS WITH OTHER CEREAL CROPS. THE EXPERIMENTAL FOCUS WILL BE TO TEST THE HYPOTHESIS THAT CYTOKININ PLAYS A POSITIVE ROLE IN MEDIATING RESISTANCE TO DROUGHT AND SALT STRESS IN RICE, PARTICULARLY AT THE REPRODUCTIVE STAGE OF GROWTH THAT IS KEY TO GRAIN YIELD. THE ROLE OF CYTOKININ WILL BE EVALUATED BY GENERATING AND CHARACTERIZING MUTANTS THAT ALTER THE CYTOKININ RESPONSE, A PREDICTION BEING THAT MUTANTS WITH AN ENHANCED CYTOKININ RESPONSE WILL ALSO DEMONSTRATE ENHANCED RESISTANCE TO DROUGHT AND SALT STRESS. THE RESULTS FROM THIS PROJECT WILL FORM A BASIS FOR IMPROVING PLANT PRODUCTIVITY THROUGH FOUNDATIONAL STUDIES ON ABIOTIC STRESS, WITH THE INFORMATION OBTAINED FROM RICE HAVING SIGNIFICANCE FOR OTHER AGRONOMICALLY IMPORTANT CROPS SUCH AS MAIZE, WHEAT, BARLEY, RYE, AND SORGHUM.