THIS STANDARD RESEARCH PROPOSAL ADDRESSES UTILIZATION OF NOVEL INDUCED MUTANTS TO ENRICH GENETIC DIVERSITY AND ACCELERATE BREEDING PROGRESS IN ONE OF THE MOST ECONOMICALLY IMPORTANT AND GENETICALLY VULNERABLE MAJOR US CROPS, COTTON. THIS RESEARCH IS FOUNDED ON THE DISCOVERY THAT SCREENING OF LARGE MUTANT POPULATIONS IDENTIFIED LINES CONFERRING STRIKING FIBER QUALITY IMPROVEMENTS, FOR WHICH A SUBSET HAVE BEEN VALIDATED IN 5 YEARS OF TESTING IN THEIR NATIVE BACKGROUND AND TWO ADDITIONAL BACKGROUNDS. MOREOVER, PYRAMIDING OF MULTIPLE MUTANTS BY INTERCROSSING RESULTED IN SUPERIOR LEVELS OF ONE FIBER QUALITY COMPONENT (FIBER LENGTH) AND SHOWED CORRELATED IMPROVEMENTS OF OTHER COMPONENTS. THE PROPOSED RESEARCH INCLUDES DEVELOPMENT AND EVALUATION OF TRAIT-FOCUSED POPULATIONS THAT PYRAMID MULTIPLE MUTANTS TO ATTAIN SUPERIOR LEVELS OF ADDITIONAL KEY FIBER QUALITY COMPONENTS, GENETIC MAPPING OF FIBER MUTANTS CONFERRING STRIKING PHENOTYPES TO QUANTIFY THEIR INDIVIDUAL AND INTERACTIVE PHENOTYPIC EFFECTS AND IDENTIFY DIAGNOSTIC DNA MARKERS, INTERCROSSING AMONG SUPERIOR LINES FROM MULTIPLE-MUTANT POPULATIONS TO INVESTIGATE SCOPE FOR CONTINUING GENETIC GAINS, AND INVESTIGATING THE IMPACT OF MUTANT-DERIVED FIBER QUALITY IMPROVEMENTS ON YIELD COMPONENTS. INTEGRATIVE ANALYSES WILL TEST A RECENT HYPOTHESIS ABOUT THE NATURE OF COTTON FIBER QUALITY QTLS, AND PROVIDE A FRAMEWORK FOR DEPLOYMENT IN MAINSTREAM COTTON BREEDING OF LINES SELECTED FROM THE STUDY POPULATIONS, ACCOMPANIED BY DIAGNOSTIC DNA MARKERS TO FACILITATE THEIR MANIPULATION. PARTNERSHIP BETWEEN A PLANT BREEDER AND A GENOME BIOLOGIST WILL INTEGRATE TRAINING IN FIELD-BASED BREEDING WITH EFFECTIVE UTILIZATION OF GENOMIC DATA AND TOOLS TOWARD MITIGATING GENETIC VULNERABILITY OF COTTON, IN A MANNER THAT IS ALSO APPLICABLE TO MANY OTHER CROPS.