**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** PEANUT IS AN ALLOTETRAPLOID CROP WITH CLOSELY RELATED SUBGENOMES FOR WHICH RESPECTIVE PROGENITORS HAVE BEEN IDENTIFIED AND NOW SEQUENCED ALONG WITH THE CULTIVATED GENOME. THE CULTIVATED POLYPLOID LIKELY AROSE FROM A SINGLE HYBRIDIZATION EVENT CREATING A BOTTLENECK THAT CONSTRAINED DIVERSITY. NOVEL ALLELES FOR DISEASE RESISTANCES AND OTHER TRAITS EXIST IN WILD RELATIVES AND ARE BECOMING MORE ACCESSIBLE THROUGH CONVENTIONAL BREEDING APPROACHES INFORMED BY KNOWLEDGE OF GENETIC RELATIONSHIPS, GENOME INTERACTIONS, AND MOLECULAR DIVERSITY. THE OBJECTIVES OF THIS PROPOSAL ARE ALIGNED WITH THE FARM BILL PRIORITY OF PLANT HEALTH AND PRODUCTION AND PLANT PRODUCTS UNDER THE PROGRAM AREA OF PLANT BREEDING FOR AGRICULTURAL PRODUCTION AND SPECIFICALLY ADDRESSES BREEDING FOR IMPROVED CROP PRODUCTIVITY, EFFICIENCY, QUALITY, PERFORMANCE, AND LOCAL ADAPTATION TO BIOTIC AND ABIOTIC STRESS.ONLY RECENTLY HAS PEANUT BREEDING BEEN FACILITATED BY MARKER ASSISTED SELECTION (MAS) FOR A LIMITED NUMBER OF TRAITS, PRIMARILY NEMATODE RESISTANCE AND HIGH OLEIC ACID. WHILE MARKER-TRAIT ASSOCIATIONS ARE USEFUL TO SELECT FOR QUALITATIVE TRAITS WHERE PHENOTYPING IS DIFFICULT OR DESTRUCTIVE, THE GREATER BENEFIT TO BREEDING WOULD BE FOR QUANTITATIVE TRAITS THROUGH GENOMICS-ENABLED BREEDING. ONE GOAL OF THE PEANUT GENOMIC INITIATIVE HELPED TO INCREASE THE NUMBER OF MAPPED QUANTITATIVE TRAIT LOCI (QTL) THROUGH GENOTYPING AND PHENOTYPING OF STRUCTURED POPULATIONS; HOWEVER, GREATER DIVERSITY TO IDENTIFY MARKERS LINKED TO BENEFICIAL ALLELES IS NEEDED TO INCREASE DESIRABLE VARIATION IN BREEDING PROGRAMS AND IMPLEMENT MAS FOR ECONOMICALLY SIGNIFICANT QUANTITATIVE TRAITS. THROUGH THE RESEARCH OUTLINED IN THIS PROPOSAL WE WILL EXPAND OUR KNOWLEDGE OF INTER- AND INTRA-SPECIFIC GENETIC BEHAVIOR AND DEVELOP TOOLS TO IDENTIFY AND SELECT FOR QTL THAT UNDERLIE DESIRABLE VARIATION. SPECIFIC OBJECTIVES WILL ADDRESS 1) VARIATION THAT ARISES DUE TO EARLY GENE CONVERSION EVENTS IN DIPLOID HYBRIDS THAT MAY IMPACT RECOVERY OF USEFUL ALLELES IN SYNTHETIC TETRAPLOIDS; 2) GENETIC ANALYSIS OF INTERSPECIFIC DERIVATIVES WITH ARACHIS DIOGOI THAT ARE RESISTANT TO TOMATO SPOTTED WILT AND OTHER DISEASES TO DEVELOP MATERIALS AND TOOLS USEFUL FOR PEANUT CULTIVAR IMPROVEMENT; 3) IMPROVED POPULATION DIVERSITY FOR MARKER-TRAIT ASSOCIATION BY DEVELOPMENT OF A MULTI-PARENT ADVANCED GENERATION INTERCROSS (MAGIC) POPULATION ENCOMPASSING A BROAD SPECTRUM OF DISEASE AND PEST RESISTANCES, AS WELL AS QUALITY TRAITS; AND 4) NEED FOR DEVELOPMENT OF COST-EFFECTIVE MARKER-ASSISTED SELECTION TOOLS FOR PEANUT BREEDERS. THIS PROPOSAL IS SUBMITTED IN RESPONSE TO THE CO-FUNDED PROGRAM WITH THE NATIONAL PEANUT BOARD TO IDENTIFY GENETIC MARKERS TO DEVELOP IMPROVED CULTIVARS AND BREEDING LINES OF PEANUTS WITH SUPERIOR DISEASE AND NEMATODE RESISTANCE, INCREASED SHELF LIFE, PREFERRED SIZE AND SHAPE TO FACILITATE PROCESSING, AND OTHER DESIRABLE TRAITS.