**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CLIMATE CHANGE REQUIRES IMPLEMENTATION OF RESILIENCE IN CROPS. CROPS MUST ADAPT TO NOVEL ABIOTIC STRESSES, SUCH AS FLOODING, AND BIOTIC STRESSES, SUCH AS PLANT PATHOGENS. IN CROP CENTERS OF DIVERSITY, LANDRACES (TRADITIONAL VARIETIES) OFTEN HARBOR STRESS RESISTANCE USEFUL FOR CROP IMPROVEMENT. THE MOST DETRIMENTAL DISEASE ON PEPPERS (CAPSICUM ANNUUM) IN THE US AND GLOBALLY IS ROOT ROT FROM WATER MOLD PHYTOPHTHORA CAPSICI. THE CENTER OF DIVERSITY FOR PEPPERS IS MEXICO, HOME OF LANDRACE CRIOLLO DE MORELOS 334 (CM-334), THE ONLY SOURCE OF ROOT ROT RESISTANCE IN BREEDING. HOWEVER, CM-334LIKELY CONTAINS NON-DURABLE SINGLE GENE RESISTANCE. PEPPER LANDRACES THROUGHOUT MEXICO ARE UNDEREXPLORED FOR RESISTANCE TO P. CAPSICI, LET ALONE FOR DURABLE BROAD-SPECTRUM RESISTANCE. PEPPER GERMPLASM SCREENS ARE TYPICALLY LIMITED TO ONE PATHOGEN ISOLATE, STALLING DISCOVERY OF BROAD-SPECTRUM RESISTANCE TO A GENETICALLY DIVERSE PATHOGEN. COLLEAGUES AT THE OHIO STATE UNIVERSITY (OSU) AND COLLABORATORS AT THE NATIONAL AUTONOMOUS UNIVERSITY OF MEXICO (UNAM) HAVECOLLECTED AND GENOTYPED HUNDREDS OF LANDRACE PEPPER ACCESSIONS THROUGHOUT MEXICO. PEPPER ACCESSIONS WILL BE IDENTIFIEDWITH BROAD-SPECTRUM RESISTANCE TO ROOT ROT, ANDUNDERLYING GENOTYPIC VARIATION WILL BE INVESTIGATED USING GENOTYPING-BY-SEQUENCING AND GENOME WIDE ASSOCIATION. USING 200 LANDRACE PEPPERS FROM MEXICO, INCLUDING COLLECTIONS FROM OSU AND THE USDA, THE OBJECTIVES OF THIS PROJECT ARE:1: QUANTIFY PHENOTYPIC VARIATION IN P. CAPSICI RESISTANCE AMONG LANDRACE PEPPERS.2: IDENTIFY GENETIC VARIATION ASSOCIATED WITH P. CAPSICI RESISTANCE.AS AN APPLIED RESEARCH PROJECT, RESULTS WILL SHED LIGHT ON THE GENETIC DIVERSITY THAT UNDERLIES BROAD-SPECTRUM PHYTOPHTHORA ROOT ROT RESISTANCE IN PEPPER, PROVIDING VALUE TO PLANT BREEDERS FACING NEW CHALLENGES WITH CLIMATE CHANGE. THIS PROJECT WILL ALSO ADVANCEGOALS WITHIN RESEARCH, LEADERSHIP AND EDUCATION.