POTATO RELATIVES OFFER A MORE DIVERSE AND ACCESSIBLE GERMPLASM RESOURCE THAN IS FOUND IN ANY OTHER CROP. POTATO AND WILD SPECIES RELATIVES GROW FROM SEA LEVEL TO 4300 M AND ARE FOUND IN A TREMENDOUSLY WIDE ARRAY OF ENVIRONMENTS. MOST OF THESE WILD RELATIVES CROSS READILY WITH CULTIVATED POTATO, PRODUCING OFFSPRING WITH ACCEPTABLE TUBER YIELD AND TYPE THAT CAN PROVIDE THE GENETIC DIVERSITY TO NEEDED FOR POTATO PRODUCTION IN STRESSFUL ENVIRONMENTS, INCLUDING THOSE WITH HEAT STRESS AND DISEASE PRESSURE. ONE DIPLOID SPECIES THAT WAS CENTRAL IN THE DOMESTICATION AND IMPROVEMENT OF POTATO WAS SOLANUM MICRODONTUM WITH CLEAR ASSOCIATION OF ADAPTIVE TRAITS PRESENT IN MODERN CULTIVARS THAT CAN BE TRACED TO INTROGRESSIONS DURING THE MOVEMENT OF CULTIVATED POTATOES FROM PERU/BOLIVIA TO SOUTHERN ARGENTINA. TO BUILD ON GERMPLASM RESOURCES FOR A DIPLOID POTATO BREEDING APPROACH, IN THIS PROJECT, WE WILL PHENOTYPICALLY CHARACTERIZE AVAILABLE S. MICRODONTUM GERMPLASM FOR KEY AGRONOMIC TRAITS THAT CAN BE READILY INCORPORATED INTO BREEDING MATERIAL. WE WILL ALSO GENERATE A CHROMOSOME-SCALE REFERENCE GENOME AND CATALOGUE GENETIC DIVERSITY IN THIS SPECIES TO UNDERSTAND THE UNDERLYING GENETIC DIVERSITY THAT CONTRIBUTES TO PHENOTYPIC DIVERSITY. THROUGH THE IDENTIFICATION OF LOCI AND ALLELES LINKED TO LATE BLIGHT RESISTANCE AND HEAT TOLERANCE, WE WILL ADDRESS NOT ONLY THE MAJOR DISEASE PRESSURE IN POTATO PRODUCTION BUT ALSO POSITION POTATO BREEDING SUCH THAT IT CAN ADDRESS CONCERNS ASSOCIATED WITH CLIMATE CHANGE.