Development of SSR and SNP markers and QTL analysis for disease and pest resistance in sweetpotato. Specific objectives. 1) Develop high-density linkage SSR and SNP maps for populations segregating for sweetpotato virus disease and weevil resistance. 2) Phenotype the populations for disease and weevil resistance. 3) Profile phytochemical (octadecyl and hexadecyl ester) production conferring weevil resistance in the mapping population. 4) Detect and validate the QTL associated with the field and phytochemical basis of weevil resistance and SPVD resistance in sweetpotato.