DNA MARKER-BASED STUDY OF GENETIC RELATEDNESS IN UNITED-STATES SWEET-POTATO CULTIVARS

The polymerase chain reaction (PCR)-based DNA amplification fingerprin ting (DAF) approach was used to investigate genetic relationships amon g 30 U.S. sweetpotato (Ipomoea batatas L. Lam.) genotypes including he irloom cultivars and recent releases, Phenogram, pairwise similarity m atrix, and principal coordinate plots were developed based on Jaccard' s coefficients using band-sharing data generated by seven octamer prim ers, All cultivars showed unique fingerprint patterns indicating the u tility of DAF in cultivar identification, Many heirloom cultivars such as 'Creole' and 'Porto Rico' were readily differentiated from recentl y developed cultivars, Modern cultivars such as 'Jewel', 'Carver', 'Nu gget), and 'Scarlet' exhibited a high degree of similarity reflecting ancestral relatedness, 'Regal' and 'Excel', recently developed using a population-based breeding approach, showed greater divergence from al l other cultivars, Those cultivars, developed as a result of somatic m utations, exhibited high levels of genetic similarity to their normal- type parents and Set had distinct fingerprint profiles, With few excep tions, genetic relationships derived from DAF data appear to be consis tent with available pedigree information.