Genomic variation and genetic relationships in Ipomoea spp.

Random amplified polymorphic DNA (RAPD) markers were used to develop geneti c fingerprints and analyse genetic relationships among 29 Ipomoea accession s from different geographical locations around the world, including unique wild species, and reproducible profiles were obtained for all accessions us ing random decamer primers. The primers generated 46 polymorphic markers, o ne primer alone having 10 products, enabling the discrimination of all 29 a ccessions. A high level of genetic variability in sweet potato collections was suggested by the degree of polymorphism. Half of the Japanese land race s were closely related while accessions from Papua New Guinea and The Phili ppines were distinct and exhibited the greatest genetic diversity. The wild species Ipomoea gracilis and Ipomoea tiliacea formed a group distinct from the cultivated sweet potato. The wild tetraploid accession K233 and the sp ecies Ipomoea trifida were progressively more related genetically to the cu ltivated sweet potato and are the probable progenitors of Ipomoea batatas, and may be suitable as germplasm for genetic enhancement. RAPDs proved to b e useful for sweet potato systematics and should be valuable for germplasm management, gene tagging and efficient choice of parents in breeding progra mmes.