ANALYSIS OF GENETIC DIVERSITY IN SWEET-POTATO (IPOMOEA-BATATAS) GERMPLASM COLLECTION USING DNA AMPLIFICATION FINGERPRINTING

A DNA amplification fingerprinting (DAF) approach was employed to develop individual-specific profiles and analyze genetic relationships among 73 plant introductions of sweetpotato (Ipomoea batatas (L.) Lam.) including unadapted lines from around the world and a few selected U.S.A. cultivars. Reliable and informative fingerprint profiles were obtained employing single octamer primers and Stoffel fragment Taq polymerase in the polymerase chain reaction, polyacrylamide-based vinyl polymer for electrophoresis, and silver staining to visualize the DNA. Using seven highly informative octamer primers, individual-specific DAF profiles were obtained for all accessions tested. The degree of polymorphism in the sweetpotato collection was very large, indicating a high level of genetic variability. Several accessions clustered together based on their geographic source. Most U.S.A. cultivars formed a separate cluster in the phenogram, while accessions from Papua New Guinea exhibited the highest genetic diversity. The wild species I. triloba and tetraploid I. batatas formed a group distinct from the cultivated sweetpotato. DAF appears to be useful in sweetpotato germplasm characterization and may be employed to identify duplicate accessions or for creation of core subsets. DAF data may also be useful for facilitating the selection of parents for a breeding program to ensure a broad genetic base.