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

A DNA amplification fingerprinting (DAF) approach was employed to deve lop individual-specific profiles and analyze genetic relationships amo ng 73 plant introductions of sweetpotato (Ipomoea batatas (L.) Lam.) i ncluding unadapted lines from around the world and a few selected U.S. A. cultivars. Reliable and informative fingerprint profiles were obtai ned employing single octamer primers and Stoffel fragment Taq polymera se in the polymerase chain reaction, polyacrylamide-based vinyl polyme r for electrophoresis, and silver staining to visualize the DNA. Using seven highly informative octamer primers, individual-specific DAF pro files were obtained for all accessions tested. The degree of polymorph ism in the sweetpotato collection was very large, indicating a high le vel of genetic variability. Several accessions clustered together base d on their geographic source. Most U.S.A. cultivars formed a separate cluster in the phenogram, while accessions from Papua New Guinea exhib ited the highest genetic diversity. The wild species I. triloba and te traploid I. batatas formed a group distinct from the cultivated sweetp otato. DAF appears to be useful in sweetpotato germplasm characterizat ion and may be employed to identify duplicate accessions or for creati on of core subsets. DAF data may also be useful for facilitating the s election of parents for a breeding program to ensure a broad genetic b ase.