Isozyme and RAPD analysis of the genetic diversity within and between Vigna luteola and V-marina

Nineteen accessions of Vigna luteola, five of V. marina ssp. oblonga, and two of V. marina ssp. marina were analysed using variation of isozymes and RAPD markers to obtain better insight into genetic relationships within and between these taxonomic entities. Thirteen putative isozyme loci were scored, seven of which were polymorphic. Both species showed very low genetic diversity indices and most of the variation was detected among populations. Pairwise Nei's genetic distances based on allozyme frequencies were also very low and the accessions of V. marina ssp. marina were the least related to the others. RAPD analysis was more discriminating and 66 bands out of a total of 85 were polymorphic. Based on the presence or absence of bands, Jaccard's similarity index was calculated. Similarity ranged from 0.476 to 0.98. Matrices derived from both isozyme and RAPD data were used to construct UPGMA dendrograms. In the tree obtained from Nei's genetic distance, based on allozyme frequencies, accessions belonging to V. marina ssp. oblonga were mixed with V. luteola accessions; on the other hand, the two V. marina ssp. marina clustered separately, with one V. luteola. The dendrogram derived from RAPD data showed three main groups corresponding to the three taxa analysed. Moreover, according to these data, V. marina ssp. oblonga is more closely related to V. luteola than to V. marina ssp, marina. (C) 1997 Annals of Botany Company.