ISOZYME AND RAPD ANALYSIS OF THE GENETIC DIVERSITY WITHIN AND BETWEENVIGNA-LUTEOLA AND VIGNA-MARINA

Nineteen accessions of Vigna luteola, five of V. marina ssp. oblonga, and two of V. marina ssp. marina were analysed using variation of isoz ymes and RAPD markers to obtain better insight into genetic relationsh ips within and between these taxonomic entities. Thirteen putative iso zyme loci were scored, seven of which were polymorphic. Both species s howed 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. mari na ssp. marina were the least related to the others. RAPD analysis was more discriminating and 66 bands out of a total of 85 were polymorphi c. Based on the presence or absence of bands, Jaccard's similarity ind ex was calculated. Similarity ranged from 0.476 to 0.98. Matrices deri ved from both isozyme and RAPD data were used to construct UPGMA dendr ograms. In the tree obtained from Nei's genetic distance, based on all ozyme frequencies, accessions belonging to V. marina ssp. oblonga were mixed with V. luteola accessions; on the other hand, the two V. marin a ssp. marina clustered separately, with one V. luteola. The dendrogra m 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.