RAPD based DNA fingerprinting and analysis of genetic diversity in radiation induced mutants of cowpea [Vigna unguiculata (L.) Walp.]

Thirteen radiation-induced mutants of cowpea [Vigna unguiculata (L.) Walp.] cv. V-130 showing distinct morphological differences, besides the parental line, were screened for random amplified polymorphic DNA (RAPD) variation. Sixty-four random decamer primers used for amplification generated a total of 495 bands, of which 230 (46.5%) were polymorphic. Mutant-specific polymorphic markers either alone or in combination, were detected. Eight mutants and the parent can be identified by using specific markers, while combination of two markers could identify three other mutants. The Jaccard's similarity coefficient revealed considerable genetic diversity among the mutants. The dissimilarity between the mutants was as high as 61 per cent. The UPGMA based dendrogram showed two clusters, as supported by bootstrapping, with seven sub-clusters. The high range of genetic diversity observed among the mutants affirms the potentiality of radiation in inducing variability in cowpea. DNA fingerprinting of the mutants will facilitate their identification, registration and determination of seed purity.