Efficiency of RAPD and ISSR markers in assessing genetic diversity and relationships in black gram (Vigna mungo L. Hepper) varieties

The DNA fingerprinting methodologies, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), were used to estimate genetic diversity and relationships among 20 black gram (Vigna mungo L. Hepper) varieties. Thirty selected RAPD primers amplified 255 bands, 168 of which were polymorphic (66.5%). On average, these primers produced 8.5 bands, 5.6 of which were polymorphic. Polymorphic band number varied from 2 (A-05) to 10 (OPA-02), with sizes ranging from 100 to 2550 bp. Twenty-four selected ISSR primers produced 238 amplified products, 184 of which were polymorphic (77.8%). On average, these primers generated 9.8 bands, with 7.7 polymorphic bands ranging in number from 4 (ISSR-13) to 11 (ISSR-03), and size from 100-2650 bp. Genetic relationships were estimated using similarity coefficient (Jaccard's) values between different accession pairs; these varied from 30.7 to 85.0 for RAPD, and from 37.2 to 88.4 with ISSR. UPGMA analysis indicated that the varieties ranged in similarity from 0.50 to 1.00 (mean of 0.75) for RAPD, and from 0.47 to 1.00 (mean of 0.76) with ISSR. Cluster analysis of RAPD and ISSR results identified three clusters with significant bootstrap values, which revealed greater homology between the varieties. Principal coordinates analysis also supported this conclusion. Among the black gram varieties, WBU-108 and RBU-38 were highly divergent, whereas LBG-648 and LBG-623 were genetically similar. The markers generated by RAPD and ISSR assays can provide practical information for the management of genetic resources and these results will also provide useful information for the molecular classification and breeding of new black gram varieties.