Genetic diversity in urdbean [Vigna mungo (L.) Hepper] revealed by ISSR markers

Inter simple sequence repeat (ISSR) markers were used to study the DNA polymorphism in advance lines and cultivars of intervarietal and interspecific crosses in urdbean. Amplification of genomic DNA of 33 urdbean and one mungbean genotype using 10 ISSR primers yielded 71 bands, of which 65 were polymorphic with an average of 6.5 polymorphic bands per primer. Number of amplified bands with ISSR primers ranged from four (primer 4824-050) to ten (primer 4824-039) and varied in size from 100 bp to 3000 bp. Percentage polymorphism ranged from 50.0% (primer 4824-050) to a maximum of 100% (primers 4824-038, 4824-041, 4824-043, 4824-049 and Primer 4824-051), with an average of 80%. Cluster analysis grouped the 33 urdbean (V. mungo) and 1 mungbean (V. radiata) genotypes into two main clusters, I and II comprising of 22 and 11 genotypes, respectively. The clustering pattern indicated that the variation observed in morphological characters was not corroborated by molecular variation. The Jaccard similarity coefficient between different Vigna genotypes ranged from 0.47 to 1.00. All the genotypes and checks exhibited more than 61% similarity and in most of the genotypes similarity ranged from 86–100%. The higher degree of commonness in their pedigree may explain the high degree of closeness among genotypes studied. The genetic variation among 33 genotypes of urdbean and one mungbean cultivar revealed by ISSR analysis could be useful in selecting parents for hybridization in blackgram improvement programmes.