Genetic Diversity Analysis of Rice Bean Using Molecular Markers

Vigna umbellata (Thunb.) Ohwi and Ohashi commonly known as rice bean or climbing mountain bean is under exploited tropical legume, used as vegetable and fodder. Genetic variation between 10 landraces of rice bean was evaluated using random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. RAPD fingerprinting (70.30 %) detected more polymorphic loci than the ISSR fingerprinting (61.79%). Mean PIC (polymorphic information content) for each of these marker systems (0.243 for RAPD and 0.203 for ISSR) suggested that both the marker systems were equally effective in determining polymorphisms. The dendrograms constructed using RAPD and ISSR marker systems were perfectly correlated with each other as revealed by high Mantel correlation (r=0.95). Pair wise similarity index values ranged from 0.530 to 0.782, 0.608 to 0.862 and 0.559 to 0.777 for RAPD, ISSR and combined RAPD and ISSR data respectively. The cluster analysis grouped the 10 land races into 2 major clusters in both the marker systems. Our research suggests that, both RAPD and ISSR marker systems were equally useful to identify variation within the land races of V. umbellata.