Assessment of Genetic Diversity of Ricebean [(Vigna umbellate) (Thunb.) Ohwi & Ohashi)] Varieties and their Narrow Leaf Cross Derivatives using RAPD Markers

Genetic diversity in 13 ricebean (Vigna umbellata (Thunb.) Ohwi & Ohashi) varieties and their 11 narrow leaf crosses was studied using in RAPD markers. A total of 147 amplicons were scored out of which 91 (61.9%) showed polymorphism indicating fair amount of variation at DNA levels. Per cent polymorphism among twenty four ricebean varieties and their crosses ranged from 38.9 per cent to 59.8 per cent, on the other hand, percent polymorphism among eleven crosses alone ranged from 40.5% to 53.0%. Cluster analysis based on UPGMA (Unweighted Pair-Group Method for Arithmetic Average) analysis with Squared Euclidean Distance revealed the patterns of relatedness among the ricebean varieties and their crosses. The polymorphism observed between the varieties and crosses were used as markers for hybrid analysis. The patterns of RAPD markers were classified into seven types according to the presence or absence of bands. The present investigation indicated that out of the seventeen RAPD primers used most of them were useful with good amount of reliability to identify ricebean crosses showing 49.5% to 68.0% shared markers with the parents (Type I, III and IV). However, Type VII markers were useful in identifying new cultivars of ricebean with 5% to 17.4% non-parental bands.

The present study aimed to elaborate on the application of RAPD marker technique to characterize and determine genetic relationship between the parental lines and their near homozygous progenies would be useful in marker assisted breeding programme in ricebean. The information obtained through germplasm characterization using RAPD will also be useful for screening of duplicates, assessing genetic diversity and monitoring the genetic stability of conserved germplasm.