GENETIC DIVERSITY IN MUNG BEAN GERMPLASM REVEALED BY RAPD MARKERS

Knowledge of the genetic relationships among landraces is useful to ge ne bank managers because it permits a better organization of the crop' s gene pool management, more efficient sampling of the available germp lasm resources and better access to useful genetic Variation for breed ers. Genetic diversity of 19 landraces of the cultivated mung bean, Vi gna radiata, and three weedy and wild relatives including Vigna mungo, Vigna luteola and Vigna radiata var, sublobata, was investigated at t he DNA level with the random amplified polymorphic DNA (RAPD) procedur e. Sixty random decamer primers were employed in amplification reactio ns; 28 of these were informative and yielded 246 bands, of which 229 w ere polymorphic with a mean of 8.2 bands per primer. A genetic distanc e matrix based on Nei and Li coefficient was converted to a dendrogram and a two-dimensional plot using multidimensional scaling (MDS). The accessions studied were separated into three main clusters, which incl uded V. radiata landraces, V. mungo and V. luteola, respectively. The variation of this cluster supports the view that the genetic distance of V. mungo and V. luteola varies considerably from the accession VO29 55 (V. radiata). The multidimensional scaling plot confirmed that V. m ungo, V. luteola and most of the accessions of V. radiata formed disti nct clusters with no overlap, and two mung bean accessions (PI177493 a nd VO4134-1 from Turkey and India, respectively) were genetically dist ant from other V. radiata landraces. V. radiata and V. mungo are posit ioned in separate botanical species and V. radiata var, sublobata is c lassified within other V. radiata landraces. Based on the limited rang e of accessions tested, the approach herds promise for the classificat ion of mung bean germplasm, identification of mung bean landraces and applications of molecular markers to mung bean breeding.