Selection criteria for yield potential in a large collection of Vigna radiata (L.) accessions

Green gram [Vigna radiata (L.)] is an important pulse crop in tropical and sub-tropical regions around the globe. We evaluated green gram germplasm comprising a large collection of 533 accessions for qualitative and quantitative traits. On the basis of average linkage, germplasm was grouped in five main clusters, where cluster I and cluster V grouped the accessions with contrasting traits, similar to clusters II and IV which also differ strikingly.Majority of the positive qualitative traits, particularly of breeder's interest, were concentrated in clusters I-III, including tolerance against yellow mosaic virus and leaf curl virus. In principal component analysis (PCA), quantitative traits contributed positively to first two PCs. The results of PCA, phenotypic and genotypic coefficients of variations and genetic advance suggested that selection for higher pods/plant, branches/plant, seeds/pod and 100 seed weight can significantly improve yield potential and hence, can be used as effective selection indicators. Overall negative association between days to maturity (DM), days to flowering (DF) and major yield traits suggested that selection for short duration plant will compromise yield potential. Appropriate harvest index (HI) range was determined on the basis of selection score (SC). The highest HI range was from 25.1-30.0% (12.07 SC) followed by 30.1-35.0% (10.34 SC), provided strong basis for future mungbean selection. Mungbean germplasm used in the current study displayed significant diversity for DF, DM and major yield traits and hence, can help to break negative linkage drag between DM and major yield contribution traits to develop high yielding short duration green gram varieties for hybridization-based breeding programs.