Genetic diversity in blackgram (Vigna mungo L. Hepper)

Blackgram germplasm comprising 484 accessions was evaluated for qualitative and quantitative traits at NARC, Islamabad, Pakistan (33.40 degreesN and 7 3.07 degreesE). Quantitative traits were analyzed for cluster and principal component analyses. The first four PCs with eigenvalues >1 contributed 79. 5% of the variability amongst accessions. Populations with high PCI values were high yielding and characterized by low harvest index (HI). The populat ions with high PC2 values were late in flowering and maturity but low in HI , grain yield, branches, pods and pods/branch. Nine important characters co ntributed more positively to the first three PCs. The germplasm was catagor ized in five clusters based on average linkage and clusters II, III and IV were more clearly separated than I and V. A selection score (SC) to find ap propriate HI range was calculated and high SC was observed for HI range fro m 30.1 to 35.0% (14.71) and 25.1 to 30.0% (13.84), which is suggested as on e of the selection criteria for future blackgram improvement. The germplasm under investigation displayed a wide range of diversity for most of the tr aits along with some accessions with unique characters which could help to identify landraces with suitable traits to be used in hybridization program me for breeding to broaden genetic base. (C) 2001 Elsevier Science B.V. All rights reserved.