Study on genetic variability and trait evaluation for yield in Blackgram (Vigna mungo (L.) hepper) genotypes

Abstract:

The present investigation, entitled "Study on Genetic Variability and Trait Evaluation for Yield in Blackgram (Vigna mungo (L.) Hepper) Genotypes," was undertaken to assess the extent of genetic variability, character association, and cause-and-effect relationships governing seed yield in blackgram. Ten diverse genotypes — TAU-1, NLU-7, LBG-402, AKU-16, BDU-1, AKU-15, PU-31, IC-410049, PU-35, and PDU-1 — were evaluated in a Randomized Complete Block Design with three replications. Observations were recorded on eleven quantitative traits, viz., days to 50% flowering, days to maturity, number of branches per plant, number of clusters per plant, number of pods per plant, pod length, number of seeds per pod, test weight, biological yield per plant, harvest index, and seed yield per plant, and the data were subjected to analysis of variance, estimation of genetic variability parameters, correlation, and path coefficient analysis. Analysis of variance revealed highly significant genotypic differences for nine of the eleven traits, confirming the presence of substantial exploitable variability in the experimental material. Phenotypic coefficient of variation exceeded genotypic coefficient of variation for all traits, though the narrow gap between them for most characters indicated a predominant genetic component. Number of seeds per pod recorded the highest genetic advance as percent of mean (22.61%) coupled with high heritability (84.05%), signifying additive gene action and strong scope for direct selection. Correlation studies established biological yield per plant as the trait most strongly and consistently associated with seed yield per plant, both genotypically (rg = 0.82) and phenotypically (rp = 0.66), with number of pods per plant, number of clusters per plant, and test weight also showing significant positive associations. Path coefficient analysis, which accounted for over 99% of the variation in seed yield, identified biological yield per plant and harvest index as the principal direct contributors to yield, while most other yield components acted mainly indirectly through their strong coupling with biomass, revealing a classical biomass–partitioning trade-off. The genotype PU-35 emerged as the best overall performer, recording the highest seed yield, pod number, and test weight, and is recommended, along with the cross PU-35 × BDU-1, as a promising base for future selection and hybridization programmes aimed at combining high biomass production with superior partitioning efficiency in blackgram improvement.