Evaluation of Dolichos Bean (Lablab purpureus var. typicus) Germplasm for Their Morphological, Physiological Characters, Yield Attributing Traits and Genetic Variability

Abstract

Dolichos bean (Lablab purpureus var. typicus) is a nutritionally rich, drought-tolerant legume of significant agronomic importance in tropical and subtropical regions, valued for its contribution to food security, soil fertility, and sustainable agricultural systems. The study aimed to evaluate twenty germplasm lines of dolichos bean (Lablab purpureus var. typicus) to assess variability, identify superior genotypes, and determine yield-contributing characters. A field experiment was conducted at farmer’s field at Punapakkam village, Tiruvallur dt in 2023-24. The experiment was laid out in a Randomized Block Design with three replications. Observations were recorded on qualitative and quantitative morphological traits, along with key physiological parameters such as days to flowering, maturity, and biomass production. Significant variability was observed among the germplasm for most traits. The mean performance of genotypes showed that plant height ranged from 120 cm (TKM DB 8) to 170 cm (TKM DB 7), indicating substantial genetic diversity. The days to 50% flowering ranged from 46 days (TKM DB 8, TKM DB 18) to 170 cm (TKM DB 7), indicating the presence of both early and late maturing genotypes. Traits such as number of pods per plant, pod length, and pod weight showed a strong positive association with yield thus making selection of parents easier for further programmes. Days to 50% flowering showed a moderate positive correlation (r = 0.62) with yield, suggesting that slightly longer duration genotypes tend to produce higher yields. This positive association proves to be a highly effective and rewarding strategy to select parents to obtain high yielding varieties. High heritability coupled with genetic advance was observed for yield-related traits, suggesting the effectiveness of selection. The study identified the germplasm TKM DB 7 and 17 as promising genotypes that can be utilized in breeding programs for improving productivity and adaptability.