Genetic Analysis for Yield and Its Related Characters in Greengram [vigna Radiata (L.) Wilczek]

Abstract

The present study, titled "Genetic Analysis for Yield and its Related Characters in Greengram [Vigna radiata (L.) Wilczek]," aimed to evaluate genetic parameters, gene action (gca and sca), heterosis, correlation, path analysis, and genetic divergence for eleven yield-related traits in greengram. The investigation involved 45 F1 crosses developed using a 10 × 10 half-diallel mating design with ten diverse genotypes. The experimental material was evaluated in a randomized block design with three replications at the Crop Research Centre, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut. Observations were recorded for twelve key yield-related traits like, days to 50% flowering, days to maturity, plant height, number of primary branches per plant, pod length, number of pods per plant, number of seeds per pod, protein content, 100-seed weight, harvest index, and seed yield per plant. The analysis of variance (ANOVA) revealed highly significant differences among the genotypes for all traits, indicating a broad range of genetic variation. General combining ability (gca) variance was highly significant for traits such as days to 50% flowering, days to maturity, number of pods per plant, plant height, and protein content. This suggested the importance of additive gene action for these traits. Specific combining ability (sca) variance was also significant for most of the characters, indicating the role of non-additive gene action in trait expression. For all traits except protein content, gca variance was greater than sca variance, confirming the dominance of additive gene effects in the inheritance of most traits. Three parental genotypes—MH-521, WHM-16, and SMM 15-72—exhibited significant and positive general combining ability effects for seed yield per plant, making them valuable sources of desirable alleles for future breeding efforts. Among the specific crosses, PM-4 × WHM-16, WHM-16 × IPM-0219, SMM 15-72 × MH-521, and PM3 × PUSA-9531 displayed significant and positive specific combining ability effects for seed yield per plant, and PM-5 × SMM-15-72 had high sca and significant effect for number of primary branches per plant, number of pods per plant, 100 seed weight (g). Heterosis for seed yield ranged from -13.68% to 24.97% over better parents, with the highest heterobeltiosis observed in the cross SMM 15-72 × MH-521. Relative heterosis values ranged from -10.60% to 26.45%, with 23 crosses showing positive and significant heterosis, further emphasizing the potential for hybrid vigor in yield improvement. The analysis of gene action revealed that non-additive gene effects predominantly governed most traits, as indicated by a σ²g/σ²s ratio of less than unity for traits like days to 50% flowering, days to maturity, number of primary branches, and pod length. Additive genetic components (D) were highly significant for days to 50% flowering, number of pods per plant, and pod length, confirming the importance of these traits in breeding. Dominance components (H1 and H2) were significant for traits like number of pods per plant, protein content, and 100-seed weight, with the magnitude of H1 greater than H2 for most traits, suggesting an unequal distribution of positive and negative alleles in the population. The degree of dominance (H1/D)¹/² was greater than unity for all the traits, confirming the presence of overdominance, a genetic condition that favors hybrid vigor. The study revealed high genetic and phenotypic coefficient of variation for the number of pods per plant indicating significant potential for selection in this traits. Moderate variation was found for the number of primary branches per plant and 100 seed weight, while traits such as plant height, days to maturity, seeds per pod, pod length, seed yield, harvest index, and protein content exhibited low variation, suggesting limited scope for genetic improvement in these traits.Heritability estimates were high for several traits, such as number of pods per plant, number of primary branches per plant, days to 50% flowering, and 100-seed weight. This, coupled with high genetic advance, indicated that these traits are governed by additive gene effects and can be effectively improved through direct selection. Seed yield per plant exhibited a significant and positive correlation with traits such as 100-seed weight, number of seeds per pod, pod length, and plant height at both phenotypic and genotypic levels, indicating that these traits are vital for the improvement of seed yield. Seed yield showed a significant positive correlation with 100 seed weight, number of seeds per pod, pod length, and plant height at both the phenotypic and genotypic levels. These traits are valuable for genetic improvement in greengram, making them key targets for breeding programs aimed at enhancing yield. Path coefficient analysis demonstrated that traits such as 100-seed weight, pod length, number of seeds per pod, and plant height had high positive direct effects on seed yield, making them crucial targets for selection in breeding programs aimed at improving yield. The indirect effects of traits like protein content, and harvest index on seed yield were also noteworthy, as these traits showed meaningful associations with other yield components, suggesting their role in enhancing overall productivity.Genotypic path coefficient analysis highlighted the complex interplay of genetic factors influencing yield, with traits like days to 50% flowering, days to maturity, plant height, number of primary branches, and 100-seed weight exerting significant direct and indirect effects on seed yield. While some traits demonstrated both positive and negative indirect effects on yield, this underscores the importance of a comprehensive selection strategy that accounts for both direct and indirect genetic influences.The study identified WHM 16 and MH 521 as potential sources of resistance to YMV as well as five promising F1 crosses with high resistance to MYMV were, PM 9 × MH 521, WHM 16 × SML 15-72, PM3 × IPM 0219, PM 5 × PM 9 and PM 4 × Indore Moong and had good potential for further development and evaluation under field conditions.