Background: Indian bean [Lablab purpureus (L.) Sweet] is an important vegetable as well as split pulse crop in India. An attempt was made here to study the genetic variability, correlation and direct and indirect effects through path analysis for yield and yield attributing traits. Methods: Total 52 genotypes were evaluated in randomized block design (RBD) with three replications during early-rabi season, 2018-2019. Observations were recorded on 11 quantitative traits. Result: Significant variation existed in all the characters. Higher values of GCV and PCV were observed for pods per raceme, pods per plant and seed yield per plant. High heritability coupled with high genetic advance was observed for racemes per plant, pods per raceme, pods per plant, pod width and seed yield per plant. Seed yield per plant was highly significant and positively correlated at genotypic level with days to maturity, plant height, racemes per plant, pods per raceme, pods per plant and seeds per pod. Path analysis based on genotypic correlation revealed that high positive direct effects on seed yield per plant was registered by pod per raceme followed by racemes per plant, pod length, days to 50% flowering, plant height, pod weight and days to maturity.

No abstract

Twenty one crosses resulting from 7 x 7 diallel excluding reciprocal were studied to know the magnitude of heterosis over better parent and standard variety for yield and its attributing characters in rabi mungbean. The highest heterosis to the extent of 37.23% over the check Co-4 and 82.20 % over the check GBM-1 was observed in cross combination Co-4 x Meha for seed yield per plant, which also exhibited high heterosis percentage for yield and yield components. The promising hybrids viz. Co-4 x Meha, Co-4 x GBM-1, GBM-1 x Meha and Rm-9-129 x Co-4 were identified which have great potential to exploit the hybrid vigour or to isolate the desirable segregants for the development of rabi mungbean varieties with chilling tolerant ability or photo-thermo insensitivity, so as to exploit potential of rabi mungbean in heavy rainfall zone as rice fallows.

Seven genotypically diverse lines of mungbean were crossed in diallele fashion to identify genotypes with high general combining ability and specific cross combinations with high specific combining ability for yield and yield attributes in rabi season excluding reciprocals. The analysis for combining ability revealed significant mean sum of squares due to general and specific combining ability for all the characters studied indicating importance of both additive as well as non-additive gene effects involved in the expression of all the characters. Higher magnitude of general combining ability variances for most of the traits except for number of branches per plant, pod length, number of seeds per pod and harvest index pointed out the preponderance of additive component of the genetic variance in the expression of the characters under study. The good general combiners for yield attributing traits were Co-4, GBM-1 and Meha and the best specific cross combinations having the highest SCA effect for yield and yield attributing traits were Co-4 x Meha, Co-4 x GBM-1, Rm-9-126 x Rm-9-134, GBM-1 x Meha and Rm-9-133 x GBM-1. This cross combinations could be utilized for further breeding programmes for the development of rabi mungbean varieties with chilling tolerant ability or photo-thermo insensitivity, so as to exploit potential of rabi mungbean in rice fallows of heavy rainfall zone.

An experiment was conducted to estimate the combining ability using three females [Cytoplasmic-Genetic Male Sterile (CGMS) Lines], 18 males (testers) and their 54 hybrids developed through line x tester mating design in three diverse seasons (environments). Result of analysis of variance for means revealed significant differences for all the twelve characters. Combining ability analysis over environments revealed importance of both additive and nonadditive components. Close agreement between GCA and per se performance of parents was observed for most of the characters studied. Combination having high per se performance also had high SCA effects and involved at least one good general combining parent. The female parents 28A and 86A and among male parents, KR 125, KR 191, KR 196, PMSC-43, GJ 38, GSF 5 and CSV 21F were good general combiners for grain yield and its component traits. While considering the SCA effects and per se value, 10 hybrids were best for grain yield and component characters. All these hybrids were combination of parents having either good x good or good x poor GCA for grain yield.