NAGENDRA RAO, KANUHYA, VALLURI2020-03-042020-03-042019http://krishikosh.egranth.ac.in/handle/1/5810144187D5957The present investigation was carried out at Agricultural Research Station, Ghantasala, Krishna Dt., Andhra Pradesh during Rabi 2018-19 to generate information on the nature and extent of the genetic variability, genetic divergence, correlation and path analysis in 50 genotypes of blackgram for 18 characters viz., days to 50% flowering, days to maturity, plant height (cm), number of branches per plant, number of clusters per plant, number of pods per plant, number of seed per pod, 100 seed weight (g), pod length (cm), seed yield per plant (g), specific leaf weight (g cm-2), leaf nitrogen content (g m-2), total biomass per plant (g), harvest index (%), number of nodules per plant, weight of nodules per plant (mg), leaf area index and specific leaf area (cm2 g-1). Analysis of variance revealed the presence of significant differences among the 50 genotypes for all the traits studied. The genotypes viz., MBG 1069, TGBG 136, VBG 4-14, Buttaminumu and OBG 40 showed higher mean values, high GCV and PCV, high heritability and genetic advance as per cent of mean for yield contributing characters viz., number of branches per plant, number of clusters per plant, number of pods per plant, seed yield per plant among yield characters and total biomass per plant, harvest index, number of nodules per plant and leaf area index among physiological characters suggesting an ample scope for selection of these characters in rice fallow blackgram. Genetic divergence estimated by using Mahalanobis‟ D² statistic, grouped the 50 genotypes into 17 clusters. Out of 17 clusters, cluster I was the largest comprising of 32 genotypes followed by cluster X with three genotypes and the clusters II, III, IV, V, VI, VII, VIII, IX, XI, XII, XIII, XIV, XV, XVI & XVII are solitary (one genotype). The genotypes MBG 1069, TGBG 401, MBG 1050, VBG 13-003 and TADTU 45 have showed maximum inter-cluster distance in Mahalanobis‟D2 analysis, while PCA analysis revealed the genotypes, MBG 1069, TADTU 45, OBG 40 and Buttaminumu as more divergent genotypes. Combining both D2 and PCA, the genotypes MBG 1069 and TADTU 45 are viewed as more divergent. xiv Genotypic correlations in general were higher than phenotypic correlations indicating that the apparent associations are largely due to genetic reasons. The traits days to 50% flowering, plant height, number of clusters per plant, number of pods per plant, number of seeds per pod, 100 seed weight, pod length, leaf nitrogen content, harvest index, number of nodules per plant, weight of nodules per plant and leaf area index were found to possess significant positive association with grain yield per plant at both genotypic and phenotypic levels, thus revealing the possibility of simultaneous selection of all these characters for yield improvement. Path coefficient effects can be concluded as high direct effects were shown by days to 50% flowering, number of pods per plant, total biomass per plant, harvest index and number of nodules per plant at phenotypic level. High direct effects for days to maturity, plant height, number of seeds per pod, total biomass per plant, harvest index, weight of nodules per plant are shown at genotypic level. The character number of pods per plant showed high genotypic and phenotypic coefficient of variation, high heritability, high genetic advance as per cent of mean, higher positive significant correlations with seed yield per plant and higher positive direct effects. Hence, number of pods per plant could be considered as most efficient selection criteria for yield improvement in rice fallow blackgram.en-USnullThesis