Genetic evaluation of F2 generation of intervarietal crosses in greengram (vigna radiata (L.) wilczek)

Abstract

A research programme was carried out at the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani during 2000-2001 with the objective of assessing the potential of F2 progenies of greengram in terms of variability and correlation with respect to yield, yield attributes and shade tolerance. Fifteen F 2 progenies derived from intervarietal crosses were evaluated under the partial shade of coconut garden adopting a randomised block design with three replications. Data collected for seventeen characters were subjected to statistical analysis. Coefficient of variation, heritability, genetic advance, correlation and path coefficients were estimated. The 15 F 2 progenies revealed significant difference for all the characters. However, measurement of periodical shade intensity did not show significant difference among the plots indicating the prevalence of uniform shade. Phenotypic and genotypic coefficient of variation were high for grain yield, leaf area index, number of pods per plant, photosynthetic efficiency, harvest index and 100 seed weight. High heritability coupled with high genetic advance was observed for harvest index, grain yield, number of pods per plant, 100 seed weight and photosynthetic efficiency. Correlation studies indicated that the characters leaf area index, . photosynthetic efficiency, number of seeds per pod, 100 seed weight and harvest index exhibited significant positive correlation with grain yield whereas days to 50 per cent flowering and days to maturity recorded significant negative correlation. Among yield components, photosynthetic

efficiency and harvest index exhibited significant positive correlation with number of seeds per pod and 100 seed weight. Photosynthetic efficiency exhibited the highest positive direct effect on grain yield followed by harvest index. Negative direct effect on grain yield was recorded for number of seeds per pod, days to maturity and days to 50 per cent flowering. It can be concluded from the present study that under partially shaded condition, photosynthetic efficiency and harvest index are the most important yield components which can serve as selection criteria for better yield in greengram. Accordingly the genotypes T 7 (Ganga 4 x Pusa Baisakhi), T 5 (LGG 460 x Philippines), T I (IIPRM 3 x Philippines), T 2 (Ganga 4 x Philippines) and TI4 (RMG 353 x CO-2) and Tlo (LGG 460 x Pusa Baisakhi) may be selected for further work.