Genetic analysis of greengram genotypes for shade tolerance

Abstract

An investigation was carried out to evaluate the shade tolerance potential of 25 genotypes of green gram under partially shaded coconut gardens in the Department of Plant Breeding and Genetics, College of Agriculture, Vellayani. The genotypes were evaluated in a randomised block design with three replications and observations were recorded for nineteen quantitative characters. The genetic parameters, correlation and path coefficients were studied and a selection index was formulated to identify superior genotypes. The genotypes showed significant differences for all the characters except incidence of pod borer Measurement of periodical shade intensity did not show significant difference among the plots which indicated the prevalence of uniform shade. High genotypic coefficient of variation was observed for leaf area index (flowering) followed by number of abnormal, oblique, unfilled pods, LAI (pod formation), pod clusters per plant and pods per plant. High heritability coupled with high genetic advance was recorded for pods per plant, LAI at flowering and pod formation and pod clusters per plant indicating additive gene action. Correlation studies indicated that pods per plant followed by branches per plant, clusters per plant, photosynthetic efficiency (flowering) and LAI (flowering) showed strong positive correlation with grain yield whereas days to blooming, days to first harvest and grains per pod recorded negative

correlation.

The path coefficient analysis revealed high positive direct

contribution of pods per plant to grain yield per plant. In addition, pod length and plant height also showed positive direct contribution to grain yield per plant. A selection index was constructed based on grain yield per plant and 9 yield contributing characters identified through correlation and path analysis. Five top ranking genotypes viz. IIPRM 3, MGG 314, RMG 353, Ganga 4 and LGG 460 were identified for cultivation under partially shaded condition of coconut garden and for further breeding programme.