Model for selecting black gram (Phaseolus mungo Roxb.) varieties for yield and adaptability under partial shade

Abstract

A study on the parameters of variability, correlation and path coefficient were undertaken in twenty black gram varieties to formulate a model for selecting varieties having good yield and adaptability under partial shade. The study was conducted at the Department of Plant Breeding, Vellayani during May to November of 1986. The varieties showed significant differences in most of the characters studied. Genotypic coefficient of variation was maximum for Cercospora leaf spot disease (rating) and minimum for days to pod harvest initiation. High heritability estimate was observed for days to pod harvest initiation. Genetic gain was maximum for Cercospora leaf spot disease (rating). LAX at blooming and LAX at harvest recorded high heritability and high genetic gain indicating the presence of additive gene action. Days through which pod harvest continued, plant height and number of branches per plant showed moderate to high heritability and*genetic gain. At the genotypic level seed yield showed high positive correlation with days to 50 per cent flowering, days to pod harvestinitiation, number of nodes per plant, number of pod clusters per plant, number of pods per plant and number of seeds per pod. Path coefficient analysis projected days to pod harvest initiation, days through which pod harvest continued, number of pods per plant and 100 seed weight as the traits exerting high positive direct effect on seed yield. Days to 50 per cent flowering plant height, number of nodes per plant, number of branches per plant and length of root also exerted positive direct effect on yield. The study indicated that the model for plant selection in black gram under partial shade should be of taller ones with more number of branches, nodes and pods per plant.