Genetic parameters of selection and stability and identification of divergent parents for hybridization in rice bean (Vigna umbellata Thunb. (Ohwi and Ohashi)) in India

Abstract

SUMMARYFifty-two genotypes of rice bean (Vigna umbellata Thunb. (Ohwi and Ohashi)), an under-cultivated crop, were evaluated in the rainy (kharif) seasons of 2001, 2002 and 2003 in the North Eastern Hill Region, India to select suitable genotypes for cultivation in the North Eastern Hill region and to identify promising parents for hybridization programmes. The germplasm studied comprised 44 Indian and eight foreign genotypes. A wide range of variability was observed for eight characters studied (plant height, number of branches/plant, stem thickness, pod length, number of seeds/pod, 100-seed weight, pod weight/plant and seed yield/plant). Number of days to mid-flowering and number of days to maturity showed little variation. High heritability (0·58) and high genetic advance (0·53) were observed for 100-seed weight, high heritability (0·93) and moderate genetic advance (0·37) for seed yield/plant, and high heritability (0·60) and low genetic advance (0·13) for number of days to mid-flowering. Since the main aim in rice bean breeding is to develop high yielding, early maturing genotypes with low plants, selection was based mainly on the mean performance of these three traits over the 3 years, as well as their stability. One of the genotypes, RBL 1, was very high yielding, although the yield was not stable across years. Another genotype, RBS 24, was very early maturing and had very short plants compared with the other genotypes studied. These two, along with several other genotypes selected, may be promising for a hybridization programme aiming to develop dwarf, early maturing genotypes with high yield. The best yielding genotypes, namely RBL 1, RCRB1-3 and IC 187911, may be recommended for cultivation in the shifting cultivation areas (Jhum) regions of North Eastern India.