Heritability and combining ability of vegetative growth and phenological development of diallel crosses of rapeseed

Abstract

To estimate combining ability and heritability of F2 populations of 4 x 4 full diallel crosses and parents, an experiment was carried out at The University of Agriculture, during 2012-2013. Four parental lines and F2 populations of six direct and six reciprocal crosses were planted in the experiment using RCB design. Data were recorded on phenological and vegetative growth traits: Days to flowering, plant height, main stem length, main raceme length, primary branches, and days to maturity. Analysis of variance revealed significant variation among genotypes for all the parameters studied. The results of combining ability analysis showed that general combining ability (GCA) was highly significant for primary branches plant-1, significant for plant height and days to physiological maturity and non-significant for the remaining traits. Specific combining ability (SCA) and reciprocal effects (RE) were significant for plant height, days to flowering, main raceme length and days to physiological maturity. Genotype AUP-401 was best general combiner for main raceme length, primary branches plant-1 and days to physiological maturity. Among the crosses, AUP-404 x AUP-402 was best specific combiner for plant height, days to flowering and main stem length. Broad sense heritability was high (>70%) for plant height, main stem length and primary branches. Moderate heritability was observed for main raceme length, days to 50% flowering and days to physiological maturity. The variance components of SCA were greater than respective GCA components of all the characters signifying the presence of non- additive genetic effects in transfer of these traits and selection in the later generations should be practiced for improvement of these traits.