Genetic analysis of seed yield and component characters over environments in castor (Ricinus communis L.)

Abstract

Thirty six castor hybrids developed by half diallel mating design along with nine pistillate parents were studied for combining ability effects. The genotypes, parents and hybrids significantly differed among themselves for all the characters, parents and hybrids also differed among themselves for all the characters except shelling out turn. Significance of both σ2gca and σ2sca for most of the characters suggested importance of both additive and non-additive genetic variances for inheritance of traits. The estimates of potence ratio and predictability ratio revealed preponderance of additive genetic variance for number of nodes up to primary raceme, plant height up to primary raceme, total length of primary raceme, effective length of primary raceme, number of secondary spikes per plant, 100 seed weight, volume weight and shelling out turn. The parents JP-65 and DPC-9 were good general combiners and SKP-84, ANDCP-06-07-1 and ANDCP-06-07 were average general combiners for seed yield and important yield contributing characters. Crosses SKP-84 x JP-65, ANDCP-06-07 x JP-65 and JP-65 x ANDCP-06-07-1 were good specific combiners for seed yield and good / average specific combiners for rest of the characters. The crosses which involved at least one good general combiner parent would produce transgressive segregants. However, for full exploitation of existing genetic variance in these crosses intermating of elite plants in the early segregating generations would be profitable to built up elite population for early and dwarf pistillate lines with high seed yield.