Genetic variability, character association and genetic divergence studies in castor (Ricinus communis L.)

Castor (Ricinus communis L.) is an important inedible oilseed crop which, has a great value in industry, pharmaceutical and agricultural sectors. The present study aimed to estimate the nature and magnitude of variability present in castor genotypes with respect to yield and its contributing traits. A study with 15 genotypes on variability, correlation, path and genetic divergence was carried out for thirteen characters. The variability in oil content ranged from 46.75% to 51.71%. The genotypic and phenotypic coefficients of variation were high for number of capsules on main raceme. Positive association of number of nodes up to primary raceme and total length of primary raceme was observed with seed yield per plant hence, these traits may be directly attributed for the improvement of seed yield. The path coefficient analysis demonstrated that utmost positive direct effect on seed yield per plant was exerted by total length of primary raceme (0.62). Mahalanobis D2 statistic grouped the 15 genotypes into seven clusters. Number of capsules on main raceme contributed much to the total genetic divergence. Selection of genotypes from diverse clusters like cluster II and V, and cluster II and VII for hybridization programme would help in achieving novel recombinants. In conclusion, for the improvement of seed yield the main emphasis should be given on total length of primary raceme and number of nodes up to primary raceme. However, shelling out turn should also be taken into account to improve oil percentage.