Combining ability for seed yield and its component traits in castor was studied using line x tester mating design involving six diverse pistillate lines and eight inbred lines. The analysis of variance for combining ability revealed that the mean squares due to lines, testers and lines x testers were highly significant for all the characters except mean square due to lines x testers for oil content and indicated that both additive and non-additive gene actions played a vital role in the inheritance of all the traits. The estimates of gca effects for seed yield and its related traits indicated that three lines
viz., SKI-346, JI-397 and JI-399 and one tester namely JP-96 were found good general combiner for seed yield per plant and some of its component traits. The estimation of sca effects of the crosses indicated the six hybrids manifested significant and positive sca effects for seed yield per plant. The best three specific combinations were SKP-106 x SKI-346, JP-96 x JI-397 and SKP-106 x JI-401, which resulted from average x good, good x good and average x poor combiner parents, respectively. The per se performance of hybrids had significant and positive correlation with sca effects for all the traits.