Gene action and combining ability analysis for seed yield components of Jatropha curcas L.

Forty five cross combinations were produced by a half diallel-mating system using ten germplasm for gene action and combining ability analysis in Jatropha curcas L. The results showed presence of genetic diversity among the parents for all the characters. Moreover, the estimates of o2 GCA and o2 SCA revealed involvement of both additive and non-additive gene action in the inheritance of all the traits under investigation but the magnitude of non-additive gene effects was very high for all the traits. Amongst parental lines, NRCJ-1and NRCJ2 were best general combiners for plant height, collar diameter, number of branches, branch length, seed yield, number of female flowers and oil content. The most promising specific combiners for seed yield were NRCJ2 x NRCJ-8, NRCJ-3 x NRCJ-9 and NRCJ-6 x NRCJ-7 and for oil content were NRCJ-3 x NRCJ-9, NRCJ-2 x NRCJ-5 and NRCJ-2 x NRCJ-4. These crosses were found to involve at least one parent with high GCA (General Combining Ability) effect and other parents having either high, average or low GCA effect indicating the involvement of additive as well as non-additive gene action operating in these crosses. In this study, the nonadditive gene action played an important role in the inheritance of all seed yield traits, which justifies the role of heterosis breeding for rapid improvement of Jatropha curcas L.