Abstract

                                Heterosis and genetic architecture of oil-content in castor (Ricinus communis L.) was studied in a complete diallel set of 11 parents excluding reciprocals. Twenty-five and thirteen crosses, respectively, exhibited significant heterosis over mid parent and better parents. The analysis of variance for combining ability indicated the importance of both additive and non-additive gene-action, however, non-additive gone action was predom- nant, for the inheritance of this trait. The varieties viz, 2-73-11, T-4, 1-21 and Mesalio were the botter general combiners. The crosses viz, "Aruna x HC-8", "Aruna x VI-9" "Aruna x Masalio", "279 x 2-73-11", "279 x Masalio", "Ho HC-8", "Ho x 2-73-11", "Ho x T-4", "413A x VI-9", "413A x Masalio", "1-21 x 2-73-11", "1-21 x T-4", "2-73-11 xvi 9" and "VI-9 x Masalio" possessed higher mean values, significant heterosis, and higher and significant positive SCA effects which can best be exploited for developing higher ail- varieties in castor through further breeding.

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