Inheritance of Yield and Its Components in Castor

A diailel involving 17 diverse varieties of castor (Ricinus communis L.) was examined for comb ining ability analysis. General and specific combining ability effects were significant for number of nodes to flower, number of capsules per primary spike, seed yield per plant and 100 seed weight but only general combinig ability was significant for plant height and primary spike length. The tall cultivars such as 'HC-8", 'PB 1′ and 'T 1′ were better combiners for primary spike length, seed yield and 100 seed weight. Among dwarf or midtall parents, ‘Bhagya’.'1– 21′ and'Aruna' were better combiners for dwarfing, number of nodes to flower and number of capsules per primary spike. The dwarf × tall crosses were the highest yielders with longest primary spikes and more number of capsules per primary spike. Thus hybridization between dwarf × tall parents appeared to be a useful procedure for the improvement of seed yield and plant type in castor. Heritability of plant height, number of nodes to flower and 100 seed weight was 0.66, 0.83 and 0.76 respectively while heritability or primary spike length, number of capsules per primary spike and seed yield per plant was 0.54, 0.57 and 0,40 respectively. Thus, while pedigree breeding method can rapidly improve plant type, spike characters and 100 seed weight, alternate breeding methods which utilize dominance are warranted for rapid improvement of seed yield per se.