Combining ability studies for seed yield and its component traits in castor (Ricinus communis L.).

Abstract

An experiment was conducted for three consecutive years during kharif, 2014-15 to 2016-17 involving 40 entries viz. two pistillate lines(DPC-23 and M-571), 12 monoecious lines(DCS-64, DCS-86, DCS-102, DCS-105, DCS-107, DCS-108, DCS-109, DCS-110, DCS-112, DCS-118, DCS-119 and DCS-123), their resultant 24 hybrids produced through line x tester mating design and two check hybrids(DCH-177 and DCH-519). These were tested in randomized block design with three replications at AICRP on Castor, Bhawanipatna, Odisha. The data on ten different characters viz. days to 50% flowering of primary raceme, days to maturity of primary spike, plant height up to primary raceme (cm), number of nodes up to primary spike, total length of primary spike (cm), effective length of primary spike (cm), number of effective spikes per plant, number of capsules in primary spike, 100-seed weight (g) and seed yield per plant(g) were recorded in all the three years of experimentation and the pooled mean values were subjected to statistical analysis for combining ability. The general combining ability variance (σ2GCA) was observed to be higher than the specific combining ability variance (σ2SCA) for days to 50% flowering of primary raceme, days to maturity of primary spike, plant height up to primary spike, number of nodes up to primary spike and 100-seed weight, which indicated involvement of additive gene action in the inheritance of these five characters. On the other hand, higher magnitude of σ2SCA as compared to σ2GCA was observed for total length of primary spike, effective length of primary spike, number of effective spikes per plant, number of capsules in primary spike and seed yield per plant indicating preponderance of non-additive gene action in expression of these five characters. Based on the GCA effects, the parental lines DPC-23, DCS-64, DCS-102 and DCS-105 were good general combiners for earliness; M-571, DCS-108, DCS-109, DCS-110 and DCS-119 were good combiners for total length of primary spike and effective length of primary spike and the genotypes M-571, DCS-110 and DCS-112 were good combiners for characters like number of capsules in primary spike, 100-seed weight and seed yield per plant. These parental lines can be utilized in hybridization programme for improvement of the respective characters. Two cross combinations viz., DPC-23 x DCS-123 and M-571 x DCS-105 manifested high and desirable SCA effect for seed yield per plant and for one or more component traits. Besides these two hybrids, other three hybrids viz. M-571 x DCS-110, M-571 x DCS-112 and DPC-23 x DCS-110 were better in per se performance and heterosis with respect to seed yield per plant and also exhibited significant SCA effects for one or more component traits. From the results of combining ability, gene action and components of variance, it is concluded that non-additive gene action was predominant for total length of primary spike, effective length of primary spike, number of effective spikes per plant, number of capsules in primary spike and seed yield per plant which indicated that heterosis breeding would be helpful for improving these traits.