Combining ability analysis over environments of diverse pistillate and male parents for seed yield and other traits in castor (Ricinus communis L.)

A 8 x 8 half diallel study carried out in six environments over two seasons indicated that both gca and sea were influenced by environment and observed higher sensitiveness of non additive gene effects to the environmental changes. The ratio of additive to total genotype variance revealed the preponderance of additive gene effects for the inheritance of effective and total length of primary raceme, capsules on primary raceme, nodes upto primary raceme, 100 seed weight and capsules per spike, while spikes per plant and seed yield per plant were mainly governed by non-additive gene effects. Pistillate parent MCP-2 and monoecious male parent RG184 were identified as the best combiners for seed yield and some other traits. Among mostly male parent RG-299 was good combiner for spikes/plant and RG 125 was good combiner for seed weight and nodes upto primary raceme (earliness). Crosses involving mostly male parent could also exhibit high per se and desirable sea effects for seed yield and other traits. It may be concluded that male parent possessing 50% length of primary raceme covered with capsules could be utilized for breeding purpose. Seed yield in castor is governed by multiple path ways, important yield contributing characters at 120 days after sowing (DAS) were capsules on primary raceme, effective length of primary raceme, nodes upto primary raceme ar:l 100 seed weight while capsules per spike, spikes per plant and 100 seed weight were decisive components for seed yield at 240 DAS. These pathways could be combined together or optimized through selection however, considering negative relationship between some traits, use of biparental mating is suggested. To achieve quantum jump in heterosis breeding development of heterotic pool would be useful.