Heterosis and inbreeding depression for seed yield and its contributing characters in castor (Ricinus communis L.)

The present study was conducted in order to generate genetic information on heterosis and inbreeding depression for seed yield and its contributing characters using generation mean analysis in castor (Ricinus communis L.). The expression of heterosis and heterobeltiosis was maximum for seed yield per plant followed by number of effective branches per plant, number of total branches per plant, shelling out turn and 100 seed weight. For seed yield per plant, all the crosses depicted significant and positive relative heterosis and heterobeltiosis except cross JI 358 x SH 42 which showed only significant positive relative heterosis. These crosses also showed significant desirable heterosis and heterobeltiosis for number of others yield contributing traits. The crosses viz., SKI 324 x PCS 124 and ANDCI 8 x SKI 324 also showed significant and desirable estimates of relative heterosis and/or heterobeltiosis for number of total and effective branches per plant, shelling out turn, 100-seed weight and oil content, while cross ANDCI 10-7 x JH 109 exhibited significant and desirable relative heterosis and/or heterobeltiosis for number of total and effective branches per plant, number of capsules on primary raceme, shelling out turn and oil content. The magnitude of inbreeding depression varied from cross to cross indicating influence of genetic constitution of crosses. Significant inbreeding depression was observed for the characters i.e., days to flowering of primary raceme, days to maturity of primary raceme, effective length of primary raceme, shelling out turn and 100 seed weight in cross SKI 324 x PCS 124; days to maturity of primary raceme, plant height up to primary raceme and number of capsules on primary raceme in cross ANDCI 10-7 x JH 109; days to flowering and maturity of primary raceme, number of total and effective branches per plant, seed yield per plant and shelling out turn in cross ANDCI 8 x SKI 324; days to flowering and maturity of primary raceme, number of total and effective branches per plant, total length of primary raceme, effective length of primary raceme, number of capsules on primary raceme, seed yield per plant, 100 seed weight and oil content in cross JI 358 x SH 42 and days to flowering and maturity of primary raceme, plant height up to primary raceme and shelling out turn in cross ANDCI 10-7 x SKI 324.