Heterosis for seed yield and yield components over environments in castor (Ricinus communis L.)

Investigation with 10 diverse inbreds, their 45 hybrids (generated by diallel mating design excluding reciprocals) along with two standard checks viz; GCH-4 and GCH-5 was taken up over four environments (two fertility levels and two sowing dates) to determine the extent of heterosis of seed yield and eight component traits. The heterobeltiosis and standard heterosis over GCH-4 and GCH-5 for seed yield/plant across the environments ranged from -13.71% to 47.89%, -25.08% to 22.77% and -31.62% to 12.04% respectively. SKI-280 x SH-41, SKI-280 x SKI-288, SH-41 x SKI-285, SKI-280 x SKI-215, SKI-288 x SH-41, SKI-288 x SKI-232, SKI-218 x SKI-232, SKI-215 x SH-41, SKI-288 x SKI-285, SKI-215 x SKI-285, SKI-232 x DCS-9 and SKI-215 x SKI-232 had significantly out yielded their better parent while SKI-232 x DCS-9 was significantly superior over GCH-4. Across the locations, the cross SKI-232 x DCS-9 produced the highest 182.28g of seed/plant and registered 30.49%, 22.77% and 12.04% superiority over better parent, GCH-4 and GCH-5 respectively. Magnitudes of heterosis vary from character to character and cross to cross. In general, for seed yield/plant across the locations magnitude of desirable heterosis was high over batter parent but low over standard checks. For developing high yielding and earlier maturing genotypes, selection of crosses on the basis of per se performance with considerable per cent heterobeltiosis and standard heterosis would be more desirable.