Assessment of combining ability and heterosis for seed yield and its attributes in Sunflower ( Helianthus annuus L.)

The present study employed three lines and fifteen testers to assess the combining ability and standard heterosis of forty-five hybrids developed through a line x tester mating design. The analysis of variance for combining ability revealed significant variation in the mean sum of squares of parents, testers and the interaction between lines and testers regarding seed yield per plant and its related traits. Among the parents, testers GMU 498 and RHA 378 exhibited superior performance for seed yield/plant. In the hybrids, COSF 6AxCSFI 1862, HA 89AxGMU 1000 and HA 89AxRHA 378 demonstrated significantly better seed yield per plant compared to the checks. The variance for specific combining ability (SCA) exceeded that for general combining ability (GCA), indicating that all traits were governed by non-additive gene action. Among the lines, COSF 12A was identified as a good general combiner for yield-contributing traits, while the testers CSFI 1862, GMU 1000 and GMU 498 were recognized as good general combiners for seed yield per plant. Five hybrids, namely HA 89A x RHA 378, HA 89A x GMU 1000, COSF 12A x CSFI 1855, COSF 6A x CSFI 1862 and COSF 12A x GMU 311, exhibited significantly positive SCA for seed yield per plant. Heterosis over the standard checks (DRSH 1, COH 3 and GK 2002) was estimated and the hybrids HA 89A x GMU 1000 and COSF 6A x CSFI 1862 showed positive significant heterosis for seed yield per plant and related traits. The promising hybrids HA 89A x GMU 1000, HA 89A x RHA 378 and COSF 6A x CSFI 1862 were selected based on their mean performance, SCA effects and standard heterosis for seed yield per plant and its attributes.