Combining ability studies for seed yield traits in sunflower

Syeda Nasreen; Muhammad Ayub Khan; Muhammad Arshad; Maryam Kamal; Doulat Baig; M. Tariq; Talat Gilani; Musarrat Gilani

- Six cytoplasmic male sterile inbred lines and six restorers/testers were selected on the basis of variability for yield related characters. The lines and tester restorers were crossed in a line x tester mating design resulting in 36 F1 hybrids. The potential parents with high general combining ability (GCA) effects were identified for yield related traits. Among females, CMS-H55-2-2-1 expressed the highest significant GCA effects for 1000seed weight whereas female, CMS-303 represented the highest and significant GCA estimates for head diameter, yield and harvest index. Among male parents, RHA-295 expressed the highest significant magnitude for head diameter while SF-187R possessed the highest significant GCA effects for 1000-seed weight, harvest index and moisture contents. Among male parents, the highest significant value for yield was observed in RHA-854. The potential parent lines with highest GCA estimates can be utilized in different desirable combinations for varietal improvement through breeding programme. The cross of CMS-303 x RHA-271 expressed the highest specific combining ability (SCA) value for yield while CMS 303 x RHA-854 hybrid exhibited the highest SCA estimates for harvest index. CMS-53 x RHA-854 and CMS-64 x SF-187 crosses exhibited the highest SCA estimates for head diameter and 1000-seed weight, respectively. The SCA variances were higher than GCA for seed yield and related traits revealing the involvement of non-additive type of gene action controlling the characters. Estimates of proportional contribution of inbred lines, testers and their interaction to total variances for seed yield and related traits indicated the highest contribution of lines x testers in inheritance of all characters except harvest index where the contribution of lines was higher than testers and line x testers. Nonadditive type of gene action can be utilized in a hybrid improvement programme through heterosis breeding in sunflower.