Gene effect and combining abilities for plant height and head diameter in sunflower

Abstract

Plant height and head diameter are important parameters which effect on a yield in sunflower. Six restorer Rf lines, three tester A lines and their 18 Fl hybrids were studied, using line x tester method. Significant differences were found between restorer lines and testers and their Fl hybrids for plant height and head diameter. Regarding the inheritance of examined characteristic, super dominance and dominance of better parent occurred, and the intermediary too. Tester line HA-48A (188.25 cm) and Fl hybrid HA-48A x RHA-SELEUS (245.10 cm) had the highest mean value for plant height, and the lowest value had line RHA-BRE-1 (105.35 cm) and hybrid L-19A x RHA-BRE-1 (147.9 cm). For head diameter, the highest mean value had line L-19A (19.02 cm) and Fl hybrids HA-48A x RHA-TR-20 and L-19A x RHA-TR-20 (24.55 cm), and the lowest line RHA-BRE-1 (13.10 cm) and hybrid HA-26A x RHA-M-72 (20.25 cm). Based on the results, the following conclusion is that lines RHA-BRE-1 for plant height and RHA-SELEUS for head diameter have the best GCA, and the best SCA have hybrids L-19A x RHA-BRE-1 for plant height and HA-26A x RHA-SELEUS for head diameter. Analyzing components of genetic variance, the nonadditive component played the main role in the inheritance of plant height and the additive of head diameter. The largest average contribution in the expression of plant height had the tester A-lines (83.17%) and for head diameter Rf lines had the greatest influence (58.13%).