Evaluation of the Combining Abilities and Gene Effects of Agronomic Traits in Sunflower Inbred Lines (Helianthus annuus L.)

Information about combining ability of inbred lines and genetic variance components of different agronomic traits is a prerequisite for improving the productivity of sunflower hybrids. For this purpose, 20 hybrids obtained from the crosses between five cytoplasmic male sterile lines with four fertility restorer lines were evaluated in a randomized complete blocks design with three replications in the Agricultural Research Station, University of Tabriz, Tabriz, Iran in 2009. Analysis of variance indicated significant differences between the hybrids for most traits and therefore it was possible to estimate genetic variance components through line × tester method. Results showed that plant height, head diameter, 1000-seeds weight and oil content were under the control of additive gene effects. Over dominance gene effects were observed for time of flower initiation, stem diameter and grain yield. This justifies the production of hybrid varieties. Male sterile line 52 and R50 restorer line had a better general combining ability for seed yield. Hybrids 52 × R26 and 222 × R50 had the highest specific combining ability. The results of this study indicated that due to existence of genetic variability for agronomic traits in genetic materials and presence of combinations with suitable combining ability, production of superior sunflower hybrids is feasible by selection and hybridization.