Combining Ability of Sunflower Inbred Lines under Drought Stress

Abstract Sixteen sunflower hybrids obtained by crossing between four CMS and four restorer lines as tester were evaluated for combining abilities of agronomic traits under optimum and water limited conditions using line×tester mating design. There was considerable variability among genotypes for the traits in both normal and stressed experiments. The results indicated that the lines AGK344 and AGK148 with suitable GCA for early maturity and plant height respectively and AGK52 for oil content and seed and oil yield were desirable combiner under both optimum and stressed condition. In other hand, AGK344 expressed a significant GCA for plant height in suitable direction under stressed condition. Among the testers RGK26 and RGK56 had suitable GCA for days to maturity under both conditions. RGK56 and RGK26 were appropriate combiner for oil content under optimum and water stressed conditions respectively the later had desired GCA for seed and oil yield under water stressed condition too. According to the results, there was differentiate GCA of testers for days to flowering, seed weight and oil content in normal and stressed condition. Differential expressions of GCA in parent inbred lines indicated that selection of restorer lines for the agronomic traits would be more efficient than the selection of CMS lines. It is concluded that heritability of a trait determines the kind of SCA in response to different environments and the SCA effects are more stable for traits with higher heritability.