Evaluation of Combining Ability of Sunflower Lines Based on Line × Tester Analysis under Water Stress and Non-Stress Conditions

In order to investigate the combining ability of sunflowers lines under normal conditions and drought stress، a study was conducted at the Seed and Plant Improvement Institute، Karaj، Iran in 2006. A total of 41 treatments including 2 CMS and 13 restorer lines as well as their 26 corresponding hybrids were evaluated in two irrigation conditions، in a line x tester approach. The analysis of variance indicated that significant differences existed among genotypes، parents، parents against crosses، crosses and testers for most of the studied traits. The effects of lines were significant for days to maturity، plant height and grain yield in non-stress conditions، and for most of the traits in stress condition s. The effect of line × testers was significant for seed weight in non-stress condition، and for days to flowering، seed yield، plant height and oil yield in stress condition. Assessment of general and specific combining abilities showed that CMS19 (tester) and CMSb × R7 were best line and hybrid in both conditions، respectively.