The present research was conducted in Line X tester analysis for estimating combining ability and heterotic effects,restorers malesterile(CMS) crossed with seven tester lines 3x7 21 F_1 hybrids of sunflower were further used to estimate their general combining ability(GCS),specific combining ability(SCA) and heterosis effects on main traits of sunflower during 2009.For this study,seven lines of sunflower were tested with three testers 7x3 of sunflower to obtain twenty one F_1 genotypes from Line X tester mating design.It was concluded from present study that among the lines,0505 Cms-6,Peshawer-93 Cms-11,Peshawar-93 Cms-12 were the best general combiners to play the vital role in flowering,maturity,plant height,head diameter,seed index,grain per head and 100-grain yield per plant.While RHP-53,RHP-42,RHP-46 were also the best combiners for all the traits.However,hybrid 54CMS-1 x RHP-42 showed best specific combiners,while Peshawer-93 exhibited good specific combiners for grain yield per plant,the hybrids,plant height,head diameter,seed index,grain per head and grain yield per plant,respectively.Significant differences among the tested sunflower genotypes with regard to mean values of all the investigated traits were determined.The analysis of variance of combining abilities and the analysis of genetic variance components confirmed the non-additive component. The present research was conducted in Line X tester analysis for estimating combining ability and heterotic effects, restorers malesterile (CMS) crossed with seven tester lines 3x7 21 F_1 hybrids of sunflower were further used to estimate their general combining ability (GCS), specific combining ability (SCA) and heterosis effects on main traits of sunflower during 2009.For this study, seven lines of sunflower were tested with three testers 7x3 of sunflower to obtain twenty one F_1 genotypes from Line X tester mating design. among the lines, 0505 Cms-6, Peshawer-93 Cms-11, Peshawar-93 Cms-12 were the best general combiners to play the vital role in flowering, maturity, plant height, head diameter, seed index, grain per head and 100-grain yield per plant. Whh RHP-53, RHP-42, RHP-46 were also the best combiners for all the traits. Still, hybrid 54CMS-1 x RHP-42 showed best specific combiners, while Peshawer-93 exhibiting good specific combiners for grain yield per plant, the hybrids, plant height, head diameter, seed index, grain per head and grain yield per plant, respectively .Significant differences among the tested sunflower genotypes with regard to mean to the mean values ​​of all the investigated traits were determined. The analysis of variance of combining abilities and the analysis of genetic variance components confirmed the non-additive component.