Heterosis is the increase or decrease in vigor of F1 over its mid or better parental value. One of the objectives of present study was to estimate the extent of heterosis for various characters and to isolate promising hybrids over standard check hybrids for seed yield and oil content for commercial exploitation. The development of new high yielding and stable sunflower hybrids were based on hybridization which requires information on the heterotic effects for agronomically important traits in the F1 generation. Heterotic effects for seed yield and it’s attributing traits viz., plant height and head diameter, number of seeds per head, seed filling (%), 100 seed weight (g), 100 seed kernel weight (g), volume weight (g/100cc), hull content (%), oil content (%) and oil yield (kg/ha) were studied in the sunflower hybrids developed by the line x tester method. There are significant differences among the sunflower genotypes (inbred lines and F1 hybrids) we tested with regard to the mean values of all the traits involved. The male restorer inbred with good combining abilities were used as lines in the form of fertility restorers and CMS lines as Testers. There are significant differences among the sunflower genotypes (inbred lines and F1 hybrids) we tested with regard to the mean values of all the traits involved indicating considerable amount of heterosis foe most of the traits except hull content (%), oil content and seed filling per cent. Most of the crosses exhibited high heterosis especially for number of seeds per head seed yield (kg/ha) and oil yield (kg/ha). However, mean heterosis was comparatively low for hull and oil contents. The study on heterosis in sunflower showed that the crosses with favorable characteristics such as oil and seed yields, oil and hull contents could be bred from correctly selected parents. The cross CMS-853A X EC-623027 reached the breeding aim mentioned above, especially for high vigor in seed and oil yields. CMS-103A X EC-601878 and PET-89-1A X EC-601878 showed the negative heterosis for thin hull rate and high oil content.
Under present study, the genotypes, EC-601878 and EC-601751 with regard to all measured traits, CMS-852 A, CMS-103A and P-89-1A for seed yield, oil content and low hull rate could be used for increasing hybrid vigor in future sunflower breeding programs sunflower as well as the genotypes, viz., CMS 852A, CMS-853A and EC-623027, EC-623023 appeared to possess high concentration of additive genes for seed yield and component traits and, therefore, these parents can be considered as the good combiners for heterosis breeding programme for seed and oil yield improvement in sunflower.