Detection of Epistatic, Additive and Dominance Variation in Sunflower (Helianthus Annuus L.)

Three sets of triple test crosses (TTC) with 22 open-pollinated varieties of sunflower (Helianthus annus L.) were evaluated at high (90 kg N/ha) and optimum (50 kg N/ha) levels of nitrogen fertilizer in randomized complete block experiments, Epistasis was an integral part of genetic variation and the additive gene effects were predominant for all traits. The additive effects interacted with environments for seed yield while the dominance effects showed significant interaction for seed yield, plant height, head diameter, 1000-ceed weight and shelling percentage. Narrow sense heritability estimates varied from 46% for seed yield to 77% for shelling percentage.