Gene actions for seed yield in sunflower (Helianthus annuus)

Abstract

Effects of additive and dominant genes and their interactions on the inheritance of seed yield in 10 sunflower hybrids developed by crossing five inbred lines derived from the synthetic NS-S-1 were analyzed in 2001 and 2002. Relationships among the expected mean values of the progenies were checked by the scaling method (Mather, 1949). Gene affects and mode of inheritance were estimated by generation mean analysis (Mather and Jinks, 1982). The additive-dominant model was not adequate for all crosses over the two years. Epistatic gene effects played a dominant role in the inheritance of seed yield in a large number of the crosses. Duplicate epistasis between dominant decreasers and complementary epistasis between dominant increasers were each expressed in a single cross while duplicate epistasis between dominant increasers was expressed in the other crosses. Thus it ensures that sunflower geneticists and breeders should take into account the existence of epistasis in order to facilitate the selection of the method to be used for improvement of a particular trait.