Abstract: Using five varieties of upland cotton with different oil content as their parents,the genetic effects and genetic parameters of oil contents were analyzed in Hayman’s diallel genetic model with Griffing’s diallel system II. The results showed that oil content followed the “additive-dominant” model, and the additive effect, which accounted for 64.2% of total variance components, had a more important effect on the inheritance of oil content. The regression of cottonseed oil content between Wr and Vr implied that the parent E9 had more dominant genes, while 1011 and 1017 had more recessive genes. Narrow-sense heritability for oil content was as high as 49%, which suggested that to improve the cottonseed oil content, we should use high oil content lines as parents and carry out selection in early generation.

Key words: cottonseed, oil content, additive effect, dominant effect, heritability