Generation mean analysis was performed using three crosses (DH4xDH5), (DH4xSerw5) and (DH5xSerw5) to study the nature and magnitude of gene effects on vegetative characters, seed yield and oil percentage in canola (Brassica napus L.) under two locations (Mansoura and Assiut). Type of gene action varied with the plant traits, crosses and locations. Genotype x locations interaction was statistically significant in the expression of all the plant traits. Number of components of generation means varied with crosses and locations. Non-additive gene action was involved in most of the traits in different crosses under the two locations.  Also, the results showed that oil percentage (Oil %) trait influenced by types of epistatic gene effect, which included additive x dominance (ad) and dominance x dominance (dd), indicating the role of non-allelic interaction in the genetic expression of this trait. Therefore, it could be concluded that the production of hybrids is the best breeding program for the improvement the studied traits.