Abstract: Self_incompatibility in Brassica is controlled by a single multi allelic locus (designated as S locus) that is responsible for pollen recognition on the stigma surface. SLG and SRK are thought to be the key molecules of self_incompatibility in Brassica. This article reviewes the identification, structure and function of S locus genes (including SLG, SRK and pollen S gene), and some aspects on signal transduction pathway involved in self-incompatible reaction.