Abstract:Inheritance of S-gene in apricot was studied with 4 - 5 years old Katy(self-compatibility) ,Xinshiji ( self-incompatibility) , and F1 progenies from Katy ×Xinshiji, Katy ×Hongfeng ( self-incompatibility) and Katy ×Taianshuixing ( self-incompatibility) as materials. Self-compatibility was determined by investigating fruiting percentage of self-pollination in fields, and S-genotypes were detected by S-allele specific PCR. The results were as follows: according to the standard that fruiting rate of self-pollination in self-compatible cultivar was higher than 6%, the ratios of self-compatible to self-incompatible seedlingswere 27∶25, 9∶12 and 15∶19 in the above three families, respectively, and they were proved to be a 1∶1 segregation by X2 test, so it could be concluded that the self-compatibility of Katy was transferable and heterozygous, and self-compatibility was dominant to self-incompatibility. Ulterior 38 seedlings from the F1 population of Katy (ScS8) ×Xinshiji (S9S10) crosswere studied bymeans of S-allele-specific PCR, and four S-genotypes, 21 (ScS8 ,S8S9 ) ∶9 (ScS10 ) ∶8 (S8S10) , were amp lified which were confirmed to 1∶1∶1∶1 expected ratio by X2 test, but the self-compatibility represented quantitative character and the fruiting percentage of self-pollination separated widely in hybridswith the same S-genotype, then it indicated that self-compatibility in apricot was not only determined by S-gene or S-genotypes, but also affected by other factors, such as modifying genes.