The germplasm of breeding large yellow croaker(Pseudosciaena crocea Richardson)was revealed using 12 microsatellite markers.The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min-Yue stocks and two hybrid groups,as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity.The value of pairwise differentiation coefficient(FST)was only 13.1% between Daiqu and Min-Yue stocks,demonstrating the low level of differentiation and a close relationship.However,STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures.Examinations of individual admixture showed that Min-Yue stock had been contaminated by alien individuals.Moreover,the genetic structures of the two hybrid groups resembled those of their parents,especially affected more by their female parents.Finally,the values of average observed heterozygosity between parents and their ascendants were compared and tested,as a result of no detectable differences(P>0.05). The germplasm of breeding large yellow croaker (Pseudosciaena crocea Richardson) was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min-Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pairwise differentiation coefficient (FST) was only 13.1% between Daiqu and Min-Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different different populations of the same species with distinct genetic structures. Examineinations of individual admixture showed that Min-Yue stock had been contaminated by alien individuals.Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents .Finally, the values ​​of average o bserved heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences (P> 0.05).