Abstract: By using eight microsatellite loci (M1, M2, M3, M4, M5, M6, M7 and M8), the genetic diversity of three Pinctada fucata populations from the pearl farms in Xuwen of Guangdong and Beihai of Guangxi, and from the experimental base of South China Sea Fisheries Research Institute in Hainan was studied. A total of fifty eight alleles of these eight microsatellite loci were detected, among which, the observed allele number was 2-9, average effective allele number was 3.72-5.06, average observed population heterozygosity was 0.41-0.56, and average observed expected heterozygosity was 0.67-0.75. All the three populations had a polymorphic information content (PIC) of 0.62-0.70, suggesting their high polymorphism (PIC>0.5). Among the three populations, the cultured population from the experimental base of South China Sea Fisheries Institute had the highest polymorphism, and that from Beihai of Guangxi had the lowest one. These results provided useful information for the selective breeding and germplast conservation of P. fucata

Key words: Extract of non-preferable plant, Panonychus citri, Oviposition repellency