Abstract:29 sib-families of Fenneropenaeus chinensiswhich were obtained by selective breeding were artificially infected with WSSV.29 samples with the longest survival time composed the WSSV resistant group and 29 samples with the shortest survival time composed WSSV-susceptible group. Random amplified polymorphic DNA (RAPD) technique was employed to analyze these samples. The results were that 5 distinctive genetic markers with disease resistant trait and 2 distinctive genetic markers with disease susceptible trait were obtained. The genetic diversity of two groups was studied with 15 primers. 82 sites (DNA bands) were revealed, 34 of which were polymorphic, representing a percentage of 41.46%. The proportions of polymorphic amplified fragments of the WSS resistant group and the WSSV susceptible group were 40.24% and 37.8%, respectively. The mean Shannon's index of genetic diversity in two groups was 0.2177. And the Shannon's index of the WSSV resistant group was 0.2190, which was a little higher than that of the WSSV susceptible group’s 0.2163. The average genetic variability of intra polulation（H-POP/H-SP）was 0.964 5, indicating 96.45% of genetic variability was from intra-polulation while 3.55% was from inter-polulation. The genetic differentiation index analyzed with the gene frequency of each site was 0.0294 that indicated no genetic differentiation.
