Genetic Variation Analysis And Screening Of Microsatellite Markers Associated With Growth Traits In Chlamys Nobilis Reeve

Chlamys nobilis Reeve, which was delicious flavor and nutrient-rich, has been cultured widely in China’s South-East coastal areas and Beibu Gulf rim since successed in artificial breeding. Because of inbreeding in the process of seedling for several decades, germplasm degradation has been existent. Then some negative effects in growth rate, ability of resisting disease and rate of survival were been found in culture populations, which seriously restrict the development of cultivation of Chlamys nobilis. Using method of multivariate statistical analysis and microsatellite molecular marker(SSR), this paper study the phenotypic difference,genetic variation and correlation that between SSR and growth trait in wild population and culture population in order to provide the reference about germplasm breeding and new variety foster in Chlamys nobilis. The following are the main contents and conclusions:1. morphological variations of different populations of Chlamys nobilis Reeve.Using method of multivariate statistical analysis( cluster analysis, principal component analysis and discriminant analysis)and morp--hological measurement data,this paper study study the morphologic-al variations among four populations( Sanya wild population, Sanya cultured population, Dongxing cultured population, Zhanjiang cultured population). Results indicate that cultured populations of Dongxing and Sanya were morphologically grouped together, and Sanya wild population was difference from other three populations. In principal component analysis, four primary components were been obtained. Contribution rate of them was 29.5%, 17.8%, 16%,10% and the total contribution rate was 73.33%.Significant differences were found among the four populations( P<0.01) by discriminant analysis. Study on morphological variations shows that there was significant difference between wild population and culture population.2.genetic variation analysis of different populations in Chlamys nobilis Reeve.By using microsatellite molecular marker(SSR), genetic difference among four populations were researched.60 alleles were tested at the 7 microsatellite loci. Eachlocus tested number of allele was range from 5 to 14, average at 8.57. Average polymorphism information contents of 7 loci in four populations range from 0.574 to0.839. Observed heterozygosity of that range from 0.409 to 0.507 and expected heterozygosity range from 0.721 to 0.827.The Hardy-Weinberg equilibrium analysis indicated that the four populations were deviated from the Hardy-Weinberg equilibrium at different levels. Genetic differentiation index was 0.0253~0.1373,gene flow(Nm) was 1.5708~9.6387. Results showed that gene flow was previous,moderate genetic variation have existed in four populations and cultivation changed the genetic structure of population.3. correlation analysis between microsatellite markers and growth traits in Chlamys nobilis Reeve.By means of correlation analysis, this study filtrated microsatellite molecular marker associated with growth traits in Chlamys nobilis Reeve. The results showed that Cn121 and Cn103 had a significant correlation with body width( P<0.05),Cn132 had a significant correlation with body height, Cn103 had a significant correlation with body weight. Allele B of locus Cn121 was speculated positive on body width. At locus Cn103, allele E was speculated positive on body width and weight. About body height, allele E, F was speculated positive and allele H was negative.