Correlation analysis of SSR markers with growth-related traits of mud clam (Tegillarca granosa)

Growth traits of mud clam (Tegillarca granosa) are quantitative traits. In order to acquire some reliable molecular genetic markers for growth-related traits, the correlation analysis of 12 SSR markers and growth-related traits in T. granosa were analyzed using 150 samples with the fourth-generation selected line of T. granosa. And the correlation and path analysis method were used to analyze the effect of phenotypic character on body weight. Then results showed that the correlations among the quantitative characters reached extremely significant levels. The shell height showed the greatest correlation coefficients to the body weight (0.930). However, the result of the path coefficient analysis showed that the highest path coefficients were the shell width (0.432). The results of the determinant coefficients were consistent with the results of the path analysis. In addition, a total of 61 alleles for the 12 loci were detected (3-8 alleles for each locus), and the average number of alleles and effective number of alleles were 5.083 and 3.038, respectively. The average observed heterozygosity (H_o), expected heterozygosity (H_e) and polymorphism information content (PIC) was 0.528, 0.646, and 0.594, respectively, both of which indicated that the population genetic diversity was high. Correlation analysis between genotypes of SSR and growth traits indicated that 3012-2 had a significant impact on shell length, shell width and shell umbo width. Locus 3564 showed a significant influence on shell height and radial rib width. Locus 2692 showed a significant correlation with shell length. Our results could provide theoretical basis for the study of genetic improvement and selective breeding of T. granosa.