Heritability estimation and path analysis for growth traits of the razor clam Sinonovacula constricta under high salinity

Abstract

Estimating of narrow-sense heritability is often the initial step in an applied animal selective breeding program. To summarize the proportion of variance due to genetics, a total of 26 families of razor clam Sinonovacula constricta were used to estimate the heritability of growth traits under high salinity (30 ppt). Path analysis for growth traits was conducted to clarify the correlation between shell length (SL), shell height (SH), shell width (SW), and body weight (BW). Significant differences in the absolute growth rate of the growth traits were detected among different families. A moderate-to-high heritability of SL, SH, SW, and BW was observed, which were 0.345 ± 0.252 (mean ± SE), 0.507 ± 0.229, 0.203 ± 0.242, and 0.497 ± 0.225, respectively. Genetic and phenotypic correlation analysis showed SL, SH, SW, and BW had a highly significant positive correlation to each other (P < 0.001). The genetic and phenotypic correlation between SL and SH was the highest. Pearson correlation coefficient indicated that SL, SH, SW, and BW showed highly correlation to each other except for the moderate correlation between SL and SW. Path analysis showed that SH and SL had the potential to indirectly reflect BW when selective breeding of razor clams was employed. This study provides guidance for the selection of new high-salinity tolerant varieties of razor clam. It also highlights SH and BW as the best candidate traits for selective breeding.