Estimation of genetic parameters for growth relevant traits in adult Pacific abalone (Haliotis discus hannai)

Pacific abalone (Haliotis discus hannai) is one of the most valuable aquaculture species in China. However, the rapid development of the aquaculture industry has caused problem of germplasm degeneration. It is important to carry out genetic improvement of economic traits for H. discus hannai. This study was conducted to estimate genetic parameters of growth traits in Pacific abalone to provide a database for selective breeding programs. Data of 10 growth-related traits-shell length (SL), shell width (SW), shell height (SH), shell weight (SWT), wet weight (WW), foot muscle weight (MW), soft tissue weight (STW), visceral mass weight (VW), foot muscle weight/wet weight ratio (MWR) and soft tissue weight/wet weight ratio (SWR)-were collected from 1059 adults sampled from 115 families. Significant growth differences existed between abalone under different culture modes. Abalone with red shell colour presented poorer growth performance than the normal shell colour group, and their hybrids displayed mid-parent heterosis. The heritability values of SL, SW, SH, SWT, WW, MW and STW were 0.65 +/- 0.06, 0.63 +/- 0.06, 0.51 +/- 0.08, 0.59 +/- 0.09, 0.54 +/- 0.05, 0.43 +/- 0.08 and 0.43 +/- 0.08, respectively, indicating high heritability. The heritabilities of VW and MWR were moderate, with estimates of 0.36 +/- 0.07 and 0.21 +/- 0.06, respectively, and SWR had low heritability with value of 0.17 +/- 0.06. Genetic and phenotypic correlations among the growth traits were positive, in the ranges 0.24-0.99 and 0.12-0.99 respectively. Genetic correlation coefficients among most of the growth traits were close to or higher than 0.9. The results of this study demonstrate the genetic improvement potential of Pacific abalone in selective breeding. Traits such as SL, SW, SH and WW could be selected and improved simultaneously.