Estimates of genetic parameters of growth-related traits for the selective breeding of deep-cupped shell Crassostrea hongkongensis

In order to breed a new strain with deep-cupped shell of Crassostrea hongkongensis and better growth traits, a breeding program of truncation selection was initiated based on the 2-year-old culture population of wild C. hongkongensis collected naturally from Taishan Town Bay, Guangdong Province. The index of shell depth was used as an indicator, with 10% retention rate and 1.755 selection strength. The genetic parameters including selection reaction, genetic gain and realized heritability in larval stage, intermediate cultivation stage and later grow-out stage were estimated. The results showed that the shell height and index of shell depth in selected group were higher than those in control group, and the genetic parameters increased with the growth of individuals, showing a favorable genetic improvement potential. The average selective reaction, genetic gain and realized heritability of shell height at larval stage was 0.363±0.167, 1.678%±0.416% and 0.207±0.095, respectively; at intermediate cultivation stage was 0.639±0.115, 7.618%±2.666%, and 0.364±0.065, respectively; and later grow-out stage was 0.668±0.179, 8.861%±3.072% and 0.381±0.102, respectively. At the later grow-out stage, the average selective reaction, genetic gain and realized heritability of index of shell depth was 0.748±0.066, 9.090%±0.565%, and 0.426±0.038, respectively. The research provided useful data for the breeding of a new strain with deep-cupped shell and good growth traits in C. hongkongensis.