深凹壳型香港牡蛎选育群体生长性状的遗传参数估计

为了培育壳型和生长性状优良的深凹壳型香港牡蛎新品系,以广东台山镇海湾野生香港牡蛎天然采苗的2龄养殖群体为基础群体,以壳型指数D为指标,按照10%留种率和1.755选择强度,利用截头法进行深凹壳型香港牡蛎的群体选育;分析了幼虫期、中间培养期、养成后期的选择反应、遗传获得和现实遗传力等遗传参数。结果发现,选择组的壳高和壳型指数D均大于对照组,遗传参数估算值随着个体的增大而增加。幼虫期,壳高的平均选择反应、平均遗传获得、平均现实遗传力分别为0.363±0.167、1.678%±0.416%、0.207±0.095,中间培养期分别0.639±0.115、7.618%±2.666%、0.364±0.065,养成后期分别为0.668±0.179、8.861%±3.072%、0.381±0.102。养成后期,壳型指数D的平均选择反应、平均遗传获得、平均现实遗传力分别为0.748±0.066、9.090%±0.565%、0.426±0.038。研究结果为培育深凹壳型、生长性能良好的香港牡蛎优良品种提供了实验依据和理论基础。

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.