高选择压力下蛤仔奶牛蛤品系两个世代连续选择的选择反应和现实遗传力

以1％为选择压力,以壳长为选择指标,对菲律宾蛤仔Ruditapes philippinarum奶牛蛤品系进行了两个世代的连续混合选择,并跟踪测量了各试验组在不同生长阶段的壳长,计算了选择反应、现实遗传力和遗传获得等遗传参数.结果表明：在奶牛蛤两个世代的各个生长阶段,选择组的平均壳长均大于对照组;F2和F3世代的选择反应在幼虫培育期、稚贝培育期和幼贝养成期的平均值分别为1.98、0.72、0.64和1.10、0.68、0.74,总平均值分别为1.19和0.90;F2和F3世代的现实遗传力在幼虫期、稚贝期和幼贝期的平均值分别为0.43、0.16、0.14和0.41、0.26、0.28,总平均值分别为0.26和0.34;F2和F3世代的遗传获得在幼虫期、稚贝期和幼贝期的平均值分别为4.79％、17.81％、13.27％和5.60％、4.28％、16.30％,总平均值分别为10.78％和7.94％;F2和F3世代的总遗传获得在幼虫期、稚贝期和幼贝期的平均值分别为10.73％、15.56％、29.34％,总平均值为16.59％.研究表明,在高选择压力下进行两个世代蛤仔连续混合选择的方法获得的选育效果较为理想,且该群体仍具有一定的改良潜力.

Realized heritability and response to sustained selection for shell length in two generations of Manila clam Ruditapes philippinarum strain with cow-like spots under high selection pressure

Shell length in different growth stages was measured and genetic parameters including response to selec- tion, realized heritability and genetic gains were analyzed in two generations of Manila clam Ruditapes philippinarum strain with cow-like spots for shell length under 1% sustained selection pressure. The results showed that average shell length in every growth stage was found to be larger in the selected groups than in the control groups. Response to selection values of F2 were 1.98 in larvae, 0.72 in juveniles, and 0.64 in spats, with an average of 1.19 and response to selection values of F3 1.10 in larvae, 0.68 in juveniles, and O. 74 in spats, with an averages of O. 90. In the F2 generation the realized heritability was found 0.43 in larvae, 0.16 in juveniles, and 0.14 in spats, with an average of 0.26 while in F3 generation 0.41 in larvae, 0.26 in juveniles, and 0.28 in spats, with an averages of 0.34. Genetic gains at the three stages were 4.79%, 17.81%, and 13.27% in Fz generation with an average of 10.78% and 5.60% , 4.28% , and 16.30% in F3 generation, with an average of 7.94%. Total genetic gains of two generation successive selection were 10.73% , 15.56% and 29.34% , with an average of 16.59%. The find- ings prove that this method is feasible and that the improvement potentiality is still found in this clam population.