合浦珠母贝幼贝生长性状的遗传参数估计

以广东徐闻和海南三亚2个地理群体合浦珠母贝(Pinctada fucata)为亲本, 采用人工授精方法构建了33个全同胞家系。在162日龄时从每个家系随机抽取50个个体, 共1 650个, 测量其壳长、壳高、壳宽和体质量4个生长性状, 利用动物模型对4个性状进行遗传参数分析。结果表明, 合浦珠母贝4个生长性状的总平均值分别为(16.28 ± 4.46) mm、(14.85 ± 4.39) mm、(4.58 ± 1.52) mm、(0.66 ± 0.67) g。4个性状的遗传力分别为0.202 ± 0.020、0.203 ± 0.020、0.200 ± 0.021和0.204 ± 0.020, 均属中等遗传力, 因此可以用选择育种进行遗传改良。4个性状间表型相关系数和遗传相关系数的范围分别为0.667~0.698和0.685~0.959, 其中壳长、壳高和壳宽之间的遗传相关系数均低于0.7, 与表型相关一致, 而三者与体重间的遗传相关系数较高(0.868~0.959), 其中壳宽与体质量间的遗传相关系数最高(0.959)。本研究中合浦珠母贝的4个性状为中等遗传力, 并可通过对壳宽的选育来改良体质量性状。上述结果为进一步开展合浦珠母贝选择育种研究奠定了基础。

Estimates of genetic parameters for growth traits in juvenile pearl oyster Pinctada fucata

The pearl oyster Pinctada fucata is an economically important oyster that is used for pearl production. There is considerable focus on improving selective breeding procedures for certain traits. We used the specimens of P. fucata from two geographic populations in Xuwen, Guangdong and Sanya, Hainan as the parents to construct 33 full-sibs families by artificial fertilization. We estimated the genetic parameters of growth traits in juvenile P. fucata. Fifty 162-day-old individuals were randomly sampled from each family. Shell length, shell height, shell width, and body weight were measured, and used for genetic analysis using a maximum likelihood algorithm based on an animal model. The total phenotypic means of the four growth traits were (16.28 ± 4.46) mm, (14.85 ± 4.39) mm, (4.58 ± 1.52) mm, and (0.66 ± 0.67) g, respectively. There was a significant difference between different traits in different families, indicating that family has a significant (P<0.01) influence on growth traits in juvenile P. fucata. The heritability of these four traits are 0.202 ± 0.020, 0.203 ± 0.020, 0.200 ± 0.021, and 0.204 ± 0.020, respectively, suggesting that there was some degree of selective potential by family selection. The pairwise phenotypic and genetic correlations between growth traits were 0.667-0.698 and 0.685-0.959, respectively. Based on our results, we predict that if one trait is improved genetically, the others will also be improved as the phenotypic and genetic correlations between the four traits were highly positive. The genetic correlation between shell width and body weight was highest (0.959), suggesting that the best way to improve body weight is by selection for shell width.