三个牙鲆育种群体亲本效应及遗传参数估计

Parent effects and estimation of genetic parameters for three Japanese flounder breeding populations

针对牙鲆(Paralichthys olivaceus)养殖品种生长速度变慢、抗病力降低这一问题。近年来构建了牙鲆抗病群体(RS)、日本群体(JS)和黄海群体(YS)3个育种群体,开展牙鲆选择育种,建立了63个家系,收集了所有家系5 328尾鱼苗的体长和体重数据。借助线形混合模型(Linear mixedmodel)、"加性-显性"模型、约束极大似然法(REML)及最佳线性无偏预测(BLUP)分别估计亲本效应值、体重和体长遗传力和遗传相关、父母本效应和杂交效应。预测结果显示,其中父本130,141,146,170,218,229,303和308随机效应达到了极显著效应水平(P<0.01),父本112,122,141,190,212达到显著水平(P<0.05),所有母本体重随机效应达到了极显著水平(P<0.01);体长和体重两性状的加性、显性、表型和基因型相关分量都达到极显著水平(P<0.01),体长和体重的加性方差比率均大于显性方差比率,可见两性状的遗传效应主要取决于基因的加性效应。体长的总遗传效应率为31.20%,体重的总遗传效应率为33.58%,体长和体重的随机方差比率分别达到68.80%和66.41%,说明养殖环境等因素对牙鲆体长和体重的影响较大,同时说明在牙鲆选择育种中消除环境影响极为重要。体长和体重的狭义遗传率分别为0.199和0.256(P<0.01),广义遗传率分别为0.312和0.336(P<0.01),牙鲆在以上两性状上属于中等遗传力,通过选择育种可取得较大的遗传进展。对3个牙鲆育种群体杂交随机效应估计结果显示,抗病群体和黄海群体在体长和体重两性状上加性随机效应显著(P<0.05);抗病群体分别与日本群体、黄海群体杂交,其后代表现出显性随机效应达到0.10的水平(P<0.10),黄海群体自交、日本群体和黄海群体杂交随机效应不显著(P>0.05),因此在杂交组配中选择抗病群体与其他两个群体交配可取得较好的效果。

The Japanese flounder（Paralichthys olivaceus） is one of the most important species for the coastal fisheries and mariculture in China.However,in recent years,the Japanese flounder aquaculture has many problems such as disease,growth rate depression etc.due to neglect systemic breeding research.In recent years,through three methods such as artificial selection,introduction of fine stocks from Japanese and collection of local wild stocks,we have established gradually disease-resistant stock（RS）,Japanese stock（JS） and Huang hai（Yellow） Sea stock（YS） as broodstocks.Subsequently,we constructed 63 half-and full-sib families.After 230 days of growth,in total 5 328 individuals from these families were randomly captured to measure their body length and body weight.Based on these data,we estimated parents＇ random effect for each family using Linear mixed model.At the same time,we estimated the heritability and correlation coefficient between body weight and body length using Restricted Maximum Likelihood method（REML） based on additive-dominance model.Simultaneously,the parents＇ effect and hybrid effect were estimated using BLUP（Best Linear Unbiased Prediction） method.According to the estimated results of parents＇ random effect,the effect value for male 130,141,146,170,218,229,303 and 308 has reached a significant level of random effect（P〈0.01）,and male parent 112,122,141,190,and 212 has reached a significant level of random effect（P〈0.05）.While the effect value for all female parents has reached a significant level of random effect（P〈0.01）.The results of genetic correlations for body length and body weight showed that four components such as additive,dominant,phenotype and genotype have been to achieve significant level（P〈0.01）.The results of estimated heritability showed that the additive variance ratio of body length and body weight was bigger than that of dominant variance,which suggested that the genetic effect of body length and body weight depends largely on the additive effect of genes.The total genetic effect of body length and body weight was 31.20% and 33.58%,respectively,and the random variance of body weight and body length was 68.80% and 66.41%,respectively.These findings suggested that environmental factors have great impacts on body length and body weight of Japanese flounder,so the elimination of the environmental factors was important in the process of breeding.The narrow sense heritability of body length and body weight was 0.199 and 0.256（P〈0.01）,respectively,and the broad sense heritability of body length and body weight was 0.312 and 0.336（P〈0.01）,respectively.The heritability of body length and body weight was moderate,which indicated that selection for the two growth traits would result in greater genetic improvement.RS showed positive additive effect（P〈0.05） on body length and body weight,however,YS showed negative additive effect（P〈0.05） on body length and body weight.The hybrids between RS and JS showed positive additive random effect（P〈0.10）,and the hybrids between RS and YS showed negative additive random effect（P〈0.10）,however,the random effects of the offspring of RS and the hybrids between JS and YS were not significant（P〉0.05）.Therefore,RS hybridized with the other two stocks（JS and YS） could obtain good result in selective breeding of Japanese flounder.