墨西哥湾扇贝亲代选择对自交子一代的影响

试验从来自同一养殖群体的1000个随机个体墨西哥湾扇贝(Argopecten irradians concentricus Say)中选取规格最大(壳长58.3~61.9 mm)、中等(壳长49.5~50.8 mm)、最小(壳长38.9~41.1 mm)的性成熟个体各3个作为亲贝,按规格分成大、中、小3组,利用该贝雌雄同体的特性分别进行各组内亲本个体自交。在相同环境及试验条件下通过比较各自交组受精率、孵化率、稚贝育成率、海上暂养及标粗期存活率、养成期存活率、壳长壳高体重日增长率和选择反应等指标的差异,分析亲本选择对自交子代生产性能的影响。结果表明,从上述各指标看,大规格亲贝优于中规格亲贝(P<0.01);中规格亲贝优于小规格亲贝(P<0.01)。大规格亲贝壳高、壳长和体重的选择反应分别为6.0 mm、5.4 mm和6.3 g,中规格亲贝分别为-0.4 mm、-0.1mm和-0.7 g,小规格亲贝分别为-4.7 mm-、5.3 mm和-7.6 g。大规格亲贝壳高、壳长和体重的实现遗传力分别为0.52、0.49和0.40。研究证明,墨西哥湾扇贝亲代选择对自交子一代生产性能具有极显著影响(P<0.01),大规格亲贝自交后代表现出明显生长优势,截断选择策略有效。

The effect of parental selection on inbred first filial generation of Argopecten irradians concentricus Say

In the experiment the same culture population of 1000 individuals of Argopecten irradians concentricus Say was divided into 3 groups according to shell length: large group(shell length 58.3-61.9 mm),middle group(shell length 49.5-50.8 mm) and small group(38.9-41.1 mm),and 3 individuals,which as parents were sexually matured and of the same age,were chosen from 3 groups each.Autogamy experiments were carried out within each group of parents selected,respectively.Under identical environmental and experimental conditions,based on the comparisons of differences between 3 groups in terms of such indices as insemination rate,hatching rate,juvenile survival rate,survival rates across nursing period and across formal culture period,daily growth rates of shell length,shell height,survival rate and responses to selection,the effect of parental selection on the growth performance of self-fertilized progeny were examined.Results showed that large-size parents were better than middle ones(P<0.01);middle-size parents were superior to small-size ones(P<0.01).Responses to selection of shell height,shell length and wet weight for large-size parents were 6.0 mm,5.4 mm and 6.3 g respectively;-0.4 mm,-0.1 mm and-0.7 g respectively for middlingsize parents,and-4.7 mm,-5.3 mm and-7.6 g respectively for small-size parents.Realized heritabilities of shell height,shell length and wet weight were 0.52,0.49 and 0.40 respectively.Results showed that parental selection of Argopecten irradians concentricus Say had great effect on the growth performance of selffertilized progeny(P<0.01),the self-fertilized progeny of large-size parents displayed marked growth advantage,and the strategy of truncation selection is effective and should be adopted practically.