蛤仔(Ruditapes philippinarum)养成期壳长遗传力与育种值估计

采用巢式设计构建了菲律宾蛤仔的8个父系半同胞家系和24个全同胞家系。在90、300、330和450日龄,每个家系随机取30个个体测量壳长,并对数据进行遗传分析。将全同胞效应、母本效应和移入土池时壳长协变量组合成8个不同模型,应用REML法估计遗传力,BLUP法估计育种值。结果表明,移入土池时各家系平均壳长协变量是重要影响因子,全同胞效应和母本效应影响较小。在90、300和330日龄的最优模型为考虑加性遗传效应和移入土池时各家系平均壳长协变量的模型AB,450日龄的最优模型为仅考虑加性遗传效应的模型A。应用最优模型估计的90、300、330和450日龄壳长遗传力分别为0.571、0.966、0.622和0.865。应用最优模型估计育种值,对表型值选择法和育种值选择法比较的结果表明,对家系进行选择时,在300日龄用育种值选择法比表型值选择法平均壳长高3.56%,在90和330日龄时比表型值选择法分别低1.53%和3.71%。对个体进行选择时,按照10%和1%留种,在90、300和330日龄表型选择法比育种值选择法高16.86%、2.54%,16.27%和24.51%、2.03%,23.23%。除在300日龄对家系进行选择时育种值选择法优于表型值选择法外,表型值选择法均优于育种值选择法。

ESTIMATION OF HERITABILITY AND BREEDING VALUE ON SHELL LENGTH OF MANILA CLAM RUDITAPES PHILIPPINARUMAT SPAT STAGE

8 paternal half-sib families and 24 full-sib families of Manila clam Ruditapes philippinarum with cow-like spots were established by using nest design.30 individuals were selected by random of each family at the age of 60, 90, 300, 330 and 450 to measure the shell length. Addictive genetic effect, full-sib family effect, maternal effect and the average shell length of each family at the age of 60 as covariate were considered. 8 models were built based on the four factors. REML and BLUP were used to calculate the heritability and breeding value. The results indicate that the average shell length of each family at the age of 60 as covariate is a main factor to correct the model, while full-sib family effect and maternal effect are not significant effective. The best model at the age of 450 days is model A considering only the addictive genetic effect and at the age of 90, 300, 330 days the best model is model AB which considers both the addictive genetic effective and he average shell length of each family at the age of 60 as covariate. The estimated heritability at the age of 90,300,330 and 450 using the best model is 0.571, 0.966, 0.622 and 0.865. The comparison result of selection method based on phenotypic value and breeding value shows that average shell length selected by phenotypic value when selected families is 1.53% and 3.71% longer than selected by breeding value at the age of 90 and 330 days, while 3.56% shorter at the age of 300 days; when selected the longest 10 percent individuals, the average shell length selected by phenotypic value at the age of 90, 300, 330 is 16.86%, 2.54%, 16.27% longer than selected by breeding value and 24.51%, 2.03%, 23.23% longer when selected the longest 1% individuals. This result indicates that selection by phenotypic value is better than selection by breeding value except when select Manila clam strain with Cow-like spots families at the age of 300 days.