应用动物模型对罗氏沼虾育种估计的差别分析

为准确评估罗氏沼虾的育种值,利用罗氏沼虾106个家系中2628尾个体的体重资料,分别考虑日龄、性别和雌虾出池时是否抱卵等因素,设计了4种单性状动物模型,应用BLUP法估计个体的体重育种值。4种模型所估计的体重遗传力差别较大,遗传力范围在0.02～0.13之间。分析表明,家系混养前日龄与家系出池体重测定值存在极显著的相关(r=0.434,P<0.01),说明家系混养前日龄对混养后家系个体的体重有显著影响,提示在动物模型设计时,应该考虑家系混养前日龄作协变量;在考虑性别效应、雌虾出池时的抱卵效应,并以家系混养前日龄为协变量,获得的育种值估计较其他模型更为准确。实验还对育种值选择与表型值选择的效率进行了比较。结果表明,依据育种值选择与依据表型值选择的结果存在着较大差异,两种选择方法选取的前53个家系育种值的平均值分别为0.70和0.58g,前者比后者提高20.7%,提示依据育种值的选择效率要高于表型值选择效率。

Difference analysis of breeding value estimation for Macrobrachium rosenbergii by animal models

For accurate estimation of the breeding value of Macrobrachium rosenbergii,four single trait animal models were designed involving factors such as day-age,sex and female egg-carrying effect,etc.Breeding values for body weight of 2 628 individuals in 106 M.rosenbergii families were estimated using linear unbiased prediction(BLUP)procedures.There was great difference between the heritability(ranged between 0.02 ~ 0.13)of body weight estimated by the four animal models.A highly significant correlation(r=0.434,P<0.01)was found between the family age before co-culture and the final body weight at harvest,indicating that the age of families significantly affected their weight gain during co-culture;and it was suggested that family age be considered as a covariate when an animal model was designed.The animal models using sex or egg-carrying effect as fixed variables and the family age as a covariate,obtained more accurate estimation of breeding values than the other models.Comparison of the efficiency of selection based on breeding value or phenotypic value revealed great difference:average breeding values of the two selection methods for the top 53 M.rosenbergii families were 0.70 g and 0.58 g,respectively,representing a 20.7% higher efficiency in the former.It was suggested that,the efficiency of breeding value-based selection was higher than that of phenotypic selection.