应用多性状动物模型评估蛋鸡蛋形指数遗传参数

以动物模型结合平均信息约束最大似然算法(AIREML)分析蛋鸡蛋形指数遗传力、重复力和遗传相关系数,剖析蛋形指数遗传参数动态变化规律。试验素材来自白莱航鸡与绿壳蛋鸡分离群体,包括亲代、F_1代和F_2代,总计2 326只母鸡。每一世代32~60周龄,期间每4周测量1次蛋品质,共采集蛋形指数数据19825条。以WOMBAT软件估计遗传方差、永久环境方差和残差。结果表明:品种、世代和周龄,对蛋形指数有重要影响,将其列入固定效应;蛋形指数性状并非正态分布,应用平方根反正弦进行数据转换,但转换前后遗传参数估计值差异不显著(P0.05);蛋形指数遗传力为0.31~0.47,遗传方差随周龄增加而增加,至48周龄达到极大值,之后小幅回落;重复力为0.47~0.61,永久环境方差基本稳定在同一水平;不同周龄蛋形指数遗传相关系数为0.91~0.99,永久环境相关系数为0.61~0.92,相邻周龄遗传相关系数较高。蛋形指数重复力较高、周龄之间遗传相关系数接近于1,以个体选择可以有效获取遗传参数。

Genetic Parameters for Assessment of Egg Shape Index from Laying Chicken with Multivariate Animal Model

This study was designed to assess heritability,repeatability and genetic correlation of genetic parameters of laying chicken egg shape index (ESI) with animal model and Average Information REML(AIREML),and to analyze dynamic changes of genetic parameters.The animals were composed of 2 326 hens,including parents,F1 and F2 flocks from a resource population,which were crossbred between Blue eggshelled Chicken and White Leghorn.The data set was made of 19 825 items collected every four weeks thorough 32 wks to 60 wks.(Co)variance components were estimated with WOMBAT software.Results showed:factors of breeds,generations and weekages should be included in the fix effects because of their important role in ESI variations;data were transformed with sqrt arcsine method since they were not standard normal distribution,but data transformation had no effect on ESI estimators;for resource population,heritability on ESI varied from 0.31 to 0.47,and genetic variance increased until 48 weeks and fell gradually to the end;repeatability changed from 0.47 to 0.61,and permanent environmental variance maintained at the same level;genetic correlations between test weeks ranged from 0.91 to 0.99,permanent environmental correlations ranged from 0.61 to 0.92,and correlations of neighbor weeks were high.Since repeatability and genetic correlations were high,individual selection was recommended to obtain genetic gains on ESI.