我国杜洛克、长白和大白猪场间遗传联系分析

The Genetic Connectedness of Duroc,Landrace and Yorkshire Pigs in China

旨在分析我国杜洛克、长白、大白猪3个主流猪品种的场间遗传联系情况,为全国或区域性猪联合遗传评估和联合育种奠定基础。本研究采用关联率(Connectedness rating,CR)方法,利用国家种猪数据库杜洛克、长白和大白猪达100kg体重日龄性状的514 226、924 717和2 031 688条数据,计算95家国家生猪核心育种场3个品种2011-2016年场间的关联率。通过聚类分析,将每个品种划分为若干区域性联合遗传评估组。结果表明,我国杜洛克、长白和大白猪场间关联率逐年上升,平均关联率从2011年的0.04%、0.06%和0.06%,分别提高至2016年的0.32%、0.43%和0.44%;我国整体场间遗传联系偏低,大部分场间无遗传联系。但分别存在3、2、4个局部遗传评估联合体,可以进行联合遗传评估。其中,杜洛克猪3个局部联合体的平均关联率分别为1.89%、1.05%、1.58%,分别包括16、7、8个场;长白猪2个局部联合体的平均关联率分别为3.53%、1.56%,包括14和9个场;大白猪的局部联合体平均关联率为2.79%、1.01%、1.37%、1.23%,包括15、6、5、4个场;3个品种局部联合体的场数占核心场数的比例分别为35.1%、24.5%和31.6%。目前进行大规模的跨场联合评估还不可行,然而可以进行局部跨场联合评估。场间遗传交流、区域性公猪站建设、中心测定站和规范引种猪系谱登记等措施有助于增强场间联系。

This study aimed to investigate the genetic connectedness of 3 dominant pig breeds （Duroc, Landrace and Yorkshire pigs） in China, and to explore the plausibility of joint genetic evaluation in China pig breeding. The connectedness ratings （CR） from 2011 to 2016 were calculated to assess the genetic connectedness among 95 national nucleus pig breeding farms. In total, 514 226, 924 717 and 2 031 688 records of days to 100 kg for Duroc, Landrace and Yorkshire pigs from National Pig Database were analyzed and several joint genetic evaluation groups were estab- lished through clustering analysis. The results indicated that the average connectedness ratings among Duroc, Landrace and Yorkshire in China increased steadily from 0.04%, 0.06%, 0.06% in 2011 to 0.32%, 0.43% and 0.44% in 2016, respectively. In general, the connectedness rating in China was low, and even no connections among some breeding farms. However, 3, 2 and 4 groups, in which relative high genetic eonnectedness was observed among breeding farms, were clustered in Duroc, Landrace and Yorkshire, respectively. The joint genetic evaluation could be carried out in these groups. For Duroc pigs, the 3 joint genetic evaluation groups including 16, 7 and 8 breeding farms, correspondingly, the average connectedness ratings of 3 groups were 1.89%, 1.05%, 1.58%, respectively. Likewise, the 2 groups of Landrace pigs included 14, 9 herds and the corresponding average connectedness rating were 3.53% and 1.56%. The 4 groups of Yorkshire pigs included 15, 6, 5, 4 herds and the corresponding average conneetedness rating were 2.79%, 1.01%, 1.37% and 1.23%, respectively. The joint genetic evaluation groups of 3 breeds accounted for 35.1%, 24.5% and 31.6% of total nucleus farms in Duroc, Landrace and Yorkshire pigs, respectively. Nevertheless national-wide joint genetic evaluation for pig breeding in China is not practical, the regional joint genetic evaluation groups cross farms is feasible. Meanwhile, genetic eonnectedness among breeding farms need be further strengthened through enhancing genetic exchange, constructing regional AI stations, utilizing central performance test stations and standardizing pig registration etc.