Santana M L, Eler J P, Cardoso F F, Albuquerque L G, Balieiro J C C, Pereira R J, Ferraz J B S
Grupo de Melhoramento Animal de Mato Grosso, Instituto de Ciências Agrárias e Tecnológicas, Universidade Federal de Mato Grosso, Campus Universitário de Rondonópolis, Rondonópolis, MT, Brasil
Grupo de Melhoramento Animal e Biotecnologia, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, SP, Brasil.
Genet Mol Res. 2014 Apr 17;13(2):3048-59. doi: 10.4238/2014.April.17.1.
The objectives of this study were to characterize and define homogenous production environments of composite beef cattle in Brazil in terms of climatic and geographic variables by using multivariate exploratory techniques; to evaluate the presence of genotype by environment interaction (GxE) for post-weaning weight gain (PWG), yearling scrotal circumference (SC), and yearling muscling (MUS). Hierarchical and nonhierarchical cluster analysis was used to group farms located in regions with similar environmental variables into clusters. Six clusters of farms were formed. The effect of sire-cluster interaction was tested by single-trait analysis. Genetic parameters were estimated by multi-trait analysis considering the same trait to be different in each cluster. The effect of sire-cluster interaction was significant (P <0.01) for PWG and MUS. Estimates of genetic correlations among clusters ranged from 0.31 to 0.93 for PWG, 0.64 to 0.89 for SC, and 0.18 to 0.80 for MUS. These results indicate the need for a genetic analysis on a regional basis or inclusion of the GxE effect in the statistical model to permit appropriate evaluation of the animals.
本研究的目的是通过多元探索技术，根据气候和地理变量来描述和定义巴西复合肉牛的同质生产环境；评估断奶后体重增加（PWG）、周岁阴囊周长（SC）和周岁肌肉量（MUS）的基因型与环境互作（GxE）的存在情况。采用层次聚类和非层次聚类分析，将环境变量相似地区的农场分组为不同的集群。形成了六个农场集群。通过单性状分析检验父系集群互作的效应。考虑到同一性状在每个集群中不同，通过多性状分析估计遗传参数。父系集群互作对PWG和MUS的效应显著（P<0.01）。集群间PWG的遗传相关性估计值在0.31至0.93之间，SC在0.64至0.89之间，MUS在0.18至0.80之间。这些结果表明需要进行区域遗传分析或将GxE效应纳入统计模型，以便对动物进行适当评估。
