长期选择的杜洛克猪群体经济性状遗传参数及遗传进展分析

目的 对受长期选择的实际杜洛克猪育种群体3个重要经济性状进行遗传参数估计，分析各性状取得的遗传进展，并探讨实际育种群体中长期选择等因素对群体遗传参数的影响。方法 收集广西某种猪场核心育种群杜洛克猪2003—2018年共计15 760条生长性能测定记录。运用DMU软件的DMUAI模块和DMU4模块，利用多性状动物模型估计3个重要经济性状的群体遗传参数和个体育种值。并通过估计该群体的年度累计群体遗传参数以评估该群体在长期选择过程中遗传参数的变化情况。结果 杜洛克猪3个重要经济性状(达100 kg体质量日龄、背膘厚和眼肌面积)的估计遗传力分别为0.354、0.477和0.479，均属中高遗传力性状。3个性状间的遗传相关范围为-0.110~0.039，表型相关范围为-0.076~0.082，均属于弱相关。性状达100 kg体质量日龄在长期选择中取得了较大的遗传进展，而性状达100 kg体质量背膘厚和达100 kg体质量眼肌面积取得的遗传进展较小。分析年度累积群体估计的遗传参数发现，3个经济性状的加性遗传方差出现了不同程度的变化。结论 杜洛克猪群体3个重要经济性状均为中高遗传力性状且性状间相关性较弱。在实际育种群体中，长期选择及引种等因素会导致群体遗传参数发生变化，育种实践中应及时开展遗传参数估计，以获得准确的遗传评估结果，加速群体遗传改良。

Genetic parameters and genetic progress of economically important traits in a long-term selected Duroc pig population

Objective To estimate the genetic parameters of three economic traits in a long-term selection population, analyze their genetic progress, and investigate the factors including long-term selection affecting the genetic parameters in the practical breeding population.Method A total of 15 760 growth performance records of Duroc pigs were collected in a core breeding field from 2003 to 2018. Using DMUAI module and DMU4 module of DMU software, a multi-trait animal model was used to estimate the genetic parameters and breeding values of three important economic traits. We estimated the genetic parameters of annual accumulative population to evaluate the change of genetic parameters during the long-term selection.Result The estimates of heritability for three important economic traits including age, backfat thickness and loin muscle area at 100 kg body weight were 0.354, 0.477 and 0.479, respectively. All three traits had medium-high heritability. There were low correlations among three economic traits. The genetic and phenotypic correlations ranged from -0.110 to 0.039 and from -0.076 to 0.082, respectively. Among three traits, age at 100 kg body weight had relatively greater genetic progress in long-term selection, while backfat thickness at 100 kg body weight and loin muscle area at 100 kg body weight had relatively less genetic progress. Furthermore, the additive genetic variance changed in different degrees for three economic traits by estimating the genetic parameters of the annual accumulative population.Conclusion These traits of this Duroc pig population had the medium-high estimates of heritability and low correlations. Moreover, long-term selection and introduction could lead to the changing of genetic parameters. Therefore, genetic parameters should be estimated timely to obtain accurate genetic evaluation for accelerating the genetic improvement in breeding practice.