Poultry Genetics and Breeding Division, ICAR-Directorate of Poultry Research, Hyderabad, Telangana, India.
PLoS One. 2024 Jul 26;19(7):e0307987. doi: 10.1371/journal.pone.0307987. eCollection 2024.
Proper variance partitioning and estimation of genetic parameters at appropriate time interval is crucial for understanding the dynamics of trait variance and genetic correlations and for deciding the future breeding strategy of the population. This study was conducted on the same premise to estimate genetic parameters of major economic traits in a White Leghorn strain IWH using Bayesian approach and to identify the role of maternal effects in the regulation of trait variance. Three different models incorporating the direct additive effect (Model 1), direct additive and maternal genetic effect (Model 2) and direct additive, maternal genetic and maternal permanent environmental effects (Model 3) were tried to estimate the genetic parameters for body weight traits (birth weight, body weight at 16, 20, 40 and 52 weeks), Age at sexual maturity (ASM), egg production traits (egg production up to 24, 28, 40, 52, 64 and 72 weeks) and egg weight traits (egg weight at 28, 40 and 52 weeks). Model 2 and Model 3 with maternal effects were found to be the best having the highest accuracy for almost all the traits. The direct additive genetic heritability was moderate for ASM, moderate to high for body weight traits and egg weight traits and low to moderate for egg production traits. Though the maternal heritability (h2mat) and permanent environmental effect (c2mpe) was low (<0.1) for most of the traits, they formed an important component of trait variance. Traits like egg weight at 28 weeks (0.14±0.06) and egg production at 72 weeks (0.13±0.07) reported comparatively higher values for c2mpe and h2mat respectively. Additive genetic correlation was high and positive between body weight traits, between egg weight traits, between consecutive egg production traits and between body weight and egg weight traits. However, a negative genetic correlation existed between egg production and egg weight traits, egg production and body weight traits, ASM and early egg production traits. Overall, a moderate positive genetic correlation was estimated between ASM and body weight traits and ASM and egg weight traits. Based on our findings, we can deduce that maternal effects constitute an important source of variation for all the major economic traits in White Leghorn and should be necessarily considered in genetic evaluation programs.
适当的方差分解和遗传参数估计在适当的时间间隔对于理解性状方差和遗传相关的动态以及决定群体的未来育种策略至关重要。本研究基于相同的前提，使用贝叶斯方法估计 IWH 白来航鸡品系的主要经济性状的遗传参数，并确定母体效应对性状方差调节的作用。尝试了三种不同的模型，包括直接加性效应（模型 1）、直接加性和母体遗传效应（模型 2）以及直接加性、母体遗传和母体永久环境效应（模型 3），以估计体重性状（初生重、16、20、40 和 52 周体重）、性成熟年龄（ASM）、产蛋性状（24、28、40、52、64 和 72 周产蛋量）和蛋重性状（28、40 和 52 周蛋重）的遗传参数。结果表明，带有母体效应的模型 2 和模型 3 是最佳模型，几乎所有性状的准确性都最高。ASM 的直接加性遗传遗传力为中等，体重性状和蛋重性状的遗传力为中等到高，产蛋性状的遗传力为低到中等。尽管大多数性状的母体遗传力（h2mat）和永久环境效应（c2mpe）较低（<0.1），但它们是性状方差的重要组成部分。28 周蛋重（0.14±0.06）和 72 周产蛋量（0.13±0.07）等性状的 c2mpe 和 h2mat 分别报告了相对较高的值。体重性状之间、蛋重性状之间、连续产蛋性状之间以及体重和蛋重性状之间的加性遗传相关系数较高且为正。然而，产蛋量和蛋重性状、产蛋量和体重性状、ASM 和早期产蛋性状之间存在负遗传相关。总体而言，ASM 和体重性状以及 ASM 和蛋重性状之间的遗传相关系数为中度正相关。根据我们的发现，可以推断母体效应对白来航鸡的所有主要经济性状都是重要的变异来源，在遗传评估计划中必须考虑母体效应。
