ABSTRACT

1. Uniformity in animal products is an important aspect of the production system. Several studies have reported estimates of genetics on residual variance in different species, indicating that it could be exploited to improve uniformity by selection. Nevertheless, there are no reports about the possibilities of such a selection strategy in meat quail.

2. Records of hatching weight (HW) and body weight at 42 days (W42) of female and male birds from two meat quail lines (UFV1 and UFV2) were analysed. A three-step genetic evaluation was used to investigate the effect of genetic variation on residual variance of HW and W42 in both lines. In Step 1, a single-trait model was fitted to the data. In Step 2, log-transformed squared estimated residuals (ln(ê²)) were evaluated for these traits. In Step 3, a multi-trait analysis was performed to estimate the genetic correlation between the additive genetic effects for HW, W42, and their respective ln(ê²).

3. The heritability estimates ranged from 0.12 to 0.23 for HW and from 0.22 to 0.35 for W42. The estimated heritabilities for the residual part were low and ranged from 0.0003 to 0.02 for both traits, and the genetic coefficient of variation residual variance estimates ranged from 0.31 to 0.42 for HW and from 0.09 to 0.25 for W42. Genetic correlations between the means (HW and W42) and ln(ê²) values were both positive and did not differ from zero, indicating no association between mean and ln(ê²).

4. In conclusion, the uniformity of HW and W42 could be improved by selecting for lower residual variance in both meat quail lines, but the accuracy of selection may be low due to low heritability for uniformity, mainly for W42.

摘要

1. 动物产品的一致性是生产系统的一个重要方面。几项研究报告了对不同物种剩余方差的遗传学估计，表明可以利用它来通过选择来提高均匀性。然而，没有关于这种选择策略在鹌鹑肉中的可能性的报道。

2. 分析了来自两个肉鹌鹑品系（UFV1 和 UFV2）的雌性和雄性鸟类在 42 天（W42）时的孵化重量 (HW) 和体重记录。使用三步遗传评估来研究遗传变异对两个品系中 HW 和 W42 残差方差的影响。在步骤 1 中，将单特征模型拟合到数据中。在步骤 2 中，对这些性状进行对数变换平方估计残差 (ln(ê ² )) 进行评估。在步骤 3 中，进行多性状分析以估计 HW、W42 及其各自 ln(ê ² )的加性遗传效应之间的遗传相关性。

3. HW 的遗传力估计值为 0.12 至 0.23，W42 的遗传力估计值为 0.22 至 0.35。残差部分的估计遗传力较低，两个性状的遗传系数都在 0.0003 到 0.02 之间，HW 的变异遗传系数残差方差估计值范围为 0.31 到 0.42，W42 的遗传变异系数估计为 0.09 到 0.25。平均值（HW 和 W42）和 ln(ê ² ) 值之间的遗传相关性都是正的，并且没有从零差异，表明平均值和 ln(ê ² )之间没有关联。

4. 综上所述，HW 和 W42 的均匀性可以通过在两个肉鹌鹑品系中选择较低的残差来提高，但由于均匀性的遗传力低，选择的准确性可能较低，主要是 W42。