A Short-term Selection Study Using Genetic Heterogeneity of Residual Variance of Live Weight in Quails
This study aimed to investigate the genetic heterogeneity of residual variance for 4-week live weight in Japanese quails and to evaluate whether short-term selection based on this could reduce phenotypic variation. A pedigree-recorded quail population was divided into two replicated lines (light-colored and dark-colored) based on plumage color. Live weights were recorded over four weeks, and the log-transformed squared residuals obtained from the Restricted Maximum Likelihood animal model were used as a uniformity phenotype. The average number of offspring per generation was 165 for the dark line and 182 for the light line. Variance–covariance components were estimated using Gibbs Sampling within a Bayesian framework, and direct breeding values were calculated using the Best Linear Unbiased Prediction method over four generations of selection. Heritability estimates for 4-week live weight remained stable within generations, ranging between 0.25 and 0.31. The heritability of the residuals of 4-week live weight was low, with adjusted values ranging from 0.016 to 0.024 across generations. Strong negative genetic correlations were detected between direct and maternal genetic effects. As generations progressed, direct breeding values for residuals declined as expected, whereas maternal breeding values showed an opposite increasing trend. The coefficient of variation of live weight exhibited a slight decline in the light-colored line but did not display a clear trend in the dark-colored line. Overall, although genetic variation in the residual variance was detected, selection over four generations did not lead to a clear reduction in phenotypic variation of live weight. Possible reasons include low heritability of the residuals, the antagonistic correlation between direct and maternal effects, and the short duration and moderate selection intensity of the experiment. Cite this article as: Erdem, H., & Savaş, T. (2026). A short-term selection study using genetic heterogeneity of residual variance of live weight in quails. Acta Veterinaria Eurasia, 52, 0013, doi:10.5152/actavet.2026.26013.