Departamento de Biologia Geral, Universidade Federal de Viçosa, Viçosa, MG Brazil.
Genet Mol Biol. 2009 Jul;32(3):497-506. doi: 10.1590/S1415-47572009005000064. Epub 2009 Sep 1.
The prediction of gains from selection allows the comparison of breeding methods and selection strategies, although these estimates may be biased. The objective of this study was to investigate the extent of such bias in predicting genetic gain. For this, we simulated 10 cycles of a hypothetical breeding program that involved seven traits, three population classes, three experimental conditions and two breeding methods (mass and half-sib selection). Each combination of trait, population, heritability, method and cycle was repeated 10 times. The predicted gains were biased, even when the genetic parameters were estimated without error. Gain from selection in both genders is twice the gain from selection in a single gender only in the absence of dominance. The use of genotypic variance or broad sense heritability in the predictions represented an additional source of bias. Predictions based on additive variance and narrow sense heritability were equivalent, as were predictions based on genotypic variance and broad sense heritability. The predictions based on mass and family selection were suitable for comparing selection strategies, whereas those based on selection within progenies showed the largest bias and lower association with the realized gain.
选择收益的预测可以比较不同的育种方法和选择策略，尽管这些估计可能存在偏差。本研究的目的是调查在预测遗传增益时这种偏差的程度。为此，我们模拟了一个涉及七个性状、三个群体类别、三个实验条件和两种育种方法（群体选择和半同胞选择）的假设性育种计划的 10 个周期。每个性状、群体、遗传力、方法和周期的组合重复 10 次。即使遗传参数没有误差估计，预测的增益也是有偏差的。只有在不存在显性的情况下，两性的选择增益才是单一性别选择增益的两倍。在预测中使用基因型方差或广义遗传力是另一个产生偏差的来源。基于加性方差和狭义遗传力的预测是等效的，基于基因型方差和广义遗传力的预测也是等效的。基于群体选择和家系选择的预测适用于比较选择策略，而基于后代内选择的预测则显示出最大的偏差和与实际增益的较低相关性。
