Genomic selection (GS) has been promising for increasing genetic gains in several species. Therefore, we evaluated the potential integration of GS for grain yield (GY) in bread wheat (Triticum aestivum L.) in CIMMYT's elite yield trial nurseries. We observed that the genomic prediction accuracies within nurseries (0.44 and 0.35) were substantially higher than across‐nursery accuracies (0.15 and 0.05) for GY evaluated in the bed and flat planting systems, respectively. The accuracies from using only a subset of 251 genotyping‐by‐sequencing markers were comparable to the accuracies using all 2038 markers. We also used the item‐based collaborative filtering approach for incorporating other related traits in predicting GY and observed that it outperformed genomic predictions across nurseries, but was less predictive when trait correlations with GY were low. Furthermore, we compared GS and phenotypic selections (PS) and observed that at a selection intensity of 0.5, GS could select a maximum of 70.9 and 61.5% of the top lines and discard 71.5 and 60.5% of the poor lines selected or discarded by PS within and across nurseries, respectively. Comparisons of GS and pedigree‐based predictions revealed that the advantage of GS over the pedigree was moderate in populations without full‐sibs. However, GS was less advantageous for within‐family selections in elite families with few full‐sibs and minimal Mendelian sampling variance. Overall, our results demonstrate the importance of applying GS for GY at the appropriate stage of the breeding cycle, and we speculate that gains can be maximized if it is implemented in early‐generation within‐family selections.

中文翻译：

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应用基因组选择的前景与挑战-面包小麦籽粒育种的新范例。

基因组选择（GS）已有望增加几种物种的遗传增益。因此，我们评估了GS对面包小麦（Triticum aestivum）籽粒产量（GY）的潜在整合L.）在CIMMYT的精英产量试验托儿所中。我们观察到苗圃内的基因组预测准确度（0.44和0.35）分别高于在苗床和平板种植系统中评估的GY的跨育种准确度（0.15和0.05）。仅使用251个基因分型测序标记子集的准确性与使用所有2038个标记的准确性相当。我们还使用基于项目的协同过滤方法将其他相关性状纳入GY预测中，并观察到其性能优于整个苗圃的基因组预测，但是当性状与GY的相关性较低时则预测性较差。此外，我们比较了GS和表型选择（PS），并观察到选择强度为0.5时，GS最多可以选择顶行的70.9和61.5％并丢弃71。PS分别在苗圃内和跨苗圃选择或丢弃的劣质系中有5％和60.5％。GS和基于系谱的预测的比较表明，在没有完全同胞的人群中，GS较系谱的优势是中等的。然而，对于全亲同胞少，孟德尔抽样方差最小的精英家庭，GS对于家庭内部选择的优势较小。总体而言，我们的结果证明了在育种周期的适当阶段将GS应用于GY的重要性，并且我们推测，如果在早期的家庭内部选择中实施，则可以获得最大的收益。GS和基于系谱的预测的比较表明，在没有完全同胞的人群中，GS较系谱的优势是中等的。然而，对于全亲同胞少，孟德尔抽样方差最小的精英家庭，GS对于家庭内部选择的优势较小。总体而言，我们的结果证明了在育种周期的适当阶段将GS应用于GY的重要性，并且我们推测，如果在早期的家庭内部选择中实施，则可以获得最大的收益。GS和基于系谱的预测的比较表明，在没有完全同胞的人群中，GS较系谱的优势是中等的。然而，对于全亲同胞少，孟德尔抽样方差最小的精英家庭，GS对于家庭内部选择的优势较小。总体而言，我们的结果证明了在育种周期的适当阶段将GS应用于GY的重要性，并且我们推测，如果在早期的家庭内部选择中实施，则可以获得最大的收益。