The advantages of open-pollinated (OP) family testing over controlled crossing (i.e., structured pedigree) are the potential to screen and rank a large number of parents and offspring with minimal cost and efforts; however, the method produces inflated genetic parameters as the actual sibling relatedness within OP families rarely meets the half-sib relatedness assumption. Here, we demonstrate the unsurpassed utility of OP testing after shifting the analytical mode from pedigree- (ABLUP) to genomic-based (GBLUP) relationship using phenotypic tree height (HT) and wood density (WD) and genotypic (30k SNPs) data for 1126 38-year-old Interior spruce (Picea glauca (Moench) Voss x P. engelmannii Parry ex Engelm.) trees, representing 25 OP families, growing on three sites in Interior British Columbia, Canada. The use of the genomic realized relationship permitted genetic variance decomposition to additive, dominance, and epistatic genetic variances, and their interactions with the environment, producing more accurate narrow-sense heritability and breeding value estimates as compared to the pedigree-based counterpart. The impact of retaining (random folding) vs. removing (family folding) genetic similarity between the training and validation populations on the predictive accuracy of genomic selection was illustrated and highlighted the former caveats and latter advantages. Moreover, GBLUP models allowed breeding value prediction for individuals from families that were not included in the developed models, which was not possible with the ABLUP. Response to selection differences between the ABLUP and GBLUP models indicated the presence of systematic genetic gain overestimation of 35 and 63% for HT and WD, respectively, mainly caused by the inflated estimates of additive genetic variance and individuals' breeding values given by the ABLUP models. Extending the OP genomic-based models from single to multisite made the analysis applicable to existing OP testing programs.

中文翻译：

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开放式授粉的云杉（Picea glauca x engelmannii）的多环境基因组方差分解分析。

与控制杂交（即结构血统）相比，开放授粉（OP）家庭测试的优势在于可以以最小的成本和精力来筛选和排名大量的父母和后代。然而，该方法会产生夸大的遗传参数，因为OP家庭中的实际同胞亲缘关系很少满足半同胞亲缘关系的假设。在这里，我们使用表型树高（HT）和木材密度（WD）和基因型（30k SNP）数据，将分析模式从系谱（ABLUP）转换为基于基因组（GBLUP）的关系后，证明了OP测试的无与伦比的实用性1126代表25个OP家族的38岁室内云杉（Picea glauca（Moench）Voss x P. engelmannii Parry ex Engelm。）树生长在加拿大不列颠哥伦比亚省内陆的三个地点。使用基因组已实现的关系可以使遗传方差分解为加性，优势和上位遗传方差，以及它们与环境的相互作用，与基于谱系的对应物相比，可以产生更准确的狭义遗传力和育种价值估计。举例说明了训练和验证群体之间保留（随机折叠）与去除（家族折叠）遗传相似性对基因组选择的预测准确性的影响，并强调了前者的注意事项和后者的优点。此外，GBLUP模型允许对未包含在已开发模型中的家族的个体进行繁殖价值预测，而ABLUP无法做到。对ABLUP和GBLUP模型之间选择差异的反应表明，HT和WD的系统遗传增益分别高估了35％和63％，这主要是由于ABLUP模型给出的附加遗传方差估计值和个体育种值的夸大估计所致。将基于OP基因组学的模型从单站点扩展到多站点，使得该分析适用于现有的OP测试程序。