Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, MN, 55108, USA.
Theor Appl Genet. 2019 Feb;132(2):347-353. doi: 10.1007/s00122-018-3222-3. Epub 2018 Nov 2.
For genomewide selection in each biparental population, it is better to use a smaller ad hoc training population than a single, large training population. In genomewide selection, different types of training populations can be used for a biparental population made from homozygous parents (A and B). Our objective was to determine whether the response to selection (R) and predictive ability (r) in an A/B population are higher with a large training population that is used for all biparental crosses, or with a smaller ad hoc training population highly related to the A/B population. We studied 969 biparental maize (Zea mays L.) populations phenotyped at four to 12 environments. Parent-offspring marker imputation was done for 2911 single nucleotide polymorphism loci. For 27 A/B populations, training populations were constructed by pooling: (1) all prior populations with A as one parent (A/, where * is a related inbred) and with B as one parent (/B) [general combining ability (GCA) model]; (2) A/* or /B crosses only; (3) all / crosses (same background model, SB); and (4) all /, A/, and */B crosses (SB + GCA model). The SB model training population was 450-6000% as large as the GCA model training populations, but the mean coefficient of coancestry between the training population and A/B population was lower for the SB model (0.44) than for the GCA model (0.71). The GCA model had the highest R and r for all traits. For yield, R was 0.22 Mg ha with the GCA model and 0.15 Mg ha with the SB model. We concluded that it is best to use an ad hoc training population for each A/B population.
对于每个双亲群体的全基因组选择，使用较小的特定训练群体比使用单个大型训练群体更好。在全基因组选择中，可以使用不同类型的训练群体来处理由纯合亲本（A 和 B）组成的双亲群体。我们的目标是确定使用大型训练群体（用于所有双亲杂交）或与 A/B 群体高度相关的较小特定训练群体，是否会提高 A/B 群体的选择响应（R）和预测能力（r）。我们研究了 969 个在 4 到 12 个环境中表型的玉米（Zea mays L.）双亲群体。对 2911 个单核苷酸多态性位点进行了亲本-后代标记估计。对于 27 个 A/B 群体，通过以下方式构建了训练群体：（1）将所有具有 A 作为一个亲本的前群体（A/，其中是相关的自交系）和具有 B 作为一个亲本的群体（*/B）[一般配合力（GCA）模型]；（2）仅 A/*或 */B 杂交；（3）所有 */*杂交（相同背景模型，SB）；和（4）所有 /、A/*和 */B 杂交（SB+GCA 模型）。SB 模型训练群体的规模是 GCA 模型训练群体的 450-6000%，但 SB 模型训练群体与 A/B 群体之间的平均亲缘系数低于 GCA 模型（0.44 对 0.71）。GCA 模型对所有性状都具有最高的 R 和 r。对于产量，GCA 模型的 R 为 0.22 Mg ha，SB 模型的 R 为 0.15 Mg ha。我们得出的结论是，最好为每个 A/B 群体使用特定的训练群体。
