Selection for flood-tolerance in soybean [Glycine max (L.) Merr.] is mainly phenotypic. With the development of new molecular breeding tools, our research objective was to assess the effect of different selection methods at the F_4:5 and F_4:6 stages on the response to flood tolerance and yield at F_4:6 stage. Four breeding populations were subjected to six selection treatments: (a) flood tolerance screening using hill-plots (VIS_hill); (b) flood tolerance screening using long rows (VIS_row); (c) genomic selection using population-specific training (GS_hill); (d) genomic selection using broad-based training population (GS_row); (e) marker-assisted selection (MAS); (f) advanced based on agronomic adaptation under nonflooded conditions (random selection, RND). The top 15% lines within were tagged for selection, except for MAS that was adjusted based on recovery of desired haplotype. The complete base populations (BP) were advanced into flood and yield trials to determine probability of discard (POD), tolerance index (TOL), and seed yield. Analysis of variance was conducted across populations, and means were separated via Dunnett to the BP. Results indicated significantly different responses for flood tolerance (POD and TOL) across selection methods (p < .0001), with VIS_row and GS_row consistently having better tolerance selections than the BP (p < .0001). In addition, lines selected by RND had lower tolerance than BP (p = .0053 and .0618 for POD and TOL, respectively). Moreover, no significant differences were observed among selection treatments (p = .6797) for yield. In conclusion, when breeding for flood tolerance, selections under standard agronomic practices are inadequate, and genomic selection (GS_row) or field screening using long rows (VIS_row) are favored selection methods.

中文翻译：

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大豆抗洪育种方法对选择的响应

大豆 [ Glycine max (L.) Merr.]的抗洪性选择主要是表型。随着新分子育种工具的发展，我们的研究目标是评估不同选择方法在 F _4:5和 F _{4:6阶段对 F 4: 6}阶段抗洪和产量响应的影响。_{对四个繁殖种群进行了六种选择处理：（a）使用山丘（VIS hill} ）进行抗洪筛选；_{(b) 使用长排（VIS排}）的耐洪性筛选；(c) 使用特定人群训练的基因组选择 (GS _hill )；(d) 使用基础广泛的训练群体（GS_{行）进行基因组选择}); (e) 标记辅助选择 (MAS)；(f) 基于非淹水条件下的农艺适应性（随机选择，RND）。其中前 15% 的行被标记以供选择，除了基于所需单倍型的恢复进行调整的 MAS。将完整的基础种群 (BP) 推进洪水和产量试验，以确定丢弃概率 (POD)、耐受指数 (TOL) 和种子产量。对人群进行方差分析，并通过 Dunnett 将平均值分离到 BP。结果表明不同选择方法对洪水耐受性（POD 和 TOL）的响应存在显着差异（p  < .0001），VIS_行和 GS_行始终具有比 BP 更好的耐受性选择（p < .0001)。此外，RND 选择的线的耐受性低于 BP（对于 POD 和 TOL， p  = .0053 和 .0618，分别）。此外，在选择处理 ( p = .6797)之间没有观察到 产量的显着差异。总之，在抗洪育种时，标准农艺实践下的选择是不充分的，基因组选择（GS_行）或使用长行（VIS_行）的田间筛选是受青睐的选择方法。