Institute of Agronomy and Plant Breeding II, Justus Liebig University, Giessen, Germany.
Theor Appl Genet. 2011 Jul;123(2):251-60. doi: 10.1007/s00122-011-1581-0. Epub 2011 Apr 8.
Application of marker-assisted backcrossing for gene introgression is still limited by the high costs of marker analysis. High-throughput (HT) assays promise to reduce these costs, but new selection strategies are required for their efficient implementation in breeding programs. The objectives of our study were to investigate the properties of HT marker systems compared to single-marker (SM) assays, and to develop optimal selection strategies for marker-assisted backcrossing with HT assays. We employed computer simulations with a genetic model consisting of 10 chromosomes of 160 cM length to investigate the introgression of a dominant target gene. We found that a major advantage of HT marker systems is that they can provide linkage maps with equally spaced markers, whereas the possibility to provide linkage maps with high marker densities smaller than 10 cM is only of secondary use in marker-assisted backcrossing. A three-stage selection strategy that combines selection for recombinants at markers flanking the target gene with SM assays and genome-wide background selection with HT markers in the first backcross generation was more efficient than genome-wide background selection with HT markers alone. Selection strategies that combine SM and HT assays were more efficient than genome-wide background selection with HT assays alone. This result was obtained for a broad range of cost ratios of HT and SM assays. A further considerable reduction of the costs could be achieved if the population size in the first backcross generation was twice the population size in generations BC(2) and BC(3) of a three-generation backcrossing program. We conclude that selection strategies combining SM and HT assays have the potential to greatly increase the efficiency and flexibility of marker-assisted backcrossing.
应用标记辅助回交进行基因导入仍然受到标记分析成本高的限制。高通量 (HT) 检测有望降低这些成本，但需要新的选择策略才能在育种计划中有效地实施。我们的研究目的是研究 HT 标记系统与单标记 (SM) 检测相比的特性，并为 HT 检测的标记辅助回交开发最佳选择策略。我们使用包含 10 条 160cM 长染色体的遗传模型进行计算机模拟，以研究显性靶基因的导入。我们发现，HT 标记系统的一个主要优势是它们可以提供等间距标记的连锁图谱，而提供小于 10cM 的高密度标记连锁图谱的可能性在标记辅助回交中只是次要的。一种三阶段选择策略，在第一回交代中结合 SM 检测对侧翼标记的重组体进行选择，以及利用 HT 标记进行全基因组背景选择，比仅利用 HT 标记进行全基因组背景选择更有效。结合 SM 和 HT 检测的选择策略比仅利用 HT 检测进行全基因组背景选择更有效。这一结果适用于 HT 和 SM 检测成本比广泛的范围。如果第一代回交群体的大小是三代回交计划的 BC(2)和 BC(3)代群体大小的两倍，则可以进一步显著降低成本。我们得出结论，结合 SM 和 HT 检测的选择策略有可能大大提高标记辅助回交的效率和灵活性。
