Commercial hybrid breeding operations can be described as decentralized networks of smaller, more or less isolated breeding programs. There is further a tendency for the disproportionate use of successful inbred lines for generating the next generation of recombinants, which has led to a series of significant bottlenecks, particularly in the history of the North American and European maize germplasm. Both the decentralization and the disproportionate inbred use reduce effective population size and constrain the accessible genetic space. Under these conditions, long term response to selection is not expected to be optimal under the classical infinitesimal model of quantitative genetics. In this study we therefore aim to propose an alternative rational for the success of large breeding operations in the context of genetic complexity arising from the structure and properties of interactive genetic networks. For this we use simulations based on the NK model of genetic architecture. We indeed found that constraining genetic space and reducing effective population size, through program decentralization and disproportionate inbred use, is required to expose additive genetic variation and thus facilitate heritable genetic gains. These results introduce new insights into why the historically grown structure of hybrid breeding programs was successful in improving the yield potential of hybrid crops over the last century. We also hope that a renewed appreciation for "why things worked" in the past can guide the adoption of novel technologies and the design of future breeding strategies for navigating biological complexity.

中文翻译：

---

回到未来：遗传复杂性对杂交育种策略的影响

商业杂交育种操作可描述为规模较小，或多或少孤立的育种计划的分散网络。成功地将近交系用于产生下一代重组体的趋势还有不成比例的趋势，这导致了一系列重大瓶颈，特别是在北美和欧洲玉米种质史上。权力下放和不成比例的近交使用都减少了有效种群规模，并限制了可利用的遗传空间。在这些条件下，在定量遗传学的经典无穷小模型下，预期对选择的长期反应不是最佳的。因此，在这项研究中，我们旨在为交互遗传网络的结构和特性引起的遗传复杂性提出大型育种成功案例的另一种合理性。为此，我们使用基于遗传结构的NK模型的模拟。我们确实发现，需要通过程序分散化和不成比例的近交使用来限制遗传空间并减少有效种群数量，以暴露出附加的遗传变异，从而促进可遗传的遗传收获。这些结果为为什么在过去的一个世纪中历史悠久的杂交育种计划结构成功地提高了杂交作物的产量潜力提供了新的见解。我们还希望对“为什么行得通”再次表示赞赏