QTL underlying crop adaptation to mega-environments in soybean

利用外来种质来提高作物的生产力一直受到限制，因为根据所使用的物种和种质的不同，所遇到的成功率相对较低且变化很大。在大豆方面，在上个世纪首次引入祖先系后，中国(原产地和多样性中心)和北美大豆育种计划之间交换的育种材料很少使用，即使是来自相似种植区的材料也是如此。通常，在非寄主环境中缺乏环境适应阻碍了利用外来种质的进展，导致适应亲本的产量在后代中罕见地恢复或超过。如果种子产量是一种特定作物适应潜力的最终衡量标准，那么它似乎不能仅仅由成熟度组或引入材料的纬度来解释。在之前的NSERC发现基金中，我们已经确定了普遍的与大陆特有的数量性状基因座(QTL)的比率似乎驱动着适应大环境的力量。在本提案中，我们将尝试解决以下问题。即使采用了假定选择的随机性的育种方法，繁育群体所处的大环境是否也会影响非随机的基因类型选择？即使育种方法具有随机性，非随机的基因选择是否也会造成分离扭曲？表现分离扭曲的标记在产量QTL表达中的作用有多大？相互作用的QTL(上位性)在决定适应中的作用是什么？在中国大豆种质资源中观察到的种子和农艺性状QTL等位基因多样性的一部分，能否部分解释为中国大豆育种计划更多地使用野生大豆祖先大豆？这项研究的概念意义在于，确定作物适应的潜在遗传原理可能有助于开发更具战略性和基于遗传的新遗传变异导入一些物种。

The use of exotic germplasm to improve the productivity of crop plants has been limited due to relatively low and variable success that has been encountered, depending on the species and germplasm used. In soybean, after the initial introduction of ancestral lines in the last century, there has been little use of breeding materials exchanged between the Chinese (centre of origin and diversity) and North American soybean breeding programs, even for materials coming from similar growing regions. Typically, the lack of environmental adaptation in non-host environments has hampered progress in using exotic germplasm resulting in a rare recovery of, or surpassing, of the adapted parent's yield in the progeny. If seed yield is the ultimate measure of a given crop's adaptation potential, it does not seem to be explained solely by the maturity group or the latitude the introduced materials came from. Within the previous NSERC Discovery grant, we have determined that a ratio of universal vs. continent-specific quantitative trait loci (QTL) appears to drive the forces of adaptation to mega-environments. In this proposal, we will attempt to address the following questions. Does the mega-environment in which the breeding population is developed influence a non-random selection of genotypes, even when breeding methods that assume randomness of selection are practiced? Is segregation distortion caused by non-random selection of genotypes, even when breeding methods assume randomness? How important a role do markers that show segregation distortion play in the expression of yield QTL? What is the role of interacting QTL (epistasis) in determining adaptation? Can a portion of the observed diversity in QTL alleles for seed and agronomic traits in the Chinese germplasm be explained in part by the greater use of the wild soybean progenitor, Glycine soja, by the Chinese soybean breeding programs? The conceptual significance of this research is that the determining of the underlying genetic principles of crop adaptation may aid in the development of a more strategic and genetically-based introgression of new genetic variation into a number of species.