Postpollination Mechanisms and Relative Fitness Contribution of Differential Outcrossing Distance

研究将集中在确定哪些个体与形成下一代的种子有共同的亲缘关系。通过研究两种具有代表性的非木质多年生植物的交配系统，研究人员将检验一种植物的最佳交配取决于配偶的物理距离，因为这反映了遗传相似性。先前的研究表明，在相距中等距离的植物之间，杂交成功率最高，因此遗传上既不太相似也不太不同。本研究的一个主要目标是获得幼苗生存和繁殖的完整寿命估计，以检验“最佳异交距离”的后代最适合的假设。第二个目标是通过使用一种复杂的实验性授粉来评估适合度差异有多大。第三个目标是评估在与亲本植物不同距离上发芽的适应性成本。第四个目标是观察“授粉后”选择是否会使实际交配系统与最优交配系统更接近。这些研究对其他植物也有启示，包括作物物种。总的来说，适应性对配偶遗传相似性的敏感程度可能比迄今为止认识到的要小，授粉后的选择将改变结果。这项研究将对这些可能性进行更深入的调查。

Research will focus on characterizing which individuals share parentage of the seeds that form the next generation. By studying mating systems of two species that are representative of non-woody perennial plants, the investigators will test the idea that the best mating for a plant will depend on the physical proximity of mates, because this reflects genetic similarity. Previous research has indicated that crossing success should be highest between plants separated by an intermediate distance, and thus neither too similar nor too dissimilar genetically. A major goal of this research is to obtain complete lifetime estimates of seedling survival and reproduction in order to test the hypothesis that offspring from the "optimal outcrossing distance" are most fit. A second goal is to assess how great the fitness differences are by using a complex kind of experimental pollination. A third goal is to assess fitness costs associated with germinations at various distances from parental plants. A fourth goal is to see whether "postpollination" selection will bring the actual mating system into closer agreement with the optimal mating system. These studies have implications for other plants, including crop species. It seems likely in general that fitness will be sensitive to genetic similarity of mates on a finer scale than hitherto recognized, and that postpollination selection will modify the outcome. This research will provide a closer investigation of these possibilities.