Admixture increases performance of an invasive plant beyond first generation heterosis

1. Through its potential to enhance progeny performance, admixture (between-population crossing) may promote invasiveness of alien plants. The few studies that tested this idea found evidence for heterosis (positive effects of admixture) in the first generation (F1), but have not considered further generations. In this paper, we test whether admixture-benefits can be maintained in subsequent generations of an invasive plant.
2. We follow up on a previous study, in which we made crosses between plants of Mimulus guttatus from native- (western North America) and invaded-range populations (New Zealand and Scotland), and showed that admixture increases F1 performance. Here, we performed further crosses to create non-admixed progeny, F1 progeny resulting from within- and between-range admixture, and subsequent F2 progeny both through outcrossing and through self-fertilization. As heterosis, out- and inbreeding depression may depend on the environment, we assessed progeny-performance under b...

1. 跨种群杂交（admixture）通过提升子代表现的潜力，或可促进外来植物的入侵性。目前为数不多验证这一假说的研究仅在子一代（F1）中发现了杂种优势（heterosis，即跨种群杂交的正向效应）的相关证据，但均未考虑后续世代。本研究旨在验证入侵植物的跨种群杂交优势是否可在后续世代中得以维持。
2. 本研究延续此前一项工作：此前我们对来自原生分布区（北美西部）与入侵分布区（新西兰与苏格兰）的沟酸浆（Mimulus guttatus）进行杂交，证实跨种群杂交可提升子一代（F1）的表现。本次研究中，我们通过进一步杂交构建了三类实验材料：非杂交子代、由分布区内杂交与跨种群杂交产生的子一代（F1）子代，以及通过异交（outcrossing）与自交（self-fertilization）获得的后续子二代（F2）子代。鉴于杂种优势、异交优势与近交衰退（inbreeding depression）均可能受环境影响，我们在b……条件下评估了子代表现。