Weedy and invasive plants often experience different environments than their predecessors, and evolutionary changes may be needed for them to survive in new habitats. Such shifts may be most pronounced when invaders are the hybrid offspring of two species, because they represent a mixture of their parents' traits. Using crop-weed hybrids between weedy radish (Raphanus raphanistrum) and the crop (Raphanus sativus), the graduate student will examine the "evolvability" of hybridizing populations. Specifically, the proposed dissertation research will: 1. Measure shifts in the time to reproduction and the average size at reproduction of weedy radishes in experimental populations, with and without hybridization. 2. Determine how genetic variation in the plants' time to reproduction and size at reproduction affects their weediness by comparing different selected lineages in common garden experiments
Changes in developmental traits may have major implications for the evolution of weediness. In a novel way, hybrids may be able to benefit from traits from both of their parental species, perhaps becoming weedier than either parent. Thus, hybridization could be stimulus for invasiveness. This research will to improve our understanding of weed evolution, providing important insights for land managers who are concerned with invasive species, agricultural weeds, and their impacts on biodiversity.
