Hybridization alters early life-history traits and increases plant colonization success in a novel region

Hybridization is hypothesized to promote invasiveness, but empirical tests comparing the performance of hybrid versus parental taxa in novel regions are lacking. We experimentally compared colonization ability of populations of wild radish (Raphanus raphanistrum) versus populations of advanced-generation hybrids between wild and cultivated radish (R. sativus) in a southeast Texas pasture, well beyond the known invasive range of hybrid radish. We also manipulated the strength of interspecific competition to better generalize across variable environments. In both competitive environments, hybrid populations produced at least three times more seeds than wild radish populations, a distinction that was driven by greater hybrid seedling emergence, earlier hybrid emergence and more hybrid seedlings surviving to flower, rather than by greater individual fecundity. Flowering duration in hybrids was less negatively affected by competition than it was in wild radishes, while early emergence was as...