hybridization
Campbell LG & Snow AA 2009 Can feral weeds evolve from cultivated radish (Raphanus sativus, Brassicaceae)? Am J Bot 96:498-502.
- unharvested crop seeds may generate feral populations, at times causing serious weed problems
- but little is known about the evolution of ferality
- we explored the potential for cultivated radish, Raphanus sativus, to become feral
- three late-flowering populations went extinct
- two others apparently hybridized with local R. raphanistrum
- a common garden experiment showed that the two surviving populations had earlier flowering, smaller root diameters, and greater individual fecundity than did nonhybridized populations
- it seems unlikely that radishes could spontaneously become feral in our study area without gene flow from R. raphanistrum
- wild R. sativus var. hortensis f. raphanistroides, a biennial plant, is common in Japan and Korea along beaches, cliffs, abandoned fields, and other ruderal areas
- and sometimes occurs adjacent to cultivated daikon radishes (Yamagishi and Terachi, 2003)
- but these populations may be derived from R. raphanistrum rather than R. sativus (Hegde et al., 2006)
- for cultivated European radishes to evolve endoferality, key mutations and strong selection may be needed to reduce frequencies of deleterious crop traits such as delayed flowering and increase frequencies of "weedy" traits
