by Micheal D. K. Owen
March 22, 2007 - The ability of
weeds to evolve resistance to glyphosate has been well-documented.
Furthermore, the introgression of herbicide resistance between crops and weeds
has been widely characterized. However, the transfer of herbicide
resistance between different weed species is less well described in the
scientific literature. A recent publication in the American Journal of
Botany [94 (4):660-673]
"Transfer of glyphosate resistance: evidence of hybridization in Conyza
(Asteraceae)" by Zelaya, Owen and VanGessel describes the introgression of
a glyphosate resistance gene between Conyza canadensis (horseweed) and
C. ramosissima (dwarf horseweed). While the immediate implications on
agriculture are not likely significant, the ability for herbicide resistance to
move via pollen between weed species is indicative of the complexity of weed
management in crops.