BALTIMORE -- Weeds that acquire genes for herbicide resistance from genetically-altered crops reap little backlash and lots of benefit, according to an Ohio State University study.
Scientists have known for years that transgenic crops -- those that are engineered with specialized traits like herbicide resistance -- can pass their traits on to nearby weeds via hybridization. These hybrid, transgenic weeds resist the herbicides that were designed to kill them.
"When a crop grows near its weedy relative, it's inevitable that the genetically-engineered trait will move into the weed," said Allison Snow, associate professor of plant biology at Ohio State.
Still, scientists hypothesized that hybridization might cause some negative characteristics to emerge in a weed that would limit its reproduction. For instance, a hybrid weed might produce fewer flowers or seeds than a pure weed.
Snow collaborated with Risoe National Laboratory in Denmark to find out whether this was the case for oilseed rape, the plant from which canola oil is derived. The study showed that the offspring of herbicide-resistant hybrids between transgenic oilseed rape and one of its weedy relatives reproduced as prolifically as unaltered weeds.
The study suggests that, at least in the case of oilseed rape, weeds that cross with commercial crops and acquire a specialized transgene will encounter few obstacles to prosperity in the field. The researchers presented their results August 6 in Baltimore at the 1998 Ecological Society of America Annual Meeting.
Snow and her colleagues crossed a transgenic, herbicide-resistant
version of oilseed rape, or Brassica napus, with its weedy cousin, Brassica
rapa, and cultivated their progeny in indoor growth chambers in Denmark. The
researchers wanted to see how the transgenic weeds would fare compared to
unaltered weeds that weren't hampered by insects, disease, and herbicide as they
Contact: Allison Snow
Ohio State University