GM Crop May Aid Weeds
Mark Graffis
Posted 12 August 1999, 5 pm PST
Spokane, Washington--Crops can be engineered to resist the barley
yellow dwarf virus (BYDV), but the strategy may backfire. A report
presented here yesterday at the Ecological Society of America's annual
meeting suggests that engineered genetic protection against the virus
has the potential to spread from oats and other grains into wild oats,
a significant agricultural weed.
Researchers have engineered strains of [7]barley [LINK] and
[8]oats [LINK] that resist BYDV. But these crops can hybridize with
wild relatives--raising the possibility that modified genes will
escape into related weeds. Wild oats, for example, is a particularly
difficult weed for farmers to control. If wild oats gain resistance to
BYDV, they might become a much larger problem for farmers, says Alison
Power, an ecologist at Cornell University. The oats might also disrupt
natural habitats by competing better against native species, she says.
To examine these risks, Power grew oats and wild oats in
greenhouses and infected them with BYDV. The sick wild oats had much
thinner and shorter roots than did both uninfected controls and
infected oats. Infected wild oats also produced fewer seeds than
normal. "A BYDV-resistant transgene transfer seems likely to help wild
oat survivability," concludes Power.
The finding suggests that a natural virus can suppress weeds as
well as crops, says entomologist David Andow of the University of
Minnesota, St. Paul, who has done research on transgenic corn.
Researchers will have to assess the potential risks and agricultural
impacts of transgenes escaping into the wild, he adds.
--Stephen Leahy
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