canola found growing freely in North Dakota.
GM crops with herbicide resistance spread beyond farmland, they could become
problematic weeds. IStockphoto
modified (GM) crop has been found thriving in the wild for the first time
in the United States. Transgenic canola is growing freely in parts of North
Dakota, researchers told the Ecological Society of America conference in
Pittsburgh, Pennsylvania, today.
scientists behind the discovery say this highlights a lack of proper monitoring
and control of GM crops in the United States.
have dramatically increased their use of GM crops since the plants were
introduced in the early 1990s. Last year, nearly half the world's transgenic
crops were grown in US soil — Brazil, the world's second heaviest
user, grew just 16%. GM crops have broken free from cultivated land in several
countries, including Canada, the United Kingdom and Japan, but they have
not previously been found in uncultivated land in the United States.
extent of the escape is unprecedented," says Cynthia Sagers, an ecologist
at the University of Arkansas in Fayetteville, who led the research team
that found the canola (Brassica napus, also known as rapeseed).
and her team found two varieties of transgenic canola in the wild —
one modified to be resistant to Monsanto's Roundup herbicide (glyphosate),
and one resistant to Bayer Crop Science's Liberty herbicide (gluphosinate).
They also found some plants that were resistant to both herbicides, showing
that the different GM plants had bred to produce a plant with a new trait
that did not exist anywhere else.
says the previous discoveries in other countries of transgenic canola populations
growing outside of cultivation were often in or near fields used for commercial
transgenic canola production. By contrast, her research team found feral
populations of herbicide-resistant canola growing along roads, near petrol
stations and grocery stores, often at large distances from areas of agricultural
researchers took samples of plants at 8-kilometre intervals along roads
in North Dakota from 4 June to 23 July 2010. The number of B. napus plants
in each sample plot was counted, and one plant was collected and tested
for the presence of proteins that could give it resistance to either of
team found B. napus at nearly half of the 288 sites tested. Of these, 80%
had at least one herbicide-resistant transgene (41% were resistant to Roundup
and 40% resistant to Liberty). They also found two plants that contained
says the discovery of plants that are resistant to both herbicides shows
that "these feral populations of canola have been part of the landscape
for several generations". Further studies are needed to establish whether
these escaped GM canola plants have any ecological consequences. But those
that have evolved resistance to both herbicides could become a weed problem
for farmers, adds Sagers.
regulatory protocols designed to reduce or prevent escape and proliferation
of feral transgenic crops are ineffective. Current tracking and monitoring
of GM organisms are insufficient," she says. Sagers blames the delay
in discovering escaped populations of transgenic plants in the United States
largely on the lack of funding for research in this area.
Nickson, head of environmental policy at Monsanto in St Louis, Missouri,
told Nature, "Those familiar with canola know that these plants are
readily found on roadsides and in areas near farmers' fields. This was true
prior to the introduction of GM canola, and a common source is seed that
has scattered during harvest and fallen off a truck during transport."
agrees that feral populations could have become established after trucks
carrying cultivated GM seeds spilled some of their load during transportation.
She notes that the frequency and population density of GM canola that they
found may be biased as they only sampled along roadsides.
Snow, an ecologist at Ohio State University in Columbus, says it is not
surprising that escaped transgenic plants have now been found in the United
States, given that this has already happened elsewhere. The escaped populations
"could be a problem if you are worried about herbicide use", she
says. A major advantages of herbicide-resistant crops is that non-selective
herbicides can be used, reducing the number of applications needed. But
if transgenic crops escape and breed with related weed species, then that
advantage could be eroded, and different and more herbicides might have
to be used.