New study published

USA: Genetically modified oilseed rape found on uncultivated land

When genetically modified oilseed rape is grown on a large scale, the plants also grow on uncultivated land. According to a recent study presented at the Ecological Society of America conference in Pittsburgh, 86 per cent of canola plants, a variety of oilseed rape, found on verges and at petrol stations are genetically modified. The scientists warn that the feral GM canola could become a weed problem for farmers.

GM oilseed rape on roadsides in North Dakota, USA

Oilseed rape along verges: The study conducted in the USA found numerous GM oilseed rape plants on unfarmed land, most of them on roadsides or at road construction sites. It is likely that rapeseed was lost when the harvest was transported or was transported to construction sites along with fill dirt.

Ruderal oilseed rape on a grass verge by the side of a road

This is not really surprising, since rape plants are often found along verges in areas where oilseed rape is farmed (photo from Germany)

Over 90 per cent of oilseed rape fields in the USA and Canada now grow genetically modified (GM) plants. Scientists at the University of Arkansas (Fayetteville, USA) have now shown for the first time how far the GM rape has spread in the uncultivated environment. In June and July 2010, the researchers collected random samples of oilseed rape plants from verges along highways and expressways over a distance of around 5600 kilometres and studied them.

The results were surprising, according to Cynthia Sagers, who led the research team: Around 80 per cent of the 231 plants examined were genetically modified. Sagers highlighted the fact that these GM rape plants were growing a long way away from rape-growing areas. In other studies conducted in Canada and the UK, feral GM rape plants have only been found in the vicinity of rape fields.

Sagers criticised the way GM crops are managed in the USA, claiming the regulations were not sufficient to prevent the plants from spreading and that there were no suitable measures in place for environmental Monitoring.

The GM plants found contained a herbicide-resistance gene with the active ingredient glyphosate (Roundup) or glufosinate (Liberty). Two plants even contained both herbicide-resistance genes. This, according to the study, could indicate that the GM rape has been growing in these locations for several generations. It is possible that oilseed rape plants with the two different herbicide-resistance genes have crossed. It is also possible that the genes have transferred to wild relatives.

Will feral GM rape cause weed problems?

The scientists fear that the uncontrolled spread of GM rape that is resistant to both herbicides could become a problem for farmers. It could become a stubborn weed in other crops because it would not be possible to control it with two of the most widely available herbicides.

Monsanto, one of the producers of GM oilseed rape, takes a less dramatic view of the situation. Tom Nickson, head of environmental policy, attributes the high numbers of GM rape plants along verges to the transport of rape harvests along these routes. Since seeds fall from the trucks as they pass, oilseed rape populations had become established there even before the introduction of GM varieties. The incidence of feral oilseed rape plants was also limited, he claimed, to certain places like verges and areas near fields. These oilseed rape populations could be controlled by mowing or by using other herbicides.

In this context, Sagers agreed that the results of her study might overestimate the actual spread of GM rape in the environment because all the samples were taken along roads and no other data was available. There were also indications that Roundup had been used at some of the survey sites in the past. This might also have increased the proportion of GM plants.

Alison Snow, an ecologist at Ohio State University, was not surprised by the research findings either, but said that the increasing spread of GM rape could be problematical: the broad-spectrum herbicides Liberty and Roundup require fewer applications each year. Feral GM rape plants and a transfer of the herbicide-resistance genes to wild relatives could negate this advantage. It could then become necessary to use different herbicides and more of them in future.