23 October 1998

GM crop trials set to produce new guidelines

A major new research

project is to pinpoint the

potential risks and benefits

of growing genetically

modified herbicide-tolerant

crops within typical farm

rotations. Charles Abel

takes a closer look

ON-FARM management of genetically modified herbicide-tolerant crops is the key to their environmental and economic success.

To help farmers make the most of the opportunities and minimise the risks, a new £600,000 research programme has been launched to develop practical guidelines to help farmers manage such crops throughout the rotation.

The four-year study will look at the potential for economic benefits, plus possible downsides, including herbicide-tolerant volunteers and the movement of herbicide tolerance into related weed species.

"The biggest impact of genetically modified herbicide-tolerant crops will come from the way the crop is managed on the farm, rather than the crops themselves," warns Jeremy Sweet scientific co-ordinator of the project and head of pathology and chemistry at NIAB.

With that in mind the new BRIGHT project (Botanical and Rotational Implications of Genetically modified Herbicide Tolerance) will examine three types of herbicide tolerance in four crops, grown in five rotations at five sites across the UK.

"Our aim is to produce an advisory package to guide farmers, to help them get the best from these crops and limit any potential risks, says project chairman and independent consultant Windsor Griffiths.

"The work will not repeat the risk assessment work which has already been done or is underway through other projects, although it may provide additional data."

The study will look for benefits throughout the rotation, particularly from savings on pernicious weed control in following crops. "By allowing good blackgrass control in broad-leaved crops we could see savings in cereals, for example," says weed researcher Peter Lutman of project partner IACR Rothamsted.

On the risk side, one of the key concerns is the stacking of different herbicide tolerance genes in volunteers or related weeds. "We do need to look at this, particularly the risk of genes for tolerance to different herbicides from an adjacent crops or adjacent farms," notes Dr Sweet.

That could result in volunteers and weeds able to resist more than one herbicide. "Our aim is to produce guidelines for minimising that risk and to show growers how to deal with it if it arises," he says.

The project includes a conventionally-bred oilseed rape which is tolerant to a development broad-leaved and grass weed herbicide from Cyanamid. Although free from GM crop regulations, it poses similar practical risks to farmers, notes Dr Sweet.

Large-scale plots were sown this autumn and initial findings will start emerging early next year, explains funding co-ordinator Robert Cook. Annual reports will lead towards overall guidelines in 2002. &#42

BRIGHTPROJECT

&#8226 Impact of GM herbicide-tolerant crops across rotation.

&#8226 £600,000, 4-year study.

&#8226 MAFF/industry-funded.

&#8226 15ha of plots.

&#8226 Investigating economic benefits; volunteer risks; crossing with weeds; risk of multiple resistances; weed seed bank effects.

&#8226 Crops: Osr, maize, sugar beet, fodder beet.

&#8226 Five rotations.

&#8226 Sites: IACR Rothamsted, Herts; NIAB, Cambridge; IACR Brooms Barn, Suffolk; Morley Research Centre, Norfolk; SAC, Aberdeen.

&#8226 GM tolerance to glyphosate (Roundup) and glufosinate (Liberty), plus conventional rape tolerant to an imidazolinone herbicide.

&#8226 Funding: MAFF, Monsanto, AgrEvo, Cyanamid, HGCA cereal and oilseed grower levies.

&#8226 Results: From next year.