19 June 1998

Lots of benefits from GM crops if seed price right

IF they get a political green light, genetically-modified crops will offer growers considerable benefits and maybe cost savings too.

But much will depend upon the price of modified seed.

Potential gross margin boosts of up to £40/ha (£16/acre) have been seen in initial trials on oilseed rape which has been genetically-modified to be tolerant to glufosinate herbicide, says the SACs Elaine Booth, a member of the part-EU funded FACTT project which aims to familiarise the industry with GM crops.

Key practical gains include more flexible spray timings and less dependence on seed-bed conditions for pre-emergence herbicides, she explains.

The new technology also offers rotational advantages, such as being able to control volunteer barley more effectively, adds ADASs Mike Green, also of FACTT.

Growers will benefit from higher yielding hybrids made possible by biotechnology, adds Greta de Both of Plant Genetic Systems.

Countering the pluses, for some growers at least, may be the need to keep more accurate cropping and spray records. But those should be no more stringent than the ones kept by conventional seed producers, says Mr Green.

Colin Merritt for Monsanto estimates that weed control costs in Roundup (glyphosate) tolerant oilseed rape and sugar beet could be cut by 50% and 66%, respectively.

Against that there will be a premium for the seed, though the price has yet to be determined, he says. "Clearly there will have to be an overall saving or there will be no incentive for farmers to take it up."

AgrEvos Brian Harrison believes transgenic sugar beet, realistically at least two to three years away from commercial reality, could transform the way the crop is grown.

"It goes far beyond weed control." Fewer machinery passes will boost yield and root uniformity, and sowing cover crops more widely could bring beneficial spin-offs of nitrogen use and wildlife habitat. But everything depends on British Sugar relaxing its current stance against such crops, he says.

Simplicity of weed control is the main appeal of herbicide resistant sugar beet, says Lewis Dyer of Novartis. For commercial reasons it decided to omit oilseed rape from its transgenic runners and concentrate on beet and maize.

But Dutch trials suggest beet output can be boosted by 4-5% merely by avoiding damage to the crop by conventional herbicides, he notes. &#42