BioWorld International Correspondent

LONDON - BASF Plant Science GmbH has applied for permission to stage field trials of potatoes genetically modified to resist late potato blight, reviving controversy over GM crops three years after it was concluded existing products had little to offer UK agriculture.

On the face of it, the blight-resistant potato should have more going for it.

The cost of fungicide to prevent blight caused by Phytophthora infestans costs £20 million (US$47 million) annually in raw material costs alone. Added to this is the time taken to spray potato fields, the need for continual checking to ensure there is no infection from the fast-spreading fungus and - despite those precautions - the loss of around 5 percent of the total crop to blight each year.

The GM potato might have other factors in its favor compared to its GM counterparts. The blight resistance comes not from a transgene but from two genes derived from a wild potato relative Solanum castanum that is native to Mexico. However, it does contain a marker gene from Arabidopsis also.

In attempting to get UK approvals, BASF is not only up against public opinion, but also the weight of evidence from the world's largest field scale trials of GM crops, sponsored by the UK government.

The results for the fourth crop to be studied - winter oilseed rape, published in March 2005 - showed there were fewer butterflies and bees in GM fields compared to conventional varieties. Results for three other crops - spring-sown oilseed rape, beet and forage maize - published in October 2003, showed conventional oilseed rape and beet were better for many groups of wildlife, while GM maize was better than conventional maize.

The GM maize results were called into question subsequently, because atrazine, the weedkiller used on the conventional crop, was about to be banned by the European Union.

In March 2004, the UK government gave the go-ahead for the GM maize, Chardon LL, developed by Bayer CropScience to be grown in the UK, but said it would contest the approval of GM beet and GM spring oilseed rape by the EU. However, it attached a condition to the GM maize approval saying seed companies would have to fund a scheme to compensate non-GM farmers if their produce was contaminated with GM material. Three weeks later, Bayer CropScience withdrew its application for a license.

The publication of the results for winter oilseed rape was the last act in a series of initiatives dating back to 1999, which were designed to sway public opinion in favor of GM crops. In addition to the farm scale trials, the UK government funded a massive public consultation exercise involving more than 600 meetings, a cost-benefit assessment and a review of 600 scientific papers.

While the review concluded there was no evidence that eating GM crops posed any threat to human health, the cost-benefit analysis said weak consumer demand meant the current generation of GM crops was of little economic value to the UK.

Meanwhile, the assumption that a better informed public would support GM crops turned out to be wrong. In fact, attitudes hardened, and the more people found out, the more convinced they were that not enough was known about the long-term effects on human health.

If BASF gets approval to plant GM potatoes in the UK, two trial areas of one hectare each could be planted in April 2007.

Potatoes containing one of the introduced genes were first planted in Sweden in 2005, with trials in Germany and the Netherlands taking place this year.

BASF was given approval also to trial the GM potatoes in Ireland in May 2006, but decided not to go ahead this year because of restrictions on the approval. However, the permit remains valid until 2010.