Montreal

In a major boost for agricultural biotechnology, Canada's supreme court has ruled that a patent on a genetically modified seed extends to the cells and genes in the resulting plant.

The 21 May ruling is the last word in a seven-year battle between biotech firm Monsanto, based in St Louis, Missouri, and Saskatchewan farmer Percy Schmeiser.

Monsanto brought the action because its transgenic canola was found growing in Schmeiser's fields when he did not have a licence from the firm to cultivate the crop. Schmeiser, who maintains that the canola seeds blew on to his property, was ruled to have infringed Monsanto's patent by growing the plants without a licence. The gene in question renders canola resistant to Monsanto's Roundup weed-killer.

The ruling, said to be the first of its type in any country, thrilled the biotech industry and angered consumer, environmental and farmers' groups. In a statement, Monsanto said that the ruling set “a world standard in intellectual property protection”.

The case was seen as critical for the agricultural biotechnology industry, which holds thousands of patents likely to be affected by it and has many more pending. But critics say that the decision will give the industry too much control over farmers.

“This decision does not just condemn Percy Schmeiser, it also condemns the broader community,” says Andrea Peart, director of health and environment with the environmental group Sierra Club of Canada. “The responsibility of dealing with the environmental contamination by genetically engineered genes will now be shouldered by the public, not the polluter.”

The ruling contrasts with the Supreme Court's 2000 decision on the Harvard Mouse, a transgenic rodent used in cancer research. It said that the mouse could not be patented in Canada, although courts in the United States and Europe have permitted patents. But the court found that the nature of commercial agriculture meant that plants grown from the seeds constituted a ‘use’ of the technology covered by the patent.