SAN FRANCISCO — As genetically engineered agriculture takes off worldwide, the biggest growth in its popularity in 2007 came in the developing world, according to an international report.

Farmers in 12 developing countries planted biotech crops in 2007, for the first time exceeding the number of industrialized countries where such crops are grown, according to the report from the International Service for the Acquisition of Agri-biotech Applications, an industry-supported nonprofit that promotes the use of biotechnology to alleviate poverty and hunger around the world. The report, released Wednesday, was funded by the Rockefeller Foundation and Ibercaja, a Spanish bank.

Of the 12 million farmers worldwide who sowed genetically engineered seeds, the report described 11 million as "resource-poor."

Critics warned the embrace signaled greater corporate encroachment on traditional agriculture. They also said that because so few genetically engineered crop varieties exist, adopting them could trap poor farmers in a cycle of debt to the multinational companies that own patents on the seeds.

And the critics said much of the harvest is used for animal feed, fabric and processed foods.

"It has almost nothing to do with feeding people," said Claire Hope Cummings, a former environmental lawyer for the U.S. Department of Agriculture and author of the upcoming book "Uncertain Peril," a critique of biotech farming. "It's an industrial commodity for industrial agriculture."

Feed and fiber crops typically precede food in the development of new agricultural technologies, said Clive James, the report's primary author.

More and more land will be devoted to genetically engineered foods, especially rice, as scientists make advances and regulators approve new products, James said, adding that it is not realistic to expect all of agriculture to change at the same time.

The ISAAA advocacy group he was writing for counts several of the world's largest biotech agriculture companies among its donors.

In 2007, a record 282.3 million acres of the world's cropland were planted with soybeans, corn, cotton and other crops genetically altered to resist pests and herbicides, an increase of about 12 percent from the previous year, according to the report.

Reduced pesticide spraying and increased yields have brought down the price of production in "a very significant way and a sustainable way," putting more money in poor farmers' pockets, James said.

"Poverty today is a rural phenomenon. It is concentrated in agriculture," James said. "This technology can make a contribution."

U.S. farms continued to dominate biotech agriculture with more than 142 million acres devoted to engineered crops, led by soy. The nation also saw the planting of biotech corn spike 40 percent over 2006 to nearly 20 million acres, driven mainly by the demand for ethanol.

Argentina led developing countries with about 47.2 million acres in biotech corn, soy and cotton.

It was second only to the U.S. in total acreage and followed by Brazil, which had just over 37 million acres of biotech cotton and soy. India grew 15.3 million acres of genetically engineered cotton in 2007, its only biotech crop.

Spain ranked highest among European countries with about 173,000 acres of genetically engineered corn but 12th overall, behind Paraguay, South Africa, Uruguay and the Philippines.

European countries have been among the most resistant to genetically engineered crops, where health and environmental concerns have long kept them out of farmers' fields. According to the report, eight out of 27 European countries planted biotech crops in 2007, up from six the previous year, totaling about 260,000 acres.