INDIANAPOLIS — Inside bright greenhouses at Dow AgroSciences' sprawling complex, corn plants grow tall and lush, with no signs of rootworms, corn borers or other pests that munch away at crops and farmers' profits.

The corn is grown from biotech seeds that share genes from different types of corn to produce a plant able to resist the toughest pests and weed killers.

Demand from farmers is brisk. To keep up, Dow is growing and harvesting corn plants as fast as it can, even expanding into winter production in Hawai'i, Argentina and Chile.

"We're bulking up, but it will be another two or three years before we can meet demand," said Thomas R. Wiltrout, global business leader for Dow's plant genetics.

Already consumers are gobbling up genetically altered ingredients in foods from chips to desserts, probably without realizing it, creating a $6 billion industry that shows no sign of slowing.

Dow is positioning itself to grab a bigger share. The company, better known for its agricultural chemicals, is a small player in the corn seed market, but wants to change that. Over the next three years, it wants to produce a super seed with eight genetic traits to fight pests and weed killers on multiple fronts, significantly more than the three traits now available on genetically modified seeds.

It is teaming up with agribusiness giant Monsanto Co. to share genetic traits now available only in products from each company.

It's the latest step in the wave of genetically modified foods, changing the way farmers grow crops and how consumers feed their families.

Critics call the crops "frankenfoods" — unnatural, scary and possibly dangerous to human health and biodiversity. They want more testing and more regulations. But supporters call genetically modified crops a biotechnology marvel that helps farmers produce more food from America's shrinking farmland and help feed the planet.

"We believe the currently marketed genetically engineered crops are safe to eat, and have some benefits to the environment and farmers, and Americans should embrace those," said Gregory Jaffe, who oversees biotech issues for the Center for Science in the Public Interest, an advocacy and educational organization based in Washington.

Dow is counting on the eight-gene combination, called SmartStax, to help it gain market share at the expense of larger competitors.

But Dow needs to gain support worldwide to sell more of the biotech seeds. While U.S. consumers are supporting biotech foods — or at least not actively resisting them — Europeans are less willing to embrace such products.

Some surveys show more than 70 percent of Europeans are against biotech food. For years, many European countries banned the importation of genetically altered foods. But recently, the European Commission approved Dow's biotech corn for use in animal feeds, for human consumption and other uses, although it did not lift its ban against raising the crops.

Dow and Monsanto hope to launch their super seeds by 2010. The seeds will represent a combination of traits from the two companies, such as Dow Agro's insect-resistant Herculex and Monsanto's Roundup herbicide.

"We've already developed our traits. Monsanto has already developed theirs. So it's simply a matter of putting them together," Wiltrout said.

Global acreage of biotech crops more than doubled from 2000 to 2006, from 109 million acres to 252 million acres, according to the Biotechnology Industry Organization trade group.