More than 30 farm groups across the country today warned their members about the dangers of planting genetically engineered crops, saying the practice had become so unpopular with consumers that farmers were risking their livelihoods if they cultivated them again this year.

The farm groups, which included the National Family Farm Coalition and the American Corn Growers Association, also warned that inadequate testing of gene-altered seeds could make farmers vulnerable to "massive liability" from damage caused by genetic drift--the spreading of biologically modified pollens--and other environmental effects.

The farmers called on chemical companies engaged in bioengineering to promote the sale of traditional seed varieties for the coming crop year until an independent assessment of the environmental, health and economic impacts of gene-altered seeds is available.

In their first coordinated declaration on the potential impact of planting genetically engineered seed, the groups held a teleconference with reporters in Washington in which several Midwestern farmers and the heads of farm groups representing tens of thousands of producers said their chief concern was the marketability of foods created through biotechnology.

Many of the farm groups represented, including Farm Aid, which convened the conference, have been active in the fight to preserve family farming and curtail the growth of corporate agribusinesses.

"Export markets in Europe and Asia are saying 'no' to foods produced from genetically engineered crops [and] farmers know they have to respond to consumer demand if they are to survive," said Gary Goldberg, head of the corn growers association. "Right now, farmers may decide it is best for them to say 'no' to GMO seed." GMO is an acronym for genetically modified organism. Genetically engineered crops contain genes from bacteria and viruses to make them resistant to insects and weed killers.

Val Giddings, vice president for food and agriculture for the Biotechnology Industry Organization, said it "wouldn't be surprising if there was some slacking off" in the sale of biotechnology seeds this season, but he said the farm groups' market assessment was grossly distorted. "Fears of a market impact are nil," Giddings said. He also said numerous independent studies of bioengineered foods had proved them to be safe.

One farmer at today's news conference, Rodney Skalbeck of Sacred Heart, Minn., said he has planted genetically engineered corn and soybeans on his 750 acres for the last two years but doubts if he will this spring. "There's no problem, except how are you going to sell them?," Skalbeck said. "They haven't told us the truth about what's really happening. Are we going to lose the European market? Are we going to have a market here?"

Other farmers said they were concerned about having to pay premium prices for biotech seeds and then having to sell their crop at a discount, if they can sell it at all. As they prepare to place their seed orders for spring planting, the farmers said they are in a quandary because of the uncertain markets and the spreading controversy over bioengineered foods.

Seed dealers and grain buyers contacted independently before today's news conference said they also have become frustrated trying to anticipate the effects of consumer anxiety over the safety of gene-altered crops. They point out that commodities prices are already depressed by a worldwide glut of some grains, increased foreign competition and shrinking markets abroad.

Some seed dealers said they are bracing for a falloff in anticipated sales of genetically altered seeds, which last year topped $1 billion nationally and which, according to some estimates, had been expected to double this year.

"I think we're going to see them stepping away from GMOs, particularly corn," said Ken Hintzsche, a dealer in Maple Park, Ill. "I don't know how much, but there's a lot of concern out there."

Jerry Bertrand, a grain dealer in Grant Park, Ill., said, "Farmers are pretty confused, and with good reason. I can't tell them with any certainty that I'll take their GMO corn and soy next year because I don't know if there'll be a market for it."

Bertrand said that a year ago, most farmers he knows thought that gene-altered seeds were "the next best thing to sliced bread." Now, he said, "all of this misinformation and hysteria is going to hurt the market."

Bertrand said he thought that biotechnology companies such as Monsanto Co. and DuPont Co.'s Pioneer Hi-Bred International Inc., which in recent weeks have been sending representatives to farm regions to reassure producers about the market, "didn't do a very good job of selling this to the public in the first place."

Another grain buyer, Robert Seegers Jr. of Crystal Lake, Ill., said, "I think there's going to be a reluctance to plant [gene-altered] corn. I don't think they'll risk it this year." Seegers said that while he does not agree with the widespread public perception that genetically modified food is unsafe, "often perception is more important than reality."

Dean Urmston, executive vice president of the American Seed Trade Association, said that while it is too early to define a trend, "I do know that our members are concerned because of the emotional things being expressed by the media and others."

To counter the fears, the association has put on its World Wide Web site a grain handlers' database in which farmers can enter their Zip codes and instantly view a list of buyers who will take their genetically altered crops even if they don't meet the safety specifications of the European Union, which has led the resistance against agricultural biotechnology.

Urmston said 80 percent of the U.S. grain crop is purchased domestically and 54 percent of that is bought by about 2,000 grain handlers who say they will accept gene-altered crops. "So, the market is here. . . . Where's the panic?" Urmston asked.