Editor's Note: This article was published by Reuters and Forbes, and also includes statements from a Monsanto news release.

Key players in the U.S. seed industry are working to head off an antitrust probe into allegations of unfair competition even as farm groups ratchet up pressure on the government to take action against what they say are escalating prices and constriction of market choice.

Fresh concerns about unfair market dominance were raised Wednesday when a network of 34 U.S. farm organizations issued a report saying seed prices have tripled in recent years as the industry faces "unprecedented ownership and control over plant genetic resources in major field crops."

The group, the Farmer to Farmer Campaign on GE, said the market was dominated by a handful of players, notably Monsanto Co., and they want policy changes to limit industry concentration that hurts farmer interests.

The report comes as the U.S. Department of Justice and the U.S. Department of Agriculture are probing allegations of anti-competitive behavior in agriculture, including in the seed industry, and are looking in particular at Monsanto.

The first public hearing on seed industry concerns is slated for March in Iowa.

Meanwhile, Monsanto and other key seed industry companies said they had formed an industry "working group" to try to allay any regulatory concerns.

American Seed Trade Association Chief Executive Andy LaVigne said the group hoped to convince investigators that efforts to rein in large players like Monsanto could hurt the industry by limiting technology innovations.

"We don't feel they understand the challenges of the market," LaVigne says. "Our push will be to ensure that nothing comes out of the Department of Justice to hinder innovation."

Monsanto and ASTA have been in regular discussions with investigators, and have been answering inquiries about contracts, pricing and products, officials from both organizations say.

Some have alleged that Monsanto is forcing seed dealers to sell higher-priced Roundup Ready 2 soybeans rather than lower-priced versions. But concerns that Monsanto unfairly dominates the market are ill-founded, says Brett Begemann, executive vice president of Monsanto's global commercial business.

"It is a highly competitive industry," Begemann says. "Farmers have thousands of choices. There is all this hype, but there is a lot of misunderstanding of the market."

Still, in its report, the farmer group was particularly critical of Monsanto, saying its genetically engineered traits are planted on more than 80% of U.S. corn acres and 90% of U.S. soybean acres.

The group says as market dominance has mounted, seed prices have jumped. Citing USDA data, the group said corn seed prices in 2009 were up more than 30% over 2008 and soybean prices were up 25%.

Monsanto is the largest driver of prices increases, with costs for some seeds tripling in recent years, the report says.

Begemann says farmers were willing to pay more for Monsanto's seed technology because of the value it brings in better yields and healthier crops. He also says Monsanto has broadly licensed its technology to rivals.

Bergemann adds the accusatino that Monsanto's approach is hurting smaller seed companies' ability to compete is "just plain wrong."

"The facts are no seed company has invested more in the last 10 years to bring new seed products to farmers than Monsanto, and no company has done more to broadly license those inventions than monsanto," Bergemann says. "This includes both seed genetics and trait technologies."

Bergemann says Monsanto is open to discussions with smaller seed companies about stacking technologies, but that none have inquired.

"Unless that small local company can gain regulatory approvals globally, every farmer growing corn or soybeans could be impacted by lower commodity prices due to the loss of export markets," he says. "Technologies that don't have a U.S. regulatory clearance and.or a clearance in certain markets can disrupt trade, and you've seen a couple of examples of this over the last decade."