St. Louis ? Executives from Monsanto Co. and Pioneer Hi-Bred International Inc., the world’s two largest seed companies, met in the 1990s and agreed to charge higher prices for genetically modified seeds, The New York Times reported Tuesday.

Monsanto and Pioneer acknowledged that their executives met to discuss genetically modified seeds but denied engaging in illegal price fixing.

“We believe that all the discussions we’ve had with Monsanto regarding technology licenses were appropriate and legitimate business negotiations,” Doyle Karr, a spokesman for Des Moines, Iowa-based Pioneer Hi-Bred said Tuesday. “We set our price independently and have always done it that way and without consultation with our competitors.”

The talks, which the Times said occurred from 1995 to 1999, involved licenses that let Pioneer sell genetically altered seeds developed by St. Louis-based Monsanto, which spent billions in the 1980s to invent the specialized seeds and sold the rights to make them to big seed companies.

Monsanto said Tuesday it had a legal right and business need to discuss the value of its technology when licensing it.

“The real distinction here is we did not dictate or determine the price the licensee would charge for their product,” spokeswoman Lori Fisher said.

Together, Pioneer and Monsanto control about 60 percent of the nation’s market for corn and soybean seeds.

Citing interviews with dozens of executives and court and other documents, The Times said the companies discussed prices, swapped profit projections and even talked about cooperating to keep the prices of genetically modified seeds high.

Analysts estimate more than $10 billion worth of genetically altered seeds have been sold in the United States since they were commercialized in 1996.

To have violated the Sherman Antitrust Act, Monsanto and Pioneer merely had to agree to coordinate prices, legal experts told the Times.