Subscribe for 99¢
Monsanto sign at Lindbergh offices

Monsanto headquarters on Lindbergh Boulevard.

The ongoing legal tangle between arch-rivals, Monsanto Co. and E.I. DuPont de Nemours & Co. will continue today in federal court in St. Louis.

During the trial, which began Monday with jury selection, the court will decide if DuPont's Pioneer seed division illegally used Monsanto's Roundup Ready technology. DuPont, based in Delaware, will challenge Monsanto by going after the validity of the Roundup Ready patent, which it says Monsanto filed improperly.

The patent is at the core of the Creve Coeur-based company's sweeping business, which pulled in nearly $12 billion in sales last year.

In 2009, Monsanto sued DuPont, saying the company violated a 2002 licensing agreement when it began combining, or “stacking,” the Roundup Ready trait with its own technology.

DuPont is one of hundreds of companies that buy the Roundup Ready technology for use in seeds, paying Monsanto as much as $200 million a year to do so.

The technology enables plants to withstand applications of the herbicide, glyphosate – or Roundup, as its known in the marketplace – that kills weeds but not the plants themselves. The technology is now embedded in the vast majority of the corn and soy grown in the country, representing billions of dollars to the agricultural economy.

Monsanto said its rival was merely stacking the glyphosate-resistant trait with its own technology in a soybean product called Optimum GAT because DuPont's technology was not good enough to stand on its own.

DuPont, in turn, accused Monsanto of anti-competitive behavior, saying the company was blocking access to the technology. DuPont's accusations dovetail with an ongoing Department of Justice antitrust investigation looking into Monsanto's possible monopoly on seed biotechnology. A trial related to the anti-trust matter is slated to begin in 2013.

In 2010, a judge ruled in favor of Monsanto, saying the 2002 licensing agreement prevents DuPont from stacking the Roundup Ready technology with its own.

The current trial, analysts say, represents a big challenge for DuPont, which has the most to gain from a victory.

“This is significant for DuPont,” said Jeff Windau, an analyst with Edward Jones. “If they get the patent invalidated, they can use the trait and bundle it with their traits.”

DuPont's track record, however, is shaky. So far, Monsanto has prevailed in at least five trials.

Get updates every weekday morning about the latest news in the St. Louis business community.