The rub: a 2002 contract between DuPont and Monsanto that gave DuPont access to Monsanto's gene prohibits DuPont from combining it with any other company's glyphosate-tolerant gene in the same plant.
Monsanto wants to enforce the contract. DuPont says this "stacking" clause in the contract was nullified when in 2008 the U.S. Justice Department ordered Monsanto to abandon similar restrictions on cottonseed breeders.
The WSJ noted the DuPont position: "Monsanto's so-called 'stacking' restriction is one of many practices that Monsanto engages in to limit the availability of competitive products. Seed companies should be able to offer combinations of traits and germplasm without restrictions imposed by trait providers that attempt to limit those combinations."
The St. Louis BizJournal gives some of the rhetoric from Monsanto: "As the saying goes, imitation is the sincerest form of flattery," said Monsanto Chief Executive Officer Hugh Grant in a statement. "However, unlawfully taking technology is neither imitation nor flattery; it is unethical and wrong. A true technology company respects patents and its contractual agreements and delivers new products through its own innovation and honest collaboration. DuPont has failed on all counts."
The BizJournal gave further detail on the DOJ action (via statements from James Borel of DuPont: In 2008, the U.S. Department of Justice required that Monsanto abandon similar “stacking” restrictions it imposed on its licensees producing Roundup Ready cottonseed as a condition to its acquisition of cotton seed company Delta & Pine Land, according to Borel.
“Monsanto has a long history of using litigation and aggressive tactics to preserve their monopoly and attempt to intimidate customers, seed partners and competitors," he said in a statement.
Note that Borel mentioned aggressive tactics as to seed PARTNERS. Here, the dispute is more about license terms (state law issue) than it is about the patent itself.