DuPont has filed a patent lawsuit against biotech firm Monsanto, accusing the manufacturer of genetically modified crops of using a "novel seed-production technique" without permission.
The lawsuit, filed in a U.S. federal court in Iowa, concerns a patented technique that "increases seed-corn vigor to improve germination under stress," DuPont said in a statement Tuesday.
Monsanto vowed to fight the lawsuit, which it said is "without merit."
"DuPont's claim pertains to defoliating corn plants with Paraquat or Roundup. This approach is not used in any Monsanto production fields," the St. Louis-based company said.
"This filing appears to be another in a series of frivolous claims initiated by DuPont against our business and aimed at distracting us from our mission of investing in and delivering new-product offerings to farmers around the world."
In 2009, Monsanto sued DuPont subsidiary Pioneer Hi-Bred International, alleging infringement of its patents for Roundup Ready herbicide-resistant crops. DuPont countered that Monsanto was trying to "intimidate" competitors.
A key Monsanto technology involves genetically modified crops that are resistant to herbicides such as Roundup.
The technology boosts crop yields by allowing farmers to use the herbicide without damaging crops, but the practice has drawn fire from environmentalists and is banned in some countries.
Copyright Agence France-Presse, 2011