Delegates from more than 130 nations on Saturday adopted the first global treaty regulating trade in genetically modified products, the first time that environmental concerns and trade rules have been reconciled in an international agreement. The treaty allows countries to bar imports of genetically modified seeds, crops, and animals, even if scientific studies have not yet determined that they are dangerous, a provision that the U.S. had opposed. The treaty does not address whether food containing genetically altered ingredients, like corn flakes made with GM corn, should be labeled as such on store shelves. And disputes over GM foods could still erupt within the World Trade Organization. But many enviros were generally pleased with the agreement.