The U.S. Department of Agriculture opened the door Friday to commercial sales of corn and soybean seeds genetically engineered to resist the weed killer 2,4-D, which is best known as an ingredient in the Vietnam War-era herbicide Agent Orange.

An agricultural dragnet has found no cases of unapproved genetically engineered wheat outside of a 123-acre field in Oregon after two months of an ongoing investigation, the USDA said recently. The discovery of the wheat, not approved for cultivation anywhere in the world, shook the global market when it was announced on May 29. Some U.S. customers in Asia and Europe halted purchases or said they would test incoming wheat shipments for biotech grain.