The contamination of U.S. long-grain rice supplies by a genetically engineered variety appears to be more widespread than previously believed, the State Plant Board said Thursday. Traces of Bayer Crop-Science’s experimental variety LLRICE601 or two of its Liberty Link siblings have been detected in 10 samples of Clearfield 131 rice seed, the agency said. Since August, the U.S. rice industry has been aware that trace amounts of LLRICE601 were present in U.S. rice supplies. Until Thursday, however, such contamination was thought to be limited to only one variety, Cheniere.