A partial equilibrium four-region world trade model for the soybean complex is developed in which Roundup Ready (RR) products are weakly inferior substitutes to conventional ones, RR seeds are priced at a premium, and costly segregation is necessary to separate conventional and biotech products....

We relate the labeling of genetically modified (GM) products to the theory of grading and minimum quality standards. The model represents three stages in the supply chain, assumes a vertical product differentiation framework, allows for the accidental commingling of non-GM products, and treats...