Canadian researchers expected resistance genes to accumulate, he says, and because there are more herbicides than resistance genes, the plants are just as easy to control as singly modified varieties.

• 他说，加拿大的研究人员早就预期会有抗药基因的累积，但由于除草剂的种类远多过抗药基因，因此控制这些植物的生长，不会比单一基因改造的品种更困难。