Insect resistance management in GM crops: Past, present, and future

AGRO 98

Richard T. Roush, rroush@unimelb.edu.au, Faculty of Land and Food Resources, University of Melbourne, Building 142, The University of Melbourne, 3010, Australia
By the early 1990s, a number of tactics had been proposed for insect resistance management in insecticidal GM crops, including using low or high expression, tissue and temporal specific expression, seed mixes of susceptible and transgenic plants, and mosaics, rotations, and pyramids of multiple toxins. The development of higher expression of Bt toxins, to which Fred Perlak directly contributed, solved the problem of dose. Tissue or temporal specific expression and seed mixes conceivably might still be useful, but only under unique circumstances. Mosaics are the worst way to deploy different toxins, but pyramids of different toxins with refuges are currently the most robust resistance management strategy. Perlak contributed not only in creating pyramided plants, but also in raising questions about how they would work. The future of resistance management should include better expression of transgenes and a closer marriage of GM and marker-assisted breeding of naturally-occurring insecticidal traits.