Probability of Mutation to Multiple Virulence and Durability of Resistance Gene Pyramids.

The purposes of this letter are to demonstrate that empirical data are not supportive of the probabilities hypothesis and to cite evidence countering the assumption of the probabilities hypothesis that mutations to virulence at different loci are necessarily independent. In doing so, rust disease will be used as examples because of the vast literature available on them and because resistance gene pyramids have been associated with an increase in the durability of race-specific resistance to wheat stem rust (...)