Revision of Flor's Gene-for-Gene Theory for the Phenomena of Interaction of Cereals Seedlings with Rust Pathogens.

Monopustule isolates of wheat, oats and barley rust pathogens reproduced under different environmental conditions were used to infect experimental samples of these crops. Differences in the types of reactions after infection of one plant genotype with one pathogen genotype reproduced at different temperatures, as well as in the presence of potassium chloride, ammonium nitrate and maleic acid hydrazide indicate the impossibility of explaining the phenomena of plant-pathogen interaction within the framework of Flor's classical gene-for-gene theory. Each gene of the host resistance corresponds to several complementary virulence genes, or to several different alleles of one same gene for virulence.