Induced resistance to rust diseases and its possible role in the resistance of multiline varieties

SUMMARY Inoculation of wheat seedlings with a non‐virulent race of Puccinia striiformis delayed the onset of sporulation of a virulent race and also decreased the spore mass produced. Similarly, the sporulation of a virulent race of Uromyces appendiculatus on bean seedlings was reduced by application of a weakly virulent race. We suggest that these effects of induced resistance could retard the development of rust diseases in the field particularly in multiline varieties.