The Interaction of Either an Effective or a Defeated Major Gene with Non‐specific Resistance on Mildew Infection (Erysiphe graminis f. sp. hordei) and Yield in Mixtures of Barley

Abstract Three‐component mixtures of two barley cultivars expressing partial resistance to mildew (Erysiphe graminis f. sp.hordei) with the third component either expressing complete resistance or a defeated major gene gave more yield than the mean of their components in monoculture in a series of field trials. However, there was no reduction in mildew infection in the mixtures and even a significant increase in one trial. The potential for using partially resistant cultivars in mixtures is discussed.