Yields in mixtures of resistant and susceptible field pea cultivars infested with powdery mildew - defining thresholds for a possible strategy for preserving resistance

Abstract

Bing, D., Gan, Y. and Warkentin, T. 2011. Yields in mixtures of resistant and susceptible field pea cultivars infested with powdery mildew - defining thresholds for a possible strategy for preserving resistance. Can. J. Plant Sci. 91: 873-880. Powdery mildew (caused by Erysiphe pisi var. pisi DC.) resistance of field pea (Pisum sativum L.) cultivars is dominated by the single gene er1. Monoculture of the er1 gene may encourage pathogen evolution for more virulent race(s) and breakdown of the resistance. We promote the use of cultivar mixtures made up of resistant and susceptible cultivars to limit the pathogen evolution and to preserve the resistant gene in current cultivars. The objective of this study was to evaluate if such cultivar mixtures could cause significant yield losses and to identify the proper ratio of resistant and susceptible cultivars in a mixture. Three powdery mildew resistant cultivars were mixed with 0, 10, 20, or 30% of a susceptible cultivar, and gown in replicated trials at four lo...