Comparison of Durum and Common Wheat Cultivars for Reaction to Leaf Spotting Fungi in the Field

Abstract

Durum (Triticum turgidum var. durum) and common (T. aestivum) wheat cultivars (Canada Western Red Spring, Canada Prairie Spring, and Canada Western Soft White Spring), grown at two locations for 3 years, were assessed for severity of the leaf spot complex and relative proportion of leaf spotting fungi. The most prevalent fungi isolated were Pyrenophora tritici-repentis and Phaeosphaeria nodorum. Their percent isolation and leaf spot severity varied among years and between locations. The relative prevalence of the leaf spotting fungi in the individual cultivars, or cultivars grouped by species, varied with year, whereas the leaf spot score varied with location. Cultivars and species differed in susceptibility to the leaf spotting fungi. The common wheat classes were mostly colonized by P. nodorum and the durum wheat by P. tritici-repentis. Cultivars, but not cultivars grouped by species, also differed in the severity of the leaf spot complex. Within both durum and common wheat there were cultivars with low and high leaf spot scores.