Powdery Mildew Resistance Phenotypes of Wheat Gene Bank Accessions

SIMPLE SUMMARY: Bread wheat is one of the most important sources of human and animal food and powdery mildew is a serious disease of this crop. Breeding and growing resistant cultivars are an effective and environmentally friendly way of reducing the adverse impact of the disease on grain yield and quality. The main aim of this study was to detect major resistances against powdery mildew in a set of wheat accessions from the Czech gene bank and to group them according to their responses. Ear progenies of 448 varieties originating from 33 countries were inoculated with three isolates of the pathogen. One hundred and ten varieties showed resistance to at least one isolate and 59 varieties were resistant to all three isolates. Resistance to the three isolates was present mostly in varieties of Northwest Europe and was more than three times more frequent in spring than in winter wheats. Results will facilitate a rational and practical approach of breeding new wheat cultivars using this set of gene bank accessions as recipients of novel genes from wheat-related species and accumulate minor resistance genes to improve resistance durability. ABSTRACT: Powdery mildew (Blumeria graminis f. sp. tritici) is a common pathogen of bread wheat (Triticum aestivum L.), and genetic resistance is an effective and environmentally friendly method to reduce its adverse impact. The introgression of novel genes from wheat progenitors and related species can increase the diversity of disease resistance and accumulation of minor genes to improve the crop’s resistance durability. To accomplish these two actions, host genotypes without major resistances should be preferably used. Therefore, the main aim of this study was to carry out seedling tests to detect such resistances in a set of wheat accessions from the Czech gene bank and to group the cultivars according to their phenotype. Ear progenies of 448 selected cultivars originating from 33 countries were inoculated with three isolates of the pathogen. Twenty-eight cultivars were heterogeneous, and 110 cultivars showed resistance to at least one isolate. Fifty-nine cultivars, mostly from Northwest Europe, were resistant to all three isolates were more than three times more frequently recorded in spring than in winter cultivars. Results will facilitate a rational and practical approach preferably using the set of cultivars without major resistances for both mentioned methods of breeding wheat cultivars resistant to powdery mildew.