Identification of genes for resistance to powdery mildew in common wheat (Triticum aestivum L.). IV. Breeding lines derived from wide crosses of Russian cultivars with species T. timopheevii Zhuk., T. militinae Zhuk. et Migush., T. dicoccum (Schrank.) Schuebl., Aegilops speltoides Taush

Using tester isolates of powdery mildew, the resistance genes to this pathogen were identified in 48 breeding lines and isolated in progeny of wide crosses between common wheat cultivars and related tetraploid species. It is shown that recurrent common wheat cultivars have no effective resistance genes to powdery mildew. Introgressive lines involving T. timopheevii are protected either by the gene Pm6, the gene combination Pm2 + Pm6, or Pm2 + Pm4 + Pm6. The resistance of derivatives (T. militinae x T. timopheevii) is controlled by genes, that we failed to identify using our tester isolates. Out of 34 breeding lines originated from the cross combination T. dicococcum x Ae. speltoides, only in four lines, were the resistance genes Pm5 and Pm2 + Pm9 identified.