Juvenile resistance to diseases in Aegilops tauschii Coss. samples

Seedling (juvenile) resistance to 4 diseases was studied in 452 Ae. tauschii samples from VIR World Collection. Eight accessions were highly resistant to leaf rust and they likely have gene for resistance Lr41. Rust from their naturally infected leaves was nonpathogenic on 25 wheat varieties that evidently indicates to the existence of the causal agent of leaf rust specialized to Ae. tauschii. Two samples possess high resistance to dark-brown leaf spot blotch; level of resistance was not changed after 9 continuous subcultivation of artificial B. sorokiniana population on leaves. Six samples were classified as resistant after inoculation with mixture of 7 Stagonospora nodorum isolates, but as susceptible to single isolate of the pathogen. All samples were susceptible to common root rot. Usefulness of selected Ae. tauschii samples for introgression hybridization to transfer juvenile resistance into bread wheat is discussed.