Potential use of Aegilops speltoides Taush genes for durable defense of common wheat from leaf rust in Western Siberia

Common wheat is the main grain crop in Russia. Leaf rust caused by the fungus Puccinia triticina Erikss. regularly affects crops and leads to economic damage. To protect wheat, the use of genes of related cereals is promising. The effect of Lr-genes introduced from Aegilops speltoides Tausch was estimated in Western Siberia and the Southern Urals in 2013-2018. Plant damage was assessed in the field, and the frequency of virulent clones in P. triticina population was detected. The Lr28 and LrSp genes provided plant immunity, and virulent clones were absent in the population. An outbreak of reproduction of a clone virulent to Lr47 was first recorded in the steppe zone of the Omsk region, bordering with Northern Kazakhstan in 2013, with subsequent migration to the East, North and West. Virulence to Lr47 disappeared in the Southern Urals in 2018, but is annually detected in Western Siberia with a low frequency. The tendency to overcome the adult Lr35 gene and the low efficiency of Lr36 in Western Siberia and the Southern Urals was noted. The breeding of wheat varieties with Ae. speltoides genes and their cultivation should take into account the pathogen variability and migration.