Defense of bread wheat with the tall wheatgrass genes while accelerating the physiological specialization of the causative agent of stem rust

Recently, there is a threat of loss of the harvest of bread wheat Triticum aestivum L. due to the outbreaks of stem rust caused by the pathogenic fungus Puccinia graminis f. sp. tritici Erikss. et Henn. To protect the crops from the disease, it is necessary to expand the spectrum of resistance genes in the varieties. In Omsk State Agrarian University (Omsk), new introgressive lines of bread wheat with the genetic material of the Tall Wheatgrass Agropyron elongatum Host. (Beuv.) have been created. The aim of the work was to study the valuable features of introgressive lines of spring bread wheat with Ag. elongatum genes and to monitor their resistance to stem rust in Western Siberia. The research was carried out in the field conditions of the southern forest-steppe of Western Siberia (Omsk). The resistance to stem rust was assessed on intense natural infectious background in 2014-2019. In 2014, 48% of the lines showed immunity or high resistance to the disease. In the conditions of epidemics in 2015 and intensive disease development in 2018-2019, a number of lines lost rust resistance due to the change in the physiological specialization of the pathogen. The resistance of the remaining lines is controlled by a set of genes other than the known Sr24 and Sr25 . Six medium-early and medium-ripened lines have been identified. They are characterized by stable high resistance to the disease and high yield in 2017-2019. Two lines have shown high yields in conditions of severe rust damage and may be used to create tolerant varieties. By grain quality (protein content, raw gluten and grain-unit) the best resistant lines corresponded to strong wheat of the 1st and the 2nd class, and in terms of vitreousness - valuable wheat of the third class. According to the indicator “protein yield per haˮ, six lines exceeded the varieties Pamyaty Azieva and Duet by 10-40%. These lines are a valuable breeding material for resistance and tolerance to stem rust in Western Siberia and may be used for breeding varieties for food and fodder purposes.