Genetics and breeding for triticale resistance to the pathogen of stem rust <i>Puccinia graminis</i> Pers.: Review

Stem rust caused by the fungus Puccinia graminis f. sp. tritici (Pgt) remains one of the most dangerous diseases of grain crops. This review provides an analysis of the evolution of the relationship between triticale (×Triticosecale Wittmack) and Pgt since the beginning of commercial cultivation of this crop, covering the historical aspects of the spread of the pathogen, changes in its virulence and adaptation to various varieties of triticale, as well as the response measures taken by breeders to increase the resistance of the crop to the disease. The paper presents the regional features of the pathogen’s spread in Russia and in the world’s triticale and wheat growing centers. Special attention is paid to the features of the pathological process of stem rust development on triticale, which, like in wheat, includes the stages of spore germination, penetration into plant tissues and formation of urediopustules. It is noted that triticale, being a hybrid of wheat and rye, is susceptible to both wheat and rye forms of stem rust. The review also covers modern methods for studying triticale resistance to Pgt, including the use of molecular markers for the identification of resistance genes and screening of breeding material. A number of stem rust resistance genes have been described for triticale, such as Sr27, Sr31, SrNin, SrSatu, SrBj, and SrVen, which can be effectively used in breeding programs aimed at creating varieties with long-term and effective resistance to stem rust.