Effectiveness of Leaf Rust Resistance Genes in the Adult and Juvenile Stages in Southern Russia in 2011-2020.

Erikss. is a causative agent of wheat leaf rust spread worldwide. Wheat rust is a major disease on wheat in southern regions of Russia, which are leaders in grain production and have favorable conditions for pathogen development. In this paper we studied the effectiveness of 52 NILs of cv. Thatcher with genes in field trials and 41 NILs-in the juvenile phase in a greenhouse during 2011-2020. We conclude that the lines with , and genes remained immune in the adult phase during ten years of research. Lines with genes: , , , , , , , , , showed efficiency in field tests (1-5 R on the CIMMYT scale). No immune lines to were registered in the juvenile phase during 2011-2020. The line with the gene remained immune up to 2020; and -up to 2015; -up to 2018, and -up to 2019. In 2020, there was an increase of isolates with virulence to Thatcher lines with : , , , , , , , , , , , . Additionally, we registered a change in infection types towards more susceptible in isogenic gene lines: , , , , , , , , , , , , , , , , , , in the field. A sharp increase in the frequencies of virulent isolates was recorded in 2018-2020 due to unfavorable weather in the growing seasons. This indicates the ability of a dangerous pathogen to rapidly evolve in response to biotic and abiotic stresses. Therefore, annual monitoring of the reaction of isogenic lines, selected released varieties and the study of the virulence of the phytopathogen are important measures necessary to prevent and control leaf rust in grain-producing regions of the world.