Long-Term Studies of Wheat Leaf Rust in the North-Western Region of Russia

Leaf rust, caused by Puccinia triticina (Pt), is a widely occurring disease of wheat in the North-Western Region Russia. Annual Pt surveys this region have been conducted between 2001 and 2021. In total, 740 single urediniospore isolates were analyzed over 20 years. Virulence to Lr9, Lr19 Lr24 rare 2001–2010 was not detected after 2010. Temporal variation virulence determined on Thatcher lines with Lr1, Lr2a, Lr2b Lr2c genes found be relatively high. Lr1 increased 100% from 2014. Until 2010, most northwestern avirulent Lr2a virulent Lr2c. middle avirulence Lr2b, Lr15 began increase. Strong variability years revealed for Lr20 Lr26. Based set differential lines, 122 pathotypes detected. More than half those observed only once across all Pathotypes divided into groups B-, C-, D- F-, dominating until 2009. From 2010 pathotype M- P-, dominate. differentiation population determined. High similarity accessions 2001–2009 2010–2015 these two differed moderately each other. 2016–2019 2020–2021 other previous collection period. Field response Lr studied during 1998–2022. Wheat genotypes Lr19, Lr23, Lr24, Lr25, Lr28, Lr29, Lr35, Lr39, Lr42, Lr43, Lr45, Lr47, Lr48, Lr49, Lr50, Lr51, Lr53 Lr57 remained resistant throughout period study. rust severity TcLr12, TcLr21, TcLr22a, Gatcher (Lr27+31), TcLr44 Pavon (Lr46) varied 1% 30% before 2014 significantly decreased A general trend decreasing pathogen has recent