Physiological specialization of wheat leaf rust (Puccinia triticina Eriks.) in the Czech Republic in 2009-2011

In 2009–2011 virulence of the wheat leaf rust population was studied on Thatcher near isogenic lines with Lr1, Lr2a, Lr2b, Lr2c, Lr3a, Lr9, Lr11, Lr13, Lr15, Lr17, Lr19, Lr21, Lr23, Lr24, Lr26 and Lr28. Samples of leaf rust were obtained in different parts of the Czech Republic. A total of 164 wheat leaf rust isolates were analysed. Resistance gene Lr9 was effective to 98% of all tested isolates. No virulence to Lr19 was found. Gene Lr24 was effective to 93% of isolates. A lower frequency of virulence to Lr2a, Lr2b and Lr28 was also observed. Recently registered cultivars were tested with six older and five most widespread leaf rust pathotypes at present. Winter wheat cultivars Carroll and Citrus were resistant to all tested older pathotypes at the seedling stage and they were also resistant to almost all pathotypes widespread at present. They displayed resistance also in official yield trials. Genes Lr34, Lr37, Lr10, Lr24 were determined in the tested cultivars by molecular markers.