LAUSR

The research report presents a summary of wheat leaf rust virulence surveys in the Czech Republic from 2002 to 2011. Determination of virulence was based on infection types on Thatcher near-isogenic lines (NILs) with the resistance genes Lr1, Lr2a, Lr2b, Lr2c, Lr3a, Lr9, Lr10, Lr11, Lr13, Lr15, Lr17, Lr19, Lr21, Lr23, Lr24, Lr26 and Lr28 , respectively. Virulence for Lr9 and Lr19 occurred only sporadically in the investigated period. On average, virulence for Lr2a, Lr2b, Lr24 and Lr28 was low. The highest frequency of virulence was found for Lr3a, Lr10, Lr11, Lr13, Lr15, Lr17, Lr21, Lr23 and Lr26 . During the investigation period we recorded a shift from prevailing virulence for Lr2c and avirulence for Lr1 to avirulence for aLr2c and virulence for Lr1 . There virulences in the leaf rust population were compared with matching resistance genes in the registered wheat cultivars. The most frequent resistance gene was Lr37 , while the genes Lr3a and Lr26 were less frequent.