Crown rust pathotypes determined on oats in the Czech Republic from 2004 to 2006 and reaction to oat cultivars

The incidence of oat crown rust (Puccinia coronata var. avenae Fraser et Ledingham) pathotypes was recorded in the Czech Republic in 2004-2006. The virulence of collected 79 monopustule oat crown rust isolates was assessed on 23 differentials. High diversity was observed; the isolates possessed from 0 to 8 virulence genes. More than 80% of pathotypes were recorded only once. Pathotypes BLBG and BLBC were the most frequent. None of the tested isolates was virulent to resistance genes Pc39, Pc50, Pc52, Pc59, Pc62 and Pc68. Registered cultivars Avenuda, Dalimil, Auron, Isak were susceptible to the majority of pathotypes, cvs. Abel, Ardo, Atego, Azur, Neklan, Radius and Saul to all used pathotypes. Only the Czech cultivar Vok was resistant to all but four used pathotypes. Acquired data are useful for resistance breeding.