Races of Pyrenophora tritici-repentis in the Czech Republic

Abstract

Pyrenophora tritici - repentis, causal agent of tan spot, is one of the most important wheat leaf spot pathogens worldwide. The race structure of P. tritici - repentis isolates obtained from wheat (except one from noncereal grass species) in the Czech Republic was studied. The 86 monosporic isolates of P. tritici - repentis originated from different parts of the Czech Republic were grouped into five known races based on necrosis/chlorosis induction on standard differentials (Katepwa, Glenlea, 6B365, Salamouni). The isolates recovered from wheat were races 1, 2 and 4. Race 1 was the most frequent (50%), races 2 and 4 were found rarely (3% and 5% respectively). The isolate of P. tritici - repentis recovered from noncereal grass species was determined as race 4 which seems to be typical for noncereal hosts. The reaction of 30 isolates (42%) was difficult to be compared to reactions of so far identified P. tritici - repentis races. They have to be tested again on additional wheat genotypes.