Distribution of races of <I>Pyrenophora tritici-repentis</I> in Algeria and identication of a new virulence type

Abstract

Tan spot, caused by Pyrenophora tritici-repentis, is a foliar disease  of wheat, responsible for high economic losses in several wheat  growing areas in the world. There are eight known races of P. tritici-repentis based on ability to induce necrosis and/or chlorosis on a set of differential cultivars. Fifty five isolates of P. tritici-repentis  originating from diverse wheat growing regions in Algeria were  studied to determine which races are present and to identify new  races. Races 1, 4, 5, 6, 7 and 8 were found and a new virulence pattern was identified. Isolates with this pattern induced necrosis in durum  wheat but failed to induce any disease in the common wheat  genotypes in the differential set.