Analysis of Host-Specific Differentiation of in the South and North-West of the European Part of Russia.

Yellow (stripe) rust, caused by Westend. (), is a major disease of cereals worldwide. We studied virulence phenotypes on , , and triticale in three geographically distant regions of the European part of Russia (Dagestan and Krasnodar in North Caucasus, and Northwest) with different climate and environmental conditions. Based on the set of twenty differential lines, a relatively high level of population diversity was determined with 67 different pathotypes identified among 141 isolates. Only seven pathotypes were shared by at least two hosts or occurred in the different regions. No significant differentiation was found between regional collections of pathotypes either from or from . A set of pathotypes from triticale was subdivided into two groups. One of them was indistinguishable from most durum and common wheat pathotypes, whereas the second group differed greatly from all other pathotypes. All sampled isolates were avirulent on lines with , , , and genes. Significant variation in virulence frequency among all collections was observed on lines containing , , , , and genes and cvs Strubes Dickkopf, Carstens V, and Nord Desprez. Relationships between Russian regional collections of from wheat did not conform to those for .