First report of virulence for resistance genes Yrsp, Yr1 and Yr3 by wheat yellow rust pathogen (Puccinia striiformis f. sp. tritici) in Ardabil, Northwest of Iran

Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici is the most devastating disease of bread wheat (Triticum aestivum) in the world. The disease represents a constant threat to wheat production in many wheat-producing countries. A wide range of virulent yellow rust pathotypes (races) is evolving in different regions of the world causing the breakdown of widely utilized sources of resistance in wheat (Chen 2005). On the other hand, comprehensive information on pathogen virulences and its variation and also epidemiological information on pathogen movements provides a basis for the development of an early effective warning system (Yahyaoui et al. 2001).