A survey of race and virulence types of Blumeria graminis f.sp. tritici in China’s northeastern spring wheat region during 2004-2008 Establishment of ISSR-PCR reaction system for Blumeria graminis f.sp. tritici and its application in diversity analysis of this pathogen Parasitic fitness of Blumeria graminis f.sp.tritici isolates with different sensitivity to temperature Analysis on 2004-2005 racial virulence of Blumeria graminis f.sp.tritici in northern China and the resistance in wheat cultivars in the disease epidemic related zones