Virulence of Puccina graminis f.sp. tritici and Postulated Resistance Genes for Stem Rust in Ten Wheat Varieties in Egypt

Stem rust (Puccina graminis f. sp. tritici) samples were collected from different areas of Egypt during two season 2008/2009 and 2009/2010 growing seasons. The single pustule method of isolation was followed, and the type of infection was recorded as well for each rust samples. The identification of physiologic races revealed the presence of forty fifth and fifty fifth race groups of stem rust races. The race identification evinced the presence of race groups TT--- and TK--- as well, which run to 11.59 and 10.14 percents of samples in 2008/2009, respectively. However in season 2009/2010 race groups TT--- was the most frequent one (21.50 %), The frequency of virulence of isolates on lines possessing the resistance genes Sr,s 24, 31, 26, 6, 9e, 29, 35, 9a and 9g were the lowest among the tested lines and should be considered in breeding for resistance. The most effective resistance genes at seedling stage were Sr,s 24, 31, 29, 6, 9a, 26+9g and 9e. The postulation of genes revealed that the vars. Giza 164 and Sohag 3 probably have (tow genes, each), Sakha 94 (four genes), Sids 1 and Sakha 93 (five genes each), Sids 13 (nine genes), Giza 168 (ten genes); Gemmeiza 7 (thirteen genes) on the other hand, Giza 160 and Sakha 8 did not have any genes.