Wheat stripe and stem rust situation in Egypt: Yr27 and Sr31 virulence
Wheat stripe (Puccinia striiformis f. sp. tritici,=Pst) and stem (Puccinia graminis f. sp. tritici =Pgt) rusts are the most important wheat disease in Egypt as well as present in all wheat growing areas. This study to evaluate a set of tester lines of wheat carrying stripe Yr's, stem Sr's rust genes and selected Egyptian varieties have been studied for their response to Pst and Pgt at adult plant stage under field conditions in Sakha Agriculture Research Station, during the 2011 to 2014 growing seasons. The results revealed that stripe rust, it has been observed that the new race Yr27-virulence to Pst. In addition pathotypes were virulent for Yr2, Yr6, Yr7, Yr8, Yr9, Yr27, while Yr18 showed moderate susceptibility. On the other hand, Yr1, Yr5, Yr10, Yr15, Yr17, Yr32 and YrSP exhibited high levels of resistance. Regarding, evaluation of resistance genes sources of stem rust on ICARDA, CIMMYT wheat germplasm, and Egyptian wheat varieties released i.e. Misr1 and Misr2 which having Ug99_resistance genes Sr2 and Sr25 were found susceptible to Pgt, also Sr31 recorded infection moderately susceptible to susceptible at adult stage. Genes Sr2 complex, Sr24, Sr26, Sr27, and Sr32 were resistant at adult plant stages. The combination of Sr26 with Sr2 and Sr25 provided stem rust resistance in some CIMMYT wheat germplasm. The objectives of this work are: race analysis of wheat stem and stripe rust disease, evaluation the level and distribution of wheat stripe and stem rust in Egypt, and identification the resistance genes in commercial varieties or new promising lines using standard and molecular genetic markers. Egyptian germplasm such as Misr1, and Misr2 and others tester lines of wheat carrying stem rust Sr's were evaluative under field condition at adult stage in Egypt during 2014 growing season, Egyptian cultivars Misr1 and Misr2 were susceptible rated 10S-20S and Sr31 rated MSS. that results clearly presence a new Sr31-virulence. On other hand, genes Sr2 complex, Sr24, Sr26, Sr27 and Sr32 were resistant and combination of Sr26 with (Sr2 and Sr25) produced stem rust resistance in some CIMMYT wheat germplasm. Shahin et al., 2015, in APS Annual Meeting, Aug. 1-5, Pasadena, CA, US, (In Press).