First report of the Ug99 race group of wheat stem rust, Puccinia graminis f. sp. tritici, in Egypt in 2014.
Since the first detection of race TTKSK (Ug99) of Puccinia graminis f.sp. tritici in Uganda in 1998, it has been a priority to track its further spread to other wheat growing areas. To date, 10 variants in the Ug99 race group have been detected in 12 countries, i.e. Uganda, Kenya, Ethiopia, Sudan, Tanzania, Eritrea, Rwanda, South Africa, Zimbabwe, Mozambique, Yemen and Iran. In the 2014 crop season, the presence of virulence to Sr31 in Egypt was suspected based on preliminary field observations of high infection on sources of Sr31 planted as international stem rust trap nursery at (i) Sakha Agricultural Research Station in Kafrelsheikh, (ii) Al-Sharqia and (iii) Nubaria. At Sakha, wheat cv. PBW343 (carrying Sr31) was scored 30MS-S, and the monogenic line Benno Sr31/6*LMPG was scored 20MS-S at Al-Sharqia. Three samples from each of these lines were sent to the Global Rust Reference Centre (GRRC, Denmark). At Nubaria, stem rust was observed on wheat cultivars Misr-1, Misr-2, Giza 168 and Giza 171, and infected samples were collected. Three races in the Ug99 race group were detected; TTKST (four isolates, IT 3+4 for Sr24, Sr31, and cv. Siouxland) from Al-Sharqia, TTKTK (13 isolates, IT 4 for Sr31, SrTmp, and cultivar Triumph 64) from Sakha, and TTKSK (2 isolates, IT 4 for Sr31) from Nubaria. This is thought to be the first confirmation of races in the Ug99 race group in Egypt, thereby extending the geographical distribution of Ug99-related races.