Occurrence of the Warrior Race of Wheat Stripe Rust (Puccinia striiformis f. sp. tritici) in Egypt, 2015
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici, [Pst] is a widespread and damaging disease of wheat (Triticum aestivum L.), causing significant losses in yield and quality. During the 2015, eight stripe rust physiological races were identified in greenhouse tests i.e. 0E0, 6E4, 70E20, 128E28, 134E244, 143E245, 250E174, and 450E214. Race 0E0 was the most common and avirulent race, and races 143E245, and 450E214 had high virulence on most of tested Yr resistance gene wheat lines. In the same season, an unusual stripe rust infection occurred in spring wheat at Sakha region in Egypt. Some of the most important commercial cultivars such as (Misr 2, Giza 168 and Sakha 61), known as resistant to the previously characterized races of Pst in Egypt have become susceptible under field conditions. Infections of stripe rust was observed on some wheat lines with Yr genes previously known to be resistant, such as Yr1, Yr17 and Yr32, in a yellow-rust trap nursery at Sakha (30.601400? N, 31.510383? E), northern Egypt. Independent race analysis of collected samples from four governorates i.e. Kafrelsheikh, Al-Sharqia, Dakahleia and Damietta at Sakha Agricultural Research Station in Kafrelsheikh confirmed the detection of a new Pst race in Egypt. Aggressive races with virulence to Yr27 were detected on differentials with Yr27 (Yr27/6*Avocet S), and (Ciano 97) during the 2012 in Egypt. In addition, the Warrior race (virulent on: Yr1, Yr2, Yr3, Yr4, Yr6, Yr7, Yr9, Yr17, Yr25, Yr32, and YrSp) was observed in the 2015 crop season, which indicated continued changes in the Pst the population. In Europe, the Warrior race first identified in 2011 in the United Kingdom, has caused significant change in yellow rust susceptibility of several varieties of both wheat and triticale. In a conclusion, some of wheat cultivars, known to be resistant, were shifted to susceptible due to these new races.