Significance and Virulence Spectrum of Wheat Stem Rust (P. graminis)

Of the 77 wheat fields assessed along five routes of Eastern Showa of Central Ethiopia 30 (38.9%) of the fields were affected with stem rust. P.graminis f. sp. tritici variability study was resulted in the identification of 16 races which included the most prevalent race SRKSF with a frequency of 14.3% and the most virulent races of TTKSK and TTTTF with frequencies of 7.1% and 3.6% respectively. Differential host carrying Sr24 was effective to all while gene Sr36 was resistant to 85.7% of the races identified. In contrast differential hosts carrying SrMcN Sr9g and Sr11were ineffective to 100% 82.1% and 82.1% of the races identified respectively. Besides ten durum wheat varieties evaluated at adult plant growth stage to stem rust population of Debrezeit showed severities of 20S in the variety Geredo to 70S in the variety Foka while at Ambo only the susceptible check Morocco was infected up to 20S. At seedling stage 60% of the varieties tested with the virulent stem rust isolate from Debrezeit exhibited resistance while all varieties were resistant to Ambo isolate. The results indicated that stem rust from Debrezeit was virulent to durum wheat varieties