Status of Wheat Yellow Rust (Puccinia striiformis) Races and their Virulences in major Wheat Growing areas of Ethiopia

Abstract

Yellow rust c?used by Puccinia striiformis Westend. f.sp. tritici is one o f the major wheat diseases in the highlands of Ethiopia. Monitoring races and inventory of resistance genes would be very important for the control of the disease. A total of 10 different yellow rust races had been identified from samples collected in the southeastern Ethiopia from 1998 to 2003. Three of these
(230E158, 198E158 and 206E158) were detected for the first time in Ethiopia and exhibited virulence for most of the seedling resistance genes except YrCy, Yrsp, Yrl, Yr4, Yr5, YrI0, Yrt5 and Yrn . One of the high yielding bread wheat cultivars, ‘Kubsa’ and many others succumbed to race 230E158. Based on the results of this study and perusal of past reports, the races so far identified in the
country could be grouped into three categories. Races in the first group are assumed to be evolved from the parental race 82E0, and have had virulences for Yrsv (Suwon x Omar,), Yr7, f r y (Fed 4*/KVZ) and Yr,(, combinations. These races were detected mainly in the central and northwestern Ethiopia where durum wheat used to be dominant. The commonly occurring races in the southeastern Ethiopia have apparently been originated from the third parental race (6E16), that had virulences for Yr6, Yr- and Yr8 combinations. To contend with the ever evolving yellow rust races and virulence in Ethiopia, the genetic basis of resistance of bread wheat should be broadened and diversified.