Abstract

Chausiku Dennis

Stem or black rust, caused by Puccinia graminis, has historically caused severe losses to wheat (Triticum aestivum) production worldwide. The causal race, commonly known as Ug99 and designated as TTKS based on the North American nomenclature, carries virulence for several genes commonly present in wheat germplasm. All Kenyan germplasm are known to be susceptible or partially susceptible to Ug99 although no proper documentation has been done. This study was aimed at evaluating the Kenyan bread wheat varieties on their response to Ug99. The varieties were screened for resistance at seedling stage and adult plant resistance stage. None of the varieties apart from Bonny were resistant at seedling stage. Some old Kenyan varieties were found to have adult plant resistance probably due to the presence of non-race specific gene Sr2 complex which among others can be exploited in breeding for resistance in Kenyan wheat.