Abstract

Leaf rust caused by the pathogen Puccinia triticina is one of the important diseases of wheat in Ethiopia; and yield loss due to this disease has reached up to 75%. A study was carried out to detect physiologic races of the pathogen from some parts of Bale, Gondar and Shewa and to identify seedling resistance of Ethiopian durum cultivars. Twenty-four mono pustule isolates were made, and out of those, only three P. triticina races namely; BBBB, BBBN and BBBQ were identified. Race BBBN was detected for the first time in Ethiopia and was less virulent to commercial durum wheat cultivars than BBBQ and BBBB, while phenotype BBBB was relatively highly virulent to Ethiopian durum wheat and it infect 42.5% of the tested cultivars and is not virulent to Thatcher and Thatcher isoline leaf rust differential cultivars. Thirty six commercial durum wheat cultivars and three land race cultivars were evaluated against those three leaf rust pathogen races at seedling stage in the green house at Debre-Zeit Agricultural Research Center. Varieties Utuba, Lelisa, Worer, Bekelcha, Tate, Filakit, Foka, Alem tena, Hitosa, Kilinto, Denbi, Ude, LD-357, Boohai, Mukuye, Robe, Mangudo and Assasa exhibited resistance reaction (; to 2) to all the three leaf rust races, while the rest showed susceptible at least to one of the race. All the three land race cultivars (Mcd4-12, Mcd4-32 and Mcd7-42) were susceptible to all pathogen races.

Key words: Durum wheat, leaf rust, Puccinia triticina, race, seedling resistance.