Possible New Genes for Resistance to Powdery Mildew, Septoria Glume Blotch and Leaf Rust of Wheat

An Ethiopian wheat collection consisting of 293 tetraploid and hexaploid entries was investigated for resistance to powdery mildew, Septoria glume blotch, and leaf rust with the aim of finding probable new genes for resistance to these diseases. Seedlings were screened with isolates of these diseases in the greenhouse or growth chamber. The material was also scored for field resistance to powdery mildew after the fifth leaf stale. The diversity of the reaction types to powdery mildew and Septoria glume blotch was estimated by the Shannon-Weaver diversity index. Thirty-nine entries (13%) of the collection were resistant to moderately resistant co the mildew isolates, 14S-77 and 46—77, that had: a combined virulence spectrum effective against nine identified genes for resistance to powdery mildew. One hundred and et till TV-tour entries (63 %) of the collection showed field resistance to mildew. One hundred and eighty-one entries (62 %) of the collection were at least moderately resistant in an aggressive isolate of Sartorial nodorum. Resistance to a race of leaf rust was detected in one hundred and sixty-eight entries or 58.% of the collection. Generally, resistance to these diseases is concentrated in Central and Southern Ethiopia. The different reaction types of the resistant entries to these diseases and the high estimates of diversity for reaction types indicated the presence of many different probable new genes and genetic backgrounds for resistance to these diseases.