The transfer of leaf rust resistance from Triticum timopheevii to durum and bread wheat and the location of one gene on chromosome 1A

Abstract

Triticum timopheevii (Zhuk.) Zhuk. is noted for its resistance to diseases including leaf and stem rust of wheat. Only one gene (Lr18) for leaf rust resistance has been transferred from T. timopheevii to bread wheat. The objectives of this work were to study the inheritance of leaf rust resistance in five accessions of T. timopheevii and to transfer genes for resistance into durum and bread wheats. A diallel set of crosses was made among five T. timopheevii accessions that gave a fleck infection type with an isolate of leaf rust race CBB. None of the F2 populations of the 10 crosses segregated for resistance, indicating that the five accessions all had at least one gene for resistance in common. Several accessions were crossed and backcrossed twice to durum and to bread wheat. At least three genes for leaf rust resistance were transferred to durum wheat and one to bread wheat. The gene transferred to bread wheat and one of those transferred to durum wheat conditioned good resistance to a set of 10 diverse races of leaf rust. Resistance conditioned by all three genes was dominant in durum wheat but the one gene was recessive in bread wheat. Monosomic analysis of the bread wheat line showed that the gene is on chromosome 1A. It should be useful in breeding for leaf rust resistance in both durum and bread wheat. Key words: Triticum timopheevii, leaf rust resistance, durum wheat, bread wheat