Abstract:In order to screen new wheat resources for leaf rust resistance, and to exploit and use novel leaf rust resistance genes, monosomic analysis was conducted on Am3, a synthesized amphidiploid from the cross between resistant tetraploid Ps5(Triticum carthlicum)with leaf rust resistance gene LrPs and susceptible diploid Ae38(Aegilops tauschii). Am3 was crossed with Chinese Spring monosomic and disomic respectively, and the chromosome numbers of F1 plants were checked, and the leaf rust resistance of F1 and F2 plants were tested in the seedling stage. The results indicated that the resistance of Am3 to pathotype DHS/GD of Puccinia triticina was controlled by a recessive gene for leaf rust resistance at a temperature of 18℃, which sourced from Triticum carthlicum (Ps5). The gene displayed a dosage effect, and was located on chromosome 5A.