Creation of a Stripe Rust- and Leaf Rust-Resistant Wheat– Elymus trachycaulus Translocation Line with Reduced 1H t S Alien Chromatin

Elymus trachycaulus is a perennial species highly resistant to stripe rust and leaf rust, two devastating diseases of wheat worldwide. The wheat– E. trachycaulus 1H t S·1BL Robertsonian translocation line TA5072 carries the leaf rust resistance gene Lr55 and an undesignated stripe rust resistance gene. In this study, we reduced the length of the 1H t S arm in the 1H t S·1BL centric translocation by homoeologous recombination induced by the Chinese Spring ph1b mutation, resulting in a new translocation line, designated TC282. This line was characterized using newly developed fluorescence in situ hybridization (FISH) probes and molecular markers specific to chromosome 1H t S. TC282 was highly resistant to stripe rust and leaf rust, indicating that the reduced segment of 1H t S still carries both rust resistance loci. Additionally, there is no significant difference in the number of spikelets and tillers of TC282 compared with the wheat variety Jimai 22, suggesting that this translocation line can be used for wheat improvement.