Genetics Of Resistance To Wheat Leaf Rust In Aegilops Tauschii-Triticum Carthlicum Amphiploid And Identification Markers Linked To Resistance Genes

Wheat leaf rust, caused by Puccinia triticina, is one of the most important wheat diseases in the world. The leaf rust fungus is adapted to different climates, the disease can be found in diverse wheat growing areas throughout the world. Wheat cultivars that are susceptible to leaf rust regularly suffer yield reduction of 5-15% or greater. Genetic resistance is the most economical, preferabal and safety method of reducing yield losses due to leaf rust. Genetic resistance to leaf rust can be most fully utilized by knowledge of the identity of resistance genes in master resistance resources and release cultivars. Continued efforts to isolate, characterize, map wheat leaf rust resistance genes, breed wheat leaf rust resistance cultivars, and pyramid different resistance genes are important to leaf rust genetic resistance and prevention and cure.With Aegilops tauschii(DD)-Triticam carthlicum(AABB) amphiploid (Am3, Am4), we constructed the F₁, BC₁, F₂ populations with crosses between Am3, Am4 and Mingxianl69. Investigations of these populations' resistance to leaf rust with race DHD were carried out. The results showed as follows: in Am3, there is a single recessive gene controlling the resistance to leaf rust race DHD;in Am4, theresistance gene is suppressed by the D genome.The resistance gene to leaf rust in Am3 was identified with SSR molecular marker, 310 pairs microsatellite primers from wheat A and B genomes were used to analysis the DNA polymorphisms between the resistant parent, the susceptible parent, the resistance pool and susceptible pool. DNA polymorphism was found in WMC418 primer from the chromosome 3B during amplify different samples. Investigating F₂ populations of Am3×Mingxian169 indicated that this primer is linked to the leaf rust resistance gene with a linkage distance 14.0 cM. According to consensus SSR genetic map of wheat, this resistance gene is located on long arm of the 3B chromosome, different from known dominant Lr27 gene in location and characteristic on short arm of the 3B chromosome. We suggest that this gene from amphiploid Am3 most likely belongs to a novel resistance gene, and temporary designated LrPS.