Molecular cytogenetic  identification of a wheat (Triticum aestivum)-American dune grass (Leymus  mollis) translocation line resistant to stripe rust.
Leymus  mollis, a perennial allotetraploid (2n = 4x = 28), known as American  dune grass, is a wild relative of wheat that could be useful for cultivar  improvement. Shannong0096, developed from interspecific hybridization between  common wheat cv. Yannong15 and L. mollis, was analyzed with cytological  procedures, genomic in situ hybridization, stripe-rust resistance  screening and molecular marker analysis. We found that Shannong0096 has 42  chromosomes in the root-tip cells at mitotic metaphase and 21 bivalents in the  pollen mother cells at meiotic metaphase I, demonstrating cytogenetic  stability. Genomic in situ hybridization probed with total genomic DNA  from L. mollis gave strong hybridization signals in the distal region of  two wheat chromosome arms. A single dominant Yr gene, derived from L.  mollis and temporarily designated as YrSn0096, was found on the long  arm of chromosome 4A of Shannong0096. YrSn0096 should be a novel Yr gene  because none of the previously reported Yr genes on chromosome 4A are  related to L. mollis. This gene was found to be closely linked to the  loci Xbarc236 and Xksum134 with genetic distances of 5.0 and 4.8  cM, respectively. Based on data from 267 F(2) plants of  Yannong15/Huixianhong, the linkage map of YrSn0096, using the two  molecular markers, was established in the order Xbarc236-YrSn0096-Xksum134.  Shannong0096 appeared to be a unique wheat-L. mollis translocation with  cryptic alien introgression. Cytogenetic stability, a high level of stripe-rust  resistance, the common wheat background, and other positive agronomic traits  make it a desirable donor for introducing novel alien resistance genes in wheat  breeding programs, with the advantage of molecular markers that can be used to  confirm introgression.
Agronomy College, State Key Laboratory of Crop Science, Shandong Key Laboratory of Crop Science, Tai'an Subcenter of National Wheat Improvement Center, Shandong Agricultural University, Tai'an, China.
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D001487:Basidiomycota / Q000502:physiology*; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics; D003433:Crosses, Genetic; D020732:Cytogenetic Analysis; D060467:Disease Resistance / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D006824:Hybridization, Genetic; D040582:Inheritance Patterns / Q000235:genetics; D018895:Microsatellite Repeats / Q000235:genetics; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D006109:Poaceae / Q000235:genetics* / Q000276:immunology / Q000382:microbiology; D016133:Polymerase Chain Reaction; D014908:Triticum / Q000235:genetics* / Q000276:immunology / Q000382:microbiology
D005819:Genetic Markers