Cytogenetic Identification And Molecular Marker Development Of Wheat-Thinopyrum Intermedium Addition（Substitution）Lines

Thinopyrum intermedium is a perennial species in Elytrigia,Triticeae,Gramineae.As the tertiary gene pool of wheat,Thinopyrum intermedium has many excellent characters,such as perennation,big spike and many flowers,immunity to wheat leaf rust,stripe rust,stem rust,powdery mildew,high resistance to wheat yellow dwarf,smut,leaf blight and root rot,stripe mosaic,etc.It has become one of the most important wild relatives in wheat genetic improvement.Xiaoyan 78829 is a partial amphiploids from the cross between Wheat and Thinopyrum intermedium,and it carries many fine characters which wheat does not possess.In order to make better use of these superior genes,a complete set of alien addition（substitution）lines derived from Xiaoyan 78829 was created by chromosome engineering.Molecular cytological characterization and disease resistance evaluation were carried out on these lines and alien chromosome specific molecular markers were developed.The results are as follows:（1）A set of alien addition（substitution）lines from Xiaoyan 78829 was created and identified by molecular cytogenetics.A complete set of alien addition（substitution）lines was created by crossing Xiaoyan 78829with common wheat and backcrossing the F₁ plants with common wheat using chromosome engineering technique.The chromosome karyotype of Xiaoyan 78829 was constructed by sequential GISH-FISH method,and the chromosome compositions of each alien addition（substitution）line were analyzed.（2）Disease resistance evaluation of alien addition（substitution）lines derived from Xiaoyan 78829.Xiaoyan 78829 was identified as immune to wheat stripe rust CYR34 and near-immune to wheat leaf rust THTT.WTA41 exhibited moderate resistance,while WTS42 and WTA139exhibited susceptibility to stripe rust.WTA140 was found near immune to leaf rust,while WTA41 and WTS42 were moderate resistant and the rest were susceptible.WTA140 can be used in wheat breeding for resistance to leaf rust.（3）Development of foreign chromosome specific molecular markers for wheat-Thinopyrum intermedium alien addition（substitution）lines.A total of 72 Thinopyrum intermedium specific markers were screened out by SLAF-seq technique from Xiaoyan 78829,from which 12,5,4,5,5,5and 8 specific markers were amplified by chromosome 1-7 of Thinopyrum intermedium.By sequencing alien chromosome specific PCR products and comparing them to the Thinopyrum intermedium genome sequence,the alien chromosome 1-7 of Xiaoyan 78829 were found homoeologous with the 7th,2nd,5th,3rd,6th,1st and 4th homoeologous groups of wheat,respectively.In addition,the origins of Thinopyrum intermedium fragments from 4 wheat-Thinopyrum intermedium translocation lines were identified using the developed alien chromosome specific molecular markers and an alien FISH probe was developed.