Identification Of Leymus Racemosus Chromosomes And Chromosomal Segments By SSR Markers

In order to detect the genomic diversity of T. aestivum L. and Lracemosus, 337 SSR primers mapped on 7 homoelogous groups of wheat were used to amplify the gDNA of the two species. The results indicated that 113 primers could reveal the genetic polymorphism between wheat and Lracemosus. Of 113 primers, gwmll2 (7BL) have a specific amplification on Lr.2 indicating that Lr.2 might be homoelogous to wheat group 7; Primers gwm205(5AS), gwml56(5AL), gwm212(5DL) could amplify specific bands both on Lr.7 and Lr.14 revealing that Lr.7 and Lr.14, which probably have derived from different genomes of Lracemosus, might be both homoelogous to group 5 of wheat. Combined with gwm63( 7AL), which has a special amplification only on Lr.7, the four primers could be used to discriminate Lr.7 and Lr.14 chromosomes of Lracemosus, this result also indicated that chromosome rearrangements might have occurred on chromosome Lr.7 during the evolution of Lracemosus.The amplified loci of primers (gwm205, gwml56 and gwm212) have been physically mapped using a series of chromosome deletions of Chinese Spring. Among them, Xgwnaos was mapped between 0.02 and 0.25 FL in the distal of 5AS, Xgwmise between 0.44 and 0.6S in the distal of SAL and Xgwm2i2 between 0.24 and 0.26 in the distal of SDL.The reported primers not only trace the intact chromosomes of Lracemosus, but also have been successfully used to detect alien translocations of these chromosomes. In this paper, alien chromosome arms and its fragment length involving in 13 alien translocations were determined.The primers have also been used in molecular assistant selection. In this study, five plants with Lr.2 and Lr.7 chromosomes were identified; Combined with the SCAR marker of 6V chromosome of Hanaldia villosa, 25 plants integrated with both wheat-L. race/mm/ translocatin and wheat-H, villosa translocation 6VS/6AL were also selected which showed well resistance both to powdery mildew and scab of wheat.