SSR Targeting And Analysis Of Wheat Dwarfing Gene

Plant height is an important factor in wheat production;the constant discovery and utilization of dwarfing genes enabled the wheat production of the world to increase continuously.Therefore,the continuous excavation,studies and use of dwarf gene is very important to high-yield wheat breeding.In this study,the wheat variety 'MERCIA(Rht-Bla)' which has non-dwarf gene and wheat variety 'Dwarf 123' were used as the hybridized parents,the hybrid F₂ generation was used for investigation and gene mapping,and SSR(simple sequence repeat) technology was applied for dwarfing gene molecular mapping.The purpose was to dig a new dwarfing gene.In this experiment,145 pairs of primers were used.The results of amplification and selecting showed that 36 pairs had amplified polymorphism fragments between the parents,7 pairs showed polymorphism between the high and dwarf DNA bulks,4 pairs amplified corresponding polymorphism fragments were found both in parents and the F₂ plant height DNA bulks.Through the analysis by using the software of Map Manager QTXb20 and Windows QTL Cartographer 2.0,the results indicated that the dwarfing gene carrying by the new line 'Dwarf 123' was located on the long arm of wheat chromosome 4B,three genetic markers linked with the dwarfing gene.The linkage distance between dwarfing gene and those markers Xbarc20,Xgwm523 and Xgwm495 were 0.01 cM,7.92 cM and 13.89 cM respectively.The order of the dwarfing gene and three makers was Xbarc20-dwarfing gene -Xgwm513-Xgwm495 in the molecular linkage map.The comparison of molecular mapping between the dwarfing gene with the six named dwarfing genes(Rht-Blb,Rht-Dlb,Rht-Blc,Rht8,Rht-Dlc,Rht12) being valuable in wheat breeding and production,showed that the dwarfing gene in 'Dwarf 123' is not the same as others.It suggested,therefore,'Dwarf 123' carried a new dwarfing gene.The location of the gene and the acquisition of the molecular markers enriched the genetic maps of this linkage group.They also provided valuable information for both of our further research on the effects of this gene on wheat height and marker-assistant breeding in wheat.