Genetic analysis and SSR mapping of stripe rust resistant genes from Aegilops tauschii

Identification of stripe rust resistant genes was carried out in thirty eight specimens of Aegilops tauschii originating from different regions and cross between subspecies of A.tauschii.Nine of them were immune to wheat stripe rust(tiaozhong 29 31)strains,five were susceptible to the 2 strains,and others were resistant to one strain after inoculation of leaf fragments in vitro.The results of inoculation of seedlings and mature plants in the field with mixed physiological race were the same as those obtained in vitro. Nineteen of them had immunity from the wheat stripe rust(tiaozhong 29 31),10 were susceptible at the seedling stage and resistant at the mature stage.Cross-fertile ratio within Ae.tauschii varied widely from 0 to 83.33%,but a hybrid between subspecies showed cross-incompatibility.A wheat stripe rust resistance gene,temporarily designated as(YrY201,) was identified in Ae.tauschii hybrid progeny of Y201/Y2272.Using microsatellite markers and bulk segregation analysis,four microsatellite markers,Xgwm273b,Xgwm37 and Wmc14 were found to be linked to YrY201 with genetic distances of 11.5,5.8 and(10.9?cM,) respectively.From the locations of the linked markers,the resistant gene was located on chromosome 7DL.Based on the chromosomal location and resistance pattern of the gene,we propose that YrY201 is a novel dominant stripe rust resistant gene,and can be selected with marker-assisted selection.