Preliminary Mapping Of Adult-plant Stripe Rust Resistance Gene YrK1007 In Roegneria Kamoji Cv.Chuanzhong Using Wheat 55K SNP Chip

Wheat stripe rust is a fungal disease caused by Puccinia striiformis f.sp.tritici,which seriously threatens wheat yield.Although chemical control has achieved certain effects,breeding resistant wheat varieties is the most effective and environment friendly way to control wheat stripe rust.The wild relatives of the wheat are genetic source for wheat breeding and most of the favorable genetic variations required in wheat breeding.Roegneria kamoji Ohwi is a perennial species of the genus Roegneria C.Koch in Triticeae?Poaceae?.It is a hexaploid?2n=6x=42?species containing the StStYYHH genomes.It is a tertiary gene source of common wheat with excellent genes,such as powdery mildew resistance gene and yellow rust resistance gene.In this study,the F₂ populations and F_2:3 families constructed by the hybridization of Roegneria kamoji cv.Gansi No.1×Roegneria kamoji cv.Chuanzhong were used to identify resistance to stripe rust at the field.Using the wheat 55K SNP chip for locate the strip rust gene YrK1007 of Roegneria kamoji.The main results are summarized as follows:1.Identification of resistance to stripe rust at adult stage:Among the 165 F₂ populations of R.kamoji cv.Gansi No.1×R.kamoji cv.Chuanzhong in 2017,120 showed disease resistance while 45 showed susceptibility.The separation ratio was consistent with 3R:1S??2=0.455,P=0.500?.Of the 160 F₂ populations in 2018,121 showed resistance while 39showed susceptibility.The separation ratio was 3R:1S??2=0.33,P=0.855?.The results of the F_2:3:3 family of R.kamoji cv.Gansi No.1×R.kamoji cv.Chuanzhong showed that there were 37 strains with all disease resistance,40 strains with all showed susceptibility,and the remaining 83 showed a heterozygous phenotype.It consistent with a 1:2:1 separation ratio??2=0.338,P=0.845?.Genetic analysis of resistance indicated that the resistance of R.kamoji cv.Chuanzhong was controlled by a dominant resistance gene,temporarily named as YrK1007.2.165 F₂ populations of R.kamoji cv.Gansi No.1×R.kamoji cv.Chuanzhong were genotyped by the wheat 55K SNP chip.A total of 53064 markers which was divided into six types were obtained.A total of 10860 markers,which were selected from the first three types,were used for constructing genetic maps by maximum likelihood method.After eliminate the redundant markers,1662 markers were used for constructing the genetic map.Three linkage groups were obtained.The first linkage group?LG1?has a total length of 917.22 cM containing 1072 markers;the second linkage group?LG2?has a total length of 393.09 cM containing 562 markers;the third linkage group?LG3?has a total length of 102.41 cM containing 28 markers.3.QTL mapping was performed using QTL IciMapping software combined with field phenotypic traits and genetic map information.The LOD threshold was set to 2.5,and one QTL was detected.The resistant stripe rust gene YrK1007 was initially located on the first linkage group with a genetic distance of 2.3 cM between the markers AX-111575769 and AX-109554178.The LOD value was 2.56,which explained 6.29%phenotypic variation.4.Compared with the linked markers to the physical map of wheat Chinese Spring,both markers were located in about 320 Mb interval regions of 1D chromosome.Compared with the linked markers to the physical map of Aegilops tauschii Coss,both markers were located in about 324 Mb interval regions of 1D chromosome.Compared with the linked markers to the physical map of barley,both markers were located in about 8 Mb interval regions of 4H chromosome.