Identification Of Resistance To Stripe Rust Of The Wheat-Psathyrostachys Huashanica Derivative Lines And Mapping Of Stripe Rust Resistance Genes Of H5-2-9-1-1-2 In Adult Plant Stage

Wheat stripe rust caused by stripe rust pathogen is one of the main diseases of wheat,causing serious yield loss.The yield of wheat varieties bred by inter-variety hybridization decreased,and the disease resistance to stripe rust decreased or even disappeared.In addition,the frequent variation of wheat stripe rust pathogen caused the genetic basis of wheat resistance to become weaker and weaker.Psathyrostachys huashanica Keng（2n=14,Ns Ns）,an important wild relative of wheat,is immune or highly resistant to most of the major physiological races of Puccinia striiformis prevailing at present,and it is a high-quality resistance source to stripe rust.In this experiment,34 interspecific derivatives between wheat and P.huashanica were identified for resistance to stripe rust at the adult stage.Through artificial inoculation of mixed strains of stripe rust（Shuiyuan 14,CYR32,CYR33 and CYR34）,the materials resistant to stripe rust were screened and their resistance sources were analyzed.In addition,the F₂ segregation population was constructed by crossing H5-2-9-1-1-2 and Mingxian 169.The BSA method,660K SNP chip and SSR molecular marker analysis were used to preliminarily locate the resistance gene/QTL to stripe rust.The main research results are as follows:1.34 interspecific derivatives between wheat and P.huashanica were artificially inoculated with mixed strains of stripe rust（Shuiyuan 14,CYR32,CYR33 and CYR34）to identify the resistance to stripe rust in adult stage,and 5 materials were screened out with moderate or above resistance to stripe rust.H611,H5-2-9-1-1-2 and H30-2-3-1-1 are highly resistant to（HR）stripe rust.H18-1-3-1-6-2-2 and H30-4-4-1-6-2-6 are moderately resistant to（MR）stripe rust.2.These five lines were examined based on their morphology and cytogenetics,as well as by genomic in situ hybridization（GISH）and molecular markers to determine their genetic construction.The results confirmed H18-1-3-1-6-2-2 and H30-4-4-6-2-6 were wheat-P.huashanica 2Ns（2D）substitution line.H30-2-3-1-1,H5-2-9-1-1-2 and H611 were wheat-P.huashanica introgression line.3.The F₂ segregation population,which was obtained by crossing H5-2-9-1-1-2 with Mingxian 169 and then selfing for one generation,was used as the research object.Resistance to stripe rust at the adult stage was identified.The results showed that there was no significant proportional relationship between the reaction types at all levels in the F₂ population,and the normal P-P diagram indicated that the reaction types at all levels in the F₂ population conformed to the normal distribution,indicating that the resistance gene to stripe rust in H5-2-9-1-1-2 was a quantitative character.4.Select 15 extremely resistant plants and 15 extremely susceptible plants from F₂,extract DNA,mix them into resistance pool and susceptible pool.The wheat 660K SNP chip was used to detect the two parents and two pools.The results showed that the main QTL for resistance to stripe rust in H5-2-9-1-1-2 was located between 597-686 Mb on 4A chromosome.5.SSR markers were synthesized in regions with high dense differential SNPs,and seven pairs of SSR markers linked to the disease resistance gene were obtained,which were WMC650,BAR0170,WMC468,BARC1158,WMC161,WMC718 and WMC262,respectively.Linkage analysis was performed on the F₂ population by using the seven pairs of SSR markers,and a genetic map with the full length of 37.39 c M was constructed.Finally the main QTL for stripe rust resistance was located between the SSR markers BARC1158 and WMC161,with an interval of 5.30 c M,and named QYr.nwafu-4AL.The explained phenotypic variation rate of this QTL was 32.0347%.