Mapping And Analysis Of Powdery Mildew Resistance Genes In Guizimai 1

Powdery mildew is one of the important diseases that seriously affect wheat production.Mining resistant genes and breeding resistant varieties are the most direct and effective methods to control this disease.‘Guizimai NO.1',a wheat variety bred by our unit,has been resistant to powdery mildew and stable in production since it was bred in 2015.In this study,F₂and F_2:3resistant and susceptible segregation populations were constructed with‘Guizimai NO.1',‘Zhongyan Extra Large',‘Guimai 13'and other parents.The genetic analysis of powdery mildew resistance of‘Guizimai NO.1'was carried out,and the location and source of powdery mildew resistance gene were analyzed by SSR molecular markers.At the same time,the validity of the marker was verified by using the related genetic population of‘Guizimai NO.1',and 328 wheat varieties(lines)were used to test the marker.The main results are as follows:1.The F₂population of‘Guizimai NO.1'בZhongyan Extra Large'was identified by mixed physiological races of powdery mildew.142 plants were resistant and 53plants were susceptible.Chi-square tests showed that the segregation ratio of resistance and susceptibility of this population was 3:1(x₀²=0.4940<x²_0.05,1=3.84).The F_2:3population of‘Guizimai NO.1'בZhongyan Extra Large'and its resistant and susceptible parents were inoculated with physiological race E20 of powdery mildew.The results showed that‘Guizimai NO.1'was immune to physiological race E20 of powdery mildew,‘Zhongyan Extra Large'was highly susceptible.In F_2:3population of‘Guizimai NO.1'בZhongyan Extra Large',59 plants were homozygous resistant,104 plants were resistant and 47 plants were susceptible.Chi-square tests(x²)showed that x₀²=1.3904<x²_0.05,2=5.99,which indicated that the proportion of resistance and susceptibility of this population was 1:2:1.The results showed that the resistance of powdery mildew was controlled by a pair of dominant genes,and was named Pm GZ1 temporarily.2.Based on the previous research,the method of Bulked segregation nalysis(BSA)was used,167 pairs of SSR primers were used to screen the parents and gene pool,and five specific markers were obtained:Xgpw1150,Xdw06,ml GZ83,ml GZ89 and ml GZ95.The results showed that the markers ml GZ83 and ml GZ95 were linked to Pm GZ1 with linkage distances of 4.63 c M and 39.32 c M,respectively.They were located in the physical interval of 17.8 Mb(13529292-31370380)on chromosome 6A of Chinese Spring reference genome,indicating that Pm GZ1 was located on chromosome 6AS.3.In order to verify the results of genetic analysis,the F₂population of‘Guizimai NO.1'בGuimai13'and its resistant and susceptible parents were inoculated and identified by physiological race E20 of powdery mildew.The results showed that‘Guizimai NO.1'was immune to physiological race E20 of powdery mildew,‘Guimai13'was highly susceptible,131 plants of‘Guizimai NO.1'בGuimai13'F₂population were resistant,51 plants were susceptible,chi-square test showed that x₀²=0.4450<x²_0.05,1=3.84,indicating that the segregation ratio of resistance and susceptibility of the population was 3:1.In order to further verify the validity of the marker ml GZ83,a linkage test was carried out in the F₂population of‘Guizimai NO.1'בGuimai13'by using the marker ml GZ83.The genetic distance between the marker ml GZ83 and the powdery mildew resistance gene of‘Guizimai NO.1'was 17.12 c M.The results showed that ml GZ83 was an effective marker for the selection of‘Guizimai NO.1'and could be used for the marker selection of Pm GZ1,a powdery mildew resistance gene of‘Guizimai NO.1'.4.Using markers linked to powdery mildew resistance genes of emmer wheat,durum wheat,Aegilops squarrosa and Aegilops angustifolia,‘Guizimai NO.1'was tested.The results showed that Pm GZ1 was different from the powdery mildew resistance genes Pm2?Pm3h?Pm4a?Pm4b?Pm34?Pm58 and Pm68,and it is also different from the powdery mildew resistance genes pm56 and Pm21 on chromosome 6A of wheat.5.Molecular detection of 110 lines of‘Guizimai NO.1'בGuinong 19'F₅population was carried out by using marker ml GZ83.Combined with field powdery mildew resistance identification,35 homozygous resistant lines were selected.Molecular identification of powdery mildew gene Pm GZ1 in 328 wheat varieties(lines)was carried out by using marker ml GZ83.Among 328 wheat varieties(lines),41 materials amplified specific bands of Pm GZ1,including 33 wheat varieties(lines)from Guizhou Province,accounting for 10.06%;6 wheat varieties from other provinces,accounting for 1.82%;2 foreign wheat varieties,accounting for 0.60%.These materials and lines containing powdery mildew gene Pm GZ1 can be used as powdery mildew resistance sources in wheat variety improvement or breeding.