Identification Of Key Loci Of Main Agronomic Traits In Yannong Series Wheat Cultivars(Lines)and Mining Of Powdery Mildew Resistance Genes In Breeding Materials

Fungal diseases,drought,Pre-harvest sprouting（PHS）and other biotic and abiotic stresses have seriously affected the quality and yield in wheat production.Identifying related genes/loci in released cultivars/lines can provide reference information and theoretical basis for wheat improvement.Yannong series wheat cultivars/lines have distinctive characteristics in wheat cultivars and play an important role in genetic improvement and production of Chinese wheat production system.To dissect their genetic basis of the stress-resistant traits,in this study,the agronomic characters and powdery mildew resistance of 55 representative Yannong series wheat cultivars/lines by Yantai Academy of Agricultural Sciences were investigated,and also were teted by 58 molecular markers for 40 genes relateed to adaptability,disease resistance and stress tolerance to clarify the genetic composition of the key loci.The results showed that Yannong series wheat had many good key loci,but poor resistance to powdery mildew.And then,genetic analysis of segregation populations of 116 wheat cultivars/lines with highly resistance to powdery mildew at seedling stage and susceptible wheat materials using powdery mildew E09.Identification of powdery mildew resistance genes in the above materials by using 20 molecular markers of 15 Pm gene,clarify its genetic inheritance and the known genes it catties,aiming at finding excellent disease resistant germplasm resources and effective Pm gene for Yannong series wheat resistance breeding.The specific results of the experiment are as follows:1.Identification of key loci of main agronomic traits in Yannong series wheat cultivars（lines）Using 58 molecular markers of 40 genes related to wheat adaptability,disease resistance and stress tolerant to detect Yannong series wheat.The results showed that most of the tested wheat accessions carried two dwarfing genes at least,except Yannong40 and XG-14,and 42 cultivars carrieed the recessive vernalization genes vrn-A1/vrn-B1/vrn-D1/vrn-B3,the rest carried at least one recessive vernalization gene.It was also consistant with the phenotypic traits of tested Yannong series wheat which were dwarf and winter or semi winter wheat.In addition,the overall level of seedling powdery mildew resistance in 55 Yannong wheat cultivars/lines was moderate or inadequate.Eighteen of the cultivars/lines carried none of the tested Pm genes and thirty-seven of the cultivars/lines carried at least one tested gene.Then,55 wheat cultivarsd/lines were also tested by 17 diagnostic markers for 14 Yr genes.The rasults showed that 31 wheat cultivars/lines were likely to carry one or more of tested Yr genes,Yr9 and Yr10 were found in 18 and 17 cultivars,respectively.In addition,Yr17 and Yr SP were also detected in the other three cultivars.Moreover,in our study,nine markers for four genes related to drought tolerance and PHS were used to evaluate the stress tolerance of the 55 wheat cultivars/lines.The results indicated that 52 wheat cultivars/lines all carried drought resistance genes Ta-Dreb1/Ta CRT-D,and the other three varieties all contained Ta CRT-D,indicating that they had the drought resistance to extent.47 cultivars/lines all carried 1～3 elite PHS-resistant alleles Vp-1Bc/Vp-1Bf/Ta AFP-Bb.2.Genetic analysis of powdery mildew resistance in 116 wheat cultivars/lines600 wheat cultivars/lines collected in the laboratory were identified for resistance to powdery mildew at seedling stage by Bgt isolate E09,and 116 resistant materials were obtained,and were hybridized with susceptible materials to conduct F₂ and F_2:3segregating populations for genetic analysis and molecular detection of their Pm genes.To determine the inheritance of powdery mildew resistance in the resistant genotypes,Bgt isolate E09 was selected to inoculate the F₂ and F_2:3 progenies for genetic analysis.The results showed that 87 materials（75.0%）were suitable for single gene segregation ratio,85 were controlled by dominant gene,and the remaining 2 were controlled by recessice gene.19 materials（16.4%）were suitable for two genes controlling powdery mildew resistance,16 carried two dominant genes and 3 carried two recessive genes.10 materials（0.09%）were not suitable for any kind of separation ratio,maybe carried multiple Pm genes.These materials were subsequently analyzed with diagnosed moecular markers of known powdery mildew resistance genes Pm1,Pm2,Pm4,Pm5,Pm6,Pm12,Pm21,Pm24,Pm33,Pm34,Pm35,pm42,Pm45,Pm47 and Pm52,respectively.The results showed that 75 materials（64.5%）were likey to carry Pm2 alone,and 3 carried Pm21.Among the materials that may contain two genes,Pm2+Pm52 were the most,with a total of 8（0.07%）.In addition,5 materials containing three resistance genes,and the four materials combination of resistance genes was Pm2+Pm6+Pm52,and another one carried Pm2+Pm5+pm42.In particular,no known resistance gene was detected in the 4materials conforming to the single gene isolation ratio,and only one known gene was detected in the 6 materials,but its genetic isolation ratio did not conform to the genetic isolation ratio of the single gene control resistance.