| As the main grain of our people,it is of great significance to ensure the yield of wheat.Lodging is one of the important factors limiting the wheat yield and so it is very important to select and apply wheat varieties with good lodging resistance.Using molecular marker technology to find the molecular markers related to lodging resistance can provide theoretical basis and technical support for lodging resistance breeding.In this study,543 Winter Wheat Varieties（lines）in North China and Huang Huai winter wheat regions and some foreign outstanding germplasm resources were used as materials to determine lodging characters in the field.Effective identification indexes and methods of lodging resistance were determined by correlation analysis,principal component analysis,regression analysis and cluster analysis,and wheat germplasm resources with strong lodging resistance were classified and screened.At the same time,using the genotype data detected by the 90k SNP and the phenotype data,we located the SNP loci significantly related to the lodging characters of wheat through the whole genome association analysis,and predicted the candidate genes.The main conclusions are as follows:1.Six traits related to lodging resistance had great genetic variation in different environments.The correlations between thrust resistance and other five characters were significant or extremely significant.Combined with the results of multiple linear regression analysis,it confirmed that thrust resistance could be used as an index to identify lodging resistance of wheat varieties.According to the cluster analysis of thrust resistance index,the tested materials were divided into four categories,among which 73 materials had the strongest lodging resistance such as Zhou8425B,Jimai 22 and Henong 6425.2.Using MLM（PCA+K）to analyze the whole genome association,we obtained 130 loci related to lodging resistance distributed in all 21 chromosomes and the 4B chromosome had the most number of loci,reaching 20.The greatest contribution was made by Excaliburc43604751,which could explain 7.13%of the phenotypic variation.3.Haplotype analysis showed that the four loci BS0002303551,Tdurumcontig483661324,Tdurumcontig5078367 and Tdurumcontig50783285,which controlled the diameter of the first internode on 4B chromosome,were closely linked.This chromosome region was directly related to the diameter of the first internode of wheat.4.996 different candidate genes were predicted in the LD range of all significant loci,among which 75 genes contained the significant loci.These genes included protein synthesis genes,enzyme synthesis genes,regulatory genes and family protein genes.5.GO analysis and KEGG analysis were carried out on the candidate genes,and their functions and enriched pathways were classified.GO was enriched in 52 different pathways,and KEGG was enriched in 63 pathways.To sum up,the association analysis of six lodging resistance traits in wheat natural population showed that there were rich genetic variation and significant correlation in lodging resistance traits,and 73 wheat varieties（lines）with excellent lodging resistance were selected.130 SNPs significantly associated with lodging resistance were identified,and 996 candidate genes related to lodging resistance were screened. |
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