| Due to the plant height of sweet sorghum,combined with the influence of environmental factors,lodging is more serious in field planting,which not only causes trouble to modern mechanical tillage,but also has an immeasurable impact on its yield.In order to solve the influence of this situation,the barycenter height,fresh weight of main stem,stress resistance,folding resistance,puncture resistance,lodging coefficient 1,lodging coefficient 2 and lodging coefficient 3 of 403 sweet sorghum accessions with different germplasms were measured and analyzed in this study,and 18784 single nucleotide polymorphism(SNP)markers uniformly distributed in the sweet sorghum genome were combined.Genome wide association study(GWAS)was carried out using different model methods of mr MLM,FASTmr MLM,FASTmr EMMA,p LARm EB,p KWm EB and ISIS EM-BLASSO,and then the influence of heritability among traits was evaluated according to the analysis results.In order to provide theoretical guidance and material basis for lodging resistance identification and evaluation of sweet sorghum germplasm resources and selection of lodging resistance breeding parents.After comprehensive detection and analysis,50 SNP loci associated with lodging resistance-related traits were detected on 10 chromosomes of sweet sorghum.The main research results are as follows :1.Screening of dominant SNP lociEight lodging resistance related traits were detected by six model methods.Two loci on chromosome 3(chromosome＿3-11554750,chromosome＿3-27872928),two loci on chromosome 4(chromosome＿4-52122594,chromosome＿4-52145105)and two loci on chromosome 8(chromosome＿8-47146386,chromosome＿8-54163002)were detected.There were two loci on chromosome 10(chromosome＿10-24065888,chromosome＿10-44928079).Among them,the number of 11554750 and 27872928 loci on chromosome 3 detected by fresh weight of main stem and lodging coefficient 1,lodging coefficient 2and lodging coefficient 3 was the most,and 19 times were detected.It shows that the lodging resistance genes of sweet sorghum are greatly affected by the loci at these two positions.2.Effects of quantitative trait genesThe results showed that the QTN(Quan-titative trait nucleotides,QTN)effect of 65 SNPs was synergistic,and the QTN effect of 8 SNPs was attenuated.The effect value of chromosome＿8-54163002 was the highest(61.2035).According to gene expression and different model analysis,it can be speculated that the sweet sorghum lodging resistance related candidate genes.3.Genome linkage analysisIt can be seen from the analysis results that the LOD values of the detected loci of the dominant SNP were all greater than 3.The linkage relationship was first determined,and then it was indicated that the loci on the same chromosome were very close,and the detected loci were most likely to be the same dominant SNP affecting the lodging resistance gene of sweet sorghum.4.Comparison of contribution rates of dominant SNP lociAccording to the analysis,although chromosome＿10 – 24065888 was detected in both lodging coefficient 1 and lodging coefficient 3,its contribution rate r2 was the lowest,which was0.00000041324 %.The contribution rate r2 of chromosome＿4-52145105 was the highest,which was40.3384 %.5.Genetic rate analysis of dominant loci for different traitsAccording to the analysis results,the genetic rate of chromosome＿2-1147597 detected in the pLARmEB model was the highest,which was 65.4041 %.6.Comparison of analytical model methodsIt can be clearly seen that the pLARmEB model method detected the most significant SNP loci,37 times in total.pKWmEB model method detected 18 times,mr MLM model detected 29 times,ISIS EM-BLASSO model detected 22 times,FASTmrMLM model detected 19 times,and FASTmrEMMA model detected 18 times.Through the comparison between the model methods,the p LARm EB model method is more stable.In general,the research results on lodging resistance-related traits of sweet sorghum and various genome-wide association analysis models provide favorable information for gene mining and genome-wide association analysis of lodging resistance breeding of sweet sorghum germplasm. |
