Genome-wide Association Study For Wheat Yield Traits Based On RNA-Seq

Wheat(Triticum aestivum.L)is the most videly cultivated cereal in the world which provide approximately 20% of calories consumed by humans.It has been estimated that demand for wheat could increase by up to 60% by 2050.Therefore,increasing wheat yield is especially urgent.Thousand grain weight,spike number per m2 and grain number per spike are three important factors of yield,which is an important way to increase wheat yield.In addition,germplasm resources also play important roles in improving wheat yield.At present,there is a lack of germplasm resources in wheat breeding.So it is urgent to find and create new germplasm.Induced mutants,constructing the mutant library,can provide basic materials for wheat genetic research and improvement.In this study,12 main yield traits of wheat were investigated using Yannong15 and 110 mutant lines obtained by EMS mutagenesis of Yannong15.RNA sequencing technology was used to develop high throughout SNPs and InDels markers for association analysis.The study will provide candidate markers and gene for wheat breeding in future.The main results are as follow:1.In this study,three Yannong15 samples,DPA9,DPA18,DPA27 were sequenced by RNA sequencing.The transcriptome was assembled by the method of wheat genome based assembly.A total of 195,601 transcripts were obtained,and the average length was 1988 bp.2.In this study,110 Mutant lines,DPA9,DPA18,DPA27,we mixed the three periods of RNA at equal concentration and RNA-Seq sequencing.On the basis of the transcriptome,126,980 markers were identified from 110 mutant lines using the RNA sequencing,of which 101,876 SNPs and 25,104 InDels.3.Analysis of phenotype and correlation of mutant populations showed that the 12 yield traits had significant variation,the coefficient of variation ranged from 4.12 to 111.90%,the smallest variation trait is grain length,the largest variation trait is top sterile spikelet number per spike.The correlation coefficients between most traits were significant.4.For association study of yield related traits using 126,980 markers,we detected 84 markers significantly associated with 8 traits at the level of P < 7.87E-6,in which,2,1,38,5,3,1,6,25,and 3 markers were significantly associated with plant height,total number of spikelet per spike,top sterile spikelet number per spike,number of sterile spikelet number per spike,number of fertile spikelet number per spike,spike number,thousand grain weight,grain length,and grain width.We detected 16 makers significantly associated with grain number per spike at the level of P < 7.87 E-8,and detected 25 markers significantly associated with spike length at the level of P < 1E-6.The R2 ranged from 18.209 to 52.993%.