Association Analysis Of Drought Resistance Related Traits In Chinese Wheat Landraces

Wheat (Triticum aestivumL) is the most important grain crop and sources of plant protein. The number of Chinese population is the biggest in the world. Wheat landraces of China which could adapt to specific environment are the product of artificial selection and natural selection. Wheat landraces of China are valuable resources for wheat genetic improvement. A total of 710 wheat landraces of China genotypes were used to evaluate their drought tolerance at seedling stage. By using the method of water treatment, and use PEG-6000 simulated drought stressand. Using SPSS to do principal component analysis and make a comprehensive evaluation on the drought resistance of materials of subordinate wheat landraces function value, choose wheat landraces with extremely high tolerance and extremely low tolerance. By using 52460 DArTs, we also did GWAS of 17 drought related traits. We proposed a lot of putative candidate genes by searching of public databases, such like IWGSC and NCBI. The main results are described as follows:1. The principal component analysis of 17drought related traits indicated that there were 6 selected eigenvalues and the corresponding eigenvectors of cumulative contribution rate was 88.051%. The first principal component was root surface area factor, with which contribution rate at40.445%; the second principal component was plant height factor, with which the contribution rate at 14.877%; the third principal component was rootdry matter factor, with which contribution rate at 9.962%; the fourth principal component have contribution rate at 8.744%; and the fifth principal component was root morphology factor, with which contribution rate at7.738%.; and the sixth principal component was biomass factor,with which contribution rate at6.286%.2. Using subordinate function value method to calculate the D value of 710 wheat landraces of China, and evalulate the ability of resisting drought by D value. There are 32 wheat landraces with D value greater than 0.5, and 35 wheat landrace with D value less than 0.3. We found top 10 genotypes with extremely high tolerance about drougt:G59, AS661694, AS661738, AS661419, AS661147, AS661798, AS661460, AS661613, AS661520 and AS661309, especially there are 6 wheat landraces with D value greater than 0.6; We also found the bottommost 10 genotypes with extremely low tolerance about drought:AS661726, AS662055, AS661108, AS661151, G77, AS661493, AS662043, AS661099, AS661665, AS661732.3. By using 52460 DArTs genotyped in a core collection of 710 wheat langraces, we did genome-wide association study (GWAS) of tolerant traits abot drought. The results showed that by using a general linear model (GLM), we identified 396 significant DArTs, and a mixed linear model (MLM) revealed 305 significant DArTs in the CK group, we could both identified 302 significant DArTs in two models. By using a general linear model (GLM), we identified 233 significant DArTs, and a mixed linear model (MLM) revealed 46 significant DArTs in the PEG group, we could both identified 42 significant DArTs in two models.4. Searches of public databases revealed 30putative candidate/flanking genes related to drought tolerance. These genes were grouped in five categories by the types of proteins they encoded:proteins about wheat growing period, promoters and transcription factors, enzymes, response to signal transduction and others.