Genome-wide Association Analysis And Candidate Gene Mining Of Salt Tolerance In Triticale

Salt stress is one of the major abiotic stresses in the world.Salt stress can inhibit plant growth and development.Cultivating and planting salt-tolerant varieties can not only reduce crop yield and even death caused by salt stress,but also improve soil ecological environment and reduce salinization as a biological means.In order to cultivate and plant new varieties of salt-tolerant crops,germplasm resources of salttolerant crops were screened and candidate genes of salt-tolerant crops were excavated.As a hybrid variety,Triticale has excellent heterosis and strong stress resistance,so it is extremely suitable to cultivate salt-tolerant varieties,so as to reduce soil salinization harm and improve soil ecological environment.Meanwhile,Triticale is widely planted as a food and feed crop in Qinghai Province.In this study,199 Triticale germplasm resources were selected to conduct salt tolerance analysis at the germination stage and genome-wide association analysis,in order to explore the salt-tolerance related loci of Triticale.It will provide theoretical basis and reference for exploring related molecular markers and guiding triticale breeding with molecular markers.The main results are as follows:1.The salt tolerance of Triticale at bud stage was evaluated.It was found that the average level of all traits of 199 triticale seeds under salt treatment decreased to a certain extent,at the same time,their coefficient of variation was greater than that of the control group（P<0.005 significance level）,the coefficient of variation ranged from 23.33% ～54.32% in the control group and 67.77% ～135.50% in the experimental group.These results indicated that the sensitivity of these 199 triticale materials to salt stress was significantly different and the variation range was wider.The correlation between salt treatment and control treatment of physiological indexes of triticale at bud stage was analyzed.A total of 199 triticale cultivars were selected as salt-tolerant cultivars 20BL-1057,20BL-1074,20BL-1153 and salt-sensitive cultivars 20BL-1023,20BL-1074,20BL-1153.2.Genome-wide scanning of 199 Triticale populations showed that there were 153 stable hexaploid triticale germplasm resources according to SNP distribution,and434544 reliable single nucleotide polymorphisms（SNPS）were obtained from these 153 stable hexaploid Triticale germplasm resources.The population structure analysis showed that the 153 Triticale germplasm could be divided into 9 different populations.3.Germination potential and germination rate,two traits related to salt treatment,were selected by screening and SNP markers for genome-wide association analysis.The general linear model（GLM）was selected as the optimal model because it was found that there were fewer false positives and false negatives in this model.In the blank experimental group,43 SNP loci were found to be associated with the traits,and38 loci were found to be significantly associated with the traits in the salt treated materials.Two multi-effect loci,1Brs25519704 and 6Brs575808355,had a simultaneous effect on germination potential and germination rate.In this study,genome-wide association analysis was used to screen SNP markers associated with salt-tolerant Triticale,providing a reference for subsequent breeding of salt-tolerant triticale varieties,research on salt-tolerant genes and genetic improvement of Triticale.