Association Analysis Of Resistance To Fusarium Wilt In Sesame

Sesame Fusarium Wilt(SFW),caused by Fusarium oxysporum f. sp.Sesame(FOS),is one kind of fungal diseases which give great threats to high productionof sesame.Fusarium wiltis the major disease in sesame in the world.To improve the resistance level of sesame cultivars to diseases and then elevate the yield of sesame seeds is one of the main objectives of seame breeding. Meanwhile, digging the genes and developing the molecular markers related to resistancearethe key procedures. And on basis of Phenotype evaluation, whole genomics which was used to gene association analysis had been an effective method for disease resistance gene isolation and identification.A sesame association m aping population consisted of 124 sesame materials was constructed as our research materials.The disease resistance phenotype was evaluated under the condition of artificial linoculating,the populationg enetic diversity and structure was analyzed combined with SNP and INDEL makers of whole genomics and the SNPs and IDNELs correlated with sesame Fusarium Wilt resistance were located by association analysis while was on base of whole genome screening.The main results are as follows:1.124 sesame germplasm resources were identified under Fusarium disease nuseryconditions in Pingyu during 2010-2012 and Yuanyang during 2011-2013. The results indicated that 10 accessions consistently presented the high susceptibility with the ratio of 8.06% under six environmental conditions. Meanwhile, two accessions showed the high resistance with the ratio of 1.61% and no immune accessions existed in the population. The results revealed that the resistance level of Chinese sesame germplasm to Fusarium wilt is generally lowand few materials with high resistance or immune characters exist. Meanwhile,High significant differences existed among various years, the interaction between environment and year of DI (disease index).2.SNP and INDEL markers were developed in seasme.According to the obtained data of transcriptome sequences of resistance and suspectible materials to Fusarium wilt, we screened the SNP and IDNEL polymorphic locis using Clustal and Bioxm sequence analysis software. In total,443 pairs of SNP and 87 pairs of INDEL were preliminarily designed. Subsequently,234 SNP and 50 INDEL markers were found polymorphic with high quality within 124 accessions.The average gene diversity was 0.355with the variation range of 0.009～0.745; the average PIC was 0.285with the range of 0.009～0.697 and the average heterozygosity was 0.03 with the range of 0～0.263, which was mainly distributed from 0-0.031.3.The genetic structure of the population was analyzed. The genetic analysis of 124 germplasm resources was performed using 284 pairs of SNP/INDEL primers.Results indicated that 124 sesame accessions were diveded into two subgroups:G1 subgroup contained 114 materials which covered the most materials from the central, north, northwest, northeast and south of China and partial foreign resources from South korea, Tailandand Japan;G2subgroup contained 10 accessions from Anhui,Jiangxi, Zhejiang and Yunnan provinces.Meanwihe,both subgroups were clustered with over 50% of the genetic variation explained according the top two principal components.The genetic relationship analysis reflected that relationship between two individuals was relatively distant and the population represented the high heterogeneity and representative.5.The genome-wide analysis of resistance to Fusarium wilt in sesame. Three models of GLM-PCA and MLM-PCA+K were applied for the analysis. In total,13 markers were simultaneously detected associated with DI. Meanwhile,marker SNP170、SNP234 and SNP249 could be simultaneously detected by two models,and their explanation of phenotypic variation were very high.