Association Analysis Of Yield And Quality Traits In Sesame

Sesame(Sesamum indicum L.), which belongs to Sesamum genus in Pedaliaceae family, is one of the important oil crops in China. With the development and application of molecular markers, the studies of genetic diversity analysis and DNA fingerprint construction of sesame germplasm resources have been carried out in recent years. But there are few reports about the assciation analysis of yield and quality traits in sesame. In this study,112pairs of polymorphic SSR markers were selected to associate with the yield and quality traits of369sesame germplasm resources. The results of association analysis in identification of linkage sites and excellent allele mutation will give the theoretical foundation for improving sesame breeding efficiency.1. The population of369sesame germplasm resources were genotyped using112pairs of polymorphic SSR markers, which were selected from1100sesame SSR primers. A total of211alleles were detected among369sesame accessions. The numbers of detected alleles varied from2to5with an average of2.473alleles per locus. The average of polymorphism information content (PIC) values was0.3019, varied from0.028to0.6692. The average of heterozygosity values was0.1014, varied from0.0027to0.2312. The average of gene diversity values was0.3655.2. The population structure and the Q values (the probability that the i th accession’s genome variation was derived from the k th subgroup) of369sesame accessions were analyzed by STRUCTURE software program.369sesame accessions were roughly divided into two divergent subgroups.315accessions were allocated to G1subgroup, which contained most accessions come from north, northwest, southeast, south of China, and most of the foreign accessions. The rest54accessions were allocated to G2subgroup, which contained few accessions from China’s northeast and north China, and most of the Korea’s accessions.3. The phenotypes of plant height, height to first caspule, yellow pointed, capsule length,1000-grain weight, yield per plant, capsule numbers of per plant, protein content, oil content, primary flowering stage, terminal flowering stage were carried out in five environments for two years. SAS8.0was used to calculate the broad-sense heritability of traits and the phenotypic correlative coefficient between characters. The result indicated that significantly positive correlation or negative correlations were existed among these characters. In five environments for two years, there was a steady significant negative correlation between the oil content and the protein content.4. Correlation analysis was detected using TASSEL GLM (gengral linear model) and MLM (mixed linear model). Different degrees of LD were found among non-linear SSR sites, which suggested that there had been historical recombination among linkage groups. Numbers of loci pairs supporting LD with P≤0.01accounted for41.57%.24SSR loci(Hs1036. Hs205、Hs485、Hs586、Hs4061、Hs4381) were detected and associated with9agronomic traits. Moreover, six loci (Hs1036、Hs485、Hs586、Hs4061、Hs4381、 Hs4325)associated with two or more traits at the same time, which might be result from the genetic basis of correlating traits as well as pleiotropic effects of a specific gene. Some traits were associated with multiple loci. Detection of the elite alleles of the agronomic traits provided theoretical basis on molecular design breeding in sesame.