Abstract: 【Objective】Sesame is extremely sensitive to waterlogging and it is the main factor affecting the development of sesame production and the improvement of sesame yield in China, however, waterlogging tolerance related molecular biology research foundation is weak, so far, domestic and foreign studies on sesame waterlogging tolerance gene mapping has not yet been reported. This study focuses on mapping QTL related with waterlogging tolerance based on a sesame recombinant inbred lines (RIL) population, developing molecular marker related with waterlogging tolerance combining with analysis on sesame core collections, and identifying waterlogging tolerant germplasm. 【Method】RIL population was generated from 6 selfing generations after hybridization between Zhongzhi No.13 with high tolerance and Yiyangbai with extreme sensitivity to waterlogging. Based on molecular data of 113 polymorphism markers on RIL population, a genetic linkage map was constructed using MapMaker/EXP. 3.0 software. In 2009 and 2010, RIL population was tested by artificial waterlogging stress at flowering stage both at Wuhan and Ezhou, and phenotypic data of each line were obtained, including percentage of regular plants and percentage of live plants. Analysis of variance (ANOVA) on phenotypic data was carried out by Microsoft Excel 2010 software, then QTLs were mapped by QTLNetwork 2.0 software, using composite interval mapping (CIM) method. Subsequently, sesame core collections were scanned by markers linked with major QTL, their waterlogging tolerance phenotypic data were also collected and analyzed, the effective marker related with waterlogging tolerance was detected. Excellent germplasms with waterlogging tolerance were obtained by repeated identifying of waterlogging tolerance phenotype, and combined with the molecular marker assisted selection. 【Result】The length of genetic linkage map constructed in this study was 592.4 cM, a total of 70 marker loci were grouped into 15 linkage groups (LG), the average distance between adjacent markers was 8.46 cM. Total of 6 QTL related with waterlogging tolerance at flowering stage were detected, which located on LG 7, 9, 13, and 15, explaining 5.67%-17.19% of the phenotype variation, their additive effect was 2.7190-9.7302. One of them explaining the most phenotype variation was qWH10CHL09, its additive effect was 3.9394, and the alleles from the parent Zhongzhi No.13 toward increasing the trait value, SSR marker ZM428 was closely linked with this QTL (genetic distance was only 0.7 cM). This marker was verified among 186 sesame core collections, results showed that there were significant (P = 0.0163) differences between phenotypes of 2 groups of accessions with 2 different genotypes of marker ZM428, therefore, marker ZM428 can be used as effective marker for marker-assisted selection (MAS). Eight excellent germplasm with tolerance to waterlogging were also identified from the sesame core collection, their percentage of regular plants after waterlogging stress were higher than 70% and percentage of live plants after waterlogging stress were higher than 80%. 【Conclusion】In this study, 6 QTL related with sesame waterlogging tolerance were detected, one of them explaining the most phenotype variation of 17.19%, one effective marker was identified, and 8 excellent germplasm with waterlogging tolerance were identified.

Key words: sesame (Sesamum indicum L.) , waterlogging tolerance , QTL mapping , waterlogging tolerant germplasm , identification