Abstract:In our laboratory, we created a chromosome fragment substitution line CSSL91, with high salinity-tolerance, using Dongxiang common wild rice and Nipponbare as parents. In this study, it was compared with Nipponbare and Pokkali, a strong salt-tolerant germplasm, and the results showed that the salt tolerance of CSSL91 was comparable to that of Pokkali. Using the F2:3 population constructed by CSSL91 and Nipponbare, the phenotypes were normally distributed with salt tolerance grade and seedling survival rate as indicators. QTL linkage location analysis showed that a total of five salinity tolerance-related QTLs were detected, which were distributed on chromosomes 4, 9, and 10, with the LOD values ranging from 2.95 to 3.97, and the phenotypic contribution rates ranging from 9.83% to 18.48%. Among that QTL-qST4 is the highest phenotypic contribution in the salt tolerance grade, which was located between DX-C4-1 and DX-S4-16 markers on chromosome 4. Simultaneously, the bulked segregation analysis (BSA) detected a QTL exceeding the threshold value in the interval of 0-5.0 Mb on chromosome 4, which was overlapped with QTL-qST4, indicating that QTL-qST4 was a reliable salinity tolerance locus; QTL-qST4-1 and QTL-qSSR4 based on salt tolerance grade and seedling survival, respectively, were both located between markers DX-C4-12 and DX-C4-13 on chromosome 4, with LOD values of 3.36 and 3.92, and phenotypic contributions of 13.97% and 9.49%, respectively. Two QTLs based on salt tolerance grades, QTL-qST9 and QTL-qST10, were located on chromosomes 9 and 10, respectively. QTL-qST4-1, QTL-qSSR4 and QTL-qST10 are the new QTLs with salinity tolerance in this study. The results of the present study will lay a foundation for the cloning of salinity tolerance-related genes and molecular markers to assist in the improvement of rice varieties in terms of salt tolerance.