Localization of salt-tolerant QTL in rice germination stage under different salinity concentrations

Salt stress is an important abiotic stress, which has seriously affected the reproductive development of rice in many parts of the world. Therefore, it is particularly important to understand the genetic mechanism of salt tolerance in rice. In this study, we preliminarily located some quantitative trait loci (QTL) for root length, bud length, and survival percent under different salinity conditions (0, 100, 200 and 400 mM NaCl), using a population of chromosome segment substitution lines (CSSLs) constructed by Nipponbare and 9311. A total of 18 QTLs were identified, which explained the phenotypic variation of 4.76-37.59%, among which 13 QTLs were detected under salt stress condition. These salt tolerance related QTLs were divided into two categories, QTL expressed both under control and salt stress conditions (qSP3, qBL8), and QTL expressed just under salt stress condition (qBL3, qRL3, qSP4, qRL5, qSP7, qSP9, qRL10, qBL11-1, qRL11-1, qRL11, qSP12). qSP3, qSP4, qRL5, qSP7, qRL10, qRL10-1, qRL11, qRL11-1, qBL11, qBL11-1 and qSP12 were reported to be related with salt stress for the first time. These QTLs identified under salt stress may be valuable genetic factors for improving salt tolerance of rice by molecular markers technology, which will help to further understand the genetic mechanism of salt tolerance of rice.