Abstract:The tillering stage is the key period for the transition of rice from nursey to paddy. The salt tolerance at the tillering stage becomes of importance when planting rice in salinized soil. Establishment of an optimal strategy is thus of interest in order to identify the rice germplasms that show salt tolerant. This study attempted to determine the optimal salt concentration and the duration of treatment at the tillering stage. By using 26 rice varieties with the levels of salt tolerance, we conducted the experiments with the gradients of salt concentration (10 and 7 in 2015 and 2016, respectively). The salt injury score was deployed as an index for evaluating salt tolerance at the tillering stage. The results showed that, when applied with the salt concentration of 0.5%, salt injury score between varieties showed the largest difference after salt treatment about 4-6 weeks. This pipeline was considered to be optimal in order to examine for rice salt tolerance. On the contrast to the evaluation standard of salt tolerance of rice at the tillering stage that was proposed by international rice research institute (IRRI), this study proposed a updated method for evaluating the salt tolerance of rice at the tillering stage, especially by using a single plant as a unit and deploying the average salt injury score to evaluate the salt tolerance. By taking use of the aforementioned pipeline, this study carried out a three-year evaluation (2017 to 2019) in 2886 rice accessions that were collected from different ecological regions. As a result, 137 rice accessions showing salt-tolerant were identified, which might provide elite resource to support the genetic improvement and breeding research for rice salt tolerance.