Evaluation of salt-tolerant germplasm and screening of the salt-tolerance traits of sweet sorghum in the germination stage

Soil salinity is one of the major abiotic stresses that reduces agricultural productivity and affects large terrestrial areas around the world. Germination is the starting point of the growth and development process of all crops, and it is severely affected by salt stress. Sweet sorghum (Sorghum bicolor (L.) Moench.) is one of the most promising crops that has a relatively high salt tolerance and biomass. However, few studies have evaluated the salt tolerance or screened the reliable evaluation traits of sweet sorghum. In this study, the membership function value of five traits was used as a comprehensive index for the evaluation and selection of salt tolerance in 300 sweet sorghum germplasms. After salt tolerance evaluation, 23 highly salt-tolerant, 38 salt-tolerant, 195 moderately salt-tolerant, 38 salt-sensitive and 6 highly salt-sensitive germplasms during the germination stage were screened. Moreover, the germination index under the 200 mM NaCl treatment showed the highest correlation with salt tolerance during the germination stage. This information can be used for effectively evaluating sweet sorghum during the germination stage. These results are important for the evaluation of the salt tolerance of sweet sorghum germplasms during the germination stage.