Abstract: A sand culture experiment with Hoagland solution plus NaCl and Na₂CO₃ was conducted to study the responses of sorghum seedlings to salt-alkaline stress. An assessment method for identifying the salt-alkaline tolerance of sorghum at  seedling stage was established, and the salt-alkaline tolerance of 66 sorghum genotypes was evaluated. At the salt concentrations 8.0-12.5 g·L^-1, there was a great difference in the salt-alkaline tolerance between tolerant genotype ‘TS-185’ and susceptive ‘Tx-622B’, suggesting that this range of salt concentrations was an appropriate one to evaluate the saltalkaline tolerance of sorghum at  seedling stage. At the salt concentrations 10.0 and 12.5 g·L^-1, there existed significant differences in the relative livability, relative fresh mass, and relative height among the 66 genotypes, indicating a great difference in the salt-alkaline tolerance among these genotypes. The genotype ‘Sanchisan’ was highly tolerant, 16 genotypes such as ‘MN-2735’ were tolerant, 32 genotypes such as ‘EARLY HONEY’ were mild tolerant, 16 genotypes such as ‘Tx-622B’ were susceptive, and genotype ‘MN-4588’ was highly susceptive to salt-alkaline stress. Most of the sorghum genotypes belonging to Sudangrasses possessed a high salt-alkaline tolerance, while the sorghum genotypes belonging to maintainer lines were in adverse.

Key words: sorghum, germplasm, salt-alkaline tolerance, seedling stage.