Evaluation for Salt Tolerance of Hemp at Germinating and Seedling Stages and Selection of Salt Tolerance Indices

The salt tolerance at germinating and seedling stages of seven hemp cultivars under different concentrations of NaCl was studied by cluster analysis, based on the subjection values of different indices and the sum subjection value. The results showed that the appropriate concentration of NaCl for the evaluation of salt tolerance was 140 mmol/L. The salt tolerance of hemp differed with growth stage and among cultivars. Yunma No.5, Harbin Hemp and Jinma No.1 were salt-tolerant, Wandama No.1, Longma No.1 and Yunma No.1 were moderately salt-tolerant, while Bamahuoma was salt-sensitive at germinating. Relative germination potential and relative root length could be used as the parameters for evaluation of salt tolerance at germinating stage. For the seedling stage, Bamahuoma was salt-tolerant, Yunma No.1, Yunma No.5, Longma No.1 and Harbin Hemp were moderately salt-tolerant, Wandama No.1 and Jinma No.1 were salt-sensitive. Relative dry mass of shoot, relative activity of peroxidase and relative content of malondialdehyde were suggested for assessment of salt tolerance at seedling stage.