Identification of salt tolerance of different Chinese kale cultivars under NaCl stress at seedling stage

In order to understand the salt tolerance of different Chinese kale varieties at seedling stage and screen out the varieties with strong salt tolerance at seedling stage, the seeds of 26 Chinese kale varieties were used as materials. The growth indexes, physiological indexes, seedling rate and salt damage index of different Chinese kale varieties were compared and cluster analyzed by means of tissue culture. The results showed that: (1) under 160 mmol∙L−1 NaCl stress, the different Chinese kale varieties at growth indexes, physiological indexes, seedling rate and salt damage index were significantly different, the relative seedling rate of R4, R14 and R32 reached 100.00%, and the salt damage index was the lowest, which was 20.00%; The correlation analysis showed that the relative seedling rate, the relative content of soluble protein, the relative content of soluble sugar and the relative value of Leaf SPAD were all negatively correlated with the salt damage index, and the relative conductivity and the relative content of malondialdehyde were all positively correlated with the salt damage index. (2) The average value of 14 salt tolerance indexes was used to cluster analyze the salt tolerance of 26 Chinese kale varieties. The tested materials were divided into four categories: high salt tolerance, moderate salt tolerance, low salt tolerance and salt sensitivity. R14, R25, R30 and R32 were highly salt tolerant varieties and R24 was salt sensitive varieties, which laid a foundation for further breeding and genetic research of salt tolerant varieties.