Response to Salt Stress and Salt Tolerance Identification in Different Turnip Varieties

To achieve precise identification of the salt tolerance of turnips, a systematic screening system was established. This study assessed 18 salt-related indicators, including growth indices, osmoprotectants, antioxidant systems, and salt tolerance indices, by applying a 200 mmol/L NaCl + Na 2 SO 4 composite salt stress to turnip seedlings. Using mixed linear models to calculate random effect values, the study obtained the best linear unbiased prediction values for the salt tolerance of turnip germplasm. This was combined with a salt tolerance coefficient membership function for comprehensive analysis, enabling the selection of salt-tolerant turnip varieties and the establishment of a systematic turnip salt-tolerant germplasm screening system. The findings will provide a scientific basis for the rapid screening of salt-tolerant germplasms. The results indicated that total chlorophyll content, malondialdehyde content, fresh weight, dry weight, stem diameter, leaf width, and relative electrical conductivity could serve as key indicators for salt tolerance evaluation. Based on these indices, 30 turnip varieties were classified into three types: 11 were identified as salt-tolerant at the seedling stage, 14 as moderately salt-tolerant, and five as salt-sensitive. Among them, variety W12 exhibited the highest salt tolerance, whereas W17 was the most sensitive to salt stress.