Fast identification method of salt-tolerance and research on salt-tolerance at different stages of soybean cultivars

To search the simple identification method of salt tolerance in soybean cultivars and understand soybean cultivars response to salt tolerance at different stages,80mmol/L salt solution was used to identify salt tolerance in 99 soybean cultivars from seed germination.The results showed that 72h germination percentages with80mmol/L salt solution soaking could be used as a method in salt resistance identification and screening.The root length,number of branch root,dry weight and fresh weight of roots were closely correlated with the salt tolerance after seed germination.Soybean cultivars were the most sensitive to salt stress at seeding stage.The salt-sensitive cultivars cannot grow seedlings with 80mmol/L salt solution and this period is also important for understanding salt tolerance of soybean cultivars.At vegetative stage(V2 and V4),the height and biomass of plant were decreased significantly under salt stress.Salt tolerances were the greatest and biomasses had the least decrease at R2 and R4stages.Salt stress showed the greatest damage to the plant at R6 stage,namely leaf abscission and premature aging.The salt tolerance of germination period was consistent with that of late growth of plants.Germination percentage of germination period can be used to identify salt tolerance of soybean plants.