Evaluation of salinity tolerance of different clover species at germination and seedling stages

In order to study the effects of salinity stress on growth indices of three clover species including, Trifolium resupinatum, T. alexandrinum, and T. incarnatum, an experiment was conducted as factorial based on a completely randomized design arrangement with three replications. Factors included seven levels of salinity stress (0, 41, 82, 123, 164, 205, and 246 mM) and three clover species. Different performance was observed for germination and seedling parameters among the species. In addition, results indicated significant differences among the treatments in all traits and showed that the effects of salinity on all traits were the same at low-stress levels (0 and 41 mM), but differed at higher stress levels. The experimental results revealed that with an increase in salinity level, the greater reduction was observed in vigor index, seedling length, and root and shoot fresh and dry weight while MGT and GU increased. The highest levels of vigor index and root and shoot fresh and dry weight was related to T. resupinatum and T. incarnatum, respectively, while MGT and GU in T. resupinatum were higher than those of the other two species. In addition, T. resupinatum seedling length was higher than the other two species.