Effects of salt stress on seed germination and yields of four forage species

In order to make rational use of saline land, promote the industrialization of Sorghum bicolor (sweet sorghum), Medicago sativa (alfalfa), Avena sativa (oat) , and × Triticosecale Wittmack (triticale), and meet the selection needs of farmers, this study investigated the effects of different concentration gradients of NaCl (0, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1.0%) on the germination and yields of four different forage species using a salt ponding test on filter papers and in a saline-alkali soil. The results showed that the relative germination potential, relative germination rate, and germination index were inhibited with the increase of salt concentration. The relationship between the relative germination potential or relative germination rate and salt concentration was hyperbolic. By calculating the half-lethal salt tolerance, sweet sorghum seeds were found to have the best salt tolerance during germination, followed by alfalfa, triticale, and oats. The results of the salt-ponding test showed that, with an increase in salt concentration, the fresh and dry weight yields per hectare of triticale, sweet sorghum, and oats showed overall downward trends. When the NaCl concentration increased to 0.2%, the fresh weights of sweet sorghum and triticale were significantly lower compared with the corresponding control treatments. When the NaCl concentration was 0.3%, the fresh weight of oats was also significantly lower compared with the control treatment. This study on the germination characteristics and yields of four forage grasses under different concentrations of NaCl provides a better understanding of the salt tolerance of the forage grasses as well as guidance for further variety improvement.