Screening of suitable salt concentration and evaluation of salt tolerance during the germination period of foxtail millet

Objective Screening suitable NaCl salt solution concentrations for salt tolerance evaluation during the germination stage of foxtail millet, and to establish a method for salt tolerance evaluation during the germination stage of foxtail millet.

Methods Ten different varieties of foxtail millet were subjected to salt stress using NaCl solutions at four concentrations (100, 150, 200, and 250 mmol/L). Germination potential, germination rate, germination index, vitality index, radicle length, plumule length, and fresh weight were used as evaluation indicators to screen the NaCl salt solution concentration for salt tolerance evaluation during foxtail millet germination. The membership function method was further applied to comprehensively evaluate the salt tolerance of each variety under the selected NaCl solution concentration.

Results Under the salt stress of a 150 mmol/L NaCl salt solution, 40% of the varieties showed significant or extremely significant differences in germination rate compared to the control; more than 80% of varieties show significant or extremely significant differences in germination potential, germination index, vitality index, radicle length, plumule length, and fresh weight compared to the control. The D value of Longgu 13 is 0.922, and the D value of Tiansu G12 is 0.270.

Conclusion 150 mmol/L NaCl salt solution can be used for evaluating salt tolerance during the germination stage of foxtail millet; among the 10 varieties of foxtail millet, Longgu 13 has the strongest salt tolerance, while Tiansu G12 has the worst.