Response of some sorghum varieties to GA3 concentrations under different salt compositions

Germination is a very sensitive stage for the harmful effect of salinity stress. Plants respond differently to different types of salt. Gibberellic acid (GA(3)) is the most important hormone to mitigate salt stress. A controlled germination study was conducted to evaluate the impact of different salts (0, 150 mM NaCl, and 150 mM Na2SO4) and different GA(3) concentrations (0, 50, 100, 250, and 300 mg L-1) on the germination of the two most used Sudanese sorghum (Sorghum bicolor [L.] Moench) varieties Wadahmed and Tabat. The studied parameters were seed water uptake after 8 h imbibition, germination percentage, germination rate, shoot and root length, shoot and root fresh weight, shoot and root dry weight, and seed vigor index. Results showed that Na2SO4 reduced germination percentage, germination rate, shoot length, root length, root fresh weight, shoot dry weight, root dry weight, and seed vigor index by 17.0%, 50.0%, 86.99%, 89.03%, 76.8%, 54.5%, 66.6%, and 89.7%, respectively, when compared with the non-saline treatment. The maximum values for seed water uptake, germination percentage, germination rate, shoot length, and seed vigor index were achieved at 100 mg L-1 GA(3). The Na2SO4 salt had a more harmful effect than NaCl. The 100 mg L-1 GA(3) concentration can be recommended to improve seed water uptake, germination parameters, and seedling growth under salt stress in the two Sudanese sorghum varieties (Wadahmed and Tabat). 'Wadahmed' was more tolerant to salinity stress than 'Tabat' at the germination stage.