Comparison of osmotic stress tolerance in two durum wheat (Triticum durum Desf) cultivars during germination

Drought represents a significant abiotic stress affecting crops, particularly cereals, with severe impacts in arid and semi-arid regions. To mitigate the effects of rainfall deficiency and a poor spatio-temporal rainfall distribution, it is crucial to manage available water resources efficiently and utilize drought-tolerant plant varieties.

This study aimed to compare the impact of osmotic water stress, induced by polyethylene glycol (PEG₆₀₀₀), on the germination of two durum wheat (Triticum durum Desf) cultivars: Mohamed Ben Bachir and Oued El Bared. Two concentrations of PEG₆₀₀₀ (10% and 20%) corresponding to osmotic potentials of -1.37 bars and -4.64 bars, respectively, were employed to evaluate the tolerance of these varieties to water stress. The seeds were germinated at 25°C in the dark for seven days.

The results showed that osmotic water stress significantly reduced the germination parameters (germination rate and speed, germination index, and vitality index) and the initial growth parameters (fresh biomass, seedling length, roots, and coleoptiles) for both varieties, with variations in tolerance depending on the stress intensity. At a moderate concentration of PEG₆₀₀₀ (10%), both varieties showed a similar reduction in their germination and growth parameters. However, at a higher concentration of PEG₆₀₀₀ (20%), the Oued El Bared variety exhibited a more marked reduction in the parameters studied, indicating greater sensitivity compared to the Mohamed Ben Bachir variety, which demonstrated greater tolerance to severe water stress.

In conclusion, the durum wheat variety Mohamed Ben Bachir shows remarkable tolerance to severe osmotic stress, whereas the Oued El Bared variety is particularly sensitive. These findings highlight the importance of selecting varieties adapted to water stress conditions to optimize cereal production in drought-prone areas.