Impact of drought and salinity stress on early growth of tropical wheat cultivars

Resumen

The use of tropical wheat cultivars adapted to adverse environmental conditions is essential to ensure optimal development and yield of the crop, especially considering recent climate change. In this study, the impact of water and salt stresses on germination and early plant growth of 11 Brazilian tropical wheat cultivars was investigated under laboratory conditions to identify the genotypes most adapted and tolerant to drought and salinity conditions. Wheat plants were grown for 12 days at 25 °C under non-stressful (control) and simulated drought and salinity stress conditions with –0.30 MPa iso-osmotic solutions prepared with polyethylene glycol (151.40 g L^–1 PEG 6,000) or sodium chloride (3.536 g L^–1 NaCl), respectively. The germination, growth rate and dry matter accumulation of the plants were measured and then the drought and salinity tolerance indices were calculated. The results showed that the cultivars exhibited differential responses to the applied stresses. Germination was not significantly affected, except for the cultivars Biotrigo Valente (78%) under salinity and ORS FEROZ (75%) under water deficit. The water stress tolerance index indicated that TBIO Sintonia and TBIO Calibre were the most tolerant cultivars, while Biotrigo Valente and ORS FEROZ showed greater sensitivity. Under no salt stress, TBIO Convicto exhibited the highest resilience, while Biotrigo Valente was defined as susceptible. The ranking and clustering analyses demonstrated high clarity between the methods, confirming their efficiency in selecting genotypes adapted to adverse conditions. The results indicate that selecting tolerant cultivars can contribute to wheat adaptation in regions subject to water and salt stresses, enabling greater productive stability in challenged environments.