Arbuscular mycorrhizal fungi as a promising strategy to enhance root architecture in durum wheat (Triticum durum Desf.) cultivars under salinity stress

Abiotic stress from salinity poses a significant challenge for crop plants, significantly impairing their growth. This study included three experiments: the first focused on evaluating the germination parameters of four durum wheat varieties under various salinity levels. The treatments involved four varieties (Shabrang, Taban, and lines D-98–8 and D-98-10) tested with NaCl solutions at nine salinity levels (0, 2, 4, 6, 8, 12, 16, 18, and 20 dS/m). The second experiment assessed seed cell membrane permeability to differentiate between salt-sensitive and salt-tolerant cultivars. The third examined the role of arbuscular mycorrhizal fungi in enhancing salt tolerance in both cultivars. The same four durum wheat varieties were used in the second experiment. The third experiment involved two durum wheat varieties (the salt-tolerant Shabrang and the salt-sensitive D-98-8), nine NaCl salinity levels, and inoculation with the fungus Funneliformis mosseae. Results from the first experiment showed that salinity stress reduced germination parameters across all cultivars, with a greater decline in the D-98–8 line. Additionally, the seed electrical conductivity test from the second experiment indicated that salinity tolerance in durum wheat was linked to lower cell membrane permeability. The Shabrang cultivar demonstrated the lowest permeability and leakage, while D-98–8 exhibited the highest. Therefore, both experiments identified Shabrang as salinity-tolerant and D-98–8 as salinity-sensitive. The third experiment showed that introducing mycorrhizal fungi increased root phosphate levels and improved root structure under saline conditions, with more pronounced effects in the salinity-tolerant cultivar.