Evaluation of some root growth traits and activity of enzyme and nonenzyme antioxidants of different cultivars of durum wheat (Triticum turgidum var. durum) effected by phosphorous fertilizer and mycorrhizal fungi in rainfed condition

In order to evaluate the effect of mycorrhizal fungi and phosphorous fertilizer on some root growth traits and activity of enzyme and nonenzyme antioxidants of durum wheat in rainfed conditions, an experiment was carried out as factorial based on a randomized complete block design with three replications at Sarableh Agricultural Research station during growing season 2018-2019. Four cultivars of durum wheat (Dehdasht, Zahab, Savarz and Saji) as the first factor and five levels of fertilizer source (control, 25 and 50 kg.ha-1 P, mycorrhizal fungi (GM), mycorrhizal fungi + 25 kg.ha-1 P) as the second factor were considered. The average comparison results of simple effects indicated that Zahab and Saji cultivars among cultivars and combination treatment of mycorrhizal + 25 kg / ha P and then 50 kg / ha P had the greatest effect on improving the studied traits. The interaction effect of cultivars and fertilizer sources revealed that the combined use of phosphorous fertilizer and mycorrhizal fungi had better results compared to their use alone. So that, the highest fresh and dry weight, length density, and root water content and activity of ascorbate peroxidase, peroxidase, catalase, superoxide dismutase and glutathione synthetase was obtained in combined treatment of mycorrhizal and phosphorus fertilizer at Zahab and Saji cultivars. However, the lowest specific root length, and malondialdehyde and hydrogen peroxide activity were obtained in the same treatment and cultivars. In general, the results showed that inoculation with mycorrhizal fungi in rainfed conditions, especially in Zahab and Saji cultivars, in addition to reducing the application of phosphorus fertilizer can improve root growth characteristics and activity of enzyme and nonenzyme antioxidants. As a result, it reduces the peroxidation of membrane lipids (the decline in production of malondialdehyde and hydrogen peroxide) and increases drought stress tolerance.