Yield, irrigation water productivity and nutrient uptake of arbuscular mycorrhiza inoculated sesame under drought stress conditions

According to yield evaluations performed in drought stress experiments, soil microorganisms have been considered sustainable solutions to reduce drought stress damage and enhance crop production in drought-prone regions. Thus, a two-year experiment was conducted to evaluate the impacts of sesame (Sesamum indicum L.) root colonization by two mycorrhizal fungal species (i.e., Rhizophagus intraradices and Funneliformis mosseae) under various irrigation regimes on nutrients uptake, grain yield, seed oil content and irrigation water productivity. The experiment was conducted at Seed and Plant Improvement Institute, Karaj, located in the semi-arid region of Iran, during the 2017 and 2018 growing seasons. Drought stress was induced at moderate and severe water shortage levels through irrigation after 65% and 85% available water depletion, and irrigation after 45% available water depletion was regarded as normal irrigation (no stress). Despite drought stress, mycorrhizal inoculation resulted in higher grain yield and seed oil content than noninoculated sesame. F. mosseae-inoculated plants had remarkably higher grain yield under each irrigation treatment than R. intraradices-inoculated or noninoculated plants. Although leaves and seeds N percentage was reduced due to drought stress, it was enhanced by mycorrhizal fungi, especially when plants were inoculated with F. mosseae. Moreover, the F. mosseae-inoculated plants showed the greatest P percentage in the leaves and seeds. The results revealed that different arbuscular mycorrhizal fungi (AMF) species have distinct effects on sesame performance even within the same genus. The results indicated that F. mosseae better supports sesame and is more effective under drought stress. Therefore, the use of this microorganism could be critical in the farming of sesame under semi-arid and arid conditions, where water is the main factor in determining crop yield. •With increasing stress intensity, mycorrhizal colonization rate decreased.•Greatest colonization rate was found in the F. mosseae-inoculated roots.•Leaf and seed P content in inoculated sesames was fewer affected by drought stress.•Mycorrhizae-inoculated sesames produce higher yield compared to the control.•F. mosseae was a more efficient symbiont for enhancing sesame drought resistance.