The effect of mycorrhizal fungi, water stress and year on flower yield and some characteristics of medicinal plant of Borage (Borago officinalis L.) in Yasouj region

Identifying the critical time and timing of plant irrigation based on a precise and basic plan is the key to water conservation, improvement of irrigation operations and plant tolerance to water shortage in agriculture. In recent years, vesicular arbuscular mycorrhizal fungi have been used in many plants to deal with dehydration and drought stress. In this regard, an experiment was conducted as split-plot in the form of randomized complete block design with 3 replications in the Yasuj region at years 2015 and 2016. Water stress was considered as the main factor in the form of irrigation after 30, 60, 90, 120 and 150 mm of evaporation from the evaporation pan class A and mycorrhizal fungus was considered as a secondary factor in the form of no application, application of Glomus mosseae and application of Glomus intraradices. The results showed that the interaction of irrigation and mycorrhizal fungi on flower phosphorus, flower yield, biological yield and water use efficiency of Borage was significant. In irrigation levels after 60, 90, 120 and 150 mm of water evaporation from the evaporation pan, the use of mycorrhizal fungi Glomus mosseae and Glomus intraradices compared to the absence of fungi respectively increased the yield of plant flowers (30.04% and 27.35 %), (90.2% and 90.98%), (93.21% and 94.1%) and (81.73% and 78.86%), also, at these levels of irrigation, biological yield and water use efficiency of Borage flower achieved a significant increase in the presence of mycorrhizal fungus, compared to the absence of mycorrhizal fungus application. Application of both strains of mycorrhizal fungus Glomus mosseae and Glomus intraradices in irrigation levels after 90, 120 and 150 mm of water evaporation from the evaporation pan compared to no application of mycorrhizal fungus, respectively, resulted in a significant increase in the harvest index of Borage flower (44.55% and 43.36%), (13.21% and 15.96%) and (5.6% and 5.41%) and flower phosphorus (44.69% and 20.45%), (150% and 125%) and ( 267.74% and 235.48%). Mycorrhizal fungus was able to moderate the negative effects of drought stress and increase the above-mentioned traits in those irrigation levels, and based on the results of this study, irrigation treatment after 90 mm of water evaporation from the evaporation pan + the use of Glomus mosseae mycorrhizal fungi is recommended.