Evaluation of the role of mycorrhiza varities on drought tolerance in Hypericum perforantum

Dehydration has become the most important factor in reducing the growth and yield of crops in recent decades, while a number of simple and inexpensive operations can reduce the impact of dehydration on plants and increase plant growth and yield. The aim of this study was to investigate the effect of different levels of irrigation (irrigation after 70,100,130 and 160mm evaporation from pan class A) and application of mycorrhizal treatments (no Application of mycorrhizal fungus, application of Glomus mossae, Glomus Hoei, Glomus intraradise and application of all three species of mycorrhizal fungi on the growth and yield of St. John's wort and its physiological characteristics were performed. This study was carried out in two cropping years in the fields of Tabriz Azad University as a split plot based on a randomized complete block design. Based on the results of this study, the highest essential oil yield with 13.45 g was obtained in the treatment of application of all three species of mycorrhizal fungi + irrigation after 100 mm evaporation from pan class A. The treatment of application of all three species of mycorrhizal fungi had the greatest effect on dry weight and percentage of essential oil of St. John's wort. Due to the results and the importance of essential oil yield, reducing irrigation water to irrigation 100 mm in the class A pan and applying a mixture of mycorrhizal treatments, can increase the essential oil yield in the climatic conditions of the study area.