Effect of Vermicompost and Fungi Inoculation on Growth Characteristics and Steviosid Content of Stevia rebaudiana Bert.

According to the importance of Stevia rebaudiana that it’s sweetener steviol glycosides, has been introduced in recent year as a natural alternative for saccharose, the evaluation of bio-fertilizers effects on growth and development of stevia is necessary. In this research the effect of vermicompost and mycorrhiza on growth traits and steviosid (ST) content in Stevia rebaudiana was studied. This research was conducted in faculty of agriculture of Tarbiat Modarres University, Tehran, Iran, through a factorial experiment based on randomized complete block design with 12 treatments and 3 replications. The first factor was different levels of vermicompost (0, 10% and 20%) in basal medium including garden soil + 15% by weight Cow manure and also garden soil alone as a control treatment. Second factor was mycorrhiza fungi including inoculation Glomus mosseae and Piriformospora indica and treatment of non-inoculated plants. The bio-fertilizers had significant effect (P≤0.01) on the studied parameters. The maximum amount of growth parameters (chlorophyll content, and fresh and dry weight of aerial parts and root) was obtained treatment of 20% of vermicompost and Glomus mosseae inoculation. The highest content of steviosid was obtained in end of vegetative growth stage and control treatment. Application of vermicompost significantly improved the chlorophyll content and growth traits and also the highest their amounts were obtained in combination treatment of vermicompost and mycorrhizal inoculation.