Survey on efficiency of inoculation methods of Pseudomonas fluorescens on growth and yield of Thymus kotschyanus

Thyme is one of the most important medicinal plants in wild rangeland in Iran that has lots of benefits. Pseudomonas flourescence is one of the effective plant growth promoting bacteria (PGPR) as a bioinoculant for medicinal plants. This study aims to survey three inoculation techniques with PGPR on growth and oil content in Thymus kotschyanus for organic cultivation. For this research, an experiment was conducted in Randomized Complete Block Design at Research Institute Forest and Rangelands, Tehran, Iran, with four treatments and three replications. In the first method, thyme seed was treated in liquid bacterial suspension for 3 h, in the second method bacterial suspension injected around the root before cultivation in farm and in the third method both seed and root have been treated by the bacterial suspension. In all three methods of inoculation of P. fluorescence, an increase in growth and the amount of essential oil was determined. The highest amount of root volume (30 mL) compared to the control (15 mL) was significant at the level of P=0.05 and the highest amount of essential oil (1.74%) was obtained by using the third inoculation method. It could be concluded that the microbial inoculation method has a great influence on the yield of T. kotschyanus and bacterial inoculation of seeds and roots had a greater effect, rather than inoculated separately for organic cultivation.