Investigating the Use of Mycorrhiza and Trichoderma Fungi on Rhizome Yield and Active Ingredients of Ginger

Introduction Ginger (Zingiber officinale) is a perennial and monocotyledonous medicinal and spice plant, whose rhizome, essential oil and extract are of interest, and this plant has wide uses in various industries. The origin of ginger is Southeast Asia and possibly India. This plant is mainly cultivated as an annual and the rhizome or the underground stem is the used part. It should be noted that the use of biological fertilizers can improve the growth and yield of plants and is also the most natural and best way to keep soil systems healthy. In addition, benefiting from natural solutions instead of using chemicals reduces pollution and destruction of biological resources. The use of Arbuscular mycorrhizal and Trichoderma fungi can leads to a reduction in the consumption of fertilizers and fungicides and an increase in yield, and also reduces production costs and is compatible with environmental principles. Therefore, the main purpose of this study was to investigate the effects of Trichoderma harizanum, mycorrhiza (Glomus etunicatum and G. fasciculatum) and the combined treatment of fungi (G. etunicatum + T. harizanum, G. fasciculitum + T. harizanum) on the growth parameters, rhizome yield and active substances of ginger.   Materials and Methods This research was conducted as a factorial experiment based on a completely random design in the research greenhouse of the Faculty of Agriculture, Tarbiat Modares University. The rhizomes were transferred to the greenhouse and cultivated in pots with amended soil. These plants were inoculated with Trichoderma (T. harizanum), Mycorrhiza (G. etunicatum and G. fasciculatum) and combined treatment of fungi (G. etunicatum + T. harizanum, G. fasciculatum + T. harizanum). During the growing season and harvesting, the morphological characteristics and rhizomes yield were evaluated, and then the essential oil content and composition, the amount of fiber and the color of the rhizomes and precisely. The effect of treatments on ginger stem traits contains: Stem Fresh Weight (g), Stem Dry Weight (g), Number of Stems and Stem Length (cm), Leaf Traits contains: Leaf Dry Weight (g), Leaf Fresh Weight (g), Number of Leafs, Greenness Index, Rhizome Traits contains: Rhizome Dry Weight (g), Rhizome Fresh Weight (g), Darkness/Lightnees Indicator, Yellow/Blue Indicator, Rhizome Crude Fiber (%), Essential oil Traits contains: Essential oil Percentage, Essential oil Yield were investigated. Abbreviation of treatments include contains: Control, M1 (G. fasciculatum), M2 (G. etunicatum), T1 (T. harizanum), M1T1 (G. fasciculitum + T. harizanum) and M2T1 (G. etunicatum + T. harizanum).   Results and Discussion The results showed that the inoculation with G. etunicatum had the highest value of stem length (35.68 cm), fresh and dry weight of the stem (22 and 10.2 g), Spad index (18.17), fresh and dry weight of leaves (34.46 and 8.96 g), number of leaves (9.46) and fiber content of rhizome (4.28%). Also, the highest number of stems, darkness/brightness index and yellow/blue color index of rhizome were observed in the control treatment with values of 7.16, 73.29 and 98.6 respectively. The highest fresh and dry weight of rhizome (35.5 and 5.2 g) were observed in the inoculation with G. fasciculitum treatment and the highest percentage of essential oil (0.4) was observed under the combined treatment of the inoculation with G. etunicatum. Camphene, 1,8-cineole, neral and geranial were identified as the main compounds of essential oil and the amounts of these compounds in the inoculation treatment with fungi were more than the control. In general, this research showed that the inoculation of rhizomes with G. etunicatum resulted in achieving the desired growth characteristics, rhizome yield and active substances in ginger. Camphene, 1,8-cineole, neral and geranial were identified as the main compounds of essential oil and the amounts of these compounds in the inoculation treatment with fungi were more than the control.   Conclusion In general, this research showed that the inoculation of rhizomes with G. etunicatum resulted in achieving the desired growth characteristics, rhizome yield and active substances in ginger.