Plant growth promoting bacteria Bacillus subtilis promote growth and physiological parameters of Zingiber officinale Roscoe

Ginger (Zingiber officinale Roscoe) is an important medicinal crop grown for its aromatic rhizome which is used as a spice, food, flavouring agent and medicine. It has been characterised for its hypoglycemic, hypotensive, antioxidant and antibiotic properties. This study was conducted to determine the impact of plant growth-promoting potential of bacterial strain Bacillus subtilis L2 on plant growth and physiological properties of ginger. The experiment was carried out in randomised block design with three replications in pot experiments. The plants were grown in greenhouse conditions for three months. The results showed that at 8 and 12 weeks after planting (WAP) bacterial inoculation increased plant height, leaf length, number of leaves per plant and leaf width. Inoculation with B. subtilis L2 significantly increased plant height by 16, 20 and 18% compared to control at 4, 8 and 12 WAP. At 8 and 12 WAP, leaf length significantly raised by B. subtilis L2 as compared to uninoculated control. B. subtilis L2 significantly increased the number of leaves per plant and leaf width by 30 and 21% respectively when comparing with non-inoculated plants at 8 WAP. The percentage increase in chlorophyll content resulted from the inoculation with B. subtilis L2 over the control was 10.5%, 15.5% and 18.4% at 4, 8 and 12 WAP respectively. It is concluded that there is a significant positive effect of inoculation with B. subtilis L2 on the growth of ginger. B. subtilis L2 strain can be used as a potential agent or bio-fertiliser for stimulation of ginger growth