Inoculation with Selected Microbial Consortia not only Enhances Growth and Yield of Withania somnifera but also Reduces Fertilizer Application by 25% Under Field Conditions

Abstract

Withania somnifera also known as Ashwagandha is an important medicinal plant used in ayurveda as an important rejuvenator and for treatment of various ailments. The roots are rich in withanolides, which is the active constituent of this medicinal plant. Earlier pot culture studies indicated that Bacillus licheniformis (Bl) to be the best PGPR and Aculospora laevis (Al) to be the best AM fungus and the consortium consisting of both (Bl+Al) is best for inoculating W. somnifera under glasshouse conditions. These pot culture experiments were followed by field experiment to validate the results of pot culture studies and to find out the possibility of reducing the amount of chemical fertilizer application through the inoculation of selected microbial consortia. The five treatments for the field experiment were 1) Control 2) Microbial consortia (MC) of B. licheniformis + A. laevis 3) MC+50%NPK 4) MC+75%NPK 5) 100NPK% (recommended level of NPK fertilizers for this crop. The results brought out that the plant growth, dry weight, and root yield in MC+75% was significantly high compared to control and was on par with 100%NPK treatment which suggested that the fertilizer application in W. somnifera can be reduced by 25% when applied along with the selected microbial consortia. Tracking of the inoculated PGPR in the rhizosphere soil in the field experiment was also done using molecular techniques by using species specific primer for B. licheniformis (BL1-FP and BLI-RP) which indicated the presence of the inoculated organism in the rhizosphere soil.