Development of effective bio-inoculants for organic cultivation of Cymbopogon martini (Palmarosa)

Cymbopogon martini, a commercially valuable medicinal and aromatic plant used widely in the industries of perfumery, toiletry and pharmaceutics. To avoid the negative impacts of chemical fertilizers on its metabolic composition and soil fertility, application of plant growth promoting rhizobacteria (PGPR) may be an ecological solution to increase its productivity. However, such studies are rare. We report the effect of native PGPRs trains Pseudomonas protegens RPB1 and two strains of Bacillus paramycoides RPB2 and RPB3 which were isolated from rhizosphere of the aromatic grasses of Lucknow region. The isolated PGPRs have been identified and characterized for their PGP activities e.g., production of indole acetic acid, ammonia, HCN, siderophore and solubilization of phosphate in in vitro cultures. The growth and productivity of C. martinii and its oil yield were found maximum in plants treated with consortium of all three PGPRs as compared to the single and consortium of two rhizobacteria.