Effect of chitinolytic PGPR on growth, yield and physiological attributes of banana (Musa spp.) under field conditions

Plant growth promoting effects of two Pseudomonas fluorescens strains, CHA0 and Pf1 were tested alone or in combinations with chitin on banana cv.Virupakshi (Musa app. AAB) in terms of growth, yield, leaf nutrient contents and physiology in lower Pulney hills, Western Ghats, India under rainfed field conditions. The P. fluorescens strains, CHA0 and Pf1 were tested for their efficiency to produce chitinases in the presence of chitin molecules. Bio-formulations containing PGPR strains and chitin molecules were further developed to improve the chitinolytic activity of the rhizobacteria. The bio-formulations amended with chitin, viz., CHA0+ chitin significantly increased the height and girth of pseudostem, bunch yield, number of hands per bunch, fingers per hand and quality attributes compared to other treatments both in plant as well as ratoon crops. Further, the application of CHA0+ chitin significantly improved the N, P and K contents of banana leaves when compared to untreated control. These results revealed that P. fluorescens strain, CHA0 in combination with chitin has the potential to increase growth, leaf nutrient contents and yield of banana plants under perennial cropping systems. In view of environmental pollution, due to excessive use and high production costs of fertilizers, PGPR strains tested in our study have a potential to be used for sustainable and environmentally friendly horticultural production. (C) 2010 Elsevier B.V. All rights reserved.