KAUR, MOHINDERKUMARI, MANORMA2016-12-262016-12-26201347889http://krishikosh.egranth.ac.in/handle/1/92863ABSTRACT In the present study, isolation and characterization of indigenous fluorescent Pseudomonas strains from normal and replant site of apple orchard (Shimla H.P.) was done. Root colonizing bacteria that exert beneficial effects on plant development via direct or indirect mechanisms have been defined as plant growth promoting rhizobacteria (PGPR) The aim of the study to select and to develop PGP strains of fluorescent Pseudomonas species having efficient root colonizing capacity with direct and indirect plant growth promoting activities for management of replant problem of apple. The fourteen Pseudomonas species isolates were screened out for various plant growth promoting activities like siderophores, phosphate solubilization, antifungal activity, plant growth regulators (auxins, cytokinins and gibberellins), lytic enzymes and production of HCN and ammonia. On the basis of PGPR activities, nine isolates were genotypically characterized by RAPD and 16S rRNA gene sequencing. Out of them, two best isolates (Pn-13-San and An-16-Kul) were selected for 16S rRNA gene sequencing. Pn-13-San showed 99% homology with Pseudomonas aeruginosa M18 with accession number (NC_017548). An-16-Kul showed 99% homology with Pseudomonas aeruginosa PAO1 with accession number (NC_002516.2). These two strains exploited for the management of replant problem of apple in replant site at Maggota (Shimla). In replant field these two strains used individually and their consortia for treatment of apple rootstocks before planting. The performance of apple plants was much better in terms of root colonization capacity, plant establishment and increase in plant growth in terms of plant height, number of nodes and branches, chlorophyll content of leaves and NPK of rhizosphere soil over their respective control after nine and twenty months of plantation. These strains can be further exploited for management of replant problem of apple after conducting few more field trials in replant sites and can have great importance in the field of horticulture.enThesis