الفهرس 
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Abstract
Plant growth promoting rhizobacteria have positively influence plant growth performance and productivity specially under salinity stress. For this purpose, a succession of laboratory and pots experiments were designed and carried out. Under laboratory condition, one hundred and sixty-five (165) bacterial isolates were obtained and screened for their ability to grow under NaCl concentration of 2, 4, 6, 8, 10, 12, 15, 18 and 20%. Obtained data showed that all examined rhizobacterial isolates showed salt tolerance up to 6% sodium chloride. While, 70.9%, 50.9%, 31.5% and 8.5% of the examined isolates showed salt tolerance at sodium chloride concentrations of 10%, 12%, 15%, and 20%respectively. Fifty-two isolates that showed salt-tolerance at 15% sodium chloride were used for the secondary screening which was carried out to investigate the ability of chosen isolates concerning the production of indole acetic acid (IAA), gibberellins, siderophores, hydrogen cyanide (HCN) and ammonia. Moreover, phosphate and silicate solubilization were considered. from the obtained results, isolates STB6, STB121 and STB165 were chosen according to their superiority for indole acetic acid (IAA), gibberellins, siderophores, hydrogen cyanide (HCN) and ammonia production. Moreover, nitrogen fixation, phosphate and silicate solubilization were considered. The most potent isolates were identified by 16S rRNA gene sequence analysis. To study survival and vitality of PGPR strains in different carriers, compost, peat moss and sawdust were used. Peat moss and compost-sawdust (50:50%)exhibited a good capability as a carrier for the survival of the rhizobacterial strains, Paenibacillus polymyxa, Ochrobactrum intermedium and Enterobacter cloaca. Moreover, obtained results of this study indicated that the inoculation with PGPR in combination with half dose of inorganic fertilizers and humic acid or Saccharomyces extract enhanced squash and pepper growth performance and increased yield under saline stress. In view of the obtained results from the current study, it could be recommended that the inoculation of salt-affected soil with PGPR can be used as a biofertilizers and biostimulant for vegetable crops to enhance growth performance and productivity under saline stress.