Salinity hinders plant growth and decreases the yield of crops. Specific plant growth promoting rhizobacteria produces salicylic acid (SA) in significant amounts. The use of these bacteria is an environmentally friendly technique to counteract salinity stresses and play a key role in pathogens attack. In this study, the efficacy
of eight bacterial strains of Rhizobium leguminosarum bv. viciae (441 & 207), R. leguminosarum bv. trifolii (100 & 103), Bacillus polymyxa, Bacillus megaterium, Pseudomonas fluorescens and Azotobacter chroococcum were tested in vitro for SA production. Upon this test, A. chroococcum and P. fluorescens were nominated for further experiments. Both selected strains were tested for SA production as well as their in vitro diseases control effectiveness by using the extracts of some waste materials. The results indicated that the extract of onion skin and banana peels produced the maximum amounts of SA in A. chroococcum and P. fluorescens. Moreover, P. fluorescens grown on extracts of onion or banana waste materials in vitro restricted the mycelia of Fusarium solani and Sclerotinia sclerotiorum and exhibited an antagonistic effect with a high PIRG (Percent Inhibition of Radial Growth) of 53.85 and 58.97 % respectively against F. solani and 66.5 and 65.52 % respectively in case of S. sclerotiorum. Field experiments outcomes revealed that adding of A. chroococcum + P. fluorescens based on onion skin extract was the most successful treatment in raising some growth and yield parameters in comparison with other rice (Oriza sativa cv. Sakha 101) treatments grown under saline soil.