Effects of Plant Growth Promoting Rhizobacteria on Growth Indices of Tomato

Plant growth promoting rhizobacteria (PGPR) encourage the plant growth by different mechanisms including synthesizing growth promoting hormones، phosphates solubilization، sydrophore production and nitrogen fixation. In this study، the effects of single and coinoculation of Flavobacterium، Herbaspirillum، Pseudomonas and Azotobacteron growth indices of tomato were evaluated with and without chemical fertilizer. The experiment was conducted as completely randomized design (CRD) with four replications under greenhouse conditions. The results showed that there is a significant differences between the fertilized and unfertilized soil samples. The highest mean of shoot and root dry weight observed when soil samples inoculated with Flavobacterium but the highest mean of the two above mentioned indices detected when unfertilized soil samples coinoculated with mixed strains. The highest mean of plant height، number of flowering and leaf chlorophyll content was obtained in the unfertilized soil samples that were inoculated with the mixed strains. The highest number of flowering and leaf chlorophyll content were also obtained by inoculation of fertilized soil samples with foreign Pseudomonas strain. It was concluded that inoculation of PGPR had a profound effect on the growth of tomato plant grown in unfertilized soil samples، but not in fertilized soil samples