Evaluation of Endophytic Bacterial Strains Isolated from Healthy Tomato for Growth Promoting and the Ability of IAA Production in Majority Isolated Groups

Application of endophytic bacteria to induce plant growth and avoid of hazardous chemical compounds is very important. The aim of this study was searching for the most effective tomato endophytic bacteria. A total of 70 endophytic bacterial strains were isolated from healthy strong tomato plants in flowering stage. Primary screening results in a completely random design indicated significant differences among the strains in 1% level. The most effective strains increased height 1.44 and the fresh weight 2 times. Fourteen strains were applied in greenhouse in a completely random design, plants harvested after 35 days, their height and weight were recorded and analyzed. Results revealed significant differences in 1% level among the tested strains which the most effective one increased the tomato height 1.54 and tomato fresh weight 1.75 times. We observed the strong correlation between the obtained DATA from two experiments. The level of produced IAA by bacteria ranged from 0 ug/ml to 318 ug/ml in a medium contains tryptophan by spectrophotometer. The most active bacterial strains to promote tomato growth were identified ad Pseudomonas fluorescence and Bacillus subtilis.