Promoting Common Bean Growth and Nitrogen Fixation by the Co-Inoculation of Rhizobium and Pseudomonas fluorescens Isolates

1 Young Researchers Club, Science and Research Branch, Islamic Azad University, Tehran, Iran
2 Soil and Water Research Institute, Karaj, Iran
3 Young Researchers Club, North Tehran Branch, Islamic Azad University, Tehran, Iran
3 Roudsar and Amlash Branch, Islamic Azad University, Roudsar, Iran


SAMAVAT, S., S. SAMAVAT, S. MAFAKHERI and M. JAVAD SHAKOURI, 2012. Promoting common bean growth and nitrogen fixation by the co-inoculation of Rhizobium and Pseudomonas fluorescens isolates. Bulg. J. Agric. Sci., 18: 387- 395

The efficiency of five Rhizobium and two Pseudomonas fluorescens isolates in solubilizing mineral phosphate under in vitro condition, and their effects on Common bean growth and nutrient uptake and nitrogenase activity of rhizobia isolates under greenhouse conditions, were tested in this study. Results indicated that not only the mineral phosphate solubilizing ability varied between the rhizobacteria, but also some of them showed this ability more slowly than the others. Seed bacterizing with the assessed bacterial isolates improved common bean growth indices. It was also observed that the improvement of P and N uptake as the result of rhizobacterial dual application was significantly correlated with root growth factors and both root and shoot data, respectively. Besides, although both Pseudomonas isolates showed negative effects on RH7 nitrogenase activity, the interactions of tested Rhizobia × Pseudomonas isolates increased this ability in most cases. Therefore, it can be concluded that Pseudomonas and Rhizobium isolates can improve common bean growth and yield production.

Key words: nitrogenase activity, phosphate solubilizing, biofertilizer, sustainable agriculture

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