Evaluation of plant growth hormones production (auxins) ability by Iranian soils rhizobial strains and effects of superior strains application on wheat growth indexes and the loss of chemical fertilizers

Proving of rhizobia’s other abilities in spite of Nitrogen fixation ability and considering these bacteria as plant growth promoting rhizobacteria (PGPR) researching tasks in this field have incerased. Now، it’s completely proved that we can find such strins among many more strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production، in addition of their ability in N2 fixation. Such strains can be useful not only for their special host، but also for other plants and strategic products as grains. Soi biotechnology، which follows producation potential of biofertilizers too، which leads improving quality of agricultural products and soil fertility level and life sources contamination preventing، is depend on the use of rhizobia as a good substitute for chemical fertilizers. Several researches were performed about Iranian rhizobia since a decade ago in N2 fixation. Application effect of IAA super strains inoculants on growth index of wheat plant yield was evaluated. The results were indicated that indigenous rhizobia have the potential of Indole auxins production (IAA). Results from the appication of superstrains (IAA +++) inoculants in wheat plant showed that IAA +++ strain had a significant increase in biological yields and N،P and K content. So، the most important stimulation mechanism by rhizobial strains، is production of indole acetic acid (IAA) which results the better root growth، so increase of water and micronurient (N، P and K) uptake by the plant and decrese of the loss of chemical fertilizers.