USING DIAZOTROPHIC ENDOPHYTES IN IMPROVING SOME CEREAL PRODUCTION UNDER SALINE DESERT CONDITION

The present study was conducted to develop the bacterial consortia of salt tolerant endophytic diazotrohs. Forty three endophytic bacterial isolates were assayed for their nitrogen fixation and hormone production at different NaCl concentrations. All selected endophytic Azotobacter and Azospirillum isolates exhibited nitrogenase activities  ranged from 15.4 to 96.1 n.mole C₂H₄ /ml/h, indol acetic acid ranged from 31 to 168 μg/ml and gibberellins from 2.8 to 29.4 μg/ml at NaCl ranged from 1 to 5%.  Vital staining technique of wheat and barley seedlings revealed the presence of pink to purple stained endophytic bacteria in their root tissues. Different bacterial consortia were developed from the highly efficient endophytic nitrogen fixers. Two highly efficient bacterial endophytic consortia at 1% NaCl were selected for further lab and field experiments. The two bacterial consortia were investigated for their nitrogen fixation activities and indole acetic acid (IAA) production under different concentrations of salt. The obtained results revealed a dramatic decrease in the amount of fixed N with increasing the salt content from 1 to 10% NaCl for both consortia. The consortium of barley endophytes exhibited the highest IAA production at 5% NaCl, while that of wheat exhibited the maximum IAA at 1% NaCl.
                        Two field experiments conducted at Ras Sudr Experimental Station showed that inoculation of wheat and barley seeds with endophytic bacterial consortia significantly increased all the growth parameters, nitrogen content and uptake of two plants under salinity stress. Also, bacterial consortium of wheat endophytes along with half dose of nitrogen achieved the highest significant wheat and barley yields. Inoculation with endophytic bacterial consortia had a positive effect on the count of bacterial nitrogen fixers and dehydrogenase in the rhizoshere.