Influence of rhizobium inoculation combined with azotobacter chrococcum and bacillus megaterium var phosphaticum on growth, nodulation, yield and quality of two snap been (phasealus vulgaris l.) cultivars.

The present investigation was carried out during the two successive summer seasons of 2007 and 2008 at the Experimental Station, Faculty of Agriculture, Cairo University, Giza, to study the effect of inoculation with Rhizobium leguminoarum bv. phaseoli (ARC 301) (Rh), Azotobacter chroococcum (AZ1) and Bacillus megaterium var phosphaticium (BM3) on nodulation , N₂-fixation, population of rhizosphere microorganism (RMO), NPK-Content, yield and pod quality of two snap been (Phaseolus vulgaris L.) cultivars, namely Bronco and Paulista under 25% of the recommended dose of NPK chemical fertilizers. Results indicated that inoculation with biofertilizers mixture  had a significant effect on snap been growth parameters , nodulation and N₂-fixation. The highest values were recorded with Rh + AZ1 + BM3 in presence of 25% the recommended dose of NPK fertilizers. Paulista cv. surpassed cv. Bronco in plant height, plant fresh and dry weights, both number of branches and pods/plant as well as leaf chlorophyll content, whearas the reverse was true concerning the plant yield, early and total green  pod yield and dry  seed yield  per feddan, pod weight and diameter as well as pods dry matter, carbohydrates and fibres. Rhizobium (Rh) + Bacillus megaterium (BM3) with 25% the recommended dose of NPK significantly increased all traits of vegetative growth, yield and its components and pod characteristics in comparison with the control  treatment (uninoculated + 100% NPK). The best interaction treatment regarding plant growth and chlorophyll leaf content was cv. Paulista with Rh + BM3 + 25% NPK. Meanwhile, cv. Bronco with the same treatment was the best regarding yield and its components as well as pod characteristics.