Co-inoculation with Glomus intraradices and Rhizobium tropici CIAT899 increases P use efficiency for N2 fixation in the common bean (Phaseolus vulgaris L.) under P deficiency in hydroaeroponic culture

Common bean (Phaseolus vulgaris L.) genotypes CocoT and Flamingo were inoculated with Rhizobium tropici CIAT899 and Glomus intraradices (Schenck & Smith) and grown under sufficient versus deficient phosphorus supply for comparing the effects of double inoculation on growth, nodulation, mycorrhization of the roots, phosphorus use efficiency and total nitrogen. Although the double inoculation induced a significant increase in all parameters whatever the phosphorus supply in comparison to control, significant differences were found among genotypes and treatments. Nevertheless, the highest phosphorus use efficiency and plant total nitrogen were found under P deficiency in combination with arbuscular mycorrhizal fungi. It is concluded that inoculation with rhizobia and arbuscular mycorrhizal fungi could improve symbiotic nitrogen fixation even under phosphorus deficiency.