Phosphorus efficiency for symbiotic N₂ fixation of common bean (Phaseolus vulgaris) is affected by the form of phosphorus application in hydroaeroponic culture

Phosphorus uptake and utilisation by common beans (Phaseolus vulgaris) is essential for proper growth, and ensuring high yield and improved quality of the crop. To study the effects of the phosphorus application forms on the phosphorus use efficiency (PUE), for symbiotic nitrogen fixation (SNF), six common bean recombinant inbred lines (RIL) from the cross of BAT477 x DOR364 were inoculated by Rhizobium tropici CIAT 899, and submitted to five organic and inorganic treatments of P in hydroaeroponic culture in glasshouse in the south of France. The results showed significant differences in shoot and nodule biomass among inorganic and organic P sources with all RILs studied. In particular a significant increase was observed in shoot P content with bochevo and apatite compared to phytate and glycero P whereas RILs 83, 75 and 147 registered as a higher P uptake. A greater PUE was observed for RILs 34, 75 and 115 than other RILs with organic P especially under 75P (deficient P). A significant release of H⁺ was observed with organic P supply whereas bochevo buffered the pH which was suitable for nodulation and plant growth. In conclusion, the organic P forms could contribute to P uptake by nodulated common bean. Whereas bochevo was the most efficient source of P because of its positive effect on pH in hydroaeroponic culture.