Effect of seed inoculation with phosphate solubilizing bacteria isolated from phosphate solid sludge on seedling growth of wheat (Triticum durum 'Karim')

The objective of our study was to evaluate the effect of phosphate solubilizing bacteria (PSB) isolated from Phosphate solid sludge on germination and seedling growth of wheat (Triticum durum 'Karim'). Ten strains have been studied for their ability to solubilize tricalcium phosphate quantitatively in NBRIP medium, their phosphate solubilizing activity was estimated by the vanadate-molybdate method. The production of indol-1-acetic acid (IAA), siderophores by the isolates were tested. These strains tested with phosphate-solubilizing ability and plant growth promoting traits were selected to evaluate their effect on seed germination and seedling growth of wheat. The experiment was performed in Petri dishes, and under greenhouse conditions. The following parameters were measured: seed germination rate, root and shoot length, number of roots. Our findings indicate that the soluble phosphate ranged from 115.5 to 174.3 μg mL^‑1. BM11 was the most efficient strain in NBRIP liquid medium releasing 174.3 μg mL^‑1 soluble P. All l the strains have shown the ability to produce IAA. The BT3S171 strain showed the highest IAA production (43.80 μg mL^‑1). and all strain produce siderophores. Compared to control, a significant (p<0.05) increase was found in seed germination rate, root length, shoot length, number of roots of wheat inoculated with the PSB. The results of our study suggest that the tested PSB can be considered as efficient inoculum to promote wheat seed germination and seedling growth.