The Effect of Plant Growth Promoting Rhizobacteria Isolated from Dryland Farming on Available Phosphorus and Some Physiological and Growth Traits of Wheat under Water-Deficit Stress

Drought, salinity and essential plant nutrient stresses especially phosphorus (P) are the most important challenges for wheat production in dryland farming of Iran. The objective of this study was to investigate the effect of three plant growth promoting bacteria strains on soil available-P, as well as some of the physiological and growth traits of wheat under water-deficit stress. For this purpose, a pot experiment was carried out as factorial arrangement with three factors including: water deficit stress at two levels, application of P-fertilizer at six levels and strains of plant growth promoting bacteria at four levels, based on completely randomized design (CRD) with three replications within 125 days. The results show at the water deficit stress of 55% field capacity (FC) and without P-fertilizer application, bacterial treatment of Staphylococcus succinus compared to control increased available-P, P-uptake of root and grain by 2.4, 4.9 and 2.7 times respectively. At moisture treatment of 80% FC and without P-fertilizer application, treatments of Bacillus pumilus, B.safensis and S. succinus compared to control, increased available-P by 1.6, 1.6 and 1.6 times; P-uptake of root by 3.1, 3.1 and 2.9 times; P-uptake of grain by 2.2, 2.4 and 2.2 times, respectively. Maximum dry weight of root, shoot and grain (5.3, 18.2 and 4.6 g pot-1, respectively) were obtained at the maximum level of P-fertilizer treatment (F4). At the water deficit stress of 55% FC, bacterial treatment of S. succinus compared to control increased prolin, root dry weight, grain dry weight and P-uptake of shoot up to 8, 31.9, 20.4 and 25.5 percent, respectively. Generally, the use of Staphylococcus succinus strain R12N2 seems to be appropriate for increasing wheat production in dryland farming.