Influence of Plant Growth-Promoting Rhizobacteria on Corn Growth under Drought Stress

Water availability is a major constraint affecting the growth and yield of crops/plants worldwide. Some studies have shown that specific strains of free-living bacteria found in the plant rhizosphere can improve the tolerance of plants during water stress. A greenhouse study was conducted to evaluate the effects of two mixtures of plant growth-promoting rhizobacteria (PGPR) and two fertilizer sources on root establishment and biomass production of corn (Zea mays L.) during the early growth stages under drought conditions. This study was conducted as a randomized complete block design with five replications. Treatments included three irrigation levels (watering every 3, 6, and 12 days), two fertilizer materials (poultry litter and urea), and two PGPR strain mixtures and a non-inoculated control. Irrigation significantly affected plant growth and biomass accumulation of corn at the V6 to VT stages. Compared to poultry litter, urea application significantly increased plant height, leaf chlorophyll (SPAD readings), leaf area, and plant biomass. PGPR significantly improved plant height, stem diameter, leaf chlorophyll, and root morphology under drought stress conditions. The results demonstrate that PGPR inoculation can stimulate enhanced plant root development (through the production of plant growth regulators), thereby resulting in better absorption of water and nutrients from the soil.