Abstract

In order to study the combined effects of chemical phosphorus fertilizer, Phosphate-solubilising bacteria and mycorrhizal fungus they were determined on reducing drought stress damages of grain corn (SC704) under field conditions at College of Abouraihan, University of Tehran. The experiment was conducted as split plot RCBD with three replications. Experimental factors were drought stress as the main-plot (irrigation after 50 mm [without drought stress], 100 mm [low drought stress] and 150 mm [severe drought stress] evaporation from pan class (A), and fertilizer compounds as the sub-plot. Result of variance analysis showed that drought stress had significantly affected on most measured traits. All the measured traits in compounds phosphate-solubilising bacteria and Mycorrhiza fungies treatment were higher than other treatments under drought stress conditions except root colonization. Furthermore, grain yield in super phosphate triple treat under severe drought stress condition (3.55 ton/ha) was significantly less than normal irrigation (12.08 ton/ha) and low stress conditions (9.97 ton/ha). According to this experiment result, under drought stress condition, all calculated growth indices (such as LAI, CGR and NAR) decreased. Accordingly this experiment showed that phosphate-solubilising microorganisms can positively have effect on the increase of plant growth and phosphorusabsorption in maize plant, leading to plant tolerance improving under drought stress conditions.

Key words: Mycorrhiza fungies, phosphate-solubilising bacteria, super phosphate triple, ear length.