Evaluation the efficiency of growth promoting bacteria on yield and yield components of rice under deficit irrigation and reduced rates of nitrogen

In order to evaluation the efficiency of growth promoting bacteria on yield and yield components of rice under deficit irriga� tion and reduced rates of nitrogen, this research was conducted at the Rice Research Institute of Iran – deputy of Mazandaran province (Amol) in 2011- 2012, as split-split plot in a randomized complete block design with three replications. The treatment of low Irrigation were as main factor at three levels (control, no irrigation at either panicle initiation and filling grains) and nitrogen fertilizers (control or recommended dose as the rate of 100 kg.ha-1 nitrogen, 50 and 25% of recommended dose) were assigned to the sub-plots, and the four PGPR treatments [control, Azospirillum lipoferum (AZP), Pseudomonas fluorescence (PSD) and AZP㴠], were as sub-sub plots. Results showed that different levels of PGPR’s had significantly effect on paddy yield in which the maximum grain yield was obtained by the combination of Azospirillum Pseudomonas bacterium (7.43 ton.ha-1) and the minimum grain yield was obtained by the control or no bacterium application (6.13 ton.ha-1). Also, Interaction effect between N and Bacterium showed that the maximum filled grain number per panicle was obtained by the treatment of 75% N and control (recommended dose) with combination of Azospirillum Pseudomonas bacterium (183 number). Using the different treatments of irrigation had significant effects on total grain number, number of filled and hollow grain and grain yield. Among the irrigation treatments the conventional irrigation had the maximum grain yield by 7.11 ton.ha-1. In total, the result of this research showed the effective and efficient role of PGPR’s on significant improvements of rice paddy yield in terms of deficit irrigation and reduced nitrogen.