Effects of Foliar Application of Plant Growth Promoting Rhizobacteria on Forage and Grain Yield of Forage Sorghum (var. Speedfeed)

To evaluate the effects of PGPR foliar spraying on forage and grain yield of forage sorghum (var. Speedfeed), a farm experiment was conducted in Research Farm of College of Agriculture, University of Tehran in 2009. The experimental design consisted of a randomized complete blocks consisting of 17 treatments in every block. In this research, the effect of foliar application of 16 different strains of PGPR including Pseudomonas putida and pseudomonas fluorescents in three growth stages (3-leaf stage, 8-leaf stage and commencement of ear) were compared to control. The results showed that bacterial foliar application treatments significantly promoted growth and development of plants (forage yield, plant height, leaf area and grain yield) compared to control. According to the results of this experiment P. putida strain 11 increased forage yield of sorghum up to 32%. This bacteria could produce the highest leaf area amoung other treatments. In the other hand, P. putida strain 10 had a destructive effect on forage growth and caused a 10 % decrement in forage yield compared to control. However, this bacteria could produce the highest stem height, grain yield and harvest index among the other treatments. The results of this experiment showed that foliar application of PGPR (especially P. putida strain 11) have a high potential to promote plant growth and yield of forage sorghum var. Speed feed.