Effects of phosphate solubilizing bacteria and mineral phosphorous levels on yield and yield components of canola Hyola 401 cultivar

Split-plot experiment using the randomized complete block design with three replications was conducted at Dasht-e-Naz Agronomy Research Station in 2013 to study the effects of phosphate solubilizing bacteria and mineral phosphorous application on yield and yield components of canola. Treatments included four levels of bacteria (the control, Pseudomonas putida, Pseudomonas fluorescens, and simultaneous use of both bacterial species) in the main plots. Five levels of mineral phosphorous application (the control, 25, 50, 75, and 100 kg/ha of phosphorous in the form of concentrated superphosphate) were applied in the sub plots. Comparison of the means showed that phosphorous application had significant effects on all characteristics except plant height and cutting height of plants at harvest. Seed yields at 25, 50, and 75 kg/ha of phosphorous application were 963.8, 1006, and 1032 kg/ha, respectively (these differences were not statistically significant). The maximum seed yield (987.8 kg/ha) was obtained in the treatment of inoculation with P. fluorescens, but there was no statistically significant difference between this yield and that of the treatment of inoculation with both bacterial species (972.1 kg/ha). The minimum seed yield (852.4 kg/ha) was that of the treatment with no bacterial inoculation. Results also revealed that the level of phosphorous application and inoculation, and their interaction effects, had significant effects on number of pods of main stem and per plant. Under the interaction effects of phosphorous and bacteria, the minimum number of pods on the main stem (50.31) observed in the treatment in which no phosphorous was applied nor was any inoculation performed, and the maximum (66.77) in that of the treatment in which both bacterial species were used and 50 kg/ha of phosphorous was applied. Moreover, under the interaction effects of phosphorous and bacteria, the largest number of pods per plant (149.4) belonged to the treatment in which P. fluorescens was used and 75 kg/ha of phosphorous was applied