Esmaeil Ysari
Abstract
In order to study the effects of phosphate solubilizing bacteria and mineral phosphorous application on yield and yield components of canola (Brassica napus L.), a split-plot experiment using the randomized complete block design with three replications was conducted at Dasht-e-Naz Agronomy Research Station in 2013. Four levels of bacterial inoculation (the control, Pseudomonas putida, Pseudomonas fluorescens, and simultaneous use of both bacterial species) were applied as main plots and 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 as sub plots. The results of analysis of variation showed that mineral phosphorous had significant effects on number of lateral shoots, number of pods on the main stem, number of seeds per pod and seed yield. Bacterial inoculation had significantly affected all the studied traits of the canola, except plant cutting height at harvest. The results showed that minimum seed yield (845 kg/ha) was obtained as control treatment, where no mineral phosphorous were applied. Application of mineral phosphorus at 25, 50, and 75 kg/ha of phosphorous application were 963/8, 1006, and 1032 kg/ha, respectively, although the differences were not statistically significant. It was shown that maximum P level at 100 kg/ha resulted in a decrease in seed yield (839/6 kg/ha) compared to the other P levels. The results also showed that minimum seed yield obtained as control treatment of bacterial inoculation, i.e. 852/4 kg/ ha and with seed inoculation with Phosphate Solubilizing Bacteria canola seed yield showed an increasing trend. 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 interaction effects of mineral phosphorus and bacterial inoculation showed that minimum seed yield (740 kg/ha) obtained at treatment with application of neither bacterial nor mineral P. The maximum plant height and plant cutting height at harvest obtained at the interaction effects of P. fluorescens and 50 kg/ha P with 78/08 and 30/53 cm, respectively. It was also showed that maximum seed yield (1074 kg/ha) obtained at interaction effects of both bacterial species and 50 kg/ha of mineral phosphorous, coinciding with maximum number of pods per main stem (66/77).