Effect of Pseudomonas strains on grain yield and nutrients absorption of Barley under mycorrhiza fungi application

Barley is one of the most cultivated plants in Iran's dryland. Ardebil province is one of the areas where the production of barley has been successful. But one of the problems for farmers in these areas is the high cost and negative aspects of the use of chemical fertilizers. Today, the application of some microorganisms in farms is important as an alternative to chemical fertilizers. A factorial experiment was conducted in a randomized complete block design with three replications in two years at experimental farm of Ardebil Islamic Azad University. The experimental factors included mycorrhiza fungi application (application of Rhizophagus irregularis and non-application) and four strains of Pseudomonas strains (strains of S153, S169, S4, S8 and control). The results of analysis of variance showed that the interaction of Pseudomonas × mycorrhiza on the most traits was significant. Detection of shoot nitrogen concentration at different stages of plant growth showed that the highest nitrogen concentration was observed at the flag leaf emergence stage and Pseudomonas strains showed higher nitrogen concentrations under mycorrhizal application. Co-inoculation mycorrhiza-pseudomonas, while increasing mycorrhizal colonization, nitrogen concentration, Phosphorus, potassium, iron and manganese increased significantly. In addition, the activity of acid and alkaline phosphatase in the root rhizosphere increased in plants under inoculum with Pseudomonas under mycorrhizal application condition. In this experiment, the maximum grain yield was 1572 kg ha-1 in the first year and 2239 kg ha-1 in the second year was obtained from co-inoculation treatment of mycorrhizal fungus + S4 strain. According to the results, although in most of the measured traits, inoculum treatments were superior to control, the application of mycorrhizal fungus also increased the bacterial inoculation efficiency and, in addition to increasing the elements concentration in grain, also the grain yield increased. Therefore, for barley farming in Ardabil rainfed conditions, inoculation with Pseudomonas fluorescens strain S4 is recommended under the use of mycorrhiza fungi.