DIFFERENCES IN NITROGEN AND PHOSPHORUS UPTAKE AND YIELD COMPONENTS BETWEEN BARLEY CULTIVARS GROWN UNDER ARBUSCULAR MYCORRHIZAL FUNGUS AND PSEUDOMONAS STRAINS CO-INOCULATION IN RAINFED CONDITION

Drought is a major limiting factor of plant production in arid and semi-arid regions including Iran. The use of arbuscular mycorrhizal fungi and plant growth promoting rhizobacteria (PGPR) may constitute a biological alternative to increase crop yield and plant resistance in water stress conditions. In order to evaluate the synergistic effect of four strains of Pseudomonas and arbuscular mycorrhizal fungi (AMF) on nitrogen and phosphorus uptake and yield components of Iranian barley cultivars (Dasht and Sahra) under rain-fed conditions, a two-year experiment was conducted in factorial randomized complete block design. The results demonstrated that in most of the characteristics, the interaction effect of Pseudomonas x AMF on cultivars in both years was significant. While Pseudomonas strains exhibited different reactions to cultivar and AMF use, in most of the traits measured, they were superior when compared to control. In both cultivars, the maximum yield parameters studied was obtained from co-inoculation of AMF + S4 strain. The Sahra has more production sustainability in comparison to Dasht (seed yield of Dasht 1293 and 1912 kg/ha; Sahra 1752 and 1939 kg/ha in first and second year, respectively). Moreover, in both years and in both cultivars, the co-inoculation increased P and N concentration and uptake significantly. It increased seed yield, while the yield increase was more evident in the Sahra. According to the results obtained, to achieve the maximum seed yield in rain-fed conditions of Iran, cultivation of Sahra alongside co-inoculation of AMF + Pseudomonas putida S4 strain is recommended.