Microorganisms (AMF and PSB) interaction on linseed productivity under water-deficit condition

The relationship between arbuscular mycorrhizal fungi (AMF) and their associated bacteria can be has great importance for sustainable agriculture especially in the case of highly mycorrhizal plants such as linseed. To evaluate the possible effect of AMF in association with phosphate solubilizing bacteria (PSB) on linseed plants, a 2-yr factorial experiment was conducted based on a randomized complete block design with three replications at Urmia University, Urmia, Iran (37° 39? 24.82? N 44° 58? 12.42? E). The treatments included two AMF species (Glomus mosseae, G. intraradices and non-mycorrhizal control), PSB (Pseudomonas putida P13 and non-inoculated control) and various irrigation regimes (irrigation after 60, 120 and 180 mm of evaporation from Class A pan). A significant increase in mycorrhizal linseed plants yield indicated the effectiveness of the two AMF species more than bacterial inoculation. The cumulative (second year) soil spores were maximally observed in mycorrhizal (single AMF and dually inoculation) treatments. The reduction in bacterial population was found with an increase in water deficit. Dual infections caused an increase in leaf P content more than the one in PSB and AMF inoculations. Drought stress-induced yield reduction in seed and in oil was significantly compensated by mycorrhizal symbiosis for all irrigation levels. We found over 25% increase for seed yield and 30% for oil yield in mycorrhizal plants as well as co-inoculated plants. The yields improvements in mycorrhizal treatments (single and dually inoculated) leading to the highest water use efficiency.