Effect of Mycorrhizae Species on the Quantitative and Qualitative Charachteristics of Soybean (Glycine max L.) under Different Irrigation Systems

To evaluate mycorrhizal symbiosis of soybean plants (Glycine max L. cv. Williams) under different irrigation systems, a split plot experiment was conducted based on randomized complete block design (RCBD) with three replications at Urmia University in 2015. Treatments were irrigation systems (drip and sprinkler irrigation) assigned to main plots, and mycorrhizal fungi species (non-inoculated as control,Funneliformis mosseae, Rhizophagus intraradices andSimiglomus hoi) to sub-plots. Results indicated that the highest plant height, pod weight, seed yield, 100 seed weight, number of nods per stem, biological yield, harvest index of oil, oil percent and oil yield were obtained by using drip irrigation. The highest LWR (ratio of leaf/aerial parts weight) and SPAD (chlorophyll index) were observed in sprinkler irrigation system. The significant interaction effects were exhibited variable responses of soybean plants to mycorrhizal species under irrigation systems. The highest photosynthetic pigments (chlorophyll-a, -b and total chlorophyll) and carotenoids were obtained from AMF-inoculated plants under sprinkler system, regardless of fungal species. The highest leaf phosphorus belonged to inoculated plants (F. mosseae) in sprinkler irrigation system. All fungi species increased leaf protein, similarly. While the leaf potassium did not show significant differences with non-AMF inoculated control plants. Despite highest root colonization with R. intraradices under sprinkler irrigation system, colonization by all three species of fungi under both irrigation systems were higher than non-AMF inoculated soybean plants. In both irrigation systems, the ratio of fatty acids (unsaturated fatty acids which were four times higher than of saturated fatty acids) in AMF-inoculated plants were equal to that of non-mycorrhizal control soybean. Regardless of different responses of soybean plants to mycorrhizal species, biological seed and oil yields, under drip irrigation system were about 23, 53 and 84% higher than that of sprinkler irrigation system.