Interaction Efect between Water Deficit and Mycorrhizal Symbiosis on the Quantitative and Qualitative Yield of Sainfoin (Onobrychis sativa L.)

Water stress is one of the most important factors limiting the growth and production of crops in arid and semi-arid regions. To evaluate the effect of mycorrhizal fungi species on the growth and yield (quantity and quality) of Onobrychis sativa under water deficit condition, a greenhouse factorial experiment based on completely randomized design (CRD) with three replications was conducted in 2014. Treatments included five species of mycorrhizal fungi (Fanelormis mosseae, Rhizophagus intraradices, Claroideoglomus claroideum, Funneliformis caledonius, Glomus versiforme and non-mycorrhizal control) and two levels of irrigation (irrigation at 80% [well watering] and 50% [water deficit] field capacity [FC]). The highest grain yield (9.187 g/plant) was obtained from the stressed plants inoculated with Rh. intraradices with the same grain yield of F. mosseae inoculated plants (8.867 g/plant). With a significant reduction in the grain yield of stressed plants, mycorrhizal relationships even increased the yield more than the well-watered plants. Despite the decreases in the grain protein and phosphorous of water-deficit stressed mycorrhizal plants, the highest grain protein content was obtained from the plants inoculated with G. versiforme, and the highest grain phosphorus content was obtained from the plants inoculated with F. mosseae. Mycorrhizal symbiosis enhanced the yield and the quality of Sanfoin grain in water deficit stressed plants due to reducing root volume against the stimulating root elongation. In this way, the species G. versiforme exhibited the greatest positive effect.