Effects of Inoculation with Rhizobium and Mycorhizae on the Response of Three Alfalfa (Medicago Sativa) Populations to Salinity

In order to study the effects of inoculation of rhizobium and mycorhizae on the response of alfafa cultivars to different salinity levels a pot experiment was conducted. The experiment was arranged as factorial in a randomized complete block design with three replications. The treatments included three alfafa cultivars (Rehnani, Hamadani and Bami), four levels of salinity (0, 60, 120 and 180 mmol (NaCl), and four inoculations (rhizobium, mycorhizae, rhizobium + mycorhizae, and control). There was a decrease in plant height, leaf area, shoot and root dry matter, percentage of mycorhizae infection, and root characteristics. The highest amounts of the above-mentioned growth characteristics were obtained in rhizobium + mycorhizae, mycorhizae, rhizobium, and control, respectively. The highest values of root mycorhizal infection and the number and weight of nodules were also achieved in dual inoculation treatment. Root was more affected than shoot by inoculation. The extent of positive effect of mycorhizae on alfalfa was greater than that of rhizobium. Rehnani was recognized to be more a salt tolerant cultivar as compared to Hamadani and Bami. The decrease in plant dry matter due to salinity was more in non-inoculated than in inoculated treatments. The results of our experiment showed that coinoculation of rhizobium and mycorhizae may cause synergistic effects on alfalfa dry matter accumulation. However, dual inoculation was not significantly superior to other inoculation treatments in terms of the alleviation of salinity effects