Effects of Sinorhizobium strain inoculation on seedling growth and establishment of alfalfa (Medicago sativa L.) in arid and semi arid regions of Iran

In order to improve seedling growth and establish alfalfa in arid and semi-arid regions of Iran a factorial experiment was conducted using 3 alfalfa varieties and 2 levels of Sinorhizobium strains with 4 replications in Alborz Research Center. For this propose nitrogen fixed nodules were collected from root of alfalfa plants. They were washed several times with distilled water and then were sterilized in the laboratory. Seed samples were inoculated by Sinorhizobium strains solution and then they were sown in plastic pots containing sterilized sand. Data were recorded and analyzed for seedling characteristics of alfalfa such as plant height, root length, seedling length, stem dry weight, root dry weight, seedling dry weight, and nodule number per plant. The results showed significant effects (P≤1%) of Sinorhizobium strains on nodule number, seedling height, root length and seedling dry weight (Biomass).The results of correlation analysis showed positive and significant relationships among nodule number with root length, seedling length and seedling biomass. It was concluded that the effects of seed inoculation, not only improve seedling establishment, but also increase forage yield and soil fertility. Therefore, it is recommended that inoculation of proper Sinorhizobium strains with alfalfa seed could be possible to extend cultivation area of alfalfa in arid and semi arid regions of Iran.