بررسی تنوع ژنتیکی گونه ها و نمونه های مختلف یونجه دیم جهت تثبیت حداکثر ازت

The Rhizobium-legume (herb or tree) symbiosis is suggested to be the ideal solution to the improvement of soil fertility and the rehabilitation of arid lands and this is an important matter for future research. In order to determine the best genotypes for Nitrogen fixation, a number of Medicago sativa sp. were studied in green house of research institute of forests and rangelands of Iran. Seed of varieties were collected from natural resources gene bank and some provinces of Iran such as Balochestan, Boshehr, Ghazagestan, Gorgan, Iranshahr, Kerman, Khorasan, ormieh, Rasht, Yazd, Australia.Seed of varieties were sterilized with 5% NAHCL and then were tested for germination. Rhizobium strains were also collected from different climatic parts of Iran (Ardabil, Boshehr, Rasht, Sanandaj, and Yazd).First varieties were sown in a medium size plastic vase, which had been filled with insterilized inert material (striled Quartz). They were irrigated with Rhizobium contained solution till germination was occurred and then irrigation continued by using solution without Nitrogen element. There was used a factorial experiment (completely randomized design) with four replications and two factors as variety in 11 and Rhizobium strains in 6 levels. There were noted many attributes such as plant height, stem number, Root length, Nodule numbers, forage , root and Biomass(root + forage) dry weight, Plant number and etc. At the end of this experiment data's were analyzed using SAS and MINITAB software's. Mean of all characteristics were compared using Duncan method. Analyses of Data's showed that effects of varieties, Rh.strains and interaction (varietiesاRh.strains) between them were very significant for all studied attributes. 57 The results showed that forage yield of Orumieh and golestan varieties were better among studied varieties.Effect of Rhizobium strains on forage were not significant between varieties but in coparison to control were considerable. Total biomass for varieties of Orumie and Sannadaj were more than other varieties in this experiment. Although effects of Rhizobium strains on total biomass (forage+root dry weight) were better than control, but there were not observed significant difference between them. Numbers of Nitrogen fixation nodules in Iranshahr, yaz and khorasan varieties were more than other varieties. There was not cosiderable difference between Rhizobium strains for Nitrogen fixation nodules,but diversity between Rhizobium strains and control was significant. These results indicate that there is much variation between varieties and Rhizobium strains for N fixation process and forage production.Improve the plant growth and forage production, increase fixed Nitrogen and fertility of specially dried areas. Alfalfa, Genetic variation, N fixation, Rhizobium strains, symbiosis,.