Response of four annual medic cultivars to NaCl stress in germination stages and hetrotrophic

In many plant species sensitivity to NaCl is known to vary among growth stages. In order to investigation of germination and seedling growth in some annual medics cultivars exposed to NaCl، an experiment carried out in laboratory in Agriculture and Natural Resources Research Center of Golestan Province in 2007. The experiment was factorial in completely randomized design with 3 replications. Treatments consisted: Medicago truncatula G. Cv. Caliph and Mogul، M. scutellata L. Cv. Sava and Robinson، M. scutellata L. seed’s (cultivar unknown) that collected from saline soil and an indigenous species M. minima and five salinity levels (0، 5، 10، 15 and 20 dS/m). Germination percentage (Gr)، seed germinating rate (Gmax)، ratios of shoot/root length (s/rl) and shoot/ root weight (s/rw) were measured. These traits were significant at 20 dS/m and have difference responses in other salinity levels. Response of M. scutellata L. cv. Sava was better to salinity stress at seedling stage، so that this cultivar continued to grow at 20 dS/m. These results suggest that Sava could be identified as a relative successful cultivar in breeding program for utilization in saline condition. Recovery of germination in Robinson and MSS were highest as compared with the other cultivars.