Investigation the effect of salinity tension on germination, seedling growth and ionic content of alfalfa genotypes (Medicago sativa L.)

In order to investigate the germination characteristics, seedling growth and ionic content of alfalfa genotypes, two separate experiments each as the form of factorial were carried out in a completely randomized design with three replications in a petri dish culture (at the seed experiment) and potting at vegetative growth phase) at the Research Laboratory of Islamic Azad University, Khuzestan Research and Science Branch. In both experiments, factors including five levels of salinity tension included: zero, 4, 8, 12 and 16 dsi Siemens per meter and 10 genotypes of alfalfa included: KFA1, KFA3, KFA12, KFA15 (origin Nagorno alfalfa), KFA4, KFA5, KFA16 (origin Hamadani), KFA9 (origin Chaleshtar Shahrekord), KFA7 (origin Rehnani) and the tropical Yazdi. The results showed that salinity tension in petri dish culture decreased the traits of germination percentage and speed of germination significantly. The length of root growth and seedling dry weight, significantly decreased with increasing salinity tension Salinity tension increased sodium concentration and decreased seedling potassium. The highest amount of sodium concentration was observed in the interaction of salinity treatment of 16 dsi Siemens per meter and KFA5 genotype. The highest tension sensitivity index based on dry weight of seedling was related to KFA5, KFA7 and KFA 9(with the means of 1.26, 1.25 and 1.17, respectively). The highest amount of tension tolerance index was observed in KFA 1 and KFA15 genotypes (with the average of 0.82 and 0.79, respectively). Generally, genotypes that had a lower sodium to potassium ratio, had less sensitivity and more tolerated than salinity.