Due to lack of water resources in irrigated agriculture, genetically improving plants to abiotic stresses such as salinity is the necessity of food and feed production. The new third man-made amphiploids cereal, tritipyrum (2n=6x=42, AABBEbEb), is an example in this respect which is capable to tolerate high level of NaCl. In order to determine the salinity tolerance mechanisms of this new cereal, an experiment was conducted using hydroponice technique. Ten tritipyrum lines and two wheat cultivars were tested under three levels of salinity (50, 100 and 200mmol/l NaCl). The effect of salinity stress on leaf Na+ and K+ concentration, proline and chlorophyll content of these genotypes were measured at 50% ear emergence and their grain yield plant-1 was evaluated at physiological maturity. In all genotypes, Na+ concentration increased with increasing salinity. K+ concentration in tritipyrum lines did not show especial pattern but in wheat cultivar Bam increasing salinity caused decreasing of potassium content. The chlorophyll and proline content in primary tritipyrum lines were more than wheat cultivars. Despite of high sodium concentration in tritipyrum lines in comparison with wheat, the grain yield of tritipyrum lines were less affected than that of wheat. There was also a positive correlation between proline content and grain yield plant-1 in tritipyrum lines. It can be concluded that other mechanisms than Na+ exclusion such as '' tissue tolerance'' was used by tritipyrum lines to combat with salt stress and it can make tritipyrum lines capable for planting in saline soil and improving the salinity tolerance of wheat.

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