evaluation of wheat germplasm in response to salinity stress

to improve bread wheat salt tolerance, new genetic sources of salt tolerance are indispensable, and this requires a screening of wheat germplasm. in order to evaluate bread wheat germplasm, 34 accessions including; hexaploid wheats (aabbdd), tetraploid (aabb) and wild relative diploids (dd and aa genome) collected from different regions of iran were evaluated under normal vs. salinity stress (nacl) conditions, using a factorial experiment in a hierarchical design with three replications. the assessed characters were biological dry weight, tissue water content (wc; shoot h2o per dry shoot mass), na+ and stress tolerance index (st). stress tolerance was significantly correlated with tissue na+ concentration and wc. the estimated coefficient of genetic variability (%cvg) via expected mean squares showed that there is a significant genetic diversity in population. cluster analysis on the basis of ward's method rendered all the accessions clustered into four clusters at a distance of 7.4. there was a good consistence between clustering results and %cvg. some accessions were observed with a high shoot na+ concentration and a high level of st while some with low na+ along with high st. therefore, breeding for improved st in bread wheat needs a selection for traits related to both na+ exclusion and tissue tolerance as well as pyramiding of both into breeder’s lines, using marker-assisted selection that has the potential to accelerate this breeding process.