Evaluation of Sodium Chloride Salt Tolerance of Ten Bread Wheat Genotypes

Grain yield is one of the most important creteria in screening wheat genotypes for salinity conditions. In order to study the effects of NaCl induced stress on yield and yield components and to determine threshold salinity, an experiment with ten wheat genotypes (Alvand, and 9 advanced lines) was conducted in the glasshouse of Agricultural Biotechnology Research Institute of Iran. Five levels of salinity (control, 50, 100, 150 and 200 mM NaCl) were imposed through irrigation. Reasults showed that 200 mM NaCl treatment decreased time to physiological maturity, plant height, number of tillers, number of kernel per main spike, 1000 kernel weight, biomass, total grain yield, tiller grain yield and main stem grain yield, 20%, 31%, 85%, 52%, 52%, 86%,89%, 97% and 66%, respectivley as compared to control. The reduction in the number of tiller and tiller grain yield were the main cause of yield reduction. Genotype 3 had the lowest biomass and grain yield per plant in all salinity levels. Relative yield reduction and relative biomass yield of genotype 12 consistently was lower than the others in all salt levels. Salt tolerance threshold of genotype 12 for biomass (10.8 ms/cm) and grain yield (8.25 ms/cm) was higher than the others. Alvand variety that was recommended for salinity areas of cold regions, had salt tolerance threshold of 5 and 6 ms/cm, for biomass and grain yield, respectively. Genotype 12 had higher stress tolerance index (0.27) and less stress susceptibility index (0.87) than the other genotypes.