Effect of Different Salinity Levels and Irrigation Regimes on Certain Growth Properties and Water Use Efficiency in Wheat (Triticum aestivum L.) Cultivars

In this study, response of two bread wheat cultivars (Arg and Tajan) to different irrigation regimes (full irrigation and 85 percent of water requirement) and different salinity levels (0, 50, 100 and 150 mM NaCl) in a greenhouse using a factorial experiment based on a randomized complete block designe with three replications was evaluated. Treatments were imposed when the leaf 4 was fully expanded. 150 mM level of  salinity significantly decreased  shoot dry weight, root dry weigh, and water use efficeiny in grain and shoot dry weight. Although, water use efficeiny in grain and shoot dry weight of tolerant Arg cultivar (3.9 and 0.97 g/L per plant respectively) was more than sensitive Tajan cultivar (2.8 and 0.85 g/L per plant respectively), but both cultivars had the same reduction in shoot dry weight. Deficit irrigation decreased the rate of roots Na+, shoot Na+ and flag leaf Na+, and increased flag leaf K+/ Na+ ratio from 4.73 to 5.33 and water use efficeiny in shoot dry weight from 3.1 to 3.5 g/L per plant respectively. The yield of both cultivars did not affect by 50 and 100 mM NaCl. At last, 150 mM NaCl caused a same reduction in yield at full irrigation and 85 percent of water requirement in Tjan, but in Arg cultivar, the yield did not affect by this level of salinity. Because grain yield of both cultivars did not affect by deficit irrigation under salinity levels, thus they had a similar resistance to osmotic stress.