| Abstract
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Two separate investigations, on wheat and barley were conducted under control environments. In the first experiment, two wheat varieties, selection line (SL) and Yecoro Rojo (YR) were grown in 100 mM NaCl salinized sand culture with the additional 2 levels (4 and 8 meq/L) of Ca, Mg and NH4 application. Control treatments (0 salt plus 4 meq/L of Ca, Mg and NH4) were also included. The fresh and dry matter yield after 4 weeks in salinized Hoagland solution and supplemental nutrient addition reveals that salinity significantly reduced the yield and the addition of 8 meq/L NH4 increase the yield among the salt treatment pots followed by 8 meq/L supplemental Ca. Likewise, number of tillers and grain yield was also increased by the addition of 8 meq/L NH4 to salinized Hoagland solution. SL produced significantly higher yields than YR. Water and osmotic potential were significantly increased with salinity but turgor potential was not effected significantly. Concentrations of Na and Cl were significantly higher in both varieties in the salt added plants, and the uptake was reduced by the high level of supplemental NH4. Generally, YR (a salt sensitive variety) absorbed higher amount of Na, Mg, Cl and PO4, which might be the possible cause of nutritional disturbance and hence reduced yield. In the second experiment, two selected barley varieties (California Mariout and Gustoe) were grown in lysimeter, irrigated with two NaCl salinity water (150 and 250 mM) and a control with two LF (0.2 and 0.4). As the salt concentrations of irrigation water increased, vegetative growth and grain yield reduced significantly. LF 0.4 had significant effect at moderate salinity on yield but was similar as LF, 0.2 when the salinity increased to 250 mM. Both varieties achieved the highest WUE for the above ground dry matter and grain yield at moderate salinity. Mariout was salt tolerant and high yielding both in and out of salinity. Soil salinity (ECusd\rm\sb{e}usd) and Na content increased as the salinity of irrigation water increased. Na concentration of leaf tissue was significantly increased, while Ca and K concentration decreased with increase in salinity. The possible reason for reduced yield at high salinity was the Ca deficiency.
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