Effect of Water Deficit Stress and Nitrogen on Yield and Compatibility Metabolites on Two Medium Maturity Corn Cultivars

ABSTRACT: In order to study the effect of water deficit stress and nitrogen on yield and compatibility metabolites in corn cultivars, an experiment was conducted at Experimental Farm of Tehran and Kurdistan University. The experimental design was randomized complete block with treatments organized following a split-factorial with three replications. Four levels of drought stress (water deficit stress at vegetative stage, reproductive stage, both vegetative and reproductive stages and without water deficit stress or control treatments) were randomized to the main plot units and combination of two levels of nitrogen fertilizer (100 kg/ha and 200 kg/ha) and two maize varieties (S.C. 647 and T.C. 647) were randomized to the subplot units. The results showed that water deficit stress, nitrogen and cultivar had significant effects on grain yield. The result showed that water deficit stress at vegetative phase had significant effect on leaf solution proteins and reduced it in stress treatments in compared with control. Soluble protein in treatments with fertilizer was more than nitrogen deficit treatments. At the end of each phase of stress, water deficiency induced significant increase of Proline in leaves. Nitrogen levels had also positive correlation with increment of Proline. Water deficit stress led to significant decrement of chlorophyll content in examined cultivars. Water deficiency had significant effect on free amino acid content of leaf at the end of reproductive stress.