Effect of Deficit Irrigation on Yield and Biochemical and Physiological Characteristics of Corn Hybrids (Zea mays L.)

To evaluate corn yield, yield components, and water use efficiency as well as biochemical responses to deficit irrigation, a farm experiment was executed in Karaj in 2009 and 2010. The factors consisted of five different irrigation regimes [including full irrigation (I1), 12.5% (I2), 25% (I3), 37.5% (I4) and 50% (I5) water deficit] and three corn (Zea mays L.) hybrids (Sc704, Sc500 and Sc301). Deficit irrigation decreased starch content and increased soluble sugars in the leaves and roots of all three hybrids. Proline level in roots of all three hybrids was also increased in response to deficit irrigation. The increase in proline content was higher in leaves than in roots, but the increase in soluble sugar content and decrease in starch content were higher in roots than in leaves. Results indicated that the highest leaf and root proline and soluble sugars levels were related to treatment I5 and the highest leaf and root starch content were related to full irrigation. Results also indicated that the highest number of grains per ear, weight of one thousand grains and grain yield were related to full irrigation. There was no significant differences between full irrigation and 12.5% of water deficit. In the conducted test, maximum water use efficiency in Sc704 was observed in treatment I2 and in Sc500 and Sc301 were observed in treatment I3. In sum, it is concluded that the hybrid to Sc704 in 12.5% of water deficit could be recommended in order to achieve maximum yield and water use efficiency.