Effect of Zinc and Auxin Foliar Application on Grain Yield and Its Components of Grain Maize Under Water Deficit Conditions

To determine the effect of zinc and auxin foliar application on grain yield and its components of grain maize (Zea mays L.) cv. SC 704] under water deficit condition, this study was conducted in Agriculture Research Center of Varamin in south–east of Tehran in 2006 crop cycle. There were three water deficit levels: 50%, 60% and 70% water depletion of available water in soil (main-plots), factorial of zinc and auxin foliar application (sub-plots) (zinc foliar application in four levels: sulphate, EDTA, water spraying and no spraying and auxin spraying in three levels: spraying, without spraying and water spraying, respectively) arranged in a split plot–factorial using randomized complete block design with three replications. Results showed that only water deficit × auxin spraying interaction was not significant on grain yield and grain protein and oil contents. Zinc (sulphate and EDTA) × auxin spraying interactions in 50% and 60% water depletion of available soil water had the highest grain yield with 12410 and 11840 kgha-1, respectively. In addition, the effect of two zinc complex and auxin spraying in different water deficit levels on grain yield and yield components varied, but showed positive effect on grain yield and its components at the same water deficit levels.