Abstract

In order to study the effects of zeolite application on growth, yield and yield components of sunflower grown under conditions of waterdeficit stress, an experiment was conducted in research field of Islamic Azad University, Varamin Branch during 2011 growing season. The experimental design was carried out in a randomized complete block with a split plot arrangement of treatments in three replications. Main plots included three different levels of irrigation (complete irrigation, irrigation withholding at stem elongation and irrigation withholding at seed filling stages) and sub-factors included zeolite application (0, 6 and 12 t/ha). The results showed that water stress significantly decreased plant growth and production. Conversely, zeolite application led to increase in growth and improved yield and yield components. Zeolite application fairly increased stem diagonal and cap diagonal under water deficit stress. These results indicated that zeolite application (6 t/ha) increased seed yield when plants were irrigated completely. It is interesting to remark that zeolite application was more effective under stress conditions than complete irrigation condition. Biological yield increased on zeolite application. In addition, the highest oil yield was achieved when sunflower plants were treated with 6 t/ha zeolite under normal irrigation conditions. Zeolite application could improve sunflower growth and seed production even under drought stress conditions.