The effect of zinc on yield and yield components of sunflower (Helianthus.annuus L. )under drought stress

In the modern era Drought Stress is a major factor limiting the growth of sunflower crops in arid and semiarid regions of the world. To this end, a study to evaluate the effects of Stress at different growth stages in a split plot factorial by randomized block method of research station in the central province, Delijan city, Village Qlavar was done in the 2011 crop year. Drought Stress as a major factor: full irrigation (I1),no irrigation at the pollination level (I2) and no irrigation at seed filling stage (I3) and amount of secondary factors of potash and zinc fertilizers (including zero rate of potash sulfate, 100 and 200 kg in each hectare and zero rate of zinc sulfate, 60.30 kg per hectare) was considered and Data were analyzed by using MINITAB software and then based on the combined analysis of traits were evaluated. Finally, the more using of zinc and potash fertilizers on seed the better yield. This figure is based on the optimal irrigation conditions in terms of some traits such as number of leaf, plant height, plant diameter at 5% level was not significant But there was a significant difference in terms of other characteristics, and ultimately final yield of plant under drought stress is reduced.