44 Keykha et al. Int. J. Biosci. 2014 RESEARCH PAPER OPEN ACCESS Effect of water stress and applications of superabsorbent on grain yield, harvest index, biological yield and plant height in sun flower Hamed Keykha 1* , Hamid Reza Ganjali 1 , Mohammad Reza Naroui Rad 2 1 Department of Agronomy, Islamic Azad University, Zahedan Branch, Zahedan, Iran 2 Agriculture and Natural Resources Research Center of Sistan, Iran Key words: Sistan, Iran, Sunflower, superabsorbent. http://dx.doi.org/10.12692/ijb/5.3.44-49 Article published on August 02, 2014 Abstract Iran has arid and semi-arid climate, so the drought stress is considered as one of the main problems of production in this country. Water shortage is usually one of the important reasons for the reduction of performance in the unit area of arid and semi-arid areas. Superabsorbent is a dry material that absorbs one hundred times more than its weigh water and water soluble. This polymer has different applications which the most important of them are in agriculture. The experiment was conducted in 2013 at the research station and natural resources in sistan. The field experiment was laid out in randomized complete block design with split plot design with three replications. Analysis of variance showed that the effect of water stress on grain yield, harvest Index, biological yield and plant height was significant. * Corresponding Author: Hamed Keykha  Barsa200014@gmail.com International Journal of Biosciences | IJB | ISSN: 2220-6655 (Print) 2222-5234 (Online) http://www.innspub.net Vol. 5, No. 3, p. 44-49, 2014