effect of superabsorbent application on grain yield and some physiological characters of canola hybrids under terminal drought stress condition

one of the soil and water management practices in order to delay drought stress under water deficit condition; is superabsorbent application. in order to study the effect of  superabsorbent application on yield and yield components, two antioxidant enzymes activity and water relation of two canola hybrids under terminal drought stress condition, a research was carried out in ahvaz climate condition, as a split-split plot experiment using complete randomized block design with four replication, in 2009-10 cropping season. two water treatment (well-water and terminal drought stress), two canola hybrids (308 and 401), and three superabsorbent application (0, 75 and 150 kg/ha) were the main, sub and sub-sub plots respectively. yield and yield components, and some physiological characters including glutathione peroxidase (gpx), super oxide dismutase (sod) enzymes content, cytoplasm membrane leakage (cml) and leaf relative water content (rwc) were meseared. results showed that except harvest index, effect of water treatment was significant for grain yield, all other yield components and physiological characters. hybrids difference was significant only for biological yield. effect of superabsorbent application was not significant for biological yield and thousand grain weight. interaction effects of hybrids×superabsorbent application and water treatment×superabsorbent application were significant for yield and yield components. mean grain yield under well-water and terminal drought stress conditions were 2948 and 1345 kg/ha respectively. activity of gpx, sod enzymes and rwc decreased while cml increased under terminal drought stress condition. according to comparison of grain yield and yield components and also based on physiological traits which were studied in this research, however superabsorbent application decreased the water deficit affect under terminal drought stress condition, but it does not seem that superabsorbent application could be individually completely compensate the water stress damage.