effect of drought stress and sulphur fertilizer on quantity and quality yield of psyllium (plantago ovata l.) in baluchestan

management of chemical fertilizers application is very important issues on environment and plant yield especially in arid and-semi arid region. in order to determine the effects of drought stresses and fertilizer levels on quantity and quality yields of psyllium (plantago ovata l.), a study was conducted as split plot based on randomized complete block design with four replications at the natural resources and agriculture researches center of balouchestan, iran, during growing season of 2009-2010. treatments included different irrigation regimes (three, five and eight times irrigation during the growing season) as main plots and four levels of sulphur fertilizer (0, 75, 150 and 225 kg.ha-1 sulphur) as sub plot. the results showed that the irrigation regimes and sulphur fertilizer had significant effects on seed and biological yield of psyllium, so the highest seed and biological yields obtained in eight times irrigation. also, the maximum of these factors were achieved in 225 kg.ha-1 sulphur. the highest harvest index and 1000- seed weight, no. seed per spike and no. spike per plant were observed in eight times irrigation and 225 kg.ha-1 sulphur. the highest plant height was obtained in eight times irrigation and 225 kg.ha-1 sulphur and the maximum mucilage percentage and proline content were obtained in three times irrigation. the maximum mucilage yield and carbohydrate content were achieved in eight times irrigation. among sulphur fertilizer, the highest amounts for all factors were achieved in 225 kg.ha-1 sulphur. there was positive and significant correlation between seed yield with spike no. per plant, seed no. per spike, 1000-seed, biological yield and mucilage yield.