Effect of drought stress on dry forage yield, plant height, prussic acid and LAI in four varieties of sorghum bicolor

In order to determine the effect of drought stress on some sorghums variety for dry matters, plant height, prussic acid and LAI. A field experiment preformed with four Sorghum bicolor varieties, using a split plot in randomized complete block design with four replicates in 2006 at Islamic Azad university - shahr-e-Qods Branch. Experiment subjected to different soil moisture treatments of 80% (Normal irrigation, control), 40% (Medium stress), and 20% (High drought stress) relative water content (RWC) from four leaf stage to maturity by controlling irrigation in a sandy loam soil. Results showed that imposed drought stress induced, a strong increase in prussic acid, lAI, dry matter, plant height. Differences between varieties for these characters were significant. Up on these results, possible physiological role of all these characters for selection of sorghum's varieties to drought stress is discussed.