Effects of drought stress on biomass and carbohydrate contents of two sweet sorghum cultivars.

Sweet sorghum is adapted to the hot and dry climatic conditions. It can be used for different products such as food, feed, fiber and fuel. This study was carried out to evaluate the effects of four irrigation intervals and three harvesting dates on stem height, stem diameter, biomass, juice volume, brix, sucrose and invert sugar of two sweet sorghum cultivars. The results showed that delay in irrigation intervals from 7 to 21 day significantly decreased all the above characteristics expect for invert sugar which was increased. The highest biomass (56.50 t ha(-1)) and sucrose content (11.35%) were obtained at 7 to 10 day irrigation interval. Both biomass and sucrose contents decreased significantly as harvesting date delayed from physiological maturity. Since both sweet sorghum cultivars, Keller and Sofra had similar biomass, sucrose content, brix and juice volume across irrigation intervals and harvesting dates, therefore it is suggested to plant either Keller or Sofra irrigated on 7 to 10 day interval and harvested at physiological maturity.