Potential of Some Sweet Sorghum (Sorghum bicolor L.) Genotypes Under Two Water Regimes for Sugar and Bio-ethanol Production

During the last years, the total annual production of sugar in Syria has been fluctuating, but the demand of sugar is increasing rapidly. The irrigated sugar beet covers only about 40 % of the total local sugar demand; and large quantities of sugar are imported. Sweet sorghum, also called "sugar cane of desert", has emerged as a smart dual purpose and alternative crop providing food, feed, sugar and second generation bio-fuel without threatening food security and natural resources. Current study was conducted to estimate the sugar and bio-ethanol production potential of nine introduced varieties of sweet sorghum, along with a local cultivar 'Razineah' as control, under two water regimes; well watered (WW) and low moisture stress (LMS), during the summer season of 2010, very high daily maximal temperatures attaining around 45 degrees C in the field. This factor constituted another selection pressure to the trail. A wide range of variability among the ten genotypes in terms of stalk yield, Brix (%), sugar and bio-ethanol potential yield. In addition the higher Brix readings under LMS for most varieties were compensated by reduction in juice content in sugar stems, as a consequence sugar yield affected with the reduction in juice yield. Significant positive correlation between cane components (height, diameter) with stalk yield and juice yield under both WW and LMS conditions was observed. Highly positive significant correlation was observed between stalk yield, juice yield and days to 50 % flowering under LMS condition, and a significant negative correlation was observed between Brix with stalk yield and juice yield under LMS. One genotype ICSSH 30 was superior among the others in terms of drought-tolerance associated traits and high sugar and bio-ethanol potential yield under both water regimes.