The Effects of Nitrogen Treatments, Cultivars and Harvest Stages on Stalk Yield and Sugar Content in Sweet Sorghum

摘要

Due to the population increase, about 1.5 million tons of sugar is needed annually in Iran. Half of this amount is provided by sugar beet and sugarcane industries and the other half is imported. These two crops are facing many problems such as: high cost of planting and harvesting, long growing season and high water requirement. Whereas, sweet sorghum is well adapted to tropical and sub-tropical regions, highly biomass production, low water and fertilizers requirements and short growing season. So obtained sugar from this plant may replace imported sugar from aboard. This study was carried out, at Isfahan University Research Station, to evaluate the effect of three nitrogen treatments, three sweet sorghum cultivars and three harvesting stages on thestalk yield and sugar content. The results showed the effect of nitrogen treatments on stalk yield, brix value and sucrose content were not significant, but the effects of cultivars and harvesting stages on the above measurements were significant. Amongsweet sorghum cultivars, cv Rio had the highest stalk yield, brix value and sucrose content. These measurements were not significant for cv Vespa and IS2325. The effect of harvesting stage was significant for the stalk yield, brix value and sucrose content. Harvested plant at physiological maturity had the highest stalk yield, brix value and sucrose content and lowest at flowering stage. Based on these results, the highest stalk yield, brix value and sucrose content were obtained by planting cv Rio andharvested at physiological maturity stage.