Characterization of Improved Sweet Sorghum Genotypes for Biochemical Parameters, Sugar Yield and Its Attributes at Different Phenological Stages

Sweet sorghum is a multipurpose biofuel feedstock that offers grain for human consumption, fodder for livestock and ethanol for transportation purposes. The knowledge on sugar components at different phenological stages of crop growth and identification of appropriate stage of harvesting is critical for sweet sorghum commercialization and value chain sustenance. In this regard, sweet sorghum stalk yield, juice yield, Brix%, pH, sugars (sucrose, fructose and glucose) and their content were analyzed at three different phenological stages i.e. the dough stage, physiological maturity and post-physiological maturity. Variations in sugar content at different growth stages revealed that the sugar yield was high at physiological maturity, but highest at post-physiological maturity. Sucrose accounts for major fermentable sugar (about 70%) and it sharply increased by 146% from dough stage to post-physiological maturity. The variation in the monosaccharides content (glucose and fructose) is not statistically significant. This study points to the potential scope for widening the harvesting window of sweet sorghum, by cutting the stalks from physiological maturity stage and beyond up to 15 days (post-physiological maturity), thus helping the commercial distilleries by addressing a major impediment in sweet sorghum value chain. The entries SP 4495, SP 4511-3 and SPV 422 are suitable for harvesting in a wider window of time as the sugar levels are sustained at same level from physiological maturity to post-physiological maturity.