Characterization of sweet sorghum genotypes based on agro-industrial performance and fermentation potential

Abstract

The industrial yield of first-generation ethanol from sweet sorghum [Sorghum bicolor (L.) Moench] is a complex trait that depends on genetic and environmental factors, as well as on expression of a series of other traits, especially sugar yield and fermentation efficiency. The aim of this study was to evaluate the maturation curve and the period of industrial use (PIU) of sweet sorghum genotypes, as well as their fermentation potential with two strains of Saccharomyces cerevisiae. In field experiments, ten sweet sorghum genotypes were evaluated in three locations in the 2016–2017 crop season. The following traits were measured: flowering time, fresh matter production, plant height, juice extraction, total soluble solids content (TSS), and tons of Brix per hectare. Plants were harvested at seven different cutting times. Regression equations were fitted to describe the maturation curve and determine the PIU. In the fermentation experiment, the five genotypes with highest TSS in the last three cutting times in the field trials were tested. The yeast strains LNF Ca11 and a bakers’ yeast (BY) were used in the fermentation process. The profile of sugar accumulation in the stalk over the time was affected by the phenology of each sweet sorghum genotype. Some genotypes had PIU greater than 40 days. Fermentation potential was affected by the sweet sorghum genotype, by the yeast strain, and by the interaction between these factors. The combination of the yeast strain BY and the genotype CMSXS647 had the highest fermentation potential.