Evaluation of Sugar Sorghum Genotypes for Bioethanol Production

Sugar sorghum has emerged as a highly promising crop for bioethanol production owing to its high biomass yield potential and its remarkable capacity to accumulate fermentable sugars in the stalks. The aim of this study was to evaluate the productivity, sugar accumulation capacity, and bioethanol potential of 12 sugar sorghum accessions under the conditions of Northern Kazakhstan. Field experiments were carried out over the 2024-2025 growing seasons, during which key agronomic and technological traits were assessed, including green biomass yield, juice yield, total soluble solids (Brix), sugar concentration, and theoretical ethanol yield. The analysis of variance revealed that biomass yield was predominantly driven by weather conditions (p < 0.001), whereas sugar concentration was significantly influenced by genotype (p < 0.05). Several genotypes, namely Volonter, Kapital, Sevilya, Flagman, Chayka, and Sauri, consistently exhibited high sugar productivity and bioethanol potential across years, confirming considerable genetic variability in these traits. Storage of stem juice resulted in sugar losses of up to 30.7%, indicating the necessity for rapid processing of raw biomass after harvest. Under laboratory fermentation conditions, juice from the Sevilya genotype (17.9 Brix) achieved a sugar-to-ethanol conversion efficiency of 74.3% relative to the theoretical yield. Overall, the findings confirm the suitability of sugar sorghum for bioethanol production and highlight its strong potential as an energy crop under the arid agroclimatic conditions of Northern Kazakhstan.