Evaluation of sweet sorghum genotypes for bioethanol yield and related traits

The cultivation of sweet sorghum (Sorghum bicolor (L.) Moench) for bioethanol production is receiving global attention due to the plant's sugar-rich stalk juice, which can be fermented directly to ethanol. One of the important steps toward the development of a superior sweet sorghum cultivar is proper assessment of bioethanol-related traits in different environments. This study was conducted to characterize global sweet sorghum accessions for bioethanol yield and related traits. To do this and to obtain a final cultivar suitable for efficient bioethanol production, two different environments were chosen to select for the characteristics studied. In total, 53 genotypes, which were selected from 551 accessions and nine cultivars, were evaluated in two contrasting environments and two consecutive years (2014-2015). The results revealed wide variability among the genotypes for the traits investigated. In all the growing years and locations, the highest values for the extractable stalk juice yield, bioethanol yield, and juice Brix content were recorded for BSS55 (22 740 L ha(-1)), BSS46 (1569.6 L ha(-1)), and BSS67 (15.63 degrees Bx), respectively. The genotypes that originated from the USA showed some of the highest values for bioethanol yield and related traits. Positive and very high correlations were observed between the bioethanol yield and extractable stalk juice yield (r = 0.861**) and fructose and glucose concentration (r = 0.856**). The knowledge obtained in this investigation about the variation in the bioethanol yield and related traits led to potential genotypes that can be used in sweet sorghum breeding programs for bioenergy production. (c) 2020 Society of Industrial Chemistry and John Wiley & Sons Ltd