Characterization of semi-arid Chadian sweet sorghum accessions as potential sources for sugar and ethanol production

Authors: GAPILI, NAOURA - Institute For Research And Development In Agri-Environment(IRDA); Emendack, Yves; BALOUA, NEBIE - International Crops Research Institute For The Semi-Arid Tropics (ICRISAT); VOM BROCKE, KIRSTEN - Cirad, France; HASSAN, MAHAMAT - Institute For Research And Development In Agri-Environment(IRDA); SAWADOGO, NERBEWENDE - Health Sciences Research Institute; AMOS, DOYAM - Institute For Research And Development In Agri-Environment(IRDA); REOUNGAL, DJINODJI - Institute For Research And Development In Agri-Environment(IRDA); GILES, TROUCHE - Cirad, France; LAZA, HAYDEE - Texas Tech University

Submitted to: Nature Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2020
Publication Date: 9/11/2020
Citation: Gapili, N., Emendack, Y., Baloua, N., Vom Brocke, K., Hassan, M., Sawadogo, N., Amos, D., Reoungal, D., Giles, T., Laza, H. 2020. Characterization of semi-arid Chadian sweet sorghum accessions as potential sources for sugar and ethanol production. Nature Scientific Reports. 10, Article 14947.

Interpretive Summary: Sweet sorghum is a leading feedstock for plant based bio-ethanol production due to its sugary stalk and the fact that it can be cultivated in temperate, subtropical and tropical climates. A number of studies have been performed to assess the agronomic performance and yields of juice, sugar and ethanol of sweet sorghum accessions under variable management practices and climates. In semi-arid Chad, sweet sorghum plays a major economic role in the countryside where stalks are produced mainly for human consumption without any processing. Additionally, many of these sweet sorghum varieties have excellent potential for bio-energy production in arid and semi-arid production systems. To date, there is a dearth of information on the genetic diversity and sugar (brix) content of Chadian sweet sorghums. For this study, scientists from USDA-ARS, Chad, Mali, Burkina Faso, and France evaluated 105 untapped landraces of sweet sorghum locally known as sugar sorghum from the semi-arid Sudanese zone of Chad. The research aimed to identify high performance cultivars with dual-purpose use that could also be used for genetic improvement of global sweet sorghum breeding in semi-arid regions. Two cultivars, Balnda and Chian Woua, had high brix and showed quantitative and qualitative traits superior to commercially-grown varieties. These cultivars have the potential to improve elite sweet sorghum lines for bio-energy production in semi-arid regions around the world and will be investigated further in breeding experiments and yield trials. This study represents one of only a few efforts aimed at improving the utility of sweet sorghum for semi-arid and low-input environments and has the potential for significant global impact on plant-based biofuel production and small farm sustainability in developing nations.

Technical Abstract: Compared to other bio-energy crops such as corn, wheat, sugarcane, sugar beet, cassava, sweet potato, sweet sorghum is drought tolerant and can be grown in marginal regions that are not commonly used for crop production. To boost and expand bio-ethanol production from sweet sorghum in current climate, accessions with high stalk sugar production need to be identified. This study was conducted to assess the level of genetic diversity present among sweet sorghum in the semi-arid Chad's Sudanese zone using phenotypic traits, and to identify new sources of high brix content that could be used in bio-energy sorghum breeding programs globally. Two cultivars Balnda and Chian Woua showed brix level higher than most commercial hybrid; one of the most important trait to obtain a juice of high fermentable quality and thus maximize ethanol yield per hectare.