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

Abstract

Sweet sorghum (Sorghum bicolor (L.) Moench) is an important crop in Chad that plays an economic role in the countryside were stalks are produced mainly for human consumption without any processing. Unfortunately, very little information exists on its genetic diversity and brix content. Studies performed in 2014 and 2015 showed that there were significant variations (p < 0.001) for all assessed quantitative traits. Potential grain yield (0.12–1.67 t ha⁻¹), days to 50% flowering (68.3–126.3 days), and plant height (128.9–298.3 cm) were among traits that exhibited broader variability. Brix content range from 5.5 to 16.7% across accessions, was positively correlated to stalk diameter and plant height, but negatively correlated to moisture content in fresh stalk and potential grain yield. Fresh stalk yield range from 16.8 to 115.7 Mg ha⁻¹, with a mean value of 58.3 Mg ha⁻¹ across accession. Moisture content in fresh stalk range from 33.7 to 74.4% but was negatively correlated to fresh stalk yield. Potential sugar yield range from 0.5 to 5.3 Mg ha⁻¹ across accession with an average of 2.2 Mg ha⁻¹. Theoretical ethanol yield range from 279.5 to 3,101.2 L ha⁻¹ across accession with an average of 1,266.3 L ha⁻¹ which is significantly higher than values reported under similar semiarid conditions. Overall, grain yields were comparatively low. However, two accessions had grain yield of more than 1.5 t ha⁻¹; which is greater than the average 1.0 t ha⁻¹ for local grain sorghum varieties in Chad. These could have multi-purpose uses; grains, sugar and bioenergy production.