XVI International Botanical Congess

The objective of this study was to assess the potential of sweet sorghum as a source of sugar under conditions of Botswana. Samples of mature stalks from local accessions of sweet sorghum were collected from 5-months old field-grown plants. Carbohydrates were determined in internode samples from the top, middle and bottom of the stems. Mature (more than 14 months old) stalks of sugarcane were used a positive control for sugar accumulation analysis. Sucrose was the predominant sugar in the stems of both sweet sorghum and sugarcane. However, sucrose was mostly concentrated in the top internodes of sweet sorghum while it was more evenly distributed in sugarcane. Relative to sucrose, hexose sugar (glucose and fructose) amounts were significant in sweet sorghum than in sugarcane. In addition, amounts of glucose in the stem of sweet sorghum were negatively correlated to those of starch in the sametissues. Overall, these observations suggest that carbohydrate metabolism in sweet sorghum is different from that of sugarcane. Nonetheless, it is evident that sweet sorghum could serve as a source of sugar under conditions of Botswana.