Phenotypic Evaluation of Sweet Sorghum Lines for Bioethanol Production.

The stem juice of sweet sorghum is rich in fermentable sugars and is a desirable primary material for alcoholic fermentation. Today, interest in growing sweet sorghum for fermentable sugars is increasing worldwide; thus there is strong demand for elite varieties and hybrids offering high sugar yield and sustainable production. However, sweet sorghum hybrids, cultivars, and varieties suitable for bioethanol production are essentially lacking at the present time. Like other energy crops, sweet sorghum has not been bred for biofuel. Recently we initiated a research project focus on sweet sorghum germplasm enhancement and genetic improvement through germplasm evaluation, gene discovery and molecular breeding. A preliminary evaluation was conducted with a set of 687 germplasm accessions. Phenotypic characterization focused on those traits that are important for high sugar content, high biomass yield, flowering time, resistance to diseases and insects, and wide adaptability. Based on the phenotypic data, substantially genetic variations were observed among the germplasm originating from a wide range of geographic locations worldwide. These untapped genetic resources harbor an excellent gene pool for crop improvement. Furthermore, a group of selected germplasm lines will be valuable materials for breeders to do further manipulation toward the production of new cultivars or hybrids.