Development and Utilization of Sorghum as a Bioenergy Crop

Sorghum is not a newcomer crop. World-wide, it is the fifth most important cereal crop, after wheat rice, corn, and barley. Sorghum is unique in that is can grow in some of the harshest environments, where many other crops cannot be produced. It is highly resistant to drought, but can also withstand water logging much better than most of the other cereals. Sorghum’s large root system allows it to obtain nutrients from poor soils or, when fertilizers are applied, to use those nutrients very efficiently. Even though the species originated from semi-arid regions of Africa, it has been adapted to a wide variety of climates, including temperate and humid environments. Ironically, it may have been its superior tolerance to the marginal environments, common in many developing countries that hindered its wider adoption in the developed countries, as sorghum was labeled a poor-man’s crop. Additional factors that contributed to an underutilization of sorghum were the lower nutritional value of the grain and the lower yield compared to corn under good growing conditions. Although breeding efforts have produced dramatic improvements in grain and forage sorghum varieties, the amount of resources invested in the study of the crop have traditionally been minuscule compared to those invested in many other species. As a consequence, most of the abundant genetic diversity of cultivated and wild sorghums remains untapped. The renewed interest in biofuel production offers the possibility to exploit the useful traits of this species. Sorghum represents an ideal dedicated energy crop, as grain quality is now considered less important, and concerns about the environmental cost of high-input agriculture and food security grow. The lower need for fertilizers and pesticides may make it an ecologically attractive crop, especially when combined with conservation-agriculture production systems.