Prospect of sorghum as a biofuel feedstock

In this chapter we review the genetic variability and related agronomic perspectives of sweet sorghum. These characteristics are mainly presented and discussed taking in mind quantitative and qualitative traits of sweet sorghum as a multipurpose feedstock. The recent remarkable expansion of bioenergy crops, encouraged by favorable biofuel policies, has boosted intensive research programs worldwide on the use of sweet sorghum as feedstock for food, fodder, energy and in other industrial applications. In energy terms, sorghum is the only feedstock where ethanol can be produced either through grain, sweet juice, syrup or biomass, in other words having relevance to first, second and third generation biofuels. As a row crop, management practices developed for other conventional crops under a wide range of agro-climatic conditions can be easily adapted to cultivate sweet sorghum, thanks to its versatility and low input requirements. However, harvesting, transportation from field to processor and processing remain as past and present unsolved problems. Moreover the large diversity in traits, important for biofuel production, opens up excellent opportunities for sweet sorghum improvement through traditional breeding and modern molecular tools. In general biofuel candidate traits present across the sorghum genus are governed by multiple genes, and both additive and dominance components of gene action can be exploited while breeding for high stalk sugar and juice yielding genotypes. In order to take full advantage of all carbohydrate forms it would be advantageous to develop specialized cultivars that allow a single process to utilize all plant components for liquid fuel production. However, more focused research in this area may aid in enhancing the economic viability and environmental sustainability of sweet sorghum value chain.