ABSTRACT
The world population is estimated to increase from 6.7 billion to 9.2 billion by 2030. On the other hand, global oil production is expected to decline from 25 billion barrels to 5 billion barrels by 2050 (Campbell and Laherree 1998). Thus the energy demands of the future are likely to play a key role in geopolitical economics. Given this reality, nations around the world are investing heavily in alternative sources of energy, including bioethanol from a diverse set of feedstocks. Sorghum [Sorghum bicolor (L.) Moench] is the fi fth most important cereal crop, providing food, feed and fi ber for the world and is currently grown in 35 m ha (FAOSTAT 2013) in over 104 countries. This crop is considered a new generation bioenergy crop owing to its multiple uses and wider adaptability to varied agroclimatic conditions. Further, it accumulates sugary juice in its stalks, yielding higher in addition to the biomass and grain yields. Sorghum being a C4 species is more water-use effi cient and can be cultivated in areas lying between 400 South and North latitudes of the equator (Rao et al. 2009). Among different biofuel feedstocks, sorghum is of particular interest because its biomass is variously used for the production of energy, fi ber, building materials or paper, as well as for syrup and animal feed, while the grain is either used for human consumption or for ethanol production or as feed. This is the only feedstock where ethanol can be produced either through grain, sweet juice, syrup or biomass, in other words having relevance to fi rst, second and third generation biofuels. Sweet sorghum (Fig. 13-1a) has many useful traits such as a drought resistance (Rao et al. 2012), water logging tolerance, salinity tolerance (Almodares et al. 2009) and with high biomass yield, etc. In recent years biomass sorghum (Fig. 13-1b) is gaining popularity as investments on effi cient cost effective lignocellulosic biofuel production are increasing in many nations.
