ABSTRACT
To add to the complexity of the effects of climate change on crop productivity, the suboptimal growth conditions associated with global warming are occurring at a time when the world population is likely to increase by about 30% by 2050 (UN report 2011). It has been predicted that the world food demand will double from its present demand of 12 to about 25 Tetracalories d−1 in 2030 due to increased world population as well as increased per capita food consumption (Murchie et al. 2009). This has triggered an immediate need to substantially enhance seed yield and productivity of major food crops such as rice, wheat, and maize to meet the nutritional demand of the increasing population over the next 50 years (Murchie et al. 2009). For instance, the world production of wheat in 2010 was 651 million tons (FAO 2012), which needs to be increased to about 840 million tons per year by 2025 to meet the required demand of increasing population (Murchie et al. 2009). The projected increased food demand is occurring in a context of losses of agricultural land due to urbanization, desertication in most of the developing countries, increasing proportion of grain for animal nutrition and biofuel generation, and suboptimal conditions to attain maximum crop yield (Murchie et al. 2009; Zhu et al. 2010).
