ABSTRACT
Maize (Zea mays L.), a crop of worldwide economic importance, provides approximately 30% of the food calories to more than 4.5 billion people in 94 developing countries (Jat et al., 2013). Production of maize surpassed rice in 1996 and wheat in 1997, and is now close to 850 million tonnes (Mt); and maize production is increasing at twice the annual rate of rice and thrice that of wheat (Fischer et al., 2014). Factors driving this increase are the increasing demands for maize for food, feed and bio-fuel, and its resilience to biotic and abiotic stresses affecting most of the intensive production systems of the world. The demand for maize is expected to double worldwide, from about 558 Mt in 1995 to over 1100 Mt in 2050 (Dixon et al., 2008). With new analysis (Gerland et al., 2014) showing that, contrary to previous literature, world population can be expected to increase from the current 7.2 billion to 9.6 billion in 2050 and 10.9 billion in 2100, the demand for
maize may increase further. The increase in maize demand will be acute in Asia, where an 87% rise in demand from 162 Mt in 1995 to 303 Mt in 2020 is projected (Timsina et al., 2011). The human and environmental costs of expanding agricultural lands are such that, in reality, most of the necessary production gains going forward must be achieved on existing farmland through intensification of production (Foley et al., 2011).
