By 2020, 40 percent more grain will be needed throughout the world, which will require relying heavily on yield increases (Pinstrup-Andersen et al., 1999). Based on projections that land and water resources per capita will diminish during the coming decades, recent studies predict production must increase by 1.6 percent per annum over the next 20 years to meet the increasing global demand for wheat. About half of the required production increases are expected to come from crop management research (CMR), which implies that crop improvement must contribute close to 1 percent per annum. This poses an immense challenge to wheat improvement research, given that in recent years genetic gains of such magnitude have been realized infrequently (Byerlee and Traxler, 1999; Calderini et al., 1999). As Borlaug and Dowswell (1997) observed:
The only way for agriculture to keep pace with population and alleviate world hunger is to increase the intensity of production in those ecosystems that lend themselves to sustainable intensification, while decreasing intensity of production in the more fragile ecosystems.