The need for high-payoff inputs has been widely accepted because of the success achieved by modern wheat, corn, and rice varieties beginning in the 1950s and 1960s. These varieties are highly responsive to fertilizer, pesticides, and water management and have resulted in substantial growth in agricultural output in many developing countries.Some have argued that the relative absence of these inputs has been one factor holding back agricultural development in Africa compared to other developing regions. The distributional or equity effects and environmental impacts of these inputs, however, have been the subject of much debate and are discussed in more detail in Chapter 12.