摘要：It is forty years since Willard Cochrane (1958) introduced the "technology treadmill", which suggested that farmers have to adopt new technologies to maintain profitability. Cochrane's concern was the agricultural sector of the United States, but the treadmill argument has global applicability, and has arguably influenced the international agricultural research effort. For world agriculture, the CGIAR system has the task of promoting technical change and, if it is succeeding in diffusing better technologies to the poorest countries, there should be some evidence of convergence. Thus, the less agriculturally successful countries within Africa should be closing the gap between them and the leaders, and the gaps between Africa and Asia, and the developed and developing countries should be decreasing.
