Chapter 46 Contributions of National Agricultural Research Systems to Crop Productivity This chapter describes the impact of national agricultural research systems on the unfolding of the Green Revolution in four regions: Asia Latin America the Middle East and North Africa and Sub Saharan Africa. Although international institutions contributed much of the research that led to the Green Revolution national programs also proved important in the development and diffusion of modern varieties. This chapter documents the Green Revolutions that occurred in 11 food crops – wheat rice maize barley sorghum millets lentils groundnuts beans cassava and potatoes. The chapter traces the overall role of national institutions and the growing importance of national agricultural research systems in the developing world. It also discusses the interaction of National Agricultural Research Systems and International Agricultural Research Centers which have largely played complementary roles. Finally it discusses the political economy of support for national agricultural research.