Scholars of global agriculture have long acknowledged the importance of the Rockefeller Foundation’s Mexican Agricultural Program (1943-1963) as providing the developmental model for the Green Revolution, America’s Cold War-era exportation of agricultural technology to the Third World. But few scholars have linked this postwar campaign with the Rockefeller philanthropies’ first attempt at "rural reconstruction,” directed in the U.S. South under the General Education Board (1903-1914). In both regions, Rockefeller agronomic experts imagined rural people as backward, tropical, and unknowledgeable, and sought to solve their social problems with technical, scientific solutions. Yet for small farmers in both Mexico and the South, technocratic development eased neither poverty nor hunger, engendering instead rural outmigration, the expansion of agribusiness, and environmental degradation. But contrary to much recent scholarship, these transformations were the product of human contingency and politics, not technological determinism, as local elites and industrializing states co-opted the Rockefeller project for their own purposes. In narrating these two campaigns as threads of a shared transnational story, rather than a comparative study, I hope to argue that “scientific agriculture” offered both promises and perils to tenant farmers, campesinos, sharecroppers, and ejidatarios, and that the histories of the twentieth-century American South and Global South reveal much when placed in common conversation. The project of development may indeed have roots closer to home than many Americans might expect.