Most of the world's major staple food crops - barley, corn, potatoes, rice, soybeans and wheat - have been intentionally and successfully introduced into geographies, climates and habitats diverse from their centers of origin. Despite wide-scale geographic introductions and subsequent breeding to increase productivity, disease resistance, insect resistance and other desired trait, only a few agronomic introductions of food or feed crops have resulted in localized ecological disturbances. Explanations offered for the limited natural spread of introduced crops per se, include: requirements for high inputs of fertilizer and water, poor competition with weeds and native vegetation, or absence of weedy relatives in the areas in which the crops are grown. The report investigates the efficacy of the technology.