Systems of production of beans and cassava in Latin America with implications for research design

The process of identifying the "relevant constraints" and their incidence on breeding programs and agricultural research of international centers are explained and case histories are provided on the role of these 3 types of information (macro stage, micro stage, critical inference stage) related to research design in beans and cassava at the Centro Internacional de Agricultura Tropical (CIAT), The crucial decisions of the international centers consist in the definition of "relevant constraints", followed by a more mechanical process consisting of germplasm collection, identification of desired characteristics, screening and crossing, and dissemination. Regarding beans and cassava, different "relevant constraints" and different characteristics of the crops indicate the utilization of different strategies with the same output, a high-yielding var. not dependent on high levels of inputs. (CIAT)