The CIMMYT Wheat Program strives to increase the production of bread wheat, durum wheat, triticale, and barley in developing countries by helping to improve the productivity of the resources used by the millions of Third World farmers who grow these crops. In working toward this long-term goal, the Program relies on a close collegial relationship with literally thousands of scientists in national crop improvement programs around the world. Our approach is to provide several "intermediate" products and services: improved germplasm; training for national crop improvement program scientists; effective, practical research procedures, consultation with national programs on research problems, and research information. Cooperating national programs build on the work done by the Program, often refining and improving the germplasm contained in our international nurseries to better meet the needs of local farmers. The Wheat Program relies on the research and extension efforts of national programs both to implement and to multiply the impact of its work. CIMMYT has its headquarters at El Batan, 40 km northeast of Mexico City in the state of Mexico. Much of the wheat breeding work is carried out at three primary locations in Mexico: during the summer cycle (May through October) at two high elevation sites in central Mexico, El Batan and Toluca, and during the winter cycle (November through April) at the low-elevation Yaqui Valley Agricultural Experiment Station, near Ciudad Obregon in the state of Sonora in northwestern Mexico. A number of other sites in Mexico are used to screen germplasm for resistance and tolerance to specific diseases and stresses.