History of International Nurseries

In the 1950s a stem rust epidemic attacked wheat in the USA and Canada. About 60% of the wheat harvest in the US was destroyed in 1953, and about 75% in 1954. The culprit was a new pathogenic race called 15B, which was resistant to all genes present in existing commercial varieties. A similar race spread widely in Latin America. In response to the epidemic, the US Department of Agriculture requested that seven nations (Mexico, Colombia, Ecuador, Peru, Chile, Argentina, and Canada) join forces in testing 1000 lines selected from the wheat world collection.

The Office for Special Studies, CIMMYT's predecessor, was an active participant in the effort, and new lines of wheat were exposed to stem rust in Mexico. The results of the First International Stem Rust Trial exceeded all expectations. New sources of resistance were found for the 15B race, some of which may still be present in commercial varieties today. An added benefit of this trial was the creation of a network through which lines and introductions could be tested and distributed to developing countries.

In 1960 the first international spring wheat yield nursery was distributed by the Office for Special Studies to 12 countries from Canada to Argentina. In response to the expressed interest of other wheat-producing countries around the world, in 1964 CIMMYT created the International Spring Wheat Yield Nursery (ISWYN) that included lines adapted to high and low latitudes.

In 2001, the International Wheat Improvement Network (IWIN) at CIMMYT prepared 2,766 sets of 40 different bread wheat, durum wheat, triticale, and barley nurseries. Seed shipments were sent to a network of 619 wheat scientists from 117 countries around the world.