devastated the US and Canadian wheat crops, leading to estimated losses of around US 3 billion (in 2007 dollars). This disease prompted the organization of the first international nursery trial to test wheat lines for resistance in seven countries. As a result of this international breeding program, stem rust was brought under control by the mid-1950s.
FIGURE 24–1 Path of a disease outbreak.
SOURCE: Amri Ahmed, 2nd microbial commons expert workshop, Brussels, March 25, 2009.
This success was one of the motivating factors to establish the Consultative Group on International Agricultural Research (CGIAR), which coordinates international breeding programs for the main food crops based. This in turn led to the Green Revolution, golden rice, and other agricultural breakthroughs.
What is interesting is that the disease is back again. Figure 24–1 shows the path of a recent epidemic of stem rust spreading from Uganda since 1999. So we are faced here with an evolving biological reality—there is a race going on in which microbial pathogens evolve and make previous crop improvement programs obsolete. The microbial pathogen population of Puccinia graminis has been evolving and a new program of international collaborative research is needed to bring stem rust under control in East Africa and the Middle East.
An important lesson from these programs is that it is only possible to derive the benefits for disease diagnostics and crop improvement if one can gather and identify the microbial materials from all the places where the diseases are, which requires collaborative DNA sequencing arrangements of the main materials, and track down all