duced the concept of breeding for different MEs. A ME is defined as a large, not necessarily contiguous area, Improved bread wheat (Triticum aestivum L.) cultivars for diverse which usually encompasses more than one country and agroecological environments are important for success in the effort to increase food production. In the 1980s, CIMMYT introduced the S. Dreisigacker and A.E. Melchinger, Inst. of Plant Breeding, Seed recent approach allows researchers to shift from the Science, and Population Genetics, Univ. of Hohenheim, 70593 Stuttuse of anonymous markers with unknown effect on the gart, Germany; M. Bohn,