BREEDING DISEASE-RESISTANT WHEATS FOR TROPICAL HIGHLANDS AND LOWLANDS

Wheat is grown on about 10 million ha in the tropical highlands and lo wlands of the world, where it is an important food source. Many farmer s in these areas work under subsistence conditions. Wheat diseases in tropical regions can be severe and require significant efforts to cont rol. For economic and environmental reasons, host plant resistance is the most appropriate and sustainable disease control method. We descri be highland and lowland tropical wheat regions and discuss CIMMYT's br eeding strategies, philosophies, and progress in developing resistance to the major diseases such as rusts, foliar blights, fusarium scab, B YD, and spot blotch. Additionally, we review the role of national whea t research programs and beneficial spillovers of our combined breeding efforts to other wheat production areas of the world.