Enhancing Durability of Stem Rust Resistance in Spring Bread Wheat in Central and West Asia and North Africa (CWANA) Region.

Stem rust is a major foliar disease of wheat in CWANA. Because of both its ability to form new races and its air-borne dispersal mechanism stem rust continues to threaten stable wheat production and food security in CWANA. Genetic resistance is widely used for the control of rust diseases and is recognized as the most economical and environmentally friendly control measure. Progress in breeding for rust resistance has been made; however, until recently, most of the resistance used is usually based on a single major gene or combinations of major genes. Experience has shown that such resistance only last for few years. To deal with with the reoccurring pathogen threats breeding programs have recently adopted strategies that are expected enhance durability of resistance. To cope with the threat of stem rust race ug99, ICARDA has adopted a strategy that combined conventional and molecular breeding to achieve durable resistance. Early products of this shift in strategy are now available to national programs. In this presentation the methodology used to enhance durability of rust resistance is outlined and achievements are highlighted.