Submitted to: Eastern Wheat Workers and Southern Small Grain Workers Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 17, 2011
Publication Date: N/A
Technical Abstract: The control of wheat stem rust (Puccinia graminis f.sp. tritici) in the U.S. has been a remarkable success story. Since the last major epidemics of the 1950’s (race TPMK or 15B), losses to stem rust have become increasingly rare. The incidence and number of races in the U.S. east of the Rocky Mountains has declined to the point that in recent years, only one or two races have been detected in the Eastern U.S. In some years, wheat stem rust has only been found on susceptible trap plots late in the growing season. In fact, P. graminis f.sp. tritici could be considered an 'endangered species' in North America if plant pathogens ever merited such designation. This puts us in an enviable position that we should not take for granted. This situation is the direct result of the combination of the successful barberry eradication program of the last century, the widespread deployment of resistant varieties, and the very low overwintering population size of the pathogen. In response to the potential arrival of the Ug99 family of stem rust races, breeders and pathologists have placed renewed emphasis on stem rust resistance in their programs. The demand for early generation screening of materials in inoculated field nurseries in the southern states has the potential to alter the current population dynamics in the U.S. Several measures that could mitigate any negative consequences of these inoculated nurseries will be discussed. In the long term, a strategically located regional stem rust nursery, similar to the current Castroville, TX leaf and stripe rust nursery, could best serve southern wheat breeding programs and reduce the potential for damage to susceptible wheat cultivars grown in the Midwest.