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Stem rust home page

Disease resistance. Stem Rust Resistance.

Background information

Stem rust is one of the most devastating diseases affecting wheat worldwide. In North America the last epidemics were recorded in 1955, since then stem rust has been under control by the use of resistant cultivars and eradication of alternate hosts. Resistant cultivars have always been effective control of this disease worldwide. But in 1999 a new race of Puccinia graminis f. sp. tritici, the causative agent of stem rust, was detected in Uganda that was virulent against the traditional wheat resistance genes, Sr31 and Sr38 (1). This race was denominated TTKS, or alternatively, Ug99. In 2003 race Ug99 was found in Kenya and in 2007 in Yemen (1-3). This virulent race could soon migrate to the Middle East and Central Asia and can attack many of the current cultivars in use worldwide (4, 5).

Due to the widespread susceptibility to Ug99 and the potential perspectives of new widespread stem rust epidemics, the Global Rust Initiative (www.globalrust.org) set as one of its top priorities the monitoring and deployment of new sources of resistance to stem rust.

Genes that are currently effective against Ug99 are displayed on by clicking on the map below (opens in a new page, requires Javascript enabled). If you cannot see the map, the links on the left panel will take you to gene specific pages within MASWheat. It must be noted that the resistance genes confer different levels of protection and the most effective strategy is to stack several on the same genetic background.

stem rust resistance genes

Other stem resources in the web

The web sites of the Borlaug Global Rust Initiative (BGRI), CIMMYT and USDA among others, provide news, resources and other documents on stem rust. Below we highlight some of them:

Rust Tracker: CIMMYT and BGRI provides a Google Earth visualization that tracks Ug99 status world-wide.

BGRI Wheat Rust Surveillance Manual: A publication that provides guidelines for field surveys, use of GPS units and protocols on handling field samples.

Ug-99 field and greenhouse evaluations: wheat and barley susceptibility data from nurseries in Kenya and the US. Data collected by the Cereal Disease Lab of the USDA-ARS.

Plant Disease Lessons - Stem Rust: information produced by the American Phytopathological Society.


1.Detection of virulence to wheat stem rust resistance gene Sr31 in Puccinia graminis f. sp. tritici in Uganda. Pretorius ZA, Singh RP, Wagoire WW, Payne TS. In: Plant Disease, 2000, 84:203. DOI: 10.1094/PDIS.2000.84.2.203B

2. Deadly wheat fungus threatens world's breadbaskets. Stokstad E. In: Science, 2007, 315:1786-1787. DOI: 10.1126/science.315.5820.1786

3. The spread of stem rust caused by Puccinia graminis f. sp. tritici, with virulence on Sr31 in wheat in Eastern Africa. Wanyera R, Kinyua MG, Jin Y, Singh R. In: Plant Disease, 2006, 90:113. DOI: 10.1094/PD-90-0113A

4. Tracking wheat rust on a continental scale. Kolmer JA. In: Current Opinion in Plant Biology, 2005, 8:441-449. DOI: 10.1016/j.pbi.2005.05.001

5. Current status, likely migration and strategies to mitigate the threat to wheat production from race Ug99 (TTKS) of stem rust pathogen. Singh RP, Hodson DP, Jin Y, Huerta-Espino J, Kinyua MG, Wanyera R, Njau P, Ward RW. In: CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources, 2006, 1, No.054 DOI: 10.1079/PAVSNNR20061054

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