Ug99

Stem rust close up

Ug99 is a highly virulent strain of the wheat stem rust pathogen, Puccinia graminis f. sp. tritici. It was first identified in Uganda in 1999, hence the name Ug99. This strain poses a significant threat to global wheat production due to its ability to overcome many of the resistance genes that have been bred into wheat varieties over the past several decades.

Discovery and Spread

Ug99 was first discovered in Uganda in 1999 by scientists monitoring wheat crops for disease. Since its discovery, Ug99 has spread to several countries in East Africa, including Kenya, Ethiopia, and Sudan. The pathogen has also been reported in Yemen and Iran, raising concerns about its potential to spread to major wheat-producing regions in Asia and beyond.

Characteristics

Ug99 is particularly dangerous because it can overcome a wide range of resistance genes in wheat. Many of the wheat varieties grown worldwide possess the Sr31 resistance gene, which was effective against most strains of wheat stem rust until the emergence of Ug99. However, Ug99 has shown the ability to overcome Sr31, as well as several other resistance genes, making it a formidable threat to wheat crops.

Impact on Agriculture

The spread of Ug99 has significant implications for global food security. Wheat is a staple crop for millions of people around the world, and a major outbreak of stem rust could lead to severe reductions in wheat yields. This, in turn, could lead to higher food prices and increased risk of hunger and malnutrition in vulnerable populations.

Research and Management

Efforts to combat Ug99 include the development of new wheat varieties with resistance to the pathogen. Researchers are working to identify and incorporate new resistance genes into wheat breeding programs. Additionally, international collaborations, such as the Borlaug Global Rust Initiative, have been established to monitor the spread of Ug99 and develop strategies to mitigate its impact.

See Also

• Wheat
• Stem rust
• Plant pathology
• Food security
• Borlaug Global Rust Initiative