What is the Ug99 strain of black stem rust?
In 1999, a new virulent race of stem rust was identified from wheat fields in Uganda – popularly known as Ug99 after the year and country of discovery. The unique virulence associated with Ug99, or variants, has rendered a large proportion of global wheat cultivars susceptible.
How do you control black stem rust on wheat?
In-crop management of stem rust
- Inspect wheat crops every 7 to 10 days from flag leaf emergence to early dough grain development.
- Carefully inspect different plant parts, especially the lower stems, for symptoms of stem rust.
What kind of fungus is Ug99?
Race Ug99 of the fungus Puccinia graminis tritici that causes stem or black rust disease on wheat was first detected in Uganda in 1998.
What does Ug99 stand for?
graminis evolved the means to overcome mankind’s most ingenious genetic defenses. This distinct new race of P. graminis, dubbed Ug99 after its country of origin (Uganda) and year of christening (1999), is storming east, working its way through Africa and the Middle East and threatening India and China.
Which type of spores of Puccinia graminis tritici infect the plant?
Towards the end of the cereal host’s growing season, the mycelia produce structures called telia. Telia produce a type of spore called teliospores. These black, thick-walled spores are dikaryotic. They are the only form in which Puccinia graminis is able to overwinter independently of a host.
What are the symptoms of stem rust of wheat?
Stem rust on wheat is characterized by the presence of uredinia on the plant, which are brick-red, elongated, blister-like pustules that are easily shaken off. They most frequently occur on the leaf sheaths, but are also found on stems, leaves, glumes and awns.
Where is Ug99 found?
Ug99 and related variants are mostly confined to Eastern Africa but have also expanded into the Middle East. Rust spores can travel great distances on wind currents. From its initial detection site in Uganda in 1999, Ug99 has moved to Kenya, Sudan, Ethiopia, Yemen, and, most recently in 2008, Iran.
Which crop does rust Ug99 not affect?
Gene resistance Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades. These resistant Sr genes, of which 50 are known, give wheat different resistances to stem rust.
What is black rust?
Black rust can be visually identified as a thin, black film which is the result of oxidation in a low oxygen environment. This type of rust is a more stable rust layer that does not propagate as rapidly as other rust forms.
Which species of Puccinia cause black stem rust of wheat?
Black stem rust of wheat, caused by Puccinia graminis f. sp.
What causes black rust of wheat?
Stem rust, also known as black rust, is caused by the fungus Puccinia graminis f. sp. tritici. It infects wheat and other cereals across all U.S. growing regions.
What does Ug99 do to wheat?
Ug99 is a lineage of wheat stem rust (Puccinia graminis f. It can cause up to 100% crop losses and is virulent against many resistance genes which have previously protected wheat against stem rust. …
How does Ug99 differ from other strains of Black Stem Rust (BSR)?
Gene resistance Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades. These resistant Sr genes, of which 50 are known, give wheat different resistances to stem rust.
What is the history of stem rust in Kenya?
First detected in South Africa in 2000, Zimbabwe 2009, and Uganda in 2012. Discovered in Kenya in 2006 was the first Ug99 race found to be virulent against Sr gene Sr24. TTKST is now the predominant stem rust race in Kenya. Sr14 is effective against TTKST.
What is black stem rust of wheat?
Black stem rust of wheat, Puccinia graminis f. sp. tritici (Pgt), caused serious disease outbreaks in North America during the first half of the 20th century, with wheat yield losses estimated at 19%–28% in some states ( Singh et al., 2015 ).
Is TTKST a Ug99 race?
Like most Ug99 races, and unlike other stem rust varieties, it is virulent against the Sr gene Sr31. It is known to be present in Uganda, Kenya, Ethiopia, Sudan, Yemen, Iran and Tanzania. TTKST, discovered in Kenya in 2006 was the first Ug99 race found to be virulent against Sr gene Sr24.