Races
There are eight races of Ug99, which (under the North American nomenclature system) have the designations TTKSK, TTKSF, TTKST, TTTSK, TTKSP, PTKSK, PTKST, and TTKSF+. They are all closely related and are believed to have evolved from a common ancestor.
TTKSK was the first Ug99 race to be characterised. 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 the Sr gene Sr24. TTKST is now the predominant stem rust race in Kenya.
A table of the eight known Ug99 races, along with their virulences and the countries in which they have been confirmed can be found in Hodson et al., 2012.
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Famous quotes containing the word races:
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