|Wanyera, R - KENYA AGRIC. RES. INS.|
|Kinyua, M - KENYA AGRIC. RES. INS.|
|Singh, Ravi - CIMMYT, MEXICO|
Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2005
Publication Date: June 1, 2005
Citation: Wanyera, R., Kinyua, M.G., Jin, Y., Singh, R. 2005. The spread of puccinia graminis f. sp. tritici with broad virulence in eastern Africa [abstract]. APS Annual Meeting. Phytopathology 95:S49. Technical Abstract: Stem rust resistance in wheat worldwide has been effective and stable for a long period of time. Isolates of Puccinia graminis f. sp. tritici with virulence to Sr31, a gene used as the main component for stem rust resistance in many currently grown wheat cultivars worldwide, were detected in Uganda in 1999. In 2003 and 2004, many CIMMYT wheat lines planted in Kenya were susceptible to stem rust. A study was conducted to characterize the virulence of stem rust isolates from Kenya that overcame the resistance in CIMMYT wheat. Six isolates collected during 2004 at different locations were tested on the 16 stem rust race differential lines and an extended set of designated Sr genes at the seedling stage. All isolates from Kenya were virulent on Sr31 and were identified as TTKS. Stem rust resistance genes that are effective against TTKS at the seedling stage include Sr13, 22, 24, 25, 26, 27, 29, 32, 33, 35, 36, 37, 39, 40, 44, and Tmp, most of which are of alien origin. Single-gene lines carrying Sr25, 26, 29, and 44 did not confer adequate level of resistance in the adult plant stage. The virulence spectrum of the Kenyan isolates was identical to that of an isolate collected from Uganda in 1999 with virulence on Sr31, indicating that this race is now widespread in the Eastern Africa highlands.