ARS | Publication request: Resistance to Eastern African Stem Rust Isolates with Broad Virulence in Us and Cimmyt Wheat

Submitted to: APS Annual Meeting
Publication Type: Abstract
Publication Acceptance Date: June 1, 2005
Publication Date: June 1, 2005
Citation: Jin, Y., Singh, R. 2005. Resistance to eastern African stem rust isolates with broad virulence in U.S. and CIMMYT wheat [abstract]. APS Annual Meeting. Phytopathology 95:S49.

Technical Abstract: The stem rust resistance gene Sr31 was derived from rye and has been used as the main component for stem rust resistance in many wheat cultivars worldwide. Isolates of Puccinia graminis f. sp. tritici with virulence to Sr31 were identified from Uganda in 1999. Similar virulence was observed in Kenya in 2003 and 2004. An isolate collected from Uganda in 1999 and an isolate collected from Kenya in 2004, identified as race TTKS, were used to evaluate U.S. and CIMMYT wheat. Cultivars and advanced breeding lines (450) in various wheat classes from U.S. and 152 bread-wheat cultivars from CIMMYT, Mexico, were tested for resistance to these two stem rust isolates. Resistance to race TTKS was detected in all classes of wheat with the following frequencies: 16% of U.S. hard red spring wheat, 48% of the U.S. hard red winter wheat, 27% of U.S. soft red winter wheat, 50% of durum wheat, and 16% of CIMMYT spring bread wheat. Resistance in the hard red winter wheat was primarily due to Sr24, and resistance in the soft red winter wheat was primarily due to Sr36. Resistance to race TTKS due to SrTmp was present but in a low frequency. Genes conferring resistance in the spring wheat are not known, but Sr24 may be present in some lines. The adult plant resistance of some selected wheat cultivars will be assessed in the field in Kenya.