Submitted to: Washington State University College of Agriculture and Home Economics
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2009
Publication Date: 7/1/2009
Citation: Chen, X., Wood, D.A. 2009. Epidemiology and control of rusts of wheat and barley. Page 30 In: 2009 Field Day Abstracts: Highlights of Research Progress. Washington State University Extension. Interpretive Summary:
Technical Abstract: Rusts of wheat and barley were monitored throughout the Pacific Northwest (PNW) using trap plots and through field surveys during the 2008 growing season. Through collaborators in other states, stripe rusts of wheat and barley were monitored throughout the US. In 2008, stripe rust occurred in 18 states, but severities were generally low throughout the country. However, the disease caused yield losses over 20% on susceptible winter and spring wheat cultivars in our experimental plots. Leaf rust was light but stem rust caused damage in some barley fields in the PNW. A total of 33 wheat stripe rust races and 11 barley stripe rust races were identified, of which one new race was identified for each of the wheat and barley stripe rusts. We have developed gene-specific molecular markers and used them to determine genetic relationships of races and compare populations of stripe rust. The first group of linkage maps were constructed for stripe rust genes through sequence comparison with stem rust and screening our stripe rust bacterial artificial chromosomal library. We constructed the first custom gene chip for stripe rust and used it to study genes involved in the different stages of the rust lifecycle. Through cooperation, 28 races were identified from barley stem rust samples collected in 2007 in Washington. In 2008, we evaluated more than 15,000 wheat and 5,000 barley entries for resistance to stripe rust and other diseases. We developed wheat germplasm with high level of high-temperature adult-plant (HTAP) resistance through marker-assisted pyramiding of genes previously identified from ‘Alpowa’ and ‘Express’. We completed studies to determine the genetics and map genes for race-specific all-stage resistance in ‘IDO377s’, ‘Zak’, ‘PI 181434’, and ‘PI 480148’; and identified four new genes in these wheat genotypes. We also map a gene for non-race specific HTAP resistance in the Yr8 near-isogenic wheat line. To answer the questions why race-specific all-stage resistance is not durable and non-race specific HTAP resistance is durable, we completed experiments to elucidate mechanisms of stripe rust resistance using the microarray technology. In 2008, we made wheat custom gene chips based on genes identified in the previous studies to determine common and unique genes regulated by various genes for either all-stage or HTAP resistance. Molecularly, HTAP resistance is more broadly based than all-stage resistance. Through collaborating with Dr. Dubcovsky’s program at UC Davis, we cloned resistance gene Yr36. In 2008, we evaluated 18 fungicide treatments including different rates and application combinations of Topguard, BAS 556 01, and Evito for control of stripe rust in experimental fields near Pullman, WA. Better formulations and applications of fungicides were identified.