Location: Hard Winter Wheat Genetics Research Unit
2011 Annual Report
In order to produce commercially competitive varieties of the future, new stem rust resistance genes must be incorporated into a forward breeding program. In addition, a backcross breeding program is required both for parent-building and as a hedge if commercially acceptable resistant varieties are needed in the short term. Rapid breeding methods, such as doubled haploids, will be needed to achieve results as quickly as possible.
Phenotypic selection for resistance using common North American races will be difficult in most backgrounds due to the high frequency of endemic stem rust resistance genes. Therefore, marker-assisted selection for new resistance genes will be necessary. Molecular markers are available or under development for virtually all new sources of stem rust resistance. Marker genotypes will be generated locally or in a high throughput facility at the USDA-ARS Regional Small Grains Genotyping Laboratory in Manhattan, KS. Resistance of advanced lines against African races of stem rust will be confirmed by field testing at cooperative research facilities in Kenya or at the USDA-ARS Cereal Disease Laboratory. Testing for agronomic traits, yield, and quality will be performed as usual by the breeding program.
During the first year of the project, approximately 225 cross combinations to incorporate resistance to Ug99 stem rust were made. These included the following resistance genes in various combinations: Sr2, Sr24, 1A.1R, Sr25, Sr22, Sr36, Sr32, Sr35, Sr39, and Sr40 was made. We will make two-way crosses in the second year greenhouse and work with the USDA-ARS to test marker genotypes for resistance genes. Doubled-haploid technology will be used to speed the release of lines that contain pyramided resistance to Ug99.
Progress on this agreement is monitored by regularly discussing program goals and approaches in face-to-face meetings, by email and phone conferences, and by reviewing annual accomplishments reports.