Location: Hard Winter Wheat Genetics Research Unit
2012 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.
We were successful in evaluating 155 advanced breeding lines for resistance to stem rust in replicated greenhouse and field nurseries trials in South Dakota and Texas. In addition, crosses between adapted SD winter wheat varieties and breeding lines were initiated with new sources of resistance to Ug99. The new sources are represented by Th. ponticum chromosome addition and substitution lines identified by Dr. Stephen Xu, USDA-ARS, Fargo, North Dakota.
Major accomplishments over the life of the project include;.
We expect to continue to select and advance SD adapted winter wheat breeding lines with superior resistance to prevalent regional races of stem rust and to develop new lines and varieties with new sources of resistance to Ug99.