2011 Annual Report
1a.Objectives (from AD-416)
The main objective of this project is to develop wheat germplasm with genes for resistance to stem rust race Ug99 and currently encountered races of wheat stem rust. Attention will focus on the introduction of new genes to Great Plains adapted wheats, and pyramiding these genes with genes for resistance to additional pathogens.
1b.Approach (from AD-416)
The USDA-ARS Grain, Forages and Biofuels Research Unit at Lincoln, NE, is developing Great Plains adapted winter wheat germplasm with resistance to Ug99 and other races of stem rust. Stem rust resistance is being pyramided with genes conferring resistance to additional pathogens, including leaf and stripe rusts, and wheat streak mosaic and soilborne mosaic viruses. The Department of Plant Pathology at the University of Nebraska will identify breeding lines carrying stem rust resistance. Newly developed wheat breeding lines (F5 or F6 generations) derived from crosses with resistant donor parents will be assayed for stem rust resistance at the seedling stage via inoculations in the greenhouse, and for adult plant resistance, after inoculation at the University of Nebraska Agricultural Research and Development Center near Mead, NE.
The USDA-ARS Wheat Genetics program based at Lincoln, Nebraska develops germplasm (advanced wheat breeding lines) with unique quality traits, and novel disease resistances. The project focuses on the development of wheats with resistance to Wheat streak and Triticum mosaic viruses, and the development of wheats with tolerance to pre-harvest sprouting and other grain quality traits of importance to the new and rapidly developing hard white winter wheat market class. For these wheats to be useful in Great Plains breeding programs and to wheat producers, they also must contain adequate levels of resistance to native, and exotic races of wheat stem rust. The goal of this project is to identify, at early stages of development, stem rust resistant wheat lines with the unique traits cited above. Both green-house and field studies were conducted to accomplish this goal. In the greenhouse, approximately 200 lines from the virus-resistance program were screened for seedling responses to the stem rust pathogen. Resistant lines were identified, and selected to be planted in the fall of 2011 for agronomic evaluations and response to stem rust at the adult plant stage. In a field trial, a sprinkler system and artificial inoculations were used to incite stem rust in the field. Over 700 lines were evaluated for their adult plant reactions. Hard white wheats with pre-harvest sprouting tolerance, plus a selection of virus resistant wheat lines, all possessing good adult plant resistance to stem rust, were identified. Lines demonstrating adult plant resistance in 2011 will be submitted to USDA-ARS coordinated stem rust resistance trials at the Cereal Disease Laboratory in St. Paul, MN and in Kenya. The Kenya trials will allow the identification of lines with resistance to Ug99, a potentially devastating new race of stem rust not yet found in the U.S. Ultimately, this project will result in a broad array of stem rust resistant lines, also carrying unique traits of use to the wheat breeding and production industries. ADODR monitoring is accomplished via phone calls, e-mails and personal contact at professional meetings and during site visits.