2010 University of Minnesota - Special Report

Accelerated Breeding of Disease Resistant Wheat

James A. Anderson, University of Minnesota

Objectives: 

1. Develop high yielding, hard spring wheat germplasm and varieties with improved resistance to FHB, other diseases, and acceptable agronomic and end-use characteristics.

2. Use DNA markers to characterize crossing parents and screen progeny lines for presence of genes underlying important traits, including FHB, leaf, and stem rust resistance.

Objective 1    ‘Sabin’ (MN03358-4) was released in 2009. Sabin is a mid-maturity hard red spring wheat with high grain yields (Table 2) and good scab resistance. The pedigree of Sabin is MN98389/MN97518. MN03358-4 has been a consistently high yielder in Minnesota and the hard red spring wheat region, performing well in the 2006 and 2007 regional performance nurseries. Grain protein and test weight are average compared to other varieties, but Sabin has shown greater stability for grain protein. Sabin is moderately resistant to pre-harvest sprouting with good falling numbers. Straw strength is below average. Sabin is resistant to stem rust and moderately resistant to prevalent races of leaf rust and other leaf diseases. Sabin has moderate resistance to Fusarium head blight (scab), comparable to ‘Tom’ and better than ‘RB07’.Data from the last three years show that U of MN releases and variety candidates have improved levels of scab resistance (Table 1). Our project continues to identify other lines with high levels of scab resistance.

In 2009 scab nurseries were established at Crookston, Morris, and St. Paul.

Impact -- High yielding wheat varieties with good scab resistance are in demand by wheat growers because they greatly influence the profitability of wheat production in Minnesota. Our program has publicly released one new wheat variety in each of the past 5 years. Publicly developed varieties accounted for an estimated 71% of wheat acres in 2009 (Minnesota Association of Wheat Growers survey) and 40% of the public share was varieties developed at the University of Minnesota. In addition, we coordinate the testing of 20-25 wheat varieties per year in statewide trials to assess their performance in yield nurseries and reactions to important diseases. This information is critical to growers to make informed variety choices.

During the 2008/2009 crossing cycle, 271 crosses were made. The Variety Trial, which contained 30 released varieties, 11 University of Minnesota experimental lines, and 4 experimental lines from other programs and was grown at Crookston, Lamberton, Morris, St. Paul, Stephen, Waseca, and 3 on-farm locations in the Red River Valley. During the 2009 growing season, 199 advanced experimental lines were evaluated in replicated advanced yield trials at Crookston, Morris, and St. Paul. A total of 247 preliminary yield trial lines were tested in unreplicated plots at Crookston, Morris, and St. Paul. Fusarium-inoculated, misted, replicated nurseries were established at Crookston, Morris, and St. Paul. The disease nurseries involve collaboration with agronomists and pathologists at Crookston and Morris and with personnel from the Plant Pathology Department and the USDA-ARS. More than 5,600 total rows were assessed for scab resistance, representing more than 2,000 experimental lines.

Objective 2 -- We use marker-assisted selection for enrichment of early generation populations and parental characterization. Marker-assisted selection helps us select plants that have desirable gene combinations. We routinely use markers to screen for genes that provide resistance to Fusarium head blight, leaf rust, and tan spot and for the presence of particular high molecular weight glutenins that are necessary for good baking quality.

In cooperation with the USDA-ARS Genotyping Center in Fargo and funded jointly by this project and the U.S. Wheat and Barley Scab Initiative, we collected 8,120 marker data points since July 2009. This marker screening represented all of the lines that are candidates for entry into 2010 preliminary yield trials. Therefore, we know which of our varieties and elite breeding materials contain important genes, thereby directing future DNA marker screening of crosses and helping us decide which crosses to make (and not to make) to be sure that the resulting progeny contain all the desired genes. Two of the most important markers we use are UMN10 for Fhb1, a gene that provides an average of 20% reduction in scab severity, making it the most effective known gene for Fusarium resistance, and two markers for high molecular weight glutenin genes (Fig. 1) that are key determinants of baking quality.