Location: Wheat Health, Genetics, and Quality Research
Project Number: 2090-21000-033-007-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2018
End Date: Jun 30, 2023
Objective:
The ARS and Washington State University are collaborating to reduce the risk of financial losses due to low falling number for Washington and other U.S. wheat farmers through the following specific objectives. 1. Identify varieties with stable falling numbers (FN) by performing FN tests and statistical analysis of variety trials in environments that have preharvest sprouting (PHS) and/or late maturity alpha-amylase (LMA). 2. Screen winter and spring wheat breeding lines for PHS and LMA susceptibility. 3. Identify and develop molecular markers linked to LMA and PHS resistance in northwest wheat. 4. Raise antibodies to wheat alpha-amylase and develop an ELISA assay as a proxy for falling numbers.
Approach:
Low falling numbers (FN), caused by the starch degrading enzyme alpha-amylase and by other enzymes expressed during either the developmental defect called late maturity alpha-amylase (LMA) or preharvest sprouting (PHS) (the germination of grain on the mother plant). Separate programs are needed to breed for resistance to the two problems.
1. Identify wheat cultivars with stable FN by performing FN tests and statistical analysis of trials in environments that have PHS and/or LMA. The COOPERATOR will provide samples from the Washington State University variety trials for FN testing. ARS and the COOPERATOR will jointly complete FN testing. The ARS will develop statistical methods for use in comparing cultivars for FN stability and to determine the heritability of FN. The COOPERATOR will make this information available through the WSU small grains website.
2. Screen 1000 winter and spring wheat breeding lines per year for PHS and LMA susceptibility. Germplasm previously used to develop biparental mapping populations will be screened for differences in LMA and PHS susceptibility to determine if these populations can be used for mapping. The spike-wetting test will be used to screen elite breeding material for PHS tolerance.
3. Develop molecular markers linked to LMA and PHS resistance in northwest wheat. Quantitative Trait Loci associated with LMA resistance in U.S. wheat will be identified by genome-wide association mapping in a spring wheat panel which has already been genotyped. The COOPERATOR will plant the panel, assist in LMA testing, and perform association mapping. ARS will provide LMA phenotyping data. The COOPERATORS and other northwest breeding programs will provide parents from winter and spring wheat RIL mapping populations that already have been genotyped. ARS will perform LMA testing to determine which of these populations segregate for LMA susceptibility and resistance. The COOPERATOR will plant association mapping panels, assist in LMA testing, perform QTL analysis, and examine if these populations carry QTL previously associated with LMA in Australian varieties.
4. Raise antibodies to wheat alpha-amylase as a first step towards developing a lateral flow immunoassay as a proxy for falling numbers. Monoclonal antibodies specific for the wheat alpha-amylase gene TaAmy1 and/or TaAmy2 will be developed to use in an ELISA immnoassay for alpha-amylase. The COOPERATOR will synthesize peptides containing antigenic sequences specific to one protein or common to both. The COOPERATOR will test these for specificity using TaAmy1 and TaAmy2 protein expressed in E. coli. ARS will provide protein samples from grains that have experienced either LMA or PHS so that these samples can be used to test for specificity in wheat. Amy proteins will be separated by isoelectric focusing.
