Location: Wheat Health, Genetics, and Quality Research
Project Number: 2090-21000-033-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2018
End Date: Jun 30, 2023
Objective:
1. Develop new wheat germplasm with increased resistance to low falling number (FN), and winter wheat mapping populations segregating for resistance to low FN.
1A. Collaborate to identify and define molecular markers associated with resistance to low FN in winter wheat, whether caused by late maturity alpha amylase (LMA) or pre-harvest sprouting (PHS).
1B. Use phenotypic results in selection models to improve low FN resistance in wheat cultivars targeted to the Pacific Northwest (PNW) and specifically Oregon.
1C. Investigate the use of gene editing (CRISPR) strategies to develop wheat with increased resistance to PHS.
2. Examine the role of grain protein content and composition on low FN and problems with poor product quality.
2A. Determine the impact of protein content and flour protein composition (gliadins, glutenins, or protein polymerization) to alter FN due to PHS or LMA.
2B. Determine whether PHS or LMA have different effects on grain and flour protein composition.
Approach:
Low FN causes serious financial losses to U.S. wheat producers each year. Low FN can be caused by the starch degrading enzyme alpha-amylase and other enzymes expressed during grain fill (LMA) or a rain event prior to harvest (PHS).
1. Develop new wheat germplasm with increased resistance to low FN, and winter wheat mapping populations segregating for resistance to low FN.
a. Breeding lines in the F7 and F8 generations will be provided to the Agricultural Research Service (ARS) for phenotypic analysis for variation in LMA resistance. The cooperator, Oregon State University (OSU) will use the phenotypic data to select lines for crossing to increase LMA resistance in overall breeding pool of the Oregon State University breeding program. Superior lines for LMA resistance that also have high yield potential, disease resistance and superior end-use quality will be advanced for potential release.
b. Parents of biparental mapping populations developed by the cooperator will be provided to the ARS for phenotypic analysis for LMA resistance. Seed from mapping populations with parents showing variation for LMA resistance will be provided by the cooperator to the ARS for phenotypic analysis for LMA resistance. Quantitative trait locus (QTL) analysis will be used to identify loci contributing to low FN in OSU derived mapping populations. The cooperator will use the molecular markers identified to do selection for lines in the F5 and F6 generations of the breeding program to develop wheat cultivars with enhanced resistance to low FN.
c. The cooperator will examine the potential to use CRISPR gene editing to reduce PHS. The initial target for gene editing will be the gene for ABA 8’hydroxylase with the goal of silencing expression of this gene to prevent PHS through altering hormone signaling and increased seed dormancy (SD). The ARS will provide the gene sequence for targeting the abscisic acid (ABA) 8’hydroxylase with the goal to target the ABA 8’hydroxylase genes specifically expressed during grain development, increasing SD but not impacting the ability of the grain to break dormancy through after-ripening or other dormancy breaking treatments. ARS will phenotype this material to determine whether SD or PHS tolerance has been increased.
2. Examine how grain protein content and composition contributes to or prevents both low FN and problems with poor product quality.
a. The cooperator will examine whether higher protein content and/or gluten alleles associated with stronger dough reduce the negative effects of PHS and LMA on falling numbers and on wheat product quality.
b. The cooperator will examine if enzymes found in the grain, including proteases expressed during PHS but not during LMA, are the reason that PHS has an apparently more profound effect on end-use quality than LMA. If so, research will be done to examine whether additional enzymatic or other measurements on flour or meal can be used to develop an analytical method to distinguish PHS from LMA that, if successful, may later be adapted to the market stream. The ARS will induce LMA and PHS under controlled environmental conditions and supply these samples to the cooperator for analysis.
