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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #419440
Research Project: Wheat and Barley Adaptation to a Changing Climate - Discovery of Genetic and Physiological Processes for Improved Crop Productivity and Quality

Location: Wheat Health, Genetics, and Quality Research

Title: Identification of LMA-associated QTL in a biparental winter wheat mapping population (Xerpha/Bobtail)

Author
item MARSTON, ELLIOTT - Washington State University
item HOOKER, MARCUS - Washington State University
item Marlowe, Karol
item Ruff, Travis
item Liu, Yan
item CARLE, SCOTT - Washington State University
item PAARVEEN, REHANNA - Washington State University
item TRITTINGER, SUSANNE - Oregon State University
item See, Deven
item Steber, Camille

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: Late maturity alpha-amylase (LMA) is the induction of a-amylase during late grain maturation, a time with alpha-amylase levels should be decreasing. LMA is induced by a shift to cool temperatures during the susceptible time in development. This alpha-amylase persists in mature grain where it poses a risk to product quality that is detected in the wheat industry using the falling number test. LMA tolerance has been mapped in spring wheat. Because U.S. Pacific Northwest farmers have been suffering financial losses especially for LMA in soft white winter wheat, this study mapped QTL for tolerance in this market class. We did not map the major 7B QTL LMA-1 mapped repeatedly in spring wheat. Instead, we mapped a novel major QTL on wheat chromosome 7BS called QLind-wsu-7A.2 when cool temperature treatment was used to induce LMA (Lind). This new QTL and other minor QTL mapped offer an approach to breed for tolerance in winter wheat, a market class of importance in temperate wheat-growing regions.

Technical Abstract: Late maturity a-amylase (LMA) is an emerging cause of low falling numbers (FN) in U.S. wheat (Triticum aestivum) causing financial losses for growers. To facilitate breeding for tolerance in soft white winter wheat, quantitative trait loci (QTL) for LMA tolerance were mapped in an F5:6 biparental population derived from a cross of LMA-susceptible ‘Xerpha’ to LMA-tolerant ‘Bobtail’. The population was characterized for kernel a-amylase activity with and without cool-temperature LMA-induction (Lind) during the soft dough stage of grain maturation in field plots between 2019 and 2021. A novel major QTL, QLind-wsu-7A.2, was mapped to chromosome 7AS and contributed up to 15% of the total phenotypic variation for a-amylase activity in LMA-induced material. Six additional QTL associated with a-amylase activity after LMA-induction, and four QTL associated with lower a-amylase level in untreated controls were identified on chromosomes 2A, 3A, 3B, 4B, 5B, 6B, 7A, and 7D. All QTL associated with higher a-amylase levels in untreated material carried the Xerpha haplotype, and most QTL associated with lower a-amylase levels following cool-induction carried the Bobtail haplotype. The Rht-B1b and Rht-D1b GA-insensitive semi-dwarf alleles, known to be associated with LMA tolerance, reduced a-amylase levels in untreated material. Interestingly, the Rht-B1b Rht-D1b double dwarfs consistently expressed higher a-amylase levels with LMA-induction, suggesting a complex role for GA signaling in LMA.