Location: Wheat Health, Genetics, and Quality Research
2020 Annual Report
Accomplishments
1. Susceptibility to late-maturity alpha-amylase is a likely cause of poor wheat end-product quality in U.S. wheat. Farmers receive large discounts for wheat grain with low falling number, an indicator of starch breakdown. The production of late-maturity alpha-amylase during grain fill is one cause of low falling number. ARS researchers in Pullman, Washington, with collaborators at Washington State University, investigated the genetic control of late-maturity alpha-amylase production over multiple environments in a panel of 250 spring wheat varieties representing 10 North American breeding programs. 79% of genotypes showed susceptibility to late-maturity alpha-amylase. Resistance was associated with two loci previously mapped in Australian germplasm. These results indicate that late-maturity alpha-amylase is a major cause of low falling number in U.S. wheat and identified germplasm and molecular markers that are useful for development of wheat varieties with resistance.
2. Cultivars with stable high resistance to low falling number identified in northwestern U.S. winter and spring wheat cultivars. The falling number test is a standard method to assess end use quality in the grain trade. While ARS researchers have performed falling number tests on the multiple wheat varieties over multiple environments since 2013, summarizing these results was difficult because individual varieties were not included in all years or locations. ARS researchers in Pullman, Washington, with collaborators at Washington State University, used the factor-analytic statistical model to analyze data collected from 2013 to 2016. This approach compensated for the unbalanced nature of the dataset, allowing identification of varieties with stable falling number over multiple years and locations. These variety rankings have been shared through Washington State University extension with farmers and the grain industry to inform their selection and handling of wheat varieties, reduce discounts for poor quality grain and improve the grain industry’s ability to meet export market specifications.
3. New diversity available for the D-genome of wheat in the ‘DNAM’ population. Over 8,000 years ago, hexaploid (bread) wheat evolved via hybridization between tetraploid wheat and a small set of the wild diploid wheat, Aegilops tauschii spp. strangulata. The variability of the D-genome of wheat is much less that of the A and B genomes due to this bottleneck, and the lack of variability can make it difficult to improve wheat for certain traits like pest resistance and grain quality. ARS researchers in Pullman Washington, together with collaborators at Michigan State University and Washington State University, developed and characterized a D-genome nested association mapping panel comprising multiple and diverse Aegilops tauschii accessions crossed to an adapted hard white breeding line from the great plains. Novel resistance to stripe rust and to cereal cyst nematodes has been discovered in this population which has been released and deposited in the National Small Grains Collection for plant geneticists and breeders to access.
