Location: Wheat Health, Genetics, and Quality Research
2015 Annual Report
Objectives
The long-term objective of this project is to improve wheat quality, functionality and marketability in the Western U.S. Specifically, during the next five years we will focus on the following objectives:
Objective 1: Resolve the underlying genetics of end-use quality traits, and identify useful genetic variation to produce predictable and new end uses.
• Sub-objective 1A: Extend our understanding of the role(s) of kernel hardness and puroindoline genes in wheat grain quality and utilization.
• Sub-objective 1B: Extend our understanding of the role(s) of starch composition and waxy genes on wheat grain quality and utilization.
Objective 2: Increase the value and global competiveness of U.S. commercial wheat by enabling new technologies and methods to accurately assess end-use functionality; and to manipulate wheat fiber and antioxidant components to improve grain and flour quality.
• Sub-objective 2A: Develop a model system for identifying putative grain flavor loci/genes in wheat.
• Sub-objective 2B: Manipulate grain arabinoxylan content to improve flour quality, nutrition and utilization.
Objective 3: Congressionally designated as a direct mission of service, and non-hypothesis driven, the USDA-ARS Western Wheat Quality Laboratory will identify, evaluate, and screen the intrinsic end-use quality to enhance cultivar development.
Approach
Objective 1A: Puroindoline a, b, and Grain softness protein-1 genes are amplified from genomic DNA via PCR and sequenced, followed by alignments and phylogenetic analyses. Aegilops tauschii accessions are obtained from germplasm banks. Unique haplotypes are identified in synthetic hexaploid wheats and evaluated for kernel texture. Soft durum lines derived from Soft Svevo will be increased and receive complete milling and baking analyses. Kernel texture variation in the RIL population derived from Butte 86 x ND2603 will be mapped. Kernel texture variation referred to as “Super-Soft” will be mapped using an Alpowa Super-Soft derivative. RILs will be developed using single seed descent. Contingencies: Marker density will need to be sufficient to detect linkage disequilibrium. If a particular chromosome or arm has low polymorphsism, then additional markers will be added.
Objective 1B: Full waxy and partial waxy lines will be developed in Stephens, Xerpha, and MDM varieties. Waxy progeny are identified with I2/KI. Partial waxy lines are identified using PCR markers. NILs will be developed in a BC7F2 population using marker assisted selection. The 4A-null lines will be evaluated for Japanese Udon noodle. Full waxy lines will be evaluated in twin barrel extrusion.
Objective 2a: A system that uses a common check variety will be developed. Hollis (yummy) and ID703 (yucky) were used to make a DH mapping population. DH line vs. check t-values will be used as the phenotypes for mapping. Mapping will be employed to identify candidate genes/QTLs for consumption preference. Contingencies: Different ‘check’ varieties may be needed depending on the relative preference/avoidance. If the QTLs from one check variety do not fully agree with the QTLs from the second check variety, then a third intermediate preference variety will be evaluated. If LOD scores are not sufficiently large, then a sub-set of lines with contrasting consumption preference will be evaluated with a larger number of mice.
Objective 2b: Yumai 34 and Alpowa have high arabinoxylan (AX) content, whereas Louise has low levels. DH populations from Yumai 34 x Louise, Yumai 34 x Alpowa, and Alpowa x Yumai 34 were produced. These populations will be milled and baked, and evaluated by Solvent Retention Profiles and Bostwick viscosity. Total AX, water extractable AX (WE-AX), and arabinose to xylose ratio will be analyzed via GC-FID. All the DH lines will be genotyped with markers. Lines with contrasting high and low AX contents, high and low ratios of WE-AX vs. water unextractable, and high and low ratios of arabinose substitution will be identified. These traits will be compared with end-use quality phenotypes and will be analyzed via molecular markers. Contingencies: We will identify the ‘best’ choices for full AX analyses based on contrasting end-use quality traits. If there is not a ‘consensus’ among traits, then contrasting phenotypes will be selected for individual traits.
Objective 3: Testing and evaluation of experimental wheat breeding germplasm follows standard testing protocols, including Approved Methods of AACCI and AOAC. Tests include grain, milling, flour and end-products tests.
Progress Report
This is the first report for this new project which continues research from the previous project, “Enhance Wheat Quality, Functionality and Marketability in the Western U.S.”, 2090-43440-006-00D. Please see this report for additional information.
Under objective 1a., the USDA ARS collection of Aegilops tauschii was obtained and is nearing completion for sequencing and haplotyping Puroindoline a, Puroindoline b, and Grain softness protein-1; Soft Sevo & Svevo were grown at multiple locations; ND2603 x Butte 86 population is currently growing; F1 seeds of ‘Alpowa Super-Soft’ by ‘Alpowa’ cross are maturing.
Objective 1b., waxy Stephens, Xerpha and MDM germplasm were grown in the greenhouse, and backcrossed to the recurrent parent; the BC7F2 Alpowa waxy population was grown and the progeny were haplotyped for GBSS using PCR. Not all allele combinations were recovered so additional segregating plants were started in the greenhouse.
Objective 2a., hard red spring and hard white spring cultivars were evaluated in our mouse model using Yummy (Y) and yucky (y) controls; the results are being evaluated to test the utility of using the t-test as a consumption phenotype; the Hollis x ID702 doubled haploid population is currently growing in the field.
Objective 2b., the Yumai 34 x Louise and Yumai 34 x Alpowa Doubled Haploid populations are currently growing in the field.
Accomplishments
1. Soft kernel durum wheat is a new bakery ingredient for food processors. Currently, durum wheat production and utilization are limited by its very hard kernel texture, which restricts its culinary uses. An ARS scientist in Pullman, Washington, in cooperation with University of Tuscia, Viterbo, Italy researchers, have developed durum wheat with soft kernel texture. This ‘new’ durum wheat mills like soft bread wheats, using less energy and producing fine-textured flours with low levels of damaged starch. As such, this flour represents a new bakery ingredient and was shown to perform well in a range of hearth breads and other food items. Expanded utilization will increase demand for soft durum grain and farmer production.
2. The house mouse is consistent in what wheat grain it likes. Whole grain wheat foods can provide critical nutrients for health and nutrition in the human diet, but undesirable flavor(s) limit consumption. The house mouse provides a model system for studying flavor differences among wheat varieties, but the consistency and repeatability of preferences across crop years and locations is unknown. An ARS scientist in Pullman, Washington, in cooperation with Washington State University researchers, studied repeatability of consumption preference using a single elimination tournament design. In three crop year/mouse cohort combinations, the same varieties were preferred as the “winner” of both the hard red spring and hard white spring wheat varieties. The mouse model in conjunction with the single elimination tournament design was effective in providing repeatable results in an effort to more fully understand flavor differences among wheat varieties. Due to the highly conserved morphology and physiology of taste perception among mammals, this research will identify wheat varieties to use in human sensory panels.
3. Water extractable non-starch polysaccharides decrease during bread baking. Water extractable non-starch polysaccharides (WENSP) are important for food product quality and as a source of dietary fiber. ARS scientists in Pullman, Washington, and Beltsville, Maryland, in cooperation with Washington State University researchers, found a dramatic reduction in WENSP during bread baking, likely due to polymer crosslinking and the high temperatures involved. Bread quality was correlated with higher levels of WENSP. These results increase our understanding of how wheat polymers change during baking and how they affect bread quality. This is important because polymer formation affects bread dough viscosity and crumb texture; soluble vs. insoluble dietary fiber have different effects on human health and physiology, and cross-linked polymers transit to the large intestine where they participate in secondary fermentation producing health-associated compounds.
Review Publications
Kiszonas, A., Fuerst, E.P., Morris, C.F. 2015. Repeatability of mice consumption discrimination of wheat (Triticum aestivum L.) varieties across field experiments and mouse cohorts. Journal of Food Science. 80:S1589-S1594.
Kiszonas, A.M., Fuerst, E.P., Luthria, D.L., Morris, C.F. 2015. Arabinoxylan content and characterisation throughout the bread-baking process. International Journal of Food Science and Technology. 50:1911-1921.
