Project : USDA ARS

ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Research Project #428800

Research Project: Wheat Quality, Functionality and Marketablility in the Western U.S.

Location: Wheat Health, Genetics, and Quality Research

2019 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
In support of Sub-objective 1A, research continued on understanding the roles of kernel hardness and puroindoline genes in wheat grain quality and utilization. Genetic analysis of Aegilops tauschii, a close relative of wheat, was continued with over 300 accessions sequenced. The study which identified important gene loci for kernel hardness was published indicating that protein genes play a role. The development of special genetic stocks for kernel hardness genes was completed in the soft white spring wheat ‘Alpowa’. A novel ‘Super Soft’ trait in wheat was shown to likely be the result of two or more genes. In support of Sub-objective 1B, research continued on understanding of the role of starch composition and waxy genes on wheat grain quality and utilization. A complete set of eight starch biosynthetic gene combinations were grown in the field; grain and flour analyses are in progress. In support of Objective 2, research was completed in the prior reporting period on developing a model system for identifying putative grain flavor loci/genes in wheat (2A), and manipulating grain arabinoxylan content to improve flour quality and utilization (2B). In support of Objective 3, research was completed on the collaborative development of new wheat cultivars with superior end-use quality, 2018 harvest samples. Approximately 4,500 unique samples received a full milling, baking and flour analysis. Recent variety releases include ‘Dayn’ and ‘Glee’.

Accomplishments
1. Soft kernel durum is a unique new wheat. A very hard kernel has been a defining characteristic of durum wheat. However, the development of soft kernel durum wheat in Pullman, Washington, with collaborators in Italy demonstrated that soft kernel texture improved fresh pasta quality. Further, agronomic performance of soft durum was similar to some hard red spring wheat varieties with very good resistance to some pests and diseases. Soft kernel durum wheat provides a new, novel raw material for pasta and other food manufacturers.

2. Noodles made from soft durum wheat flour show low levels of discoloration. Discoloration is a major quality problem in noodles and is primarily caused by the enzyme polyphenol oxidase (PPO). Soft durum wheat developed in Pullman, Washington, was shown to have low levels of PPO and creamy yellow color. Soft durum noodles were shown to have low levels of darkening and discoloration. Soft durum wheat provides food processors a novel, high quality ingredient.

3. ‘Super Soft’ kernel texture is a new trait in wheat. Kernel softness/hardness is a key quality and processing trait of wheat grain. Softer kernels have some processing advantages over harder kernels. A novel ‘Super Soft’ trait in soft white wheat was discovered and characterized at the genetic level in Pullman, Washington. Genetic analysis indicated the action of two or more genes in conferring the Super Soft trait. The Super Soft trait will provide millers and food processors an expanded range of wheat quality.

U.S. DEPARTMENT OF AGRICULTURE

Wheat Health, Genetics, and Quality Research: Pullman, WA