Location: Wheat, Sorghum and Forage Research2008 Annual Report
1a. Objectives (from AD-416)
1. Develop winter wheats adapted to the Great Plains with novel starches for use in biofuel production and in food product manufacturing. Improve gluten strength and extractability of such wheats to produce a more economically viable package for producers and end-users. 2. Develop hard white winter wheat germplasm with tolerance to pre-harvest sprouting and with nil levels of grain polyphenol oxidase (PPO). 3. Coordinate the Hard Winter Wheat Regional Nursery Program to facilitate the evaluation, distribution, and exchange of high-yielding, high-quality, disease- and pest-resistant hard winter wheats for Great Plains environments.
1b. Approach (from AD-416)
Winter wheats with waxy (amylose-free) starch suitable for cultivation in the Great Plains and the Pacific Northwest will be developed via intermatings with adapted types and recurrent selection. Fermentation assays will be used to determine the most suitable starch composition for conversion of wheat grain and starch to ethanol. Transgenic wheats over-expressing native high-molecular-weight glutenin proteins will be tested as a means of overcoming the technical problem of low gluten extraction from waxy wheats. Hard white wheat germplasm with tolerance to pre-harvest sprouting will be identified by use of controlled environment studies, and molecular markers. Hard red winter wheat lines capable of serving as donors of genes for resistance to pre-harvest sprouting in white wheats will be identified after diallel matings. Hard white winter and spring wheat germplasm, with nil levels of grain polyphenol oxidase, will be identified after intermatings of non-adapted donor lines, and adapted materials. Field and laboratory studies will be used to evaluate the environmental stability of the trait and identify molecular markers linked to the trait.
3. Progress Report
a. Development of winter wheats adapted to the Great Plains with novel starches for use in biofuel production and in food product manufacturing: i. A winter waxy (amylose-free) wheat breeding line, NX04Y2107 was entered both in the USDA-ARS coordinated Northern Regional Performance Nursery, and in the University of Nebraska Wheat Variety trial. In trials in nine Nebraska counties, grain yield of NX04Y2107 was equal to or greater than Jagalene, the most widely grown wheat in Nebraska over the past five years. In Lancaster County in Eastern Nebraska, NX04Y2107 was the highest yielding entrant. NX04Y2107 carries genes for resistance to the three major rusts, leaf, stem and stripe, that plague wheat producers. Its parents include the Nebraska developed wheats Nekota and Arapahoe and the Kansas cultivar Ike. Three additional waxy wheat breeding lines were selected from 2008 field trials and will be advanced to regional and statewide trials for further testing. ii. Using starch derived from waxy and partial waxy (reduced amylose) durum wheats, it was discovered that cross-linked waxy starches have much greater final viscosity after cooking than normal or partial waxy starches, and that mechanical blends of waxy and normal starch produces final viscosities different than both types alone. Food processors may use waxy starches, alone or in blends, to achieve any final viscosity desired Possible applications would be in soups or sauces. b. Develop hard white winter wheat germplasm with tolerance to pre-harvest sprouting and with nil levels of grain polyphenol oxidase (PPO): i. Genetic improvement of sprouting tolerance and grain polyphenol oxidase (PPO) levels: Populations based on the sprout tolerant hard white winter wheat RioBlanco were used, in collaboration with USDA-ARS scientists at Manhattan, KS, to identify potential new quantitative trait loci linked to pre-harvest sprouting tolerance. A highly efficient technique of screening for resistance to pre-harvest sprouting was developed, incorporating readings of treated spikes via use of a Li-Cor Leaf Area Meter. ii. Via intermating of lines from the USDA National Small Grains Collection, common spring with nil levels of grain PPO were identified. PPO levels of these lines, with results from three independent field seasons, have resulted in hexaploid spring wheats with PPO levels not statistically different from durum wheat controls. Genetic studies were established to evaluate the inheritance of the trait. This research is a component of National Program 301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component III. Genetic Improvement of Crops.
1. Wheat streak mosaic virus is the most prevalent pathogen negatively impacting wheat production systems in the western Great Plains. Before the 1960’s, this dubious honor was held by stem rust, a fungal pathogen. Since then, resistance breeding has controlled stem rust, but control of wheat streak mosaic virus has remained elusive. The evolution of new races of stem rust in Africa, specifically one designated Ug99 now threatens U.S. wheat production. Should Ug99 reach North America, the impact might be devastating. A major accomplishment of this project was the release of the hard red winter wheat cultivar Mace. Mace is the world’s first wheat cultivar to carry true resistance to wheat streak mosaic virus, conditioned by a gene known as Wsm-1. In addition, Mace has been found to be resistant to stem rust race Ug99. The precise nature of resistance is, however, unknown, and presently is under investigation. This accomplishment relates to National Program 301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component III. Genetic Improvement of Crops.
2. Expanding market demand for wheat via exploitation of naturally occurring starch variants: Experiments to develop new uses for partial waxy (reduced amylose) and waxy (amylose-free) starches of bread and durum wheats. Techniques for starch modification via hydroxypropylation were perfected and applied to waxy and partial waxy durum wheats. Starches from partial waxy durum wheats were compared to blends of waxy/wild-type starches, to determine optimal amylose content for performance after modification. For 2 crop years, each genotype and respective waxy/wild type blends, including commercial starch blends, were substituted and cross-linked. Pasting curves for native and both modifications of crop year, genotype and blend, including commercial starches, displayed viscosity ranges. Native and substituted intra-granularly blended amylose starches, genetic blends, produced higher viscosity pastes than comparable amylose content inter-granularly blended starches, mechanical blends. Cross-linked genetically blended amylose starches produced noticeably lower viscosity pastes than amylose content comparable mechanically blended starches. This accomplishment relates to National Program 301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component III. Genetic Improvement of Crops Sub-component b) Capitalizing on Untapped Genetic Diversity.
3. Improving the economic viability and stability of agricultural production systems in the western Great Plains: Wheat producers in the western Great Plains lack an efficient alternate crop to include in their wheat-fallow rotation. Development of adapted waxy proso millet, desired as a food grain in Asian markets, would provide an alternative crop. Proso millet is a summer annual grass that is capable of producing grain in 60 to 90 days. This characteristic, and its efficient use of water, makes it well suited short, and often hot and dry, growing season in the high plains of Kansas, Nebraska, Colorado, Wyoming, and the Dakotas. The introduction of novel end-use characteristics as waxy starch can stimulate an increased market for proso. Experimental F5 waxy lines derived from a cross of ‘Huntsman’ and PI436626 were evaluated across seven locations. Genotype by environment variation in waxy proso was mostly a matter of changes in magnitude and not crossover interaction. With the exception of testweight, waxy proso mean response for most traits was similar to check cultivars. Yield of one experimental line was not significantly different from Huntsman, and Horizon, two adapted wild-type proso cultivars. This accomplishment relates to National Program 301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component III. Genetic Improvement of Crops.
4. Coordination of the hard winter wheat regional nursery program: The United States wheat breeding community, operating as a series of independent programs, requires a concerted program to coordinate agronomic testing over a broad geographic range, and a system for effective exchange of germplasm This project successfully coordinates the USDA-ARS Hard Winter Wheat Regional Nursery Program: Information distributed in the annual reports (http://www.ars.usda.gov/Research/docs.htm?docid=11932. ) of the Hard Winter Wheat Nursery Program is used by wheat breeding programs, across the Great Plains, in release decisions, in the selection of parents for matings for future cultivar developments, and by agronomists and extension agents in formulating varietal recommendations for wheat producers. Nearly every wheat cultivar grown in the Great Plains passes through this program. This accomplishment relates to National Program 301 Plant Genetic Resources, Genomics, and Genetic Improvement, Component III. Genetic Improvement of Crops.
5. Significant Activities that Support Special Target Populations