2013 Annual Report
1a.Objectives (from AD-416):
The ultimate goal is to enhance the quality of U.S. wheat for domestic and overseas markets. Objectives are to: identify milling, baking, and pasta processing traits of experimental and advanced lines of hard spring and durum wheat that impact end-use quality and the overall development and release of new commercial cultivars of wheat; and identify specific biochemical components in wheat that are associated with end-use baking quality traits. More specifically, the latter objective includes: to develop rapid methods to characterize proteins, which are initially important for predicting end-use quality; to determine the variation in free asparagine content in wheat, which is an important precursor for the formation of carcinogenic acrylamide during bread baking and toasting; and to identify the efficacy and impact of sulfur fertilization on end-use baking quality of hard spring wheat.
1b.Approach (from AD-416):
Approximately 4000 hard spring and 1000 durum wheat experimental lines will be submitted by Federal, State, and private breeders, and special interest groups on an annual basis and evaluated for end-use quality. Wheat will be obtained from different generations of development in specific breeding programs, which will include early-generation, preliminary, and advanced lines and include commercial cultivars as controls. Measureable end-use quality traits include test weight, size, seed weight, sprout damage, physical evidence of disease, and protein and ash content; milling performance as a function of flour and semolina yield; flour and semolina color, protein, and ash content; dough strength properties; bread baking quality; and pasta processing quality. The Fargo Genotyping Laboratory will identify quantitative trait loci regions associated with end-use quality, primarily kernel and dough strength traits on selected hard spring wheat samples. Research will be conducted on the rapid characterization of protein extracts from wheat and flour by testing two different protein extraction methods. Variation in free asparagine content in wheat lines will be measured. The efficacy and impact of sulfur fertilization on end-use baking quality of hard spring wheat, specifically protein composition and amino acid profiles, will be determined as a function of dough strength characteristics.
The Hard Red Spring Wheat Quality Laboratory (WQL) analyzed physical and biochemical quality traits of approximately 3000 samples of hard spring and durum wheat. Samples were submitted by private and public wheat breeders involved in wheat germplasm improvement and by scientists involved in gene mapping to identify quantitative trait loci associated with end-use quality traits. The WQL provided over 40 different tests related to wheat kernel characteristics, milling performance, and flour, semolina, dough, baking, and spaghetti processing quality. A test to measure bread crumb firmness that is expected to enhance the objective evaluation of bread quality was added to the existing quality tests.
In cooperation with the Wheat Quality Council (WQC), fourteen experimental lines of hard spring wheat that were grown at up to 5 locations were evaluated along with the check cultivar, Glenn. The WQL tested each line for kernel, milling, flour, dough, and bread-baking quality traits, coordinated the baking quality test results from 13 independent public and private testing laboratories, and analyzed the data. Results were published, presented, and discussed at the annual meeting of the WQC. Interactions with the WQC serve as a means to obtain industry feedback on the milling and baking quality traits of advanced experimental lines of wheat that are considered for release into commercial production.
We found that polymeric proteins in SDS buffer soluble and insoluble fractions significantly affected the bread-making characteristics of hard spring wheat. We analyzed polymeric proteins from durum wheat samples and are currently investigating their relationship with durum quality traits. Also, we are investigating the effect of genetic background and growing environment on variation of polymeric proteins and quality characteristics in hard spring and durum wheat.
UV spectroscopy has been continuously tested for the rapid characterization of proteins extracted from hard spring and durum wheat samples. SDS buffer soluble and insoluble protein fractions have been extracted from hard spring and durum wheat samples and scanned at wavelengths between 190 and 350 nm using a UV spectrophotometer. We are currently examining possible correlations between UV absorbance data and durum quality traits. The utility of near infrared spectroscopy for determination of flour polymeric protein content in hard spring and durum wheat also will be assessed.
The segregation of low asparagine wheat genotypes is important to reduce acrylamide content in baking products. Free asparagine concentration was analyzed for 75 hard spring wheat lines grown at 3 locations and the data is currently being analyzed to investigate the effects of genotype and location.
Polymeric proteins and their association with grain yield in hard red spring wheat. One of the problems faced by wheat breeding programs is that varieties with high grain yield tend to have low protein content and poor end-use quality. Large protein aggregates known as high molecular weight polymeric proteins contribute to enhancing bread-making quality. In cooperation with wheat breeders from the University of Minnesota, ARS researchers in Fargo, ND found that an increase of polymeric proteins could improve bread-making quality without decreasing grain yield in hard spring wheat. This information provides breeders with knowledge needed to improve selection of wheat genotypes for improved grain yield without loss in bread-making quality.
Genetic mapping analysis of bread-making quality traits in hard spring wheat. Bread-making quality is an important characteristic considered before release of new spring wheat varieties, but measuring bread-making quality is both time and labor intensive. Screening using genetic markers has the potential to aid in this process. A mapping population derived from the wheat lines BR34 and Grandin by ARS researchers in Fargo, ND was used to identify genetic markers for bread-making quality traits in hard spring wheat. A total of 31 quantitative trait loci (QTL) were identified for quality traits. These QTL will be useful in segregating wheat lines for breadmaking quality during early generations of breeding.
Variability in arabinoxylan, xylanase activity, and xylanase inhibitor levels in hard spring wheat. Arabinoxylans, xylanase, and xylanase inhibitors have an important role in many cereal food processing applications. Xylanase is an enzyme needed to break arabinoxylans into smaller molecules, and optimum xylanase activity in wheat is beneficial to breadmaking. ARS and NDSU researchers in Fargo, ND examined the effects of genotype, growing location, and their interaction on arabinoxylans, apparent xylanase activity, and apparent xylanase inhibition activity of Triticum aestivum xylanase inhibitor (TAXI) and xylanase inhibiting protein for six hard red and six hard white spring wheats. TAXI was identified as a reliable parameter for segregating wheat genotypes with varying xylanase activity. This information will help segregation of wheat lines that have different levels of xylanase activity in wheat breeding.
Effect of a high molecular weight glutenin subunit gene on the quality of durum wheat. High molecular weight glutenin subunits Glu-D1d are proteins associated with good bread-making quality that exist in bread wheat, but not in durum wheat. ARS researchers in Fargo, ND transferred the gene encoding Glu-D1d to durum and found that this glutenin gene enhanced the bread-making quality characteristics of the durum lines. Most durum lines with this glutenin gene also had a lower free asparagine content (free asparagine is a precursor needed to form carcinogenic acrylamide during baking) than those without it. This information may be useful to breeders interested in development of a dual-use durum wheat for pasta- and bread-making that could contribute to diversifying the utilization of durum wheat.
Development of improved wheat germplasm. Wheat producers, milling and baking industries, and overseas customers require high standards in the quality of wheat to meet their evolving needs. ARS researchers in Fargo, ND contributed wheat end-use quality data that helped lead to the development of improved wheat germplasm and subsequent release of new cultivars of spring and durum wheat bred for commercial production. Such new releases provide value to both farmers and industry through improved productivity or end-use quality.
Simsek, S., Whitney, K., Ohm, J. 2013. Analysis of Cereal Starches by High Performance Size Exclusion Chromatography. Journal of Food Analytical Methods. 6(1): 181-190.
Mendis, M., Ohm, J., Delcour, J., Gebruers, K., Meinhardt, S., Simsek, S. 2013. Variability in Arabinoxylan, Xylanase activity and Xylanase inhibitor levels in hard spring wheat. Cereal Chemistry. 90:240–248.