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United States Department of Agriculture

Agricultural Research Service

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Location: Cereal Crops Research

Project Number: 5090-43440-005-01-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Aug 1, 2010
End Date: Jul 31, 2012

Evaluate utility of small quantity malting and malt analysis methodology. Tocochromanols (vitamin E) are a group of amphiphilic lipid compounds produced exclusively in photosynthetic organisms. Although largely assumed to function in ameliorating the damaging effect of reactive oxygen species principally in green tissue, there is evidence that tocols perform other physiological roles. A recent report showed Arabidopsis mutants, deficient in tocopherol biosynthesis, were retarded in growth compared to wild type when subjected to low temperature treatment. They also did not export photoassimilate to sink tissues under low temperature conditions as well as wild types. It might, therefore, be of interest to evaluate several lines of winter barley vs spring barley for their leaf tissue tocol composition to determine if varieties adapted to these growth habits present demonstrable differences.

Current methodology for evaluating the malting quality of a barley selection or line generally requires 150 – 200 g of barley of that line in order to obtain a representative malting and to provide sufficient material for subsequent analysis. The requirement for these quantities of grain for an initial malt analysis forces breeding programs to analyze only relatively advanced or to limit evaluations to a limited set of parameters on unmalted barley. We have modified the primary QA analyses to require significantly less material, while retaining analytical sensitivity and discrimination. A preliminary report suggested that representative maltings could be achieved with < 2 g of barley. Combining the modified malting and malt analysis methodologies could enable earlier-generation malt quality analysis, potentially shortening the breeding cycle by one or more years. The objective of this project is to conduct a significant test of the new methodology by malting and analyzing 1000 – 1500 barley lines using the newly-developed procedures and comparing the QA results with those from our standard malting and QA protocols on the same submissions. We will select approximately 1000 from breeders submissions and variety checks that have been submitted to CCRU for malt quality evaluation. Our intent is to sample widely, from both Midwest and Western programs, 6-row and 2-row, early-stage selections and advanced lines, as well as accepted malting varieties. We will place 1 – 2 g of each barley line in a 1.75” diameter wire mesh “tea ball”, and bury the tea balls inside additional carrier check malt (6-row or 2-row as appropriate) in 1 kg containers in one of two Joe White micromalters available in our lab. After steeping to 46% moisture, germinating and kilning following standard laboratory protocols, and cleaning rootlets and acrospires from the kilned malt, we will grind the malt using a MiniBeadBeater-96 ball mill, sample and mash triplicate 187.5 mg aliquots, and analyze the resulting worts for extract (Anton-Paar DMA 4500M) or extract calculated from refractive index (Mettler RE-50), soluble protein (Nanodrop 2000-C or equivalent), wort ß-glucan and FAN (unpublished thermocycler method developed in our lab), and compare the mean results and sample variability with results from the traditional system both for accuracy of the mean result as well as sample variability. We expect that this will be a rigorous, informative evaluation, showing both strengths and weaknesses of the reduced-quantity methodology and approach. If the results from the comparison are acceptable, this will add an attractive alternative to our standard QA analysis service for limited-quantity samples. Ultimately, this may speed up breeding line selections as well as simplifying analysis of specialized genetic populations. Several winter and spring cultivars, grown in growth chambers under a range of temperature conditions, will be analyzed for tocols. Tocols will be extracted by published methods and analyzed by normal phase HPLC chromatography using fluorescence detection.

Last Modified: 07/22/2017
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