CHARACTERIZATION OF ENVIRONMENTAL STRESS IN HARVESTED WHEAT BY NIR

Authors: Delwiche, Stephen - Steve; Graybosch, Robert

Submitted to: American Association of Cereal Chemists Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2001
Publication Date: 10/14/2001
Citation: Delwiche, S. R., Graybosch, R.A. 2001. Characterization of environmental stress in harvested wheat by NIR. 2001 AACC Annual Meeting, 10/14-10/18/2001, Charlotte, N.C. URL: http://www.aaccnet.org/meetings/2001/abstracts/a01ma211.htm.

Interpretive Summary:

Technical Abstract: Heat and moisture stress in developing wheat seedlings, particularly during the grain fill stage, is known to alter endosperm protein structure, and hence, the functional properties of the flour dough. Also established is an ability of near-infrared (NIR) reflectance spectroscopy to measure some of the biochemical and functional properties, such as SDS sedimentation volume and Mixograph dough development properties. The USDA-ARS Beltsvill and Lincoln laboratories are studying the concept that certain wavelength regions with the NIR region may be especially sensitive to environmental stress experienced by the developing wheat plant and later manifested in the resulting endosperm. The objectives of the study are to 1) develop a protocol and model, based on NIR, for detection of heat and/or water stress in harvested wheat and 2) determine the model's biochemical basis. Working with two years of historical data (one of which was unusually hot and dry) from a number of geographical locations in the Northern Plains and more than 20 varieties in a full factorial design, we have identified about 10 wavelengths (most lying beyond 1600 nm) that have the most significant sensitivity to stress. These wavelengths are further examined on a new set of data, consisting of advanced breeders' lines replicated at a number of geographical locations. With this new set, the effect of moisture is separated from protein, starch, and lipid effects.