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Influence of Cultivar and Environment on Water-Soluble and Water-Insoluble Arabinoxylans in Soft Wheat

¹Department of Food Science and Toxicology, University of Idaho, Moscow, ID 83844-2312; affiliated with the USDA-ARS Western Wheat Quality Laboratory. ²USDA-ARS Western Wheat Quality Laboratory, Washington State University, Pullman Washington, 99164-6394. Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of the name by the USDA implies no approval of the product to the exclusion of others that may also be suitable. ³Corresponding author. Phone: +1.509.335.4062. Fax: +1.509.335.8573. E-mail: morrisc@wsu.edu

Arabinoxylans are hydrophilic nonstarch polysaccharides found in wheat grain as minor constituents. Arabinoxylans can associate with large amounts of water through hydrogen bonding and can form oxidative gels. These properties are important factors in end-use quality of wheat. The objective of this study was to delineate the influence of wheat cultivar and growing environment on variation in water-soluble (WS-AX), waterinsoluble (WI-AX), and total (TO-AX) arabinoxylan contents of flour and whole grain meal. This study included seven spring and 20 winter soft white wheat cultivars grown in 10 and 12 environments, respectively (each evenly split over two crop years). Univariate analysis of variance (ANOVA) and multivariate analysis of variance with canonical analysis (MANOVA) was used to evaluate sources of variation. Variation in arabinoxylan contents and absolute amounts (xylose equivalents) among the two cultivar sample sets (spring and winter) was similar, and both cultivar and environment were significant sources of variation. The cultivar-by-environment interaction was relatively unimportant. Results indicate that the variation in arabinoxylan content is primarily influenced by cultivar and secondarily influenced by environment. Within arabinoxylan fractions, WS-AX content is primarily influenced by genotype, while WI-AX content is more greatly influenced by the environment.