Genetic Mapping of Quantitative Trait Loci Associated with Arabinoxylan Content in the Soft Wheat (Triticum aestivum L.) Cross ‘Louise' x 'alpowa'.

Arabinoxylans are non-starch polysaccharides found at low concentrations in wheat grain.  These molecules significantly influence end-use quality in wheat since they are able to associate with large amounts of water via hydrogen bonding, and can form gels via ferulate cross-linking.  International industry prefers lower arabinoxylan content in soft white wheat since arabinoxylan content greatly influences water absorption properties in dough. It is essential for wheat breeders to understand the genetic architecture underlying quantitative end-use quality traits, such as arabinoxylan content, in order to develop cultivars with superior quality. A set of 131 recombinant inbred lines (RIL) from a soft white spring wheat ‘Louise’ x ‘Alpowa’ bi-parental mapping population was grown for two crop years in Pullman, WA and one crop year in Lind, WA to identify quantitative trait loci (QTL) associated with total arabinoxylan content (TAX), water extractable arabinoxylan content (WEAX) and arabinose to xylose ratio (A/X).  TAX, WEAX and A/X were determined for white flour from a modified Quadrumat laboratory mill and for whole meal from a Udy cyclone mill. The linkage map was developed using 902 SNP markers and consisted of 29 linkage groups which covered 16 of the 21 wheat chromosomes, with chromosomes 3D, 4A, 4D, 5D, and 7B not identified.  A QTL on 1A at 23 cM was associated with white flour TAX and A/X, whereas another QTL on chromosome 1B was associated with white flour TAX and WEAX.   Several QTL found on chromosomes 5B were significantly associated with TAX and WEAX for both white flour and whole meal.  Results will assist wheat breeders in developing cultivars with better end-use quality and lower levels of WEAX through the use of marker-assisted selection.