Two mapping populations were used for the analysis of the water-extractable
arabinoxylans. One originated from a cross between the hexaploid cultivars
'Courtot' and 'Chinese Spring' and the other from a cross between an amphi
ploid (Synthetic) and cv 'Opata'. Arabinose (Ara), and xylose (Xyl) content
s were quantified for the 91 and 76 lines obtained from the two crosses, re
spectively. Relative viscosity (eta(rel)) Of the wheat flour aqueous extrac
t was evaluated by capillary viscometry. Both crosses gave similar correlat
ion coefficients between sugar contents and relative viscosity. There were
strong positive relationships between arabinose, xylose and arabinoxylan co
ntents. The relative viscosity was strongly and positively related to the a
rabinoxylan content and strongly and negatively related to the Ara/Xyl rati
o (arabinose content to xylose content). For one of the two crosses two mea
surements of relative viscosity were generated from 2 years of consecutive
harvesting. As a strong correlation was observed between these two measurem
ents, an important genotypic effect can be deduced for the relative viscosi
ty of water-extractable arabinoxylans. QTL (quantitative trait locus) resea
rch did not reveal any chromosomal segments that were strongly implicated i
n variations in sugar content. However, a QTL was found for relative viscos
ity values and the Ara/Xyl ratio on the long arm of the IB chromosome for t
he two crosses considered. This QTL explained 32-37% of the variations in r
elative viscosity and 35-42% of the variations in the Ara/Xyl ratio. Genes
located at this QTL controlled relative viscosity through modifying the Ara
/Xyl ratio. Variations in the Ara/Xyl ratio were supposedly related to diff
erences in the molecular structure of water-extractable arabinoxylans. Mino
r QTLs were also obtained for relative viscosity and Ara/Xyl ratio, but the
chromosomes concerned were different for the two populations evaluated.