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SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecularweight-and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv. 'Messapia' of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome IB, on which are located the Gli-B\/Glu-B3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on lAL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62-91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.

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