GENETIC-MAPPING OF SEDIMENTATION VOLUME ACROSS ENVIRONMENTS USING RECOMBINANT INBRED LINES OF DURUM-WHEAT

SDS-sedimentation volume (SV) is a biochemical index widely used to ev aluate flour quality in durum and bread wheats. Significant associatio n between SV and endosperm proteins (gliadin, high-molecular-weight-an d low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variabi lity. The objective of this study was to identify and locate quantitat ive trait loci (QTLs) associated with SV in a set of recombinant inbre d (RI) lines, derived from a cross between the cv. 'Messapia' of durum wheat and the accession MG4343 of the var, dicoccoides, and character ized for 259 genetic and molecular (RFLP) markers. Significant differe nces were detected for the quality index in the six environments exami ned, while the pattern of variability was that of a quantitative trait . Regression analysis of marker loci and sedimentation volume indicate d, as expected, that chromosome 1B, on which are located the Gli-B1/Gl u-B3 loci for some gliadin and glutenin subunits, is important for whe at quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and SAL, were shown to have single- factor effects on sedimentation volume at P < 0.001 and P < 0.01, resp ectively. Positive effects were contributed by both parents. A multipl e linear regression model consisting of seven significant loci on diff erent chromosomes explained 62-91% of the genotypic variation of the t rait. The availability of linked markers to QTLs may facilitate the ge netic dissection of quantitative traits and the early selection in whe at breeding programmes.