Quantitative trait loci influencing free-threshing habit in tetraploid wheats

In this study we report the identification and location of Quantitative Trait Loci (QTL) associated with free-threshing character 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 T. dicoccoides characterised for 259 genetic and molecular markers. Significant differences were detected for threshability in the three environments examined, while the pattern of variability observed was that of a quantitative trait. Regression analysis of marker loci and free-threshing index indicated, as expected, that chromosome 2B and 5A have genetic systems for free-threshing habit. An additional region on chromosome 5AL and on 6BS was shown to have effects on threshability at P ≤ 0.001 and P ≤ 0.01 respectively.