Mapping QTL involved in adult plant resistance to powdery mildew in the winter wheat line RE714 in two susceptible genetic backgrounds

The objective was to study the genetic basis of adult plant resistance to powdery mildew of the winter wheat line RE714 by quantitative trait loci (QTL) analysis and to investigate the stability of the QTL detected in two different genetic backgrounds. Two DH populations from the crosses between RE714 and the susceptible parents 'Festin' and 'Hardi' were used. Reaction of the DH lines to powdery mildew was assessed in different environments in Belgium under natural disease infection. Considering both populations and according to the environment tested, one to seven QTL were detected. Among them, residual effects of the race-specific resistance genes Pm4b and MIRE were found, Two major QTL were very stable (on chromosome 5D and at the MlRE locus), since them were detected in both populations and over all environments tested. The QTL detected varied according to the susceptible parent used. and a residual effect at the Pm4b gene was not observed with the genetic background of 'Hardi'.