Mapping of quantitative trait loci affecting Drechslera teres resistance in barley with molecular markers

Resistance loci for seedling-stage resistance to net blotch disease (Drechs lera teres) in barley were mapped with molecular markers in an F-2 populati on derived from a cross between the susceptible barley cultivar 'Arena' and the resistant Ethiopian landrace 'Hor 9088'. Disease reactions were scored with first and second leaves of 2-week-old plants 7 and 9 days after inocu lation with a single spore-derived isolate. For linkage analysis, 22 RFLP m arkers and 284 AFLP markers were used. The seven linkage groups covered 115 3.3 cM with an average marker interval of 3.76 cM. The resistance was deter mined to be inherited in a quantitative manner. Altogether, 12 QTLs were ma pped with positions depending on the leaf used for testing and the time per iod after infection. Heritability in the broad sense ranged between 0.21 an d 0.37.