Chromosomal location of a gene suppressing powdery mildew resistance genes Pm8 and Pm17 in common wheat (Triticum aestivum L. em. Thell.).

The chromosomal location of a suppressor for the powdery mildew resistance genes Pm8 and Pm17 was determined by a monosomic set of the wheat cultivar Caribo. This cultivar carries a suppressor gene inhibiting the expression of Pm8 in cv Disponent and of Pm17 in line Helami-105. In disease resistance assessments, monosomic F1 hybrids (2n=41) of Caribo x Disponent and Caribo x Helami-105 lacking chromosome 7D were resistant, whereas monosomic F1 hybrids involving the other 20 chromosomes, as well as disomic F1 hybrids (2n=42) of all cross combinations, were susceptible revealing that the suppressor gene for Pm8 and Pm17 is localized on chromosome 7D. It is suggested that genotypes without the suppressor gene be used for the exploitation of genes Pm8 and Pm17 in enhancing powdery mildew resistance in common wheat.