Identification of QTLs associated with fire blight reistance in pear

Erwinia amylovora, the causal agent of fire blight in pome fruits, is one of the main threats for pear cultivation. The disease severely affects pear production especially under favorable weather conditions to the bacterium spreading. In pear germplasm various levels of fire blight susceptibility/resistance are described. The cultivar ‘Old Home’ is known for its fire blight resistance and has been used in breeding. A mapping population (‘Abbé Fétel’ × ‘Old Home’) was evaluated to verify the presence and identify genomic regions associated with resistance. A progeny of 132 individuals was phenotyped by experimental inoculation in actively growing shoots under greenhouse conditions with a virulent E. amylovora Italian isolate (FP621). High resolution SNP- based genetic maps of the parental lines were produced via SPET technology. The QTL analysis confirmed the presence of two QTLs in the ‘Old Home’ map. These results need to be further validated with the identification of candidate genes and the development of molecular markers to be used in DNA-informed breeding.