Identification of a QTL for psylla resistance in pear via genome scanning approach

Most current breeding programs in pear are not only aimed to improve the fruit quality, but also resistance to pathogens and pests, such as psylla (Cacopsylla pyri). For this purpose seedlings derived from the crossing 'NY10353' × 'Doyenne du Comice' were grafted on quince and tested for resistance to psylla in a tunnel, considering as parameters both the number of adults (antixenosis) and of nymphs (antibiosis) found on each plant. A “Genome Scanning Approach” was then performed on 14 seedlings selected among those showing the highest degree of resistance. This approach made it possible to identify a putative QTL on chromosome 17 of the resistant parent 'NY10353', that was further confirmed by the analysis of the entire population. The presence of this QTL was stable in all the three years of phenotyping by using as phenotypic parameter the number of nymphs. No associations were found on the susceptible parent 'Doyenne du Comice'. Molecular markers located in this region represent a first tool to setup a MAS approach to select new pear genotypes resistant to psylla.