EUROPEAN PEAR CULTIVAR RESISTANCE TO BIO-PESTS: SCAB (VENTURIA PIRINA) AND PSYLLA (CACOPSYLLA PYRI)

Scab (Venturia pirina), and pear psylla (Cacopsylla pyri) lead to severe damage on European pear cultivars resulting in a loss of commercial value and requiring frequent use of chemical sprays. Most European pear cultivars are currently reported to be sensitive. Identifying scab resistance genes, developing molecular markers linked to these genes and establishing a marker-assisted-selection (MAS) would be an effective way to improve European pear breeding for pest resistance and then reduce the chemical impact on the environment. The pear cultivar ‘Navara’ was shown to carry a major scab resistance gene with phenotypic expression in seedling progenies as a typical stellate necrosis symptom. The resistance gene was called Rvp1, for resistance to Venturia pirina, and was mapped on linkage group 2 of the pear genome close to the marker CH02b10. This genomic region is known to carry a cluster of scab resistance genes in apple indicating a first functional synteny for scab resistance between apple and pear. The progeny of the European pear ‘Angelys’ crossed with a resistant genotype ‘NY10355’ allow us to analyze the quantitative resistance to pear psylla. Following screening of the parents and seedlings with microsatellite markers, a QTL (Quantitative Trait Loci) analysis has been conducted. A QTL which explains 15% of the phenotypic variability has been mapped on the linkage group 17.