ISHS Acta Horticulturae 595: International Symposium on Apple Breeding for Scab Resistance
SCAB (VENTURIA INAEQUALIS) RESISTANCE IN APPLE: THE VF-GENE AND POLYGENIC RESISTANCE IN THE BREEDING STRATEGY AT DCA - BOLOGNA |
| Authors: | S. Sansavini, S. Tartarini, F. Gennari, M. Barbieri |
| Keywords: | apple, breeding, scab polygenic resistance and tolerance, molecular markers |
| DOI: | 10.17660/ActaHortic.2002.595.3 |
| Abstract:
Vf is the main gene conferring monogenic resistance to scab in apple. Given that races 6 and 7 of Venturia inaequalis have recently overcome Vf-gene resistance, the breeding strategy at the University of Bologna’s DCA has shifted to polygenic resistance by looking for resistance sources in old Italian apple germplasm. Crosses of Prima x Durello di Forlì, the former being heterozygous for Vf and the latter having an unknown form of field resistance, have yielded 80% resistant seedlings but only 60% when the conidia of the inoculum derived from the pathotype associated with Durello di Forlì. Combining several co-dominant markers has made it possible to distinguish the homozygous from the heterozygous plants. The homozygotic plants for Vf have proved to be more resistant to scab than the heterozygotic ones. The markers made it possible to saturate a genomic map so as to identify QTLs responsible for tolerance or field resistance to scab. | |
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