STUDY OF COMPONENTS OF PARTIAL RESISTANCE TO SCAB ON A RANGE OF APPLE CULTIVARS

The objective of this work was to identify the main components of partial resistance to scab on a range of apple cultivars.
Components which were studied, are: latent period, incidence, severity, mean sporulating area and area under disease progress curve (AUC). Each component depends on a particular mechanism of defence, hence, a better understanding of these will allow us to establish a better breeding strategy for a durable scab resistance.
Furthermore these components have repercussions of epidemic importance in orchard, thus a cultivar’s resistance components should be considered in the future scab management strategies.
Each component has its own importance.
A high correlation existed between the latent period and the area under the severity progress curve; secondly, in the greenhouse, the AUC of incidence or severity are very useful to observe and to judge the global effect of partial resistance.
Finally, three groups of varieties were distinguished on the basis of the relationship between the global score in orchard conditions and the combination of areas under progress curves.
As practical results of this work, the cultivars ‘Alkmene’, ‘Président Roulin’, ‘Reinette Hernaut’, ‘Grenadier’ and ‘Mosancelj’ show the best low susceptibility to scab.

XI Eucarpia Symposium on Fruit Breeding and Genetics

I. Villette, M. Lateur, B. Lefrancq, P. Lepoivre

Malus domestica, Venturia inaequalis, polygenic, durable, resistance, biodiversity

https://doi.org/10.17660/ActaHortic.2004.663.33