BEHAVIOUR STUDIES OF NEW STRAINS OF VENTURIA PIRINA ISOLATED FROM ‘CONFERENCE’ CULTIVAR ON A RANGE OF PEAR CULTIVARS

The ‘Conference’ cultivar is one of the most cultivated pears in Western Europe; and for a long time, this cultivar has been considered as very unsusceptible to pear scab.
However, recently, since the 1990’s,’Conference’ has become very susceptible in some French orchards.
In the context of studies started in 2000, numerous strains of V. pirina were isolated from ‘Conference’ orchards established in regions close to Orleans, Annecy, and Villeneuve d’Asq.
Four of these different strains and a common strain from ‘Pierre Corneille’ were inoculated to a host range: ‘Conference’, ‘Williams’ and ‘Angelys’ (susceptible), ‘Tosca’ (low susceptible), ‘Navara’ and ‘Delice d’Avril’ (resistant cultivars in our conditions). The results obtained show a very strong specificity and aggressiveness of the new strains; they attack only the ‘Conference’ cultivar.
These same strains cause resistance (of the hypersensivity type) on most of the other cultivars; whilst the ‘Angelys’ cultivar is immune.
The strains isolated from ‘Conference’ have a very sharp co-adaptation to the cultivar ‘Conference’. This work is a prerequisite for breeding new cultivars resistant to V. pirina. The good resistance levels exhibited by ‘Navara’ and ‘Delice d’Avril’ in our conditions were confirmed.
This experiment may be prolonged by molecular studies to determine the genetic profile of these new strains.

X International Pear Symposium

M. Chevalier, M. Tellier, Y. Lespinasse, M. Bruyninckx, S. Georgeault

pear scab, susceptibility, resistance, monoconidial strain, co-adaptation, microscopy

https://doi.org/10.17660/ActaHortic.2008.800.111