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SESSION 4: GENETICS OF HOSTS – PLANT RESISTANCE TO FUSARIUM,
VARIETY DEVELOPMENT
P98 - Impact of co-infection by Microdochium spp.
and Fusarium graminearum on the assessment of new
wheat varieties’ tolerance to FHB and deoxynivalenol
B. Méléard 1 , E. Gourdain 1 , M. Gauthier 1 , P. Du Cheyron 2
1 Service Qualités-Valorisations, ARVALIS - Institut du végétal, Station Expérimentale, 91720
Boigneville, France; 2 Service Génétique, Physiologie et Protection des Plantes, ARVALIS - Institut du
végétal, IBP – Université Paris Sud, Rue de Noetzlin – Bât. 630, 91405 Orsay cedex, France
E-mail: B.MELEARD@arvalisinstitutduvegetal.fr
By choosing the variety to produce, a farmer has a good mean to manage the
Fusarium Head Blight (FHB) risk and their associated toxins. Many efforts have
been made by breeders since a few years in France to improve tolerance of new
varieties to FHB, mostly for F.graminearum. Also the assessment of new varieties
on this criterion is a major stake. For this reason the French registration system
(Comité Technique Permanent de la Sélection) has developed specific trials by
using maize debris spread on soil and water spraying. New varieties are
evaluated by a notation from very sensitive to tolerant. Sometimes the
observations reveal the presence of both F.graminearum and Microdochium
fungus in the trials. In this case the question is to know if such a situation does
impact the ranking of varieties according to the ratio between F.graminearum and
Microdochium on the grain by the way of a difference in the production of toxins.
A multilocal trials network has been used in a collaborative research project
named ECOFUSA with the financial support of CASDAR (Compte d’Affectation
Spéciale pour le Développement Agricole et Rural). Neuf varieties have been
characterised for the presence of F. graminearum and Microdochium by the mean
of visual notation, quantification of fungus and Deoxynivalenol (DON) content in
grain.
For the statistical treatment trials have been classified in 3 groups according to
the ratio between F. graminearum and Microdochium on the grain. Data have
been analysed by a mixed model taking into account the following factors, variety,
precocity, location x year and Fusarium/Microdochium ratio. Differences in the
ranking of varieties for DON content in the trials are non-significant. This
preliminary study that needs to be continued seems to show that a trial where the
rate of Microdochium compared to F. graminearum is high (until 50%) could be
used to classify varieties on their susceptibility to DON accumulation.
Keywords: FHB, DON, varieties, co-infection
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