conference schedule and program with abstracts - Horticulture ...
conference schedule and program with abstracts - Horticulture ...
conference schedule and program with abstracts - Horticulture ...
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P-97<br />
Genetic analysis of the resistance to foliar diseases on Muscadinia rotundifolia<br />
S. Blanc*, S. Wiedemann-Merdinoglu, P. Coste, V. Dumas, P. Mestre, D. Merdinoglu<br />
INRA-UDS, UMR1131 Santé de la Vigne et Qualité du Vin, Colmar, France<br />
*Corresponding author: sophie.blanc@colmar.inra.fr<br />
Viticulture is an important component of French agriculture, both in economical <strong>and</strong> cultural<br />
terms. Neverthless, a wide range of pathogens threatens French viticulture. The current strategy<br />
to control most grapevine diseases totally relies on the use of fungicides. This practice is not only<br />
expensive but also dangerous for the environment <strong>and</strong> human health.<br />
A cost-effective <strong>and</strong> environment friendly alternative to chemicals is the use of resistant<br />
varieties. However, all cultivated European grapevine varieties are susceptible to most of the<br />
pathogens, thus the resistance needs to be introduced from other Vitaceae through breeding<br />
<strong>program</strong>s. Muscadinia rotundifolia (2n=40) is a species closely related to the true Vitis (2n=38)<br />
<strong>and</strong> shows a high level of resistance to a wide spectrum of grapevine diseases.<br />
In order to analyse <strong>and</strong> exploit the syntheny between V. vinifera <strong>and</strong> M. rotundifolia <strong>and</strong> to<br />
accelerate the functional characterization of resistance to pathogens, we are developing a genetic<br />
map of M. rotundifolia, <strong>with</strong> a set of SSR markers scored on a 200 individuals S1 population of<br />
V. rotundifolia cv Regale. 150 markers out of 350 SSR have been found heterozygous, thus<br />
informative for mapping. Construction of the map is in progress.<br />
In parallel, the same population was tested for its resistance to downy mildew (Plasmopara<br />
viticola). Macroscopic <strong>and</strong> cytological observations on leaf discs allowed us to assess the level of<br />
resistance of these genotypes to downy mildew. The whole progeny is very resistant to P.<br />
viticola. Stomatic necrosis were frequently observed that may lead, in most cases, to stop the<br />
invasion of the pathogen when the biotrophic step of its life cycle starts, <strong>and</strong> then to inhibit<br />
sporulation. In few genotypes, downy mildew penetrate the leaf <strong>and</strong> develop haustoria <strong>and</strong><br />
mycelium. In this case, a weak sporulation occurs very rarely. Our next goal will to align M.<br />
rotundifolia <strong>and</strong> V. vinifera genetic maps, in order to underst<strong>and</strong> their degree of syntheny <strong>and</strong> to<br />
locate the position of the clusters of resistance genes in V. rotundifolia. The further analysis will<br />
help to underst<strong>and</strong> the resistance mecanism of V. rotundifolia to pathogens.<br />
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