On s’en serait douté mais... une étude scientifique montre que la quasi-totalité des variétés modernes de #pommes (après 1920) remonte à une demi douzaine de variétés, qui sont susceptibles aux maladies. Et la plupart ont un pedigree qui contient plusieurs fois ces variétés, réduisant la diversité génétique intrinsèque à la variété.
“The apple varieties used in the modern commercial apple cultivation are nearly all genetically based on six relatively disease susceptible “ancestorvarieties”: Golden Delicious, Cox Orange, Jonathan, McIntosh, Red Delicious and James Grieve. This applies to varieties bred after 1920 until today, including the new scab resistant varieties. The following article shows the dimension of the genetical narrowing and problems concerning the vitality of modern apple varieties. The author has compared the healthiness of old and new apple varieties in his trialorchard under no fungicide-spray conditions. As a conclusion out of his observations he calls to bethink an overall—not just reduced on scab resistance—term of vitality, as well as to use also the genetical potential of old apple varieties.”
▻http://www.kulturpflanzen-nutztiervielfalt.org/sites/kulturpflanzen-nutztiervielfalt.org/files/z.K.%20Apfelz%C3%BCchtung.Genet_.Verarmung-u.Tenden
#diversité #génétique #plant_breeding #amélioration_variétale