[Contribution to the evaluation of the genetic resources of the apple tree (Malus sp.), character variability and resistance to parasites of local varieties in Aquitaine [France; apple scab (Venturia inaequolis); powdery mildew (Podosphaera leucotricha), fireblight (Erwinia amylovora), apple bedstraw aphid (Dysaphis mali)]]

afidos agronomic characters analyse statistique aphide aphids apples bacteriose bacterioses bacteriosis biological development branching chemotaxonomy chimiotaxonomie enfermedades fungosas erwinia gene genes insecte nuisible manzana mycose mycoses pest insects podosphaera pomme ramification statistical analysis