The role of callose deposits during infection of two downy mildew-tolerant and two-susceptible <i>Vitis</i> cultivars

  • A. Kortekamp
  • R. Wind
  • Eva Zyprian
Keywords: Plasmopara viticola, downy mildew, callose, grapevine cvs Orion, Phoenix, Riesling, Kerner, disease tolerance


Semithin sections of leaves from four cultivars were analysed for callose deposition after infection with Plasmopara viticola. Two of these cultivars are tolerant to this pathogen in the field (Orion, Phoenix), while the other two are susceptible (Kerner, Riesling).
Callose was not detectable during the first 5 days after experimental inoculation. During late stages of the infection cycle however, callose deposits could be found in tolerant as well as in susceptible grapes. During the fungal infection of tolerant plants hyphal development stops 3 to 4 days post infection indicating that mechanisms other than callose deposition are the main factors of tolerance.