Résumé
Plum Pox Virus (PPV) is a serious threat for stone fruit production as there is no resistant variety commercially available. However, breeding for apricot resistance to PPV is in progress. This justifies an evaluation of the susceptibility of common rootstocks in order to boost the release of efficient methods of PPV control. The susceptibility of eight rootstocks is tested against five PPV isolates corresponding to the variability of the virus in France. A first experiment performed under greenhouse with plantlets growing in pots showed differences in susceptibility. A second five-year experiment was performed on rootstocks grown in deep soil, under insect-proof conditions to avoid cross contamination by aphids. Monitoring of infection was carried out by symptomatologic observations and DAS-ELISA tests. Analysis of data allows to notice differences along four parameters: symptomatology, latency (which can extend from 0.2 to more than 4 years), virus titer measured by ELISA OD, and stability of infection evaluated by the repeatitivity of ELISA detections throughout the years. The rootstocks susceptibility shows a differencial interaction according to the PPV isolates. Globally it appears that three rootstocks are susceptible to the five PPV isolates, four rootstocks are not infected by some or by all the PPV-D types, and one rootstock (GF677) shows resistance or only faint and transient virus multiplication. However, until now, limited experiments show that GF677 appears inefficient to protect a susceptible grafted variety against PPV infection.