Resistance of almond cultivars to sharka (plum pox potyvirus)

Abstract

Sharka, a disease caused by plum pox potyvirus (PPV), affects some Prunus species including apricot, peach and plum, and to a lesser degree, sweet and sour cherry. Previously, in almond, different PPV isolates have been experimentally transmitted to the 'Aï' cultivar. Some of these infected almond plants even acted as a source of virus for aphid vectors, showing the potential role of almond as a source of virus in the spread of sharka. In this study, the resistance of nine important almond cultivars to a Dideron Type PPV isolate was evaluated in controlled conditions, by grafting the cultivars onto inoculated GF305 peach rootstocks. The results demonstrated the resistance to PPV of all assayed almond cultivars. They did not show any symptoms and were ELISA negative in comparison to the strong symptoms observed in the GF305 rootstock.