THE DETERMINATION OF SOURCES OF RESISTANCE TO PLUM POX VIRUS SUITABLE FOR PEACH

Seventy-nine peach cultivars were tested and evaluated for resistence to Plum pox virus (PPV). None of the investigated cultivars was immune, highly resistant or resistant to PPV. Eighteen peach cultivars were classified to be medium resistant to PPV. No suitable source of resistance was proved, unfortunatelly. Therefore, seven interspecific hybrids of genus Prunus were tested as candidate sources of resistence to PPV for peach. Hybrids artificially inoculated with PPV by budding were evaluated for the presence of PPV. PPV symptoms were evaluated for three years. The presence of PPV and the relative concentration of PPV (quantitative ELISA) in leaves of evaluated trees was determined in two years. The hybrid NSB 540-73 (Prunus cerasifera × P. holoserica × P. domestica) was found to be susceptible, hybrid Barier (P. davidiana × P. persica) is medium susceptible, hybrid Pumiselect (P. pumila) is tolerant, and MRS (P. cerasifera × P. spinosa) is medium resistant to PPV. Hybrids Fire (P. amygdalus × P. persica) and Cadaman (P. davidiana × P. persica) were preliminary characterized as resistant to PPV and hybrid GF 677 (P. amygdalus × P. persica) as immune to PPV. For the definitive confirmation of resistance or immunity of three candidate sources of resistance will be applied ELISA and RT-PCR methods in the following two years.