Preliminary results for obtaining nuclear-stock plum material in Romania.

Abstract

A certification program focused on plum was established at Fruit Research & Development Station Bistrita, Romania started in 2008. The objective is to obtain in the first step the prebasic material and, subsequently, to establish plum mother plantations with basic material satisfying the EPPO recommended certification standards. Sixteen plum (Prunus domestica) cultivars (Iulia, Matilda, Geta, Zamfira, Ivan, Dani, Doina, Romaner, Elena, Jubileu 50, Delia, Flora, Renclod d’Althan, Stanley, Anna Spath and Carpatin) were subjected to this work. Selected plum trees from experimental orchards were monitored and tested. One shoot was collected from each candidate and tested before grafting onto virus-free Myrobolan 29C rootstock. Selected clones were also tested on woody indicators GF 305. Propagated material was individually tested one year later. All tests were done according to the EPPO recommendations. DAS-ELISA was used for Plum pox virus (PPV), Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV), Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV) and Myrobalan latent ringspot virus (MLRSV). To increase the sensitivity of PPV and PDV detection, IC-RT-PCR was performed. Spot-Real Time RT-PCR was also used to detect PPV. Nested-PCR method was made to detect Candidatus Phytoplasma prunorum. Delia cultivar was found infected by PPV and eliminated from propagation by grafting. This cultivar is subjected to pathogen elimination by using in vitro chemo-thermotherapy. The other fifteen cultivars were found virus-free both before and after propagation. The certification of this material as ‘Prebasic category’ is in progress.