Towards a Widening of Romanian Nuclear-Stock Plum Varieties

To reduce economic losses caused by viruses and phytoplasmas, one of the main preventive measures is to use 'certified' plant material. A nuclear-stock plum collection under insect-proof house is conserved at FRDS Bistrița and consists in twenty-one varieties and one rootstock used for stone fruits propagation. A widening of Romanian plum varieties at Pre-basic category is required to create the opportunity to establish a larger national valuable nuclear-stock collection and to secure the prerequisite for a good transfer of Romanian plum breeding results to the practical application. Plants belonging to other six Romanian plum varieties (Diana, Silvia, Tita, Pescăruș, Gras românesc and Tuleu dulce) were monitored in the field along two consecutive years for potential viral symptoms and tested by serological and molecular tools according EPPO standards. Selected trees of each variety were grafted onto virus-free Saint Julien rootstocks, into insect-proof house, and retested. Three grafted plants from each of the six varieties were chosen to become Candidate Pre-basic material and they were biological indexed onto virus free plants of GF 305. Thus, candidate Pre-basic material, the precursor for Pre-basic category, was established to other six valuable Romanian plum varieties.