ISHS II Balkan Symposium on Fruit Growing OVERVIEW OF PLUM BREEDING IN EUROPE

Worldwide, plum is one of the main species, occupying an area of about 2,600,000 ha and ensuring production about 11,700,000 tons. Even though there are over 6000 plum cultivars belonging to 19–40 species, there is still the need to create new cultivars due to the demands of growers and consumers. In addition, the large plum-growing countries (Romania, Serbia, Germany, Bulgaria, etc.) have decreased production due to plum pox virus (PPV) attack. Therefore, these countries developed breeding programs with the following objectives: resistance/tolerance to PPV, productivity, fruit quality, late blooming, self-fertility, different ripening times, short growing period, spur fructification, etc. Using different breeding methods (controlled hybridization, open pollination, selection in wild population on Prunus sp., and mutagenesis), in the last years, over 450 plum cultivars were released, from which 70% represent European cultivars and 30% Japanese cultivars.

Fruit quality of apples is influenced by the metaxenic pollen effect of the pollinators. At RIFG Pitesti, the flowers of two scab resistant cultivars (’Topaz’ and ‘Dalinette’) were hand pollinated with other apple cultivars: one scab resistant (’Priam’) and two scab susceptible (’Golden Delicious’ and ‘Idared’). Morphological parameters of fruit (diameter, weight, seed number, skin colour) and quality parameters (firmness, refraction) was investigated at the harvesting time in the Genetic and Breeding Department in order to prove the metaxenic effect. ‘Topaz’ fruits obtained from pollination with ‘Priam’ and ‘Golden Delicious’ were recorded good size parameters (diameter, weight) and flesh quality (firmness and refraction). In case of ‘Dalinette’ fruits, among cultivars used as pollinator, ‘Idared’ caused the biggest fruits with flesh firmness.

ISHS XI International Symposium on Plum and Prune Genetics, Breeding and Pomology Differences and similarities between some European and Japanese plum cultivars

In Romania, work on identification, conservation and evaluation of fruit genetic resources activities was initiated in 1970 in order to limit the loss of biodiversity. There are rich sources of germplasm located in two research centres: RIFG Pitesti with 642 accessions and UCv-SCDP Vâlcea with 361 accessions, representing wild species, local populations, named cultivars, breeder’s selections and rootstocks. Observations were made according to the IBPGR Prunus descriptors updated by the ECP/GR Prunus Working Group. The following genetic resources from the Piteşti and Vâlcea collections were used in a breeding programme in the development of several plum cultivars: ‘Grase de Becs’, ‘Carpatin’, ‘Ialomiža’, ‘Kirke’, ‘Wilhelmina Späth’ (for resistance / tolerance to Plum pox virus); ‘Vinete romāneşti’, ‘Tuleu timpuriu’, ‘Anna Späth’ (for late blooming), ‘Tuleu gras’, ‘Vâlcean’ (for fruit quality), ‘Stanley’, ‘Pescăruş’, ‘Centenar’ (for productivity), and ‘Diana’ (for self-fertility). The plum rootstock breeding programme used the following genotypes as sources of genes: ‘Rosior văratec’, ‘Brompton’, ‘Renclod Verde’, ‘Pixy’, ‘Saint Julien A’, ‘Albe mici’, ‘Scolduş’, ‘Porumbar’, etc. Breeding using the germplasm in these collections resulted in the release of 40 cultivars and 11 generative and vegetative rootstocks.