Behaviour of Serbian plum cultivars under Romanian ecological conditions

Plum is the most important fruit species in Romania and Serbia due to high productivity and favourable natural conditions for growing. Regarding the Romanian plum assortment, there are local and other cultivars from Europe, such as ‘Stanley’, ‘Anna Späth’, ‘Tuleu Gras’, designated for processing and for fresh consumption widespread in orchards. Therefore, in our plum breeding programme we aimed to improve the assortment by creating new cultivars as well as to introduce new cultivars from other programmes. As a result of the collaboration with the Fruit Research Institute, Čačak, Serbia, the following cultivars: ‘Čačanska Lepotica’, ‘Čačanska Rodna’, ‘Čačanska Najbolja’, ‘Boranka’, ‘Mildora’, ‘Valjevka’, ‘Valerija’ and ‘Timočanka’ have been introduced at Research Institute for Fruit Growing Pitesti, Romania. During 2018-2020, the following observations and measurements were carried out: flowering and ripening time, yield (kg tree^‑1), vigour (expressed by trunk diameter in mm), fruits quality (weight – g, soluble solids content – °Brix) and susceptibility to Plum pox virus (PPV). The average flowering time of the studied cultivars was in the first half of April and the average ripening time ranged from beginning of July (‘Boranka’) to the end of August (‘Mildora’ and ‘Čačanska Rodna’). The lowest vigour was recorded in ‘Boranka’ (57.60 mm) and ‘Timočanka’ had the highest vigour (68.61 mm). Regarding production, ‘Čačanska Lepotica’, ‘Čačanska Najbolja’, ‘Mildora’ and ‘Valerija’ were noted as large yielding cultivars (over 15 kg tree^‑1 in the 5^th year after planting). The average fruit weight ranged from 31.30 g (‘Mildora’) to 63.21 g (‘Timočanka’). ‘Čačanska Rodna’, ‘Mildora’ and ‘Valjevka’ had a high content of dry matter (over 18 °Brix). Except ‘Čačanska Lepotica’ and ‘Čačanska Rodna’, the other cultivars were tolerant to PPV. Most of the introduced Serbian cultivars showed very good results in Romanian climatic conditions, but most spread is ‘Čačanska Lepotica’. The cultivars ‘Boranka’, ‘Timočanka’ and ‘Čačanska Najbolja’ were used as parents in our breeding work.