Evaluation of some newly introduced plum cultivars in Bulgaria

The aim of this study was to evaluate six newly introduced plum cultivars from Germany under the agroecological conditions of Kyustendil region, Bulgaria. The plum trees were grafted on Prunus cerasifera rootstock and planted in the spring of 2011 at distance 4×3 m. ‘Stanley’ was used as a standard cultivar. The trees were formed as free-growing crowns and grown without irrigation. The vegetative growth parameters (trunk cross-sectional area and crown dimensions), term of flowering and fruit ripening, yield tree^‑1 and some fruit biometric characteristics were recorded all years. The highest yield was recorded in the standard cultivar ‘Stanley’, followed by ‘Topper’ and ‘Top 2000’. The highest values of yield efficiency had ‘Topper’ and ‘Topking’ and the lowest were recorded in ‘Topfit’. The ripening time of ‘Topfit’ was the earliest (July 22-28), while the latest was of ‘Tophit plus’ (September 15-October 5). ‘Topking’ had the largest fruits (65.9 g) followed by ‘Tophit’ and ‘Toptaste’ while relatively smaller mass was recorded in ‘Topper’ and ‘Top 2000’. According to these results, in could be concluded that all cultivars are suitable for this region and can be used as alternative cultivars in plum growing.