Results of phenological research and productivity of apple cultivars

Stanislava Dimitrova, Dimitar Sotirov

Abstract: The study was conducted during the period 2015 - 2018 in a collection apple orchard of the Institute of Agriculture - Kyustendil. Four scab-resistant apple cultivars (Rewena, Reglindis, Retina and Topaz) new to the region were studied. Florina cultivar was used as а control. 46 to 53 days and a temperature sum above 5°C from 180.2 to 249.9°C were needed to start the vegetation. Reglindis trees began to develop at the earliest - on March 25. The flowering of the cultivars was about 12-15 days. From the end of flowering to fruit ripening were needed from 117 days (Reglindis) to 176 days (Topaz) and a temperature sum above 10°C from 1435.7 to 1935.3°C, respectively. According to the fruit ripening time Reglindis and Retina are autumn cultivars and other two cultivars are winter. The highest 3-year total yield was obtained from the trees of Florina (75.1 kg) and Reglindis (63.6 kg).

Keywords: apple; flowering; ripening; temperature sums; yield

Date published: 2020-08-13