Comparison of Fruit Parameters and Elemental Composition of Commercial Varieties of Blackberries

Abstract

Blackberries are a valuable crop that has a positive effect on human health due to its fruits’ antioxidant and antihyperglycemic properties. The main goal of the research was to compare the fruit parameters of modern blackberry varieties. The experiment involved six varieties of blackberries: ‘Natchez’, ‘Loch Tay’, ‘Brzezina’, ‘Black Gem’, ‘Heaven Can Wait’, and ‘Ouachita’. The data were collected in 2021–2022 in the Rostov region of Russia. On one hectare, 3000 plants with trellises were planted. To prevent winter damage, the plants were covered for the winter period with a non-woven covering material with a density of 60 g/m2. To assess the quality of the fruits, harvesting was carried out from seven to nine in the morning once every 5–6 days. The results showed that the most productive varieties are the ‘Loch Tay’ (4.8 kg/bush), ‘Black Gem’ (4.2 kg/bush), ‘Heaven Can Wait’ (3.9 kg/bush), and ‘Ouachita’ (3.8 kg/bush) varieties. The heaviest fruits are as follows: ‘Natchez’ (13.3 g), ‘Black Gem’ (11.2 g), and ‘Ouachita’ (10.3 g). The varieties with the highest amount of sugar are the following: ‘Black Gem’ (14.7 Brix), ‘Ouachita’ (13.4 Brix), ‘Loch Tay’ (12.9 Brix), and ‘Heaven Can Wait’ (11.6 Brix). In terms of the combination of the parameters, the most promising varieties for industrial production in this region are the ‘Ouachita’, ‘Black Gem’, ‘Loch Tay’, and ‘Heaven Can Wait’ varieties. Medium and strong relationships were established between the parameters of the fruits and the elemental composition of the leaves. During the study, we also developed systems of equations for predicting the parameters of a berry based on the content of one or another macro and microelement of a leaf; these systems are suitable for both the manual calculations in nurseries and the correcting of programs for the automated determination of fruit quality and the calculation of productivity in large industrial farms. The obtained data will make it possible to increase the blackberry production area in Russia from 4.34% to 22.06% in various growing regions.