Effect of a New Pruning Method On Field Performance and Fruit Quality of Highbush Blueberries Grown as a Soilless Culture—Does Cultivar Has Influence?

Modern soilless cultivation technology of blueberries highlights the need to explore the most effective pruning method to manage plant architecture, productivity and fruit quality under specific environmentally challenging and limited space growing conditions. Moreover, considering the lack of specialized labor for this task in many blueberry growing areas, we aimed to explore the effects of novel pruning method called ‘sectorial’ pruning (SP) in comparison to conventional pruning (CP) on field performance of potted blueberry cultivars ‘Duke’ and ‘Bluecrop’ over a four-year period (2019–2022). Results showed that the average number of fruits was significantly decreased in sectorially pruned bushes of the cultivar ‘Duke’, which contributed to a yield reduction of 26%. In contrast, no significant differences in the number of fruits per bush, yield per bush and per hectare were observed between the pruning treatments in the cultivar ‘Bluecrop’. The response of the ‘Duke’ cultivar to CP led to a greater accumulation of the predominant sugars (glucose and fructose) in the fruit, while these changes were not significant in the ‘Bluecrop’ cultivar. Conversely, SP contributed to a higher synthesis of citric, malic and shikimic acids (7.10 g kg−1, 0.687 g kg−1 and 66.4 mg kg−1 FW, respectively) in the cultivar ‘Duke’, while the fumaric acid was elevated in the cultivar ‘Bluecrop’. The findings revealed that the new SP method was effective in promoting yield and fruit quality only in the ‘Bluecrop’ cultivar indicating that each blueberry cultivar grown in a pot requires a tailored pruning strategy to maximize its field performance and increase fruit size and the content of taste-related compounds.