Phenology of 'Tupy' and 'Xavante' blackberries grown in a subtropical area

- The phenological behavior of blackberries cultivars grown under subtropical conditions was investigated.
- The experiments were carried out in two consecutive crop seasons.
- The fruit development duration was quite similar for 'Tupy' and 'Xavante' blackberries. Both cultivars have comparatively unique phenological periods, earlier and shorter than temperate regions.
- The possibility to grow blackberries under two annual crops under subtropical areas is proposed.

The objective of this study was to evaluate the duration of phenological stages of 'Tupy' and 'Xavante' blackberries grown under subtropical conditions with the goal of optimizing the production system. The experiment was conducted at the Experimental Station, Agricultural Research Center, Londrina State University, PR, Brazil, during two consecutive seasons: 2013 and 2014. A completely randomized design was used with five plot replications, with each composed of five plants. The duration (in days) of each phenological stage was recorded for both cultivars through visual observations at the following times: the onset of bud sprouting, the onset of flowering, the onset of fruit maturation, the beginning of fruit harvest, the end of flowering, and the end of fruit harvest. The duration (in days) of the following fruit development stages was also recorded: flower bud, full open flower, unripe green berry, ripening pink berry, and ripe berry. The phenological development of 'Tupy' and 'Xavante' blackberries was directly influenced by the subtropical winter conditions with changes in bud sprouting, flowering and fruit harvesting periods. In the 2013 season, 'Tupy' had a later start of the growth cycle than 'Xavante', but fruit harvest for both ended at the same time in early summer. In the 2014 season, 'Xavante' maintained its characteristic early start, and 'Tupy' also resumed the growth cycle, which was earlier than the previous season. The duration of fruit development was similar for both cultivars. 'Tupy' and 'Xavante' grown in subtropical mild winter conditions demonstrated unique phenology, with earlier and shorter growth cycles than in temperate regions; thus, growing blackberries as two annual crops to optimize the production system is proposed.