Quality Differences Among Six Blueberry Cultivars After Machine Harvest

Before the 1960s, all blueberries, whether destined for the fresh or processed market, were harvested by hand. With the advent of machine harvesting, growers were able to increase harvest efficiency at a reduced cost per acre. However, the quality of machine harvested fruit has not been consistent enough to satisfy fresh market demands. The greatest obstacle facing the machine harvest of fresh market blueberries is the excessive softening or bruising caused by the harvester. While improvements in harvester technology, including techniques to soften the impact of falling fruit, have seen some success, a new approach is to breed firmer fruit that can withstand the impact of machine harvesting. The objective of this project was to determine is firmer fruit could handle the stress of machine harvesting. Three cultivars and advanced selections that were characterized as having high firmness were harvested in parallel to three industry standard cultivars by hand and machine from a local grower. Fruit were removed weekly from storage (0-1°C, 90-95% R.H.), followed by evaluation for firmness and disorders after 2 hours or 3 days at room temperature (21°C). The three firm cultigens (Sweet Crisp, Meadowlark and Farthing) yielded the most US #1 grade fruit, while the conventional cultigens (Star, Scintilla and FL 01-248) were substantially softer after both hand and machine harvesting. Average fruit size was larger when harvested by hand, but also had more stem tears.  However, the machine harvested had more attached stems. The length of storage and simulated shelf-life played a significant role in decreasing fruit firmness and increasing the incidence of mold. While using firmer varieties for machine harvesting helped decrease fruit softening, there is still a need to refine machine harvesting for use in the fresh market.