Honey Bee (Hymenoptera: Apidae) Visits and Pollen Source Effects on Fruiting of ‘Gulfcoast’ Southern Highbush Blueberry

Abstract

Bee visitation levels and pollen sources were varied in an effort to optimize fruit production (especially early ripening, fruit set, and berry weight) of southern highbush blueberry (low chill hybrids of Vaccinium corymbosum L.). Fruiting plants (‘Gulfcoast’) were enclosed in nylon-mesh cages with colonies of honey bees, Apis mellifera L., and pollinizer plants affording either intravarietal self-pollination, intervarietal crossing, or interspecific crossing with rabbiteye blueberries, Vaccinium ashei Reade. Newly opened blossoms were allowed 0, 1, 5, 10, or unlimited bee visits before being closed with a fine mesh bag. Significant improvements in fruiting characters were achieved between one and five visits and also usually between five and unlimited visits. Fruit set more than tripled between the fewest- and greatest-visit levels; set peaked near 70%. The pollination-toharvest interval, a chief determinant of blueberry prices in the early season, was shortened by 5 d to 53 ± 0.5 (SE) d. Berry weight increased 28% from the 0- and I-visit groups to 1.77 ± 0.05 g per berry with unlimited visits. Seed numbers increased 2.2-fold to 40 ± 1 seeds per berry. Sugar concentration of juice ranged from 11.0 to 12.9% and was lower at greater levels of bee visitation. Pollen source did not have a significant effect on any fruiting character measured in ‘Gulfcoast’.