2017 ASHS Annual Conference

The role of fruit scar on water loss from fresh harvested, fully blue highbush blueberry (Vaccinium corymbosum L.) fruit was studied on three germplasm lines from each of three half-sib families at the University of Talca, Chile. The fruit scar proved to be an important route of water loss, accounting for approximately 25 % of the moisture lost at 20 °C and 45 % of moisture loss at 0 °C, although this percentage varied considerably between lines. Reducing the storage temperature to 0 °C reduced the rate of water loss about by 90 %, which was largely a function of the reduction in vapor pressure deficit. Importantly, while the stem scar covered only 0.19 % to 0.74 % of the fruit surface area, its rate of transpiration on an area basis was hundreds of times higher than for the cuticle. The larger the fruit scar area, the greater was the absolute rate of water loss, but size of the fruit scar did not affect the rate of weight loss when expressed on a per gram fruit basis. Higher levels of water loss were associated with a greater loss in firmness such that fruit categorized as having a large stem scar had a greater rate of water loss and were less firm than fruit categorized as having a medium- or small-sized stem scar. The water permeance of the fruit cuticle varied two-fold and the apparent permeance of the stem scar varied three-fold among the 9 lines evaluated when held at 20 °C. Interestingly, one line exhibited a 75 % lower rate of water loss from its stem scar than the other lines than would be predicted based on its scar diameter. The highly variable nature of water loss through the stem scar and the cuticle in this study suggests that large gains in reductions in water loss are possible for the highbush blueberry once the mechanisms for transpiration are better understood.