Location: Southern Horticultural ResearchTitle: Blueberry Fruit Development and Splitting Author
Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/2009
Publication Date: 4/15/2010
Citation: Witcher, C., Curry, K.J., Marshall, D.A., Spiers, J.M. 2010. Blueberry Fruit Development and Splitting. HortScience 45(4):496. Interpretive Summary:
Technical Abstract: A problem facing blueberry growers in the southeastern United States is rain-related fruit splitting. Splitting refers to a break in the skin and/or pulp of the berry, prevalent in some cultivars, that occurs after a period of drought followed by intense rain. We hypothesize that blueberry cultivars which have a higher percent of apoplast to symplast, in ripening berries, will have an increased probability of splitting. We predict that a high percent of apoplast will result in abundant intercellular spaces filled with amorphous carbohydrate. These spaces reduce cell:cell mechanical strength of the tissue and hydrophilic carbohydrates that fill them can increase fruit turgor pressure. We evaluated the cultivars ‘Premier’ (split-resistant), ‘Tifblue’ (split-susceptible), and ‘Montgomery’ (split-resistant but with firmness measurements consistent with split-susceptible cultivars). Blueberry fruit samples were prepared for paraffin sectioning and compound light microscopic examination. A digital picture library was created, images were edited to analyze the apoplast and symplast, and the percent apoplast was established. Preliminary evidence supports our hypothesis. Split-susceptible ‘Tifblue’ averaged 32.3 percent apoplast at the attachment end of the fruit and 16.5 percent at the floral end compared with split-resistant ‘Premier’ which exhibited percent apoplast varying from 17.4 percent at the attachment end of the fruit to 24.0 percent at the floral end and Montgomery which varied from 16.3 percent at the attachment end to 24.6 at the floral end. Qualitative analysis of laboratory-induced berry splitting supported field observations. Berries were submerged in distilled water and monitored for the occurrence of splitting. ‘Premier’ and ‘Montgomery’ could not be induced to split, but ‘Tifblue’ split readily. Sections through the split of ‘Tifblue’ indicate that the fissure occurs along a weak line in the apoplast with cells lining the fissure remaining intact.