Title

Physiochemical and Microstructural Properties of Two Rabbiteye and Two Southern Highbush Blueberry Cultivars as Affected by Rain Induced Splitting and Cultural Practices Implemented to Reduce Such Splitting

Date of Award

2005

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biological Sciences

First Advisor

Kenneth J. Curry

Advisor Department

Biological Sciences

Abstract

Understanding the cause of fruit splitting in blueberries is difficult. Researchers have been working on the problem of fruit splitting in various fruit crops for more than 70 years. If a few key factors that cause splitting in blueberries can be identified and these factors can be evaluated in new potential cultivars, then long term reductions in commercial blueberry fruit splitting are feasible. Cell wall structural components were found to be the most descriptive of the differences found between splitting susceptible and splitting resistant blueberry cultivars. The splitting resistant cultivars 'Premier' and 'Magnolia' had higher water-soluble pectin (WSP) to neutral detergent fiber (NDF) ratio. The ratio of WSP/NDF for splitting resistant varieties 'Premier' and 'Magnolia' is 1.3 and 1.1 respectively, while 'Tifblue' and 'Pearl River', the splitting susceptible varieties, had ratios of 1.6 and 0.7 respectively. Water was tracked using fluorescent stains as it entered the fruit primarily through the vascular system. From the vascular system the stain and water was incorporated into the surrounding tissue and finally saturated the cell walls. Calcium plays an important role as a major nutrient affecting the developmental processes of many plants and interacts with the cell wall structure. Foliar applied calcium at 0.02% or 0.09% concentration did not successfully decrease splitting in blueberries. Calcium sprays also had no adverse affects on the fruit firmness, quality, or calcium concentration within the fruit.