Field Performance of Blueberry Trees Using Vaccinium arboreum As a Rootstock

A blueberry tree orchard, believed to be the oldest grafted blueberry planting in the United States, was discovered recently in eastern Texas.  ‘Beckyblue’ and ‘Homebelle’ rabbiteye blueberries have been grafted onto wild Vaccinium arboreum plants since the late 1980s.  The age of these grafted blueberry trees varies from two to over twenty years old and the planting has not been fertilized or irrigated until a few years ago.  The growth parameters and fruit quality were investigated in 2007.  Among over three hundred grafted trees surveyed, the graft union height is between 30 cm to 60 cm with the largest graft union being more than 10 cm in diameter.  The tallest ‘Beckyblue’ blueberry tree exceeds 4 meters.  There are strong positive correlations between tree age and tree height (r = 0.827), tree age, and rootstock trunk  diameter (r = 0.855), and tree age and canopy size (r = 0.817).  Regression analysis indicates a strong linear relationship between rootstock trunk diameter and tree height (r² = 0.822), and between rootstock trunk diameter and canopy size (r² = 0.910) among various ages of blueberry trees.  When compared to non-grafted ‘Beckyblue’ plants of the same age, grafted ‘Beckyblue’ had a larger berry size, a higher fruit soluble solids content, and a lower fruit firmness. By examining the heath of graft unions, one can conclude that rabbiteye blueberries grafted onto V. arboreum rootstocks should remain productive for the long-term, which demonstrates great potential for commercial production using blueberry trees in the future.