Effects of Substrate pH on Growth of Vaccinium arboreum from Differerent Provenances

Alkaline soil pH is a limiting factor in commercial blueberry production and tolerance of these growing conditions would benefit growers in areas with higher pH soils, as well as expand the amount of available land that is suitable for growing blueberries. Vaccinium arboreum is native to the southeastern U.S. and has been found growing in soils with a pH as high as 7.  Coupled with its alkaline soil tolerance, sparkleberries also exhibit other characteristics that make it a suitable species for use as a rootstock, such as a monopodial trunk and excellent drought resistance.  The purpose of this 2-year experiment was to determine the effects of substrate pH on growth characteristics of open-pollinated populations of sparkleberry seedlings from different provenances. Plants were placed into a deep-water culture hydroponic system containing a nutrient solution buffered to a pH level of 5.5, 6.0, 6.5, or 7.0.  In the first year, a chelated iron source was included in the nutrient solution and final fresh weight increased linearly with increasing pH. Provenance and pH were significant main effects.  In the second experiment, a different iron source was used and there were more pronounced differences between provenances.  Final fresh weight of 3 of the 4 provenances decreased linearly in response to increasing pH.  Final fresh weight of one provenance exhibited a significant quadratic trend with greatest fresh weight obtained at pH 6.5. The interaction of pH × provenance affected final fresh weight, root fresh weight, and the root dry weight.  The main effects of pH and provenance affected root:shoot ratio and photosynthesis.  Results of this study indicate that provenance does affect the growth of V. arboreum in different substrate pH levels.