Effect of Provenance On Vaccinium arboreum Soil pH Tolerance

Tolerance to more alkaline soil types would aid commercial cultivation of blueberries in areas with higher pH soils.  Vaccinium arboreum, sparkleberry, has been found growing in areas with soil pH levels as high as 7.  The tolerance of a range of pH levels, along with a monopodial trunk and excellent drought resistance make V. arboreum an ideal candidate for use as a rootstock.  We tested the effect provenance has on the soil pH tolerance of sparkleberry.  Our experiment was set up as a five by four factorial testing five provenances and four different pH levels: 5.5, 6.0, 6.5, and 7.0.  The experiment was conducted using a deep-water culture hydroponic system based on previous work by Darnell and Hiss (2006).  Each 2-liter jug was covered with aluminum foil to prevent light infiltration to the root zone.  Each jug was fitted with an airstone submerged in nutrient solution and attached to an aquarium pump that provided oxygen to the roots.  The nutrient solution was buffered with 5.0mM MES.  The pH and nutrient solution temperature was measured every other day, and the solution was changed on a weekly basis.  Plant water usage was recorded and replenished using aerated bottles containing nutrient solution without plants.  Nitrate and Fe uptake were recorded by measuring depletion from the nutrient solution.  Plant height, widest width, root length and root spread were recorded at the time of experiment initiation and again at completion.  Based on information gathered from this experiment, further testing will be conducted to reinforce our findings and to select potential rootstock candidates.