Water Relations and Yields of Three Rabbiteye Blueberry Cultivars with and without Drip Irrigation1

Drip irrigation applied to cultivars of rabbiteye blueberry ( Vaccinium ashei Reade) maintained soil moisture at 25 to 35%, (volume basis), –0.07 bars soil-water potential while no irrigation resulted in 12.5% soil moisture, –2 to –3 bars. Irrigation reduced leaf diffusive resistance (r L ) by 50% and increased transpiration (T) by 70% but had no significant effect on midday stem xylem pressure potentials ( ψ x ). Both yield and berry weight from irrigated plots were increased from 20 to 25% over those on nonirrigated plots. Seasonal changes in ψ x , r L , and T of nonirrigated bushes suggested this species has some characteristic adaptations to drought conditions, one such adaptation being wax rodlets observed in and adjacent to stomatal pores. These may have contributed to a favorable water balance under stress by increasing leaf diffusive resistance.