Effects of direct electric current on adventitious root formation of a grapevine rootstock

The effects of direct electric current (DC) on adventitious root formation of the grapevine rootstock Vitis champini cv. Ramsey were investigated. Direct electric currents of 30 and 60 volts were applied for 3, 6, or 9 hr across electrodes inserted into the pith at the cut ends of 30-cm-long dormant cuttings placed horizontally. The anode was set to the basipetal end and the cathode was set to the acropetal end. Rooting rate, number, length, and weight of root were significantly affected by direct current and duration of treatment. While effects of DC-30 V on all tested parameters generally increased with increasing duration of treatment, effects of DC-60 V decreased when its duration exceeded 3 hr. Treatment with DC-60 V for 3 hr led to the highest increase in rooting rate (122%) and number of roots (100%) compared with the control. Significant increases in rooting rate and root growth parameters indicated that DC applications may have the potential to improve propagation of grapevine rootstocks that are difficult to root by cuttings.