Stimulation of potato (Solanum tuberosum L.) tuberization by semicontinuous liquid medium surface level control

A procedure for the mass propagation of potato (Solanum tuberosum L.) tubers using a laboratory scale jar fermentor is described. Tuberization was clearly suppressed when the shoots were completely submerged in the liquid medium. Tubers were mainly formed at the medium surface. When shoots were cultured by the semi-continuous medium surface level control method, in which the medium surface level was raised or lowered throughout the culture period, tubers were induced and developed in every area in the jar fermentor. Tubers propagated by this method contained about 18 % (w/w) dry matter, slightly less than in field grown tubers, but most of the tubers weighing more than 0.2 g(FW) sprouted under room condition, without any acclimatization, during 3 month after the culture.