Nodal segments or microtubers as explants for in vitro microtuber production of potato

Experiments on recycling small microtubers back into tissue culture revealed that they have a great advantage over nodal segments when used as explants in vitro. They produced plantlets ready for micropropagation in one-half the time it took nodal segments to do so. They did not require a fixed daylength (either long or short days) for this, nor were they dependent on the presence of sucrose in the culture medium. Small microtubers were more suitable than large because the latter produced very many branches which senesced more rapidly. When maintained in culture, these plantlets from microtubers themselves produced microtubers of a similar array of sizes and fresh weights to nodal explants, but at a much faster rate. For this, the presence of a high level of sucrose (8%) was beneficial, and slightly larger microtubers produced a higher yield. The microtubers produced from these plantlets were identical to those from nodal segments, and had a similar period af dormancy.