Production of potato (Solanum tuberosum, L.) microtubers using plastic culture bags.

We have developed a system using plastic culture bags with forced aeration system for both liquid medium and gaseous phase to produce microtubers of potato (Solanum tuberosum L.). The production of microtubers under sterile conditions is a good way to produce disease-free materials for crop production, and bioreactors have been used for this purpose. However, bioreactors are expensive and difficult to handle. The plastic culture bags are relatively inexpensive and are easy to store and sterilize because they can be flattened. Microtuber production involves two stages: plant proliferation in one medium, followed by microtuber production in a different medium. Both steps are carried out using the same culture bag. Using this system, we produced 100 to 300 microtubers per 8 l culture bag, depending on the potato cultivar. We varied the nutrient concentrations in the media and found that a lower sucrose concentration in the plant proliferation medium and lower nitrogen concentration in the microtuber production medium both increased the total numbers of microtubers per bag. Notably, a higher concentration of potassium phosphate increased the numbers of larger microtubers. This is beneficial because larger microtubers are much more tolerant to field conditions. We produced about 250,000 microtubers per year in a 66 m2 tissue culture room using the culture bag system. These microtubers have been planted directly in the field and utilized for seed potato production.