A simple method for mass production of potato microtubers using a bioreactor system

Abstract

A simple protocol for mass propagation of potato microtubers was developed using an automated low-cost bioreactor system. Microtubers of potato were induced by a two-step culture method. In the first step (step A), the stock plants were inoculated in the bioreactor for growth and multiplication of plantlets, After four weeks, the medium was replaced with a new one to proceed to step B for microtuber induction. Comparative studies between solid and bioreactor culture (continuous immersion [with net or without net] and temporary immersion in liquid medium using ebb and flood) revealed that shoot multiplication and growth were more efficient in continuous immersion (with net) bioreactor. We also studied the effect of inoculation density on potato micropropagation during bioreactor culture and maximum responses were recorded when there were 50 nodal explants per bioreactor. After shoot proliferation, the culture medium was replaced with one containing a higher concentration of sucrose, with or without 6-benzylaminopurine (BAP) and kept under dark conditions. The analysis of tuber classification according to size showed that addition of BAP in the culture medium influenced the formation of microtubers larger than 1.1 g. It has also been observed that there is a strong influence of medium renewal on individual microtuber growth during bioreactor culture of potato. The results indicate that our system could be applied for mass propagation of potato tubers at low cost.