The Canon of Potato Science: 25. Minitubers

Abstract

The potato plant is versatile in the ways it can be multiplied: some of the most common propagules used are meristems, nodal cuttings, sprout cuttings, stem cuttings, tubers and true seeds. Potato plants can be grown for multiplication in the field, in greenor screenhouses and under artificial conditions in an in vitro or hydroponics facility. The type of facility needed and the way of multiplication very much depend on the phase of the seed production system. One of the most popular ways to produce pre-basic seed is to grow minitubers in the greenhouse from in vitro plantlets produced from nodal cuttings. Nodal cuttings can be produced aseptically in large numbers by in vitro laboratories specialized in rapid multiplication. Minitubers are usually defined as the progeny tubers produced on in vitro derived plantlets. The term refers to their size as they are smaller than conventional seed tubers but larger than in vitro tubers (or microtubers) produced under aseptic (laboratory) conditions on artificial media. The size of minitubers may range from 5–25 mm although in current systems larger minitubers also have become common. This size range coincides with a weight range of 0.1–10 g or more. The purpose of this phase of the seed production system is to produce as many minitubers above a certain minimum size (or within a certain size class) per in vitro plantlet as possible. For the production of minitubers the quality of the transplant (the original in vitro plantlet) is very important. Essential is that the transplant is true to type and that it is entirely free from any disease. Moreover, the in vitro plantlet should be sturdy, properly induced for a balanced growth between shoot and tubers, and equipped with large and healthy leaves and with active roots. Therefore proper Potato Research (2007) 50:305–308 DOI 10.1007/s11540-008-9051-z