Potato microtubers as research tools: a review

Although invitro production of potato tubers or microtuberization was achieved more than 40 years ago, the application of microtubers in reliable model research systems has been slow to develop. Several factors such as the use of growth regulators in microtu-ber induction and growth media, the mixotropic nature of thein vitro system, and cultivar-specific responses have led to interpretive difficulties. A cautionary note is also necessary in view of apparent growth and development differences, metabolic alterations, and soma-clonal variation encountered in microtubers that may not be found in field-grown tubers. Evidence for strong and consistent analogies between microtubers and field-grown tubers for their induction, growth and development, and metabolism often is lacking. However, several components such as the rapid and near-synchronous induction and growth, which can be modified by a range of exogenous compounds or conditions, make the microtuber a valuable model system. Complex problems such as dormancy also appear to be particularly amenable to examination by the microtuber system. In addition, the use of microtubers as experimental research tools has potential in the areas of plant metabolism, germplasm selection and evaluation, genetic transformation, somatic hybridization, and molecular farming.