INTRODUCTION
Although in vitro tubers (microtubers) were described in
the mid-20 ~ century (Barker 1953; Mes and Menge 1954)
microtubers remain enigmatic in many respects and have gen-
erally been under-utilized as a propagule. For example, uncer-
tainty surrounds microtuber production practices, their role in
the seed tuber industry, and their potential use for evaluation
of agronomic characters. The objective of this review is to
present a summary of available information in these areas. We
examined the use of microtuber production technology in the
seed tuber industry including choice of initiation propagules,
inducing agents, and commercial scale-up. We summarized
what is known of microtuber performance in comparison with
other propagules that are used in the seed tuber industry. We
also explored the utility of microtubers for evaluation of agro-
nomic characteristics and in germplasm storage and
exchange. It is hoped that this synthesis of information will
lead to increased understanding of microtuber production and
increased awareness of their potential for in vitro screening
and conservation. A previous review examined the validity of
microtubers as a model for tuber research (Coleman et al.
2001).