ABSTRACT
Almost half a century has passed since in vitro
tubers (microtubers) were first described in potato, but
their adoption as a seed propagule has been uneven glob-
ally. Consensus is lacking regarding optimal production
practices for microtubers and their relative productivity
in relation to other propagules for minituber production.
There is significant uncertainty regarding the utility of
microtubers for ev~uation of agronomic characters.
However, the application of microtubers in germplasm
conservation is widely accepted. Microtubers are pro-
duced in vitro in a plethora of different growing systems
with varying environment, media constituents, and stor-
age intervals. Many of the interactions between growth
parameters in vitro and subsequent productivity appear
to be genotype-specific. Accordingly, microtubers come
in different sizes, have different dormancy requirements,
and differ widely in relative growth potential and pro-
ductivity. Despite these differences, there is evidence for
strong analogies in growth responses between field~
grown tubers and microtubers. The use of microtuber
technology in seed tuber production, breeding programs,
germplasm conservation, and research appears to have
enormous potential. This review discusses microtuber
production, yield and performance, in vitro screening,
and germplasm storage and exchange.