Seed Potato Production - The Potato: Botany, Production and Uses - page 125

stocks and either the plantlets or minitubers
produced from these cuttings.
The recent advances in manipulating
in vitro potato stocks through a variety of methods
has made it possible to propagate large numbers
of fully tested stocks to use as the origin for field
production (Dodds, 1988). In vitro stocks are a
standard mechanism for introducing new ger-
mplasm into the certification system. Sources of
new germplasm are important because they bring
improved varietal characteristics and disease re-
sistance to the potato producers, whether seed
or commercial (de Bokx and van der Want, 1987).

cheaply for minituber production. Sprouts can
be broken off of mother stock/minitubers to be
rooted and planted in the field. Finally, tissue
culture plantlets can be sown directly in the field
for the first field generation.

Basic micropropagation techniques

Micropropagation of tissue culture plantlets has
been used extensively in crop production since
the early 1970s, but was adopted by the potato
industry in the 1980s (Roca et al ., 1978; Dodds,
1988). Tissue culture multiplication begins with
plantlets obtained from mother stocks. The
mother stocks are derived from either breeding
material or field-grown tubers that have been se-
lected for appearance and yield and verified as
the true-to-type cultivar. Tubers are cleaned, dis-
infected, and sprouted. The sprouts are then
placed into artificial media under aseptic condi-
tions (Murashige and Skoog, 1962; Xie et al .,
2004) ( Fig. 8.2 ).
After growth, each mother plant is tested
for pathogens (mainly viruses and bacteria).
Typically, up to ten individual plantlets repre-
senting the clone bank for the cultivar will be
kept for the long term. These will be tested on an

Sources of starting material
for pre-basic seed

Pre-basic, non-field-raised seed stocks can come
from a variety of methods. In vitro cuttings and
plants are important for minituber production
in protected greenhouses or screenhouses (pro-
duction in field soil protected by insect-proof
screening which lets in air but keeps out insects).
Microtubers can be produced in vitro and used
either in the greenhouse or field. Cuttings from
disease-free microprogated plantlets grown
in vivo can be used to produce more plants

Fig. 8.2. Micropropagated tissue culture plantlets in a growth room.