Liquid Culture Systems for in vitro Plant Propagation

404 V.A. Savangikar et al.
Key words: cost effective technology, cost of production, low cost technology,
micropropagation
1. Introduction
Commercial micropropagation is the method of choice for multiplication
of elite plants in ornamentals, fruit crops and woody species, further for
improvement in productivity of agricultural and field crops such as
sugarcane, banana, potato and for multiplying selected mutants and
genetically engineered plants (http1; http2; http3; http4; http5; DaSilva
1998a; DaSilva 1998b). It has been widely acknowledged, however, that
high cost of production is a limited factor in practical application of this
technology. Solving this problem is a priority area for many R&D
programmes.
Several cost reduction strategies have been adopted by several groups,
such as use of jam bottles as culture containers, use of liquid media instead
of semi-solid medium to save cost of agar and to get better growth rates, use
of alternative gelling agents (Pierik, 1989; Kodym and Zapata, 2001;
Nagamori and Kobayashi, 2001; http6), cheaper grades of chemicals, use of
natural light for culture growth (Kodym and Zapata, 2001; Savangikar and
Savangikar; 2001), securing concessional tariffs for electricity consumption,
use of bioreactors or robots. Some of these measures have indeed resulted in
some reduction in cost. However, a further reduction is desired.
In developed countries, use of bioreactors and robots are considered as
potentially most useful strategies for reduction in cost, since high wages is
the dominant factor. However, the bioreactor model, based mostly on
somatic embryogenesis, has encountered new problems related to
contamination control, loss of embryogenic potential and doubts about
genetic stability of the product. Benefits of reduction in requirement of
human labour by introduction of bioreactors and robots being offset by
increase in capital cost. The use of robots, has yet to come to a technically
satisfactory stage, as robotic has yet to adapt the vision and image analysis
required for tissue culture operations.
A new comprehensive approach, which combines several cost reduction
strategies, based on the genetically conservative technique of meristem and
shoot tip culture followed by enhanced axillary proliferation, has been
perceived to have high potential of cost reduction (Savangikar and
Savangikar, 2001). This approach was adopted by a commercial enterprise in
large-scale production to evaluate its commercial utility over the old
(conventional) model. Production data maintained by this enterprise after
this adaptation and data kept for the old model for production operations