MICROPROPAGATION OF SOME WILD SPECIES OF THE GENUS Lycopersicon
Tissue culture and protoplast fusion techniques could assist in overcoming these incompatability barriers. Research using these techniques requires access to a ready supply of contamination-free plant material for the establishment of cultures and the isolation of protoplasts. However, seeds of the wild species are available only in limited amounts and plants grown in vivo can prove to be difficult to free of fungal and bacterial contamination.
These problems could be overcome by the development of methods for the micropropagation of these wild species since micropropagated material is genetically identical, contamination-free, uniform in growth and pre-conditioned to an in vitro environment. In addition micropropagation requires little space and provides a constant supply of plant material.
Seven wild species of Lycopersicon plus the related Solanum pennellii have been successfully micropropagated from shoot tips of axenically grown seedlings. The shoot tips were grown on a growth regulator-free medium and were multiplied by culturing nodal sections in either a growth regulator-free or auxin (IAA) supplemented medium. In vitro rooting was not found to be strictly necessary although it did improve establishment in compost in some cases. Hardening-off of the plants was performed in laboratory incubators by covering the plants with polythene bags so as to maintain high humidity. Once the plants were firmly established the bags were removed and the plants hardened-off for a further period in the incubator. The plants were then transferred to the greenhouse and grown to maturity.