in vitro Germplasm collection and storage: A review
Imarhiagbe O, Osazee JO, Aiwansoba RO, Shittu OH
The efficient use of plant genetic resources requires the careful collection of germplasm, its conservation, evaluation, documentation and exchange. Over the last few decades, plant tissue culture has been used to propagate hundreds of plant species. The use of this technique has been particularly important for conservation and multiplication of plants that produce seeds, propagated vegetatively, recalcitrant or have unpredictable seed germination. In vitro collection is a natural outgrowth of this work. Tissue culture being a basic component of plant biotechnology; can expand the possibilities for obtaining plant germplasm irrespective of the nature of the material. It can supplement seed collecting, providing an alternative source of material for propagation and preservation when seeds are not available. Even so, as an in vitro operation with a certain risk of genetic instability is preferable to losing the material completely. Similarly, taking more than one type of explants can provide more opportunities for recovering plants. In vitro collection is an extension of laboratory activities and once the tissue is brought into the laboratory, further measures can be taken to acquire or maintain sterility. It is technically relatively easy; success depends entirely on the availability of methods for growing and multiplying the original explants in vitro in order to produce complete plants. In several cases (e.g. cacao, cotton), although the in vitro collection protocols successfully provided living material to the laboratory, the lack of techniques for maintaining and propagating plants from that tissue precluded the widespread application of the technique. Similarly, a better understanding of the basic biology of regeneration would likely improve the ability to regenerate plants from in vitro collected explants, thereby increasing the possibilities for collection. Currently, the number of species that have been the object of in vitro collection is limited, but as this number grows, improvements in the technique will naturally follow. The paper considers in vitro collection of germplasm as an alternative sustainable means of capturing plant genetic diversity during collection expedition.