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Viruses reduce yield and quality in asexually propagating crops, and sometimes they cause severe damages to the extent that the maintenance of the clone itself is endangered. For those clones or cultivars found to be fully infected, meristem-tip culture has been utilized for eliminating viruses from them. The apical meristem is a dome of tissue located at the extreme tip of a shoot and, when cultured in vitro on a suitable nutrient medium, it grows and differentiates into whole plants of its own type. Although it still remains to be solved as to why the meristem-tip culture produces virus-free plants, the technique has already been implemented in many countries in order to maintain, propagate and distribute virus-free planting material. For higher success rate in regenerating virus-free plants by the technique, various factors which includes the size of meristem-tip excised, the host-virus combination, thermotherapy, and antimetabolites have been discussed. To establish the production system of virus-free material, it is also important to employ reliable virus indexing and maintenance procedures.
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