Invited Review: Plant genetic resources for sustainable usage have been investigated as a basis for breeding programs for crop improvement and the advance of target gene(s) in genetic engineering. Ex situ conservation is used to preserve plant species manually in addition to in situ techniques. Orthodox seeds of temperate and subtropical species are mainly conserved as a genebank. However, methods of conservation of seedless and heterozygous orthodox tropical plant species and those with recalcitrant seeds are still limited. In vitro or live vegetative preservation is the preferred way to conserve elite species. There are many approaches to this, including short-, medium- and long-term preservation. Minimal growth in vitro culture or medium-term preservation has been widely exploited as a source of disease-free plants, which are promptly available for international material exchange. This technique is well established and is applied to a wide range of genetic conservation measures with high recovery growth and maintenance of genetic stability when compared to cryopreservation or long-term storage, identified by RAPD and AFLP genetic variation assay. Recently developed techniques and the application of minimal growth preservation will be described in this review. There are many techniques, which can be used to control the in vitro physical and chemical environments, including low temperature, low light intensity, short-photoperiod, high osmotic adjustment, low nutrient concentration and plant growth retardant supplementation for in vitro germplasm. In addition, the combination of both physical and chemical factors is a progressive channel, which can be used to develop general practices for medium-term preservation of tropical plant species.