Current Applications of Tissue Culture in Plant Propagation and Improvement

Plant tissue culture involves the culture of all types of plant cells, tissues and organs under aseptic conditions. This definition also extends to the culture of excised embryos and to protoplast culture. An overview of tissue culture techniques and their applications in plant propagation and genetic improvement of plants is presented. The areas under review include: (1) embyro culture, (2) meristem culture, (3) micropropagation, (4) somatic embryogenesis, (5) somaclonal variation, (6) in vitro selection, (7) anther culture and (8) protoplast culture. Problems and limitations of each of the techniques are also discussed. Examples are given of work that has been undertaken or that is currently in progress on the application of these techniques to the improvement of Queensland's subtropical horticultural industries. Key examples are: (1) embryo culture to facilitate incorporation of genes conferring disease-resistance from wild Cucurbita species into cultivated varieties, (2) meristem culture for virus elimination in strawberries (Fragaria × ananassa) and sweet potato (Ipomoea batatas), (3) micropropagation for rapid increase in new varieties of ginger (Zingiber officinale) and pineapple (Ananas comosus) to enable more rapid field evaluation and early release, (4) micropropagation of disease-free, genetically uniform planting material of superior female papaya (Carica papaya) selections and banana (Musa spp.) selections and (5) the use of somaclonal variation and gamma-irradiation for the genetic improvement of banana. Finally, future opportunities for the utilisation of tissue culture in plant propagation and improvement in Queensland's horticultural industries are summarised.