7:2003: Genetic diversity and propogation of mangroves

Mangrove communities have been heavily exploited for their wood, and disturbed by other activities including aquaculture, mining, and disposal of chemical wastes. This project was established with Thailand to undertake molecular biological studies on genetic variation in mangroves, and with Vietnam to develop methods for micropropagation of mangrove through tissue culture.

Excellent progress was made in achieving the objectives related to the application of DNA marker techniques for the mangrove Avicennia marina. This research was conducted at Southern Cross University, and was given a headstart when important groundwork for the molecular studies of genetic diversity in this species was initiated and supported by Southern Cross University in 1997.

The results have been disseminated in several publications in refereed journals, and have raised important questions about population structure, mating systems and gene flow that are currently being addressed in Australia (A. marina) and Thailand (Rhizophora apiculata). In Thailand, the collaborators have succeeded in establishing new techniques of DNA analysis with support and training from Southern Cross University. The project has thus clearly contributed to building research capacity in Thailand.

Glasshouse trials of A. marina from different provenances have shown that plants maintain differences in morphological and growth characters when grown in the same environment. This is an important result as it demonstrates that these traits are genetically determined. It still needs to be determined what characteristics are considered desirable for re-establishment of new plantations in specific locations, and the extent to which these can be sought out in natural populations.

A major aspect of the project has been to develop micropropagation of mangroves using tissue culture techniques. However, it has become evident that mangroves (A. marina and Rhizophora spp.) do not respond well in tissue culture. Satisfactory progress has been made at Burringbar NSW and Yen Lap, Vietnam, yet much work remains ahead before routine and efficient micropropagation of desirable genotypes can be achieved. The project has received an 18-month extension.