Purpose of Research
Rationale and Background
The coconut palm (Cocos nucifera L.) is an important livelihood crop for millions across Southeast Asia, the Asia Pacific, Africa and Latin America. Fully developed and strategically used, coconuts could increase food production, improve nutrition, create employment opportunities, enhance equity and help conserve the environment. The future of global coconut production and livelihoods critically depends on the availability of genetic diversity and the sustainable use of this broad genetic base to breed improved varieties.
Harnessing and conserving agrobiodiversity are critical to sustainably boosting productivity and livelihoods, and addressing important challenges including those posed by climate change or pest and disease epidemics. Bioversity International continues to support the development of a progressive global strategy for conserving coconut germplasm. It aims to cost-effectively optimize conservation of as much representative diversity as possible.
Because of its large, recalcitrant seed that exhibits no dormancy, coconut diversity is conserved in field genebanks, which until recently has been the only practical method for coconut ex situ conservation. They however require a large area and substantial resources to maintain, and are subject to many risks such as exposure to pests, diseases, abiotic stresses and natural and man-made calamities. Many countries also lack the capacity and financial resources to maintain their collections.
Currently, coconut embryo transfer offers a feasible means of safely sharing and conserving coconut germplasm. This includes ensuring optimal embryo (or plug) selection and transfer, according to strictly observed protocols.
Bioversity has recently produced the ‘Technical guidelines for the safe movement and duplication of coconut germplasm using embryo culture transfer protocols’ as the main output of project work producing a protocol adapted from previously existing coconut embryo culture protocols . The project aimed to validate and apply the adapted protocol to provide users with an up-to-date, reliable method for effectively transferring coconut germplasm. Most importantly, the unique accessions housed in certain coconut genebanks need to be duplicated in other genebanks to minimise the risk of losing them. Embryo transfer offers an important facility for such duplication. This duplication work is now underway. For those countries lacking embryo-management capacity, the transfer of embryo-cultured seedlings offers a more viable alternative means of sharing germplasm, and Bioversity aims to coordinate further research in this area.
As another potential means of ensuring long-term conservation, accessions can now also be cryo-preserved, that is frozen to the temperature of liquid nitrogen (-196°C). Cryopreservation arrests both the growth of plant cells and all processes of biological deterioration, so that the material can be preserved for extended periods and resuscitated into fully viable plants. The one-off cost of cryo-preserving accessions is expected to pay off against the recurrent costs of in vitro or in field maintenance over a number of years.
A robust cryopreservation protocol needs to be developed and validated. The factors governing protocol success need to be carefully identified and controlled to obtain favourable results. Recognizing this need, Korea RDA and Bioversity International, as part of their partnership to enhance the sustainable use and conservation of genetic resources in the Asia Pacific region signed a new Memorandum of Understanding (MOU) in 2009 that included an Rand D partnership for coconut cryopreservation. Following the MOU, the International Coconut Genetic Resources Network (COGENT) proposed a partnership with RDA for creating a global coconut cryobank to provide a safety duplicate of the coconut virtual collection. An expert consultation was also organised in Suwon in 2009 to assess the developments of coconut in vitro culture and cryopreservation.
Studies have indicated that mature coconut embryos are safest for their cryopreservation. The project aims to optimise existing protocols and make these more efficient for cryopreservation. Amongst the cryopreservation techniques that have been widely tested, the proposed project will emphasise on the use of vacuum assisted procedures involving physical and chemical dehydration and the droplet-vitrification method of coconut embryos. A systematic study using these alternative approaches is required to provide a solid basis for understanding the various factors leading to the success in long term storage of materials under cryogenic temperatures.
The Asia Pacific contains mega-biodiversity and is the centre of origin for many crops. Therefore, development of applicable cryopreservation protocols for those vegetatively propagated and recalcitrant seed species is needed for long-term safety backup of such genetic resources in this region. A droplet-vitrification protocol using a systematic approach, developed at RDA can be useful to develop the cryopreservation protocol for some species. There is an urgent need for improving communication between cryopreservation researchers, and it is suggested to establish an informal network among researchers at national genebanks and universities. It will facilitate information exchange and developing the cryopreservation activities in the region.
Workplan/Schedule of Activities
The activities described below will be under the responsibility of the Korean scientist seconded to Bioversity. These activities will include the following:
A. Optimisation of cryopreservation protocols for coconut
B. Enhancing national capacities and upscaling of cryopreservation techniques for sweet potato and other APO originated species