- Jean Pierre Labouisse, Cirad researcher, will visit Vanuatu in the framework of the CIDP project.
- Bibliographic studies
- Remembering of past scientific exchanges, and continue discussing...
Scientific exchanges between researchers
Roland, November 10th 2013.
- - Green sprouted seedlings harvested on IVTT will be IVTT
- - Brown sprouted seedlings harvested of IVTT will be natural hybrid IVTTxRIT
- - Seedlings harvest on RIT, all of brown of brown green colour, will be either RIT or the hybrid RITxIVTT.
- The establishment of RIT in a farming environment is risky. We have no basis for determining whether current RITs - even selected for enhanced tolerance - can withstand high pressure from the Coconut Foliar Decay disease.
- To date, we are not able to know, under the specific conditions of Vanuatu, the potential of production of such a seed garden. Indeed, with such a design using free pollination, we do not know the self-fertilization rate of each variety nor the rate of inter-crossing between trees of the same variety, nor the rate of intervarietal hybridization. All these parameters depend on the varieties, the climate, the season but also the VTT/ RIT ratio, the pollen competition, etc.
- The constraints at each stage are not negligible and, in any case, not evaluated. This includes: production of sufficient RIT seeds through hand pollination, negotiations with growers - and the costly travel required - to determine who is doing what? who cares?, choice of isolated plots from other coconut palms - difficult to find when VTT coconut is covering 80% of the cultivated land, transport and planting without varieties mixing, with a minimum monitoring of the plots by the VARTC, setting up and follow-up of a nursery, transport - always delicate - of germinated nuts (after checking the color of the germ), the need for a solvable demand for hybrids, what guarantee for the durability of the system?
- It is therefore a risky proposition (to my knowledge, such a hybrid seed garden is not in production anywhere else) of which we do not know all the parameters, neither the production potential nor all the constraints.
- It does not seem reasonable to me to put these risks on small growers; I am therefore personally not in favor of the implementation of such a seedgarden system.
- On an experimental basis, I favor the implantation of a seed garden of Improved VTT x RIT using open pollination with parents of different colors (as described by Roland) under the controlled environment of the VARTC research centre (with DFC control). And this could be done for two objectives: a) study of the general feasibility of the operation; b) study of the real number of hybrids produced, which will also give us the rate of self and inter-fertilization under local conditions. This free pollination seedgarden should be compared to a seedgarden in “oriented” pollination (mixture of both varieties with castrated females and free pollination by males). The implementation of such an experiment should be financed in full through COGENT.
- Implementation of decentralized and open-pollinated Improved VTT seed garden is encouraged and should be a national priority. Immediate use of plantations already in place and in production can be envisaged as soon as they have been planted with improved VTTT, whether the field is isolated from other coconut fields or has a significant area (2-3 ha minimum ). The communication with smallholders should be improved to promote the use of this resource with all the advantages described by Roland (reduction of transport costs, involvement of planters) without the risks and unknowns mentioned above and with much simpler conditions of implementation.
That is the best scenario we could imagine for coconuts. But we cannot ignore the challenges:
- We don’t know much about the severity of DFC on RIT (not resistant or tolerance....) on farmer's field.
- Jean Pierre point out the issue of green and brown sprout, and it will be good to have an idea of that in the station. Up to now, we have not categorise this in our current production of hybrid VTT and RIT. So it will be new activities for us.
- Up to now only 2 plots of VTT were set up recently in Pentecost island (from farmers initiatives). Buts there is need to have close follow up on that which is actually impossible financially
- Is there any fund available to undertake those activities? I understand that, it was decided during the last VARTC Board members meeting that for coconuts section to stop/ cease all genetic improvement of coconut activities at VARTC. They have given directive for coconuts section to concentrate looking at different technologies for copra production and related cost and coconuts sub product apart from copra. There are ongoing discussion with NZAID to provide consultancy and technical back up on that. That is lead to my next point:
- Renew the collection of talls varieties? Are there any available fund to Renew the collection of talls (Need to purchase coconut climbing machine for pollination, Need to purchase a Lyophyllisator for pollen drying and conservation, Need to purchase male and female pollinating bags, and Need fund to hire a technitian for all the activities for harvesting of pollen, pollination and replanting and maintenance.
- In Vanuatu there is an endemic virus that does not cause any symptoms of pathology in the indigenous tall population, yet exotic germplasm is destroyed by it.
- In Solomon Islands in 1963 I planted imported seed from Rangiroa atoll but the seedlings died due to severe leaf spot (Drechslera sp) damage yet the local tall was not affected.
- The leaf beetle Brontispa longissimia causes very little damage to the local tall in Solomon Islands yet when it reached Vietnam recently mature palms were destroyed by it.
- The hybrid Malayan orange dwarf by Rennell Tall has given a 30% increase in yield of copra in plantations in Solomons yet in New Britain (PNG) it was severely attacked by Scapanes australis – a local rhinoceros beetle.
- PB121 which yielded very well in Cote d’Ivoire was attacked by Phytophthera sp in Indonesia and I understand that many died.
- The Rennell island Tall was widely used with great success in the Pacific region; of course in some places, there is the scapanes problem, but in many other, it was OK: Papua New Guinea mainland, Fiji, Samoa, etc….
- The Sri Lanka Green dwarf and the Vanuatu Tall are the only varieties tolerant to LYD disease in Ghana – and there is no LYD in Sri Lanka and Vanuatu
- The PB121 hybrids was mainly a success, even if some problems were encountered in some places of Indonesia - the real problem was not phytophthora except in a few zones, but the small size of the fruit was not appreciated by the farmers – Many of them were very happy to turn their PB121 to heavy Toddy production.
- The case of Vanuatu Tall and the DFMT disease is very strange, and definitely we did not conduct enough research of this question. The Malayan Red Dwarf is the variety most sensitive to the DFMT disease. But MRD can be “vaccinated” in the nursery, and then it does not die anymore from the disease. Nobody tried to take seednuts from these “vaccinated” MRD, plant them and see if the progeny is sensitive of not to the DFMT disease; may be the DNA of the virus integrate the genome of the coconut palm, or something like that. May be the Vanuatu tall is not at all resistant to the DFMT, but is simply “vaccinated”. May be this kind of “Vaccination” help the Vanuatu tall to tolerate the Lyd disease in Ghana….
Mike Foale to John Randles and us, 20th October 2016
- The Vanuatu Tall is not at all tolerant to FDV, he is only "vaccinated", and this vaccination can be transmitted by seeds
- As Vanuatu Tall is also tolerant to Lethal Yellowing Disease (LYD) in Ghana, this vaccination against FDV is also efficient for LYD
- If the Vanuatu Tall is not vaccinated but really tolerant to FDV, there is a unique physiological and genetic reason why Vanuatu tall is tolerant to Both LYD and FDV
References about Vanuatu
Vanuatu’s largest coconut plantation goes organic