Saturday, 7 October 2017

Vanuatu

Things to do

-  Jean Pierre Labouisse, Cirad researcher, will visit Vanuatu in the framework of the CIDP project.
- Bibliographic studies
- Recommendations
- Remembering of past scientific exchanges, and continue discussing...

Scientific exchanges between researchers


In November 2013, discussion was conducted between Tiatia Sileye, Jean Pierre Labouisse and Roland Bourdeix about seednuts production in Vanuatu.

Roland, November 10th 2013.

Dear Colleagues,
We are presently compiling the chapter 3 of the strategy: “Where we need to be to secure diversity and increase use”, and there is a full section about “Promoting the use of coconut genetic resources”. In the section 3.4.2 Multifunctional landscape management, we use the example of Vanuatu, as in the text given under. This topic was shortly discussed with Tiata when we meet in PNG airport. Please feel free to give your comments, edits and eventually complete it. I would appreciate Dr Melteras or Tiata to appear as one of the contributors of this section.
Here is the text:
The example of Vanuatu well illustrates how the Polymotu concept could be applied to strengthen the involvement of local stakeholders in producing good, diverse and advanced planting material. The Vanuatu Archipelago counts 80 islands, but improved coconut varieties are produced in only one of those, Espiritu Santo. Until recently, VARTC was mainly producing two varieties for farmers: improved Vanuatu Tall (IVTT) and the hybrid between Vanuatu Tall and the Rennell Island Tall (RIT).
Although this Tall x Tall hybrid is performing well, production of hybrid seednuts was abandoned in 2013. Managing a seed garden of Vanuatu Tall for producing this hybrid is challenging: these palms grows very fast; climbing for emasculating the inflorescences is tedious and dangerous. Transportation cost also considerably limits the use of these varieties by farmers.
Instead of using a unique seed garden under the method of assisted pollination, which requires climbing the palm, it should be possible to plant Polymotu units in farmers fields scattered in a tenth of islands. These units will consist in planting 60 Green-coloured IVTT palms and 40 Brown-colored RIT palms. These palms will have to be carefully selected using information on their progenies because they need to be genetically homogeneous for colour. The fields will need to be protected from pollen contamination by any kind of design. These units will produce by open pollinated seednuts of IVTT, RIT and their hybrid IVTTxRIT, in the following way:
  • - 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.
So no need any more to climb the palm; production of planting material is not centralized but scattered on many islands, more accessible to users; responsibility of producing the planting material is shifted from the national institution to farmers.
  
Kind regards

Reply from Jean Pierre Labouisse, November 13th 2013
(translated from French to English) 


Hello everyone,
Being a copy of this message, I wish to give my personal point of view, the decision remaining under the responsibility of the VARTC. The proposal from Roland brings the following comments:
  • 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. 
 That being said :
  • 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.

Sincerely, Jean Pierre


Reply from Tiata Sileye, November 14th 2013

Dear Roland,
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.
Sincerely, Tiata

In August 2015, discussion was conducted between Mike Foale and Roland Bourdeix, initiated by Hugh Harries.


Mike, 28 August 2015

Dear Roland
I have adopted a cautious attitude to the use of coconut germplasm in locations remote from the place of origin and would like to have your opinion about the following examples.
  • 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.
These examples suggest to me that coconut populations have existed for perhaps millions of years in different regions of the world and undergone natural selection for local biohazards while remaining vulnerable to species and varieties of such hazards in other locations. I understand that West African Tall has not been present in West Africa for more than 500 years yet perhaps the source population (in India?) possessed adequate tolerance to varieties of Phytophthora in West Africa but not Indonesia.

I would appreciate very much your comments on my hypothesis.

Sincerely, Mike Foale, Honorary Research Fellow, University of Queensland

Roland 31 August 2015

Dear Mike and Hugh
In my opinion, they are already so many reasons (such as LYDs) for people to not conduct coconut germplasm exchanges; so I definitely would not add additional reasons to limit the coconut germplasm movements.
Of course you gave some examples of local adaptation, but please consider also these one:
  • 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….
So I continue to believe that conducting coconut germplasm exchange is efficient and useful, even if a high level of precaution is needed.

Kind regards, Roland

Mike Foale to John Randles and us, 20th October 2016
Hi John

The lack of symptoms of Foliar Decay in coconut populations in Vanuatu seems to me to be a quite remarkable thing. I just read from the summary of your 1992 paper (Localisation of coconut foliar decay virus in coconut palm): Viral DNA was detected in symptomatic and asymptomatic palms of both high and low susceptibility, in disease-free tolerant cultivars, and in palms in remission from disease.
I have the impression that populations from pretty well all the islands of Vanuatu are "disease free tolerant". What could be the evolutionary history behind the wide spread of this disease-free status over such a scattering of habitats? Added to that I gather that the population on Rennell, "down-stream" from Vanuatu with respect to oceanic current direction, has a degree of tolerance.
I plan to put together, with the collaboration of willing co-authors, a description of this and other examples where there is clear "local" tolerance or resistance of a particular bio-hazard.
These include the Solomons populations which are little troubled by Brontispa leaf beetle which currently is playing havoc in southeast Asia; also the Solomons populations which are not much troubled by Cercospora (Drechslera) fungal leaf spot whereas a population from the Tuamotus was wiped out in the nursery in 1964; also the population of Hainan Island which tolerates short periods of temperature just a few degrees above zero while all introduced germ-plasm perishes.
It appears to me that the coconut has been evolving in these habitats for long enough to develop remarkable adaptations to local physical or bio-hazards. Would you be able to hazard a guess as to how long would have been needed for a coconut population scattered around the dozens of Vanuatu islands to develop tolerance to a virus injected by a local insect?
Or do you know of anyone else who might hazard such a guess? My guess is some millions of years, but I have no idea how to support that, except that there must have been some remarkable chemical roulette going on and getting a winner must surely have taken a fair while.

Best wishes
Mike

Roland, 20th October 2016
Dear all,

This is a fascinating topic because it seems that, in Vanuatu, the coconut palms can become "vaccinated" to the Foliar Decay Virus (FDV). I saw a small experiment in Santo where Malayan Red Dwarfs, the most sensitive variety to FDV, where "vaccinated" in the nursery and grow very well during decades. This was initially done by Jean Paul Morin. So this subject is crucial, and I suggest to study further this vaccination and to test these three strange hypothesis:
  • 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
So this subject is of great importance, because it deals not only with FDV but also with LYD.

Kind regards
Roland


References about Vanuatu

Vanuatu’s largest coconut plantation goes organic











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