By Roland Bourdeix, Malua Solinuu. Valerie Saena Tuia and Alofa Leuluaialii

This website returns the information collected during four scientific visits conducted in 2001, 2010, 2012 and 2017 on behalf the Ministry of Agriculture of Samoa, the International Coconut Genetic Resources Network, the Secretatiat of the South Pacific Community, the Global Crop Diversity Trust, Bioversity International, CIRAD (French Centre for Agricultural Research and Development), the Coconut Industry Development for the Pacific (CIDP project) and the Darwin Initiative "Saving Pacific Coconuts".

Proposal for coconut conservation in the small islands of Samoa

The Polymotu concept is to use geographical and reproductive isolation to conserve and reproduce varieties of plants and trees. When a small isolated place is planted all with the same variety, the plants conserved there breed only within the same variety, and certified seed and seednuts can be produced at the lower cost. These isolated places can be small islands or small valleys; they can also be located in flat mainland, with landscaping designed to create pollen barriers.

We are suggesting the Samoan researchers and people to manage some of the small islands like Apolima, Fanuatapu, Manono, Namua, Nuusafee or Nu’utele by planting only three coconut varieties per island: a green tall (for instance Niu Afa Tall or Niu Vai Tall), Malayan Red Dwarf and Tahiti Red Dwarf (red orange fruits), as shown in the following plate.

Click on the plate to enlarge it. 

It is possible to identify varieties in the nursery by looking at the color of the sprout when the seedlings are germinating. If both a Green tall and red dwarfs are planted in the same isolated place, we will have this figure for seedlings in the nursery:
- Fruits harvested on Green Tall and giving green sprouts when germinating: pure and cheap Green Tall seedlings obtained without costly controlled pollination.
- Fruits harvested on Green Tall with brown sprouts: natural hybrids between Green Tall (as female) and Red dwarfs (as males), which can be used by farmers for plantation in OTHER islands.
- Fruits harvested on red dwarfs with red sprouts: red dwarfs due to the 95% selfing rate of these varieties
- Fruits harvested on red dwarfs with brown sprouts: natural hybrids between dwarfs (as female) and Green Tall (as male), which can be used by farmers for plantation in OTHER islands. If more of these hybrids are needed, it is possible to make some emasculation of inflorescences on the dwarf palms.

So, with only one small island planted, 6 different varieties will be produced naturally, without using costly hand pollination. For this purpose, it is necessary to spend time in these islands in order to check the available coconut germplasm. The existing coconut palms will have to be progressively removed when the new palms will began to bear.

The following plate illustrates the design for a small island (click on the image to enlarge it). It is estimated that a distance of 500 m from mainland is sufficient for the island to be isolated enough for coconut conservation purposes. Then, a very large majority of the crosses between coconut palms will occur within the island. May be the reproductive isolation will not reach 100 %. Anyway, a purity of 97% can be considered as acceptable for both conservation and breeding purposes. Phenotypic traits are often be used to detect and remove the few illegitimate palms that are unwanted mix between varieties.

In this design, not all the island is planted with coconut palms; land remains available for other crops and landscaping. The palms are planted with a spacing of 9 m on a triangular design, giving a maximum of 143 coconut palms per hectare. There are 120 green coconut palms from a unique Tall variety, 20 Malayan Red Dwarf and 10 Tahitian Red Dwarf. In this case, the total design will require a surface of 1 to 2 hectares for the conservation of one Tall coconut variety only.

Yearly production is estimated at 50 fruits per palm in average. In these conditions, if the Red Dwarfs are not emasculated, it is estimated the island will produce annually 7500 seednuts, as follow:

• 5400 certified seednuts of the Green Tall variety
• 600 seednuts of TxD hybrids (Green Tall as female and Red dwarf as male).
• 900 seednuts of Malayan Red dwarf
• 450 Seednuts of Tahiti Red Dwarf
• 150 Seednuts of DxT hybrids (Red Dwarfs as female, Green Tall as male)

This organization could be achieved not only in small islands but in any places where geographical isolation is feasible. See the message about Olomanu Seed garden for more information.

By this way, farmers will be able to produce by themselves various kinds of coconut seednuts, be they hybrids, tall and dwarf varieties. This will help to diversify the coconut varieties available to farmers. Most of farmers do not like to be unforced to choose a unique variety. Farmers should have the choice between a set of varieties including 2 or 3 hybrids, and 2 or 3 tall varieties. Giving the choice to farmers will very probably result in both the plantation of more coconut hybrids and better conservation of traditional varieties.