By R. Bourdeix, 2019, in construction
Each coconut palm (and even each other tree crop) planted in a coconut genebank should be identified by a mother palm number. This mother palm number should be recorded in a field map. It should be also recorded in a separate file indicating its geographical localisation (latitude and longitude). So, if necessary, it will be possible to return to the mother palm and, if this mother palm still alive, to collect more seednuts. For the technical application of this golden rule, please see under.
Do not plant a coconut palm in a genebank or in a breeding experiment
without knowing, recording and mapping at least its one of its parent palm, and preferably the two parents! |
Do not reproduce Tall-types allogamous populations from coconut genebanks
by using seednuts obtained from open pollination: if so, all adjacent varieties will mix. Such reproduction needs the use of the controlled polination technique with bagging. |
Each coconut palm (and even each other tree crop) planted in a coconut genebank should be identified by a mother palm number. This mother palm number should be recorded in a field map. It should be also recorded in a separate file indicating its geographical localisation (latitude and longitude). So, if necessary, it will be possible to return to the mother palm and, if this mother palm still alive, to collect more seednuts. For the technical application of this golden rule, please see under.
Collecting Tall-type coconut varieties for conservation
The Stantech manual recommends to choose 100 normal palms at random towards the middle of the population and take a sample of two nuts per palm to generate a total of 200 nuts.
In the expert opinion, taking in account the long generation time of the coconut palm, and the importance to use collected germplasm for breeding, biased sampling should be preferred. Thus, the expert recommends choosing 25 to 50 of the best palms in the population. This choice should be based on:
- On the oral recommendations of the owner of the plantation, or of the workers haversting the palms, as they generally know which are the best palms and which palms have special characteristics, such as for instance palms giving a thick and tasty coconut milk for food.
- On the visual characteristics of the palm, choosing preferably the palms that look healthy and bear a lot of fruits
- If possible on fruits characteristics, that can be evaluated under palms in the fields ; another simple way is to check the thickness of the husk by enfonçant in the husk the point of a knife. This will help to select fruits with thin husk.
- Do not choose the biggest and heaviest fruits, as there is a negative correlation between the number and the weight of fruits, as as choosing only the bigger fruits will result on a decrease of the yield of kernel per palm per year.
On this sample of 25 to 50 selected palms, harvest all mature fruits with a maximum of 8 fruits per palm, and collect up to 200 fruits. A collecting number must be given to all selected parent palm ; this number should be written of the stem of parent palms, and the latitude and longitude of each parent palms should be carefully recorded. A possible option is to take a picture of each palm using a camera with GPS; by this way, the geographical coordinates are automatically attached to the pictures, and localisation of the palm can easily be visualized on a map.
The collecting number of the parent palm should be tagged on each of the collected fruits, and conserved up to the planting of the seedlings in the genebank. By this way, when planting the material, we will have a first appraisal of the value on the progeny of each parent palm. This is very important for breeding purposes.
Collecting Dwarf and compact Dwarf varieties
When collecting Dwarf and compact Dwarf varieties, it happen quite often that only one or two individuals palms whit special characteristics are found in a particular garden. The palms are under pressure and often heavily used for food (preparation of coconut milk), drinking nuts or feeding the pigs, so often very difficult to harvest mature fruits. In this situation, expert advices are as follow:
- Ask the gardener where he got the seedlings, and if possible locate and collect also the parent palm of this dwarf
- Ask the gardener if he/she already gives seednuts of this Dwarf palm to family or friends; and if so, try to locate where this progeny is planted.
- Make a deal with the gardener, proposing he will keep and germinate the seednuts. The seednuts with sprout of the same colour than the original palm will be paid three times the price of a normal coconut.
Practical management of the pedigree of parent palms
In case of field collection, using Excel or any other database software, make a file including at least this information:
- Date of harvest
- Collecting number of the population
- Mother palm number
- Latitude of the mother palm
- Longitude of the mother palm
- Number of seednuts harvested per mother palm
When planting the seednuts in the genebank, record the pedigree of each palm in a map. Example of such a file is given under. There are here two tall populations (Rb and Vj) and the mother palm numbers are recorded in red for Rb and in blue for Vj. Each number refers to a particular female parent palm.
Here is a view of a possible full design, 5 Tall populations plus a control, in a Fisher block design with 4 replications of 24 palms (4 rows of 6 palms), so a total of 96 palms per accession. All numbers of female parent palms are recorded in the map.
In the case where the palms are obtained by controlled pollination with bagging, avoid to use pollen mix (pollen of one father palm should be crossed separately with mother palm), and record the identity of both parents for each palm planted in the genebank, in a map and in a file.
Here is a view of a possible full design, 5 Tall populations plus a control, in a Fisher block design with 4 replications of 24 palms (4 rows of 6 palms), so a total of 96 palms per accession. All numbers of female parent palms are recorded in the map.
