Friday, 24 November 2017

General principles for setting up a new coconut genebank

Genebank Standards for Plant Genetic Resources for Food and Agriculture

Well-managed genebanks both safeguard genetic diversity and make it available to breeders. The  FAO Commission on Genetic Resources for Food and Agriculture has recently published Genebank Standards. These guidelines were endorsed in 2013 at the Fourteenth Regular Session of the commission, lay down the procedures that need to be followed for conservation of plant genetic resources. Section 5 of the guideline is dedicated to field genebanks (most relevant to the coconut case). The main recommendations are summarized herunder (thanks to Charlotte Lusty):

5.1. Choice of location
  • 5.1.1. Conditions as similar as possible to environment in which accession was collected
  • 5.1.2. Site located to minimize risk from natural/man-made disaster
  • 5.1.3. Site located to minimize gene flow with crops and wildlife surrounding the collection
  • 5.1.4. Secured land tenure and sufficiently large to allow for expansion
  • 5.1.5. Easy access to supplies and facilities (e.g. phytosanitary)
5.2. Acquisition
  • 5.2.1. Legally acquired (e.g. SMTA) & relevant technical information provided
  • 5.2.2. Propagating material selected from healthy plants
  • 5.2.3. Time between collecting and establishing in the field collection as short as possible
  • 5.2.4. Pass through quarantine if international transfer
5.4. Field management
  • 5.4.1. Regularly monitored for pests and diseases
  • 5.1.2. Appropriate cultivation practices
  • 5.1.3. Monitor genetic identity regularly, ensure isolation and labelling, etc.
Quality criteria for coconut genebanks: a first detailed approach

The project "Upgrading international coconut genebanks and evaluating accessions" was funded by the Global Crop Diversity Trust from October 2011 to March 2012. The technical attachments of this report provided a first basis for assessing the quality of coconut conservation in ex situ coconut genebanks. Several tables are comparing nine genebanks for the following quality criteria:

  • Number of accessions and passport data
  • Data management in the genebanks
  • Controlled Pollination and regeneration methods
  • Germplasm movements from and to the genebank
  • Characterization data of the accessions
  • “Values” of accessions in terms of rarity and genetic representativeness
Guidelines for creating a new genebank

Orientation of the rows


According to australian researchers, location determines which direction crops should be planted for the best utilization of sunlight. The Western Australian Wheat Belt ranges from 28° to 33° south in latitude with a winter and spring growing season, making east-west crop orientation the most advantageous. Near the equator, north-south orientation would yield the best results, while latitudes up to 55° would benefit from north-south crops in the summer and east-west crops the rest of the year. At latitudes above 65°, east-west orientation would offer the best light absorption throughout the year.
The International Coconut Collection for Africa and India Ocean in Côte d'Ivoire and the VARTC coconut collection in Vanuatu were planted with row orientated North-South. The Taveuni Coconut centre in Fiji was planted with row orientated East-West;



Planting design and density

The planting density should differ according to the farming systems and the varietal type of coconut palms (Talls, Dwarf and Compact Dwars, DwarfxTall hybrids). Table hereunder show the recommended planting densities for pure strand of coconut palms. Brazilian agronomists have strongly improved the cultivation methods for Dwarf coconut palms and they plant now 222 palms per hectare.
  
Classical recommendation
 (Stantech manual)
New Brazilian way
Tall and Tall x Tall
hybrids
Dwarf x Tall hybrids           
Dwarfs,
compacts dwarfs and  D x D hybrids
Dwarf x Tall hybrids
Dwarfs,
compacts dwarfs and  D x D hybrids
Density (palms/ha)       
143     
160     
180
180
222
Density (palms/acres)   
57.9
64.7
72.8
72.8
89.8
Distance between palms 
9 m     
8.5 m   
8 m
8 m
7.3 m
Distance between rows  
7.8 m  
7.35 m
6.9 m
6.9 m
6.3 m
Note: 1 ha=2,47105 acres

Access roads


Access roads are needed in delivering seedlings and supplies, and later in hauling the produce to and from the research or germplasm blocks. These facilitate inspection, data gathering and evaluation of entries. The design of the experimental and or genetic block determines the size and length of access roads.


Planting design and size of conserved populations

Tall and dwarf types should be planted separately, using one control cultivar for each type, with preferably at least three replications, except in the designs specially conceived for seednuts production.
For a single accession, experimental designs comprising three replicates and elementary plots of 5 x 6 palms (i.e. 90 palms per accession), or four replicate and elementary plots of 4x5 palms are appropriate. However, each accession should be represented by at least 72 palms, with preferably at least two replications, set out in square or rectangular plots or blocks of at least three rows per replicate. Failing a block design, it is essential for the variety serving as control to be sufficiently represented (one control plot for every 4 to 6 collection plots). Borders rows and border palms (at the beginning and the end of rows) can be planted either with the control, either with palms of the neighbouring varieties. These border rows will have to be excluded from characterisation.
When the population size do not reach this 72 palms standards, when only a small quantity of nuts is available, or when the germination of the nuts is poor, the sampled population may be preserved while additional collecting is undertaken to meet the desired population size. If collecting cannot be repeated, the preserved material risks being a biased and incomplete sample of a population study. However, if the germplasm has been chosen for precise breeding purposes as in a target collection, its preservation as a gene source is fully justifiable. Sometimes only a unique rare coconut palm having special characteristics is found. In such a case, the best option is to deal with the farmers and ask him/her to keep at least 30 seednuts of this rare palm.

Figure hereunder gives an example of planting map. Experimental design is Ficher blocks with four replications of 20 palms (four rows of five palms) for a total of 80 palms per varieties. It compare five Tall-type varieties to a Tall-type control. Map was designed with the Word software. Modifiable word file is available on demand.


CAPTION - LEGENDE


Border palm (in Yellow).Palm of same variety than the closer palm
Arbre de bordure (en jaune), de la même variété que l’arbre utile le plus proche.
36
Experimental plot number – Each experimental plot is 4 rows of 5 palms
Numéro de Parcelle expérimentale – Chaque parcelle comprend 4 lignes de 6 .
5
Cultivar number from 1 to 6 (see next table)
Numéro de cultivar de 1 à 6 (Voir tableau suivant)
45
Row Number (From 20 to 57). Numéro de Ligne
5
Palm-on-Row Number (from 1 to 25). Numéro d’arbre sur la ligne (1 à 25)
Planting Density is 143 coconut palms per hectare (9 m triangular).
Planting date : to be precised here.
Densité de plantation 143 cocotiers à l’hectare (9 m en triangle). Date de plantation : à préciser

Cultivar Number
International code
International name
Local
code
Progeny Number
Accession Number
Numéro du cultivar
Code international
Nom international
Code
 en langue locale
Numéro de des-cendance
 
Numéro d’accession
1
To be
completed….


(Control
témoin)
2
To be
completed….



3
To be
completed….



4
To be
completed….



5
To be
completed….



6
To be
completed….




References
Borger, C. P., Hashem, A., & Pathan, S. (2010). Manipulating crop row orientation to suppress weeds and increase crop yield. Weed Science58(2), 174-178.
Calculating Plant Spacing and the Number of Plants Needed for a Given Area















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