Field genebank for banana

Contributors to this page: Bioversity International, France (Nicolas Roux), Bioversity International, Ethiopia (Michael Bolton, Alexandra Jorge); CIRAD,  France (Jean-Pierre Horry); IITA, Nigeria (Dominique Dumet).

When field banks are used

Many important varieties of field, horticultural and forestry species, including banana, are either difficult or impossible to conserve as seeds (i.e. no seeds are formed or if formed, the seeds are recalcitrant) or reproduce vegetatively. Hence they can be conserved as growing plants in field genebanks or in vitro (in tissue culture or cryo banks).

Banana stored in field genebanks have a lower risk of loosing genetic integrity (due to genetic drift) if the mother plants are maintained for many years and are readily available for study and use. However, bananas maintained in field genebanks are considerably more exposed to physical risks (climate, diseases, pests) and costs are higher for storage (labour, inputs and space) than in vitro genebanks. This balance must be considered when taking the decision to establish a field genebank for banana if other options are also possible.

Advantages of field genebanks

• Material can be evaluated and characterized while being conserved.
• Genotypes that commonly produce variants can be more easily identified and rogued out in the field than in vitro.
• Lower risk of loosing genetic integrity.
• Easy access for research and utilization (distribution).
• Establishment and maintenance requires limited technology.

Disadvantages of field genebanks

• Materials are susceptible to pests, diseases, adverse weather, theft and vandalism.
• Involves large areas of land, but even then genetic diversity is likely to be restricted.
• High maintenance costs (labour, inputs and space).
• Slow multiplication of material for distribution.

General principles

Defining objectives (Reed et al. 2004)

Before establishment any field collection a clear strategy regarding the objectives for collecting and maintenance should be defined:

• Acquisition policy.
• Range of diversity to be conserved.
• Intended functions of the genebank (e.g. whether it will be engaged in characterization and evaluation, whether it will be involved in breeding, whether it will conduct research on taxonomy, management practices or others).

It is very important to define clear purposes for the field banks as what may be a suitable practice for meeting one objective may be less suitable for another. For example, evaluation may require a greater number of plants or a special field layout suitable for replicated experimental designs.

The characterization is recommended in a collection without a particular experimental design.

Important considerations (Engelmann 1999):

• Isolation from farmers to avoid bush fires and contaminations.
• Proximity to alternative water sources (in case of droughts).
• Meet the environmental (climate, soils) requirements of the crop.
• Possibility of space for rotation and expansion.
• Good accessibility allows frequent monitoring.
• Guarantee security to avoid theft of valuable materials.
• Avoid areas prone to known diseases and pest on the same crop.
• Plant in the right season.
• Assure the long term maintenance of the field bank.
• Plant duplicates elsewhere (either in field banks in a different location or in vitro).
• Put the plants under good conditions to avoid the effects of deficiencies on the plant characteristics.

Space requirements (Tomekpe and Fondi 2008)

• Banana field collections are maintained indefinitely.
• It is necessary to have at least twice as much space as occupied by the collection (i.e. if a collection of 700 accessions occupies 3ha, you need to have 6ha available) to allow for fallowing and replanting (regeneration) which is essential for proper growth of accessions.
• There also needs to be space for expansion of the collection.

Frequency of establishment (Tomekpe and Fondi 2008)

• Banana collections should be regenerated every 4 years or so, as accumulated diseases and pests reduce plant vigour.
• This also allows maintenance (re-alignment) of the planting pattern and optimal density since successor plants of banana emerge at variable distances away from the parent stand.

References and further reading

Blomme G, Swennen R, Turyagyenda LF, Tenkouano A. 2006. Root and shoot development during the plant crop and the first ratoon of banana and plantain (Musa spp.) with implications for perennial cultivation on degraded Ultisols in south-eastern Nigeria. XVII International Meeting ACORBAT: Banana: A sustainable business. Joinville, Santa Catarina, Brazil, 15-20 October 2006. 354.

De Waele D. 2005. Book review. L.C.C.B. Ferraz and D.J.F. Brown. An introduction to nematodes: plant nematology. A student's textbook. Nematology 7 (3): 480.

De Waele D, Stoffelen R, Kestemont J. 2006. Effect of associated plant species on banana nematodes. Infomusa 15 (1-2):2-6.

Engelmann F, editor. 1999. Management of field and in vitro germplasm collections. Proceedings of a Consultation Meeting, 15-20 January 1996, CIAT, Cali, Colombia. International Plant Genetic Resources Institute, Rome, Italy. 165pp.

Olaniyi MO, Speijer PR, De Waele D, Swennen R, Tenkouano A. 2006. Influence of crop management practices in two locations on plantain response to plant parasitic nematodes. Niger Delta Biologia 5 (2):1-3.

Onwueme IC, editor. 1978. Tropical Tuber Crops: Yams, Cassava, Sweet Potato and Cocoyams. Wiley & Sons, Chichester, UK.

Reed BM, Engelmann F, Dulloo ME, Engels JMM. 2004. Technical guidelines for the management of field and in vitro germplasm collections. IPGRI Handbooks for Genebanks No. 7. International Plant Genetic Resources Institute, Rome, Italy. 106pp. Available here.

Saad MS, Ramanatha Rao V, editors. 2001. Establishment and Management of Field Genebank, a Training Manual. IPGRI-APO, Serdang. 122pp. Available here.

Sundararaju P, Van den Bergh I, Sathiamoorthy S, De Waele D, Molina AB, Borromeo KH, (ed). 2005. Banana Nematode Management. Towards Eco-friendly approach. Proceedings of the International Training Workshop on Recent Advances for Eco Friendly Management of Nematodes in Banana. National Research Centre for Banana, Tiruchirapalli, India, 16-18 March 2004. INIBAP, Montpellier, France: 102 pp.

Tomekpe K, Fondi E. 2008. Regeneration guidelines: banana. In: Dulloo ME, Thormann I, Jorge MA, Hanson J, editors. Crop specific guidelines [CD-ROM]. CGIAR System-wide Genetic Resources Programme, Rome, Italy. 9pp.
Click here to open the page on regeneration guidelines for banana

Safety duplication of banana genetic resources

Contributors to this page: Bioversity International, France (Nicolas Roux), Bioversity International, Belgium (Ines Van den Houwe); IITA, Nigeria (Dominique Dumet, Badara Gueye).

When should it be used

• For all original germplasm collected by the genebank.
• For germplasm held only by the genebank.
• Safety duplicated material should be located in a different country.

See also the general page on safety duplication procedures.

Banana germplasm should be duplicated in a systematic way, consistently sharing information and germplasm to optimize the conservation system.

Material should be duplicated in more than one location and/or using more than one method (i.e. in the field, in vitro or tissue culture and cryopreservation).

Sample specifications

Minimum sample size

• Number of samples for testing
  Bioversity – three cryotubes per accession (experiment).
  IITA – 1-5 seedlings.
• Criterion for long-term storage
  At least 95% certainty that a minimum of one plant can be regenerated per experiment.

Container specifications

To ensure seed viability in the genebank and en route to the users.

Specification of packaging

• Glass test tubes covered and sealed.

Labeling

• Placement of label
  Bioversity – written directly on cryotubes using a pencil.
  IITA – placed on upper half.
• Labeling material
  Bioversity – not applicable.
  IITA – Barcode labels pasted on tubes or on polyethylene bags.
• Label information
  Bioversity – accession ID, freezing date, experiment number.
  IITA – accession number, line number and date of in vitro introduction and  of last introduction.

Storage specifications

• Type of storage:
  Bioversity – cryopreservation in liquid nitrogen tank.
  IITA – tissue culture slow growth.
• Minimal growth media: see composition here.
• Light: 12h light/24h and light intensity: 43 μmol/m²/s.
• Temperature:
  Bioversity –  -196°C
  IITA –  +18 ± 1 °C

Shipping method

• Prepare the documentation of outgoing plant material shipments with phytosanitary certificate, the import permit and other necessary documentation.
• Follow the same procedures for the plant material shipments from the genebank.
• Packages should be shipped using the safest, most reliable, most cost effective and fastest route and carrier possible, to avoid delays and deterioration of plant material quality during transfer.
• Avoid shipments during hot times of the year.

Transport

• Type of container
  Bioversity – dry shipper.
  IITA – plastic boxes.
• Method and duration
  Bioversity – Air courier or hand carried.
  IITA – car (4x4) 5 to 6 hours drive.
• Conditions
  Bioversity – frozen in liquid nitrogen.
  IITA – ambient temperature.
• Frequency of shipment
  Bioversity – initially 3-4 times a year; once a year thereafter.
  IITA – every 3-4 months.

Storage duration

• Life expectancy of clones
  Bioversity – indefinite.
  IITA – 4-6 months.

Legal arrangements

The genebank, host country and importing centre and country policies and practices for germplasm movement for black-box storage must be fulfilled. The documentation listed below should be included to facilitate customs clearance:

• MOU for safety back-up.
• Phytosanitary certificate.
• Certificate of origin.
• Certificate of no-commercial value.
• Electronic and hard copy of associated passport information.
• GMO-free certificate (if required).

IITA-Nigeria has the following procedure:

• An agreement with IITA-Cotonou to keep a black-box, including:
  • Special agreement with the Plant Quarantine Services of Benin to use only an import permit and no need for phytosanitary certificates.
  • Germplasm cannot be used in Benin or distributed elsewhere.
  • If material needs to be transferred to the field, should be first repatriated to Nigeria.

Bioversity follows slightly different procedures:

• An agreement with IRD, France & KULeuven, Belgium to keep banana samples maintained as safety duplicates in liquid nitrogen (cryopreservation).

Data arrangements

Bioversity – germplasm ID, inventory of black-box content sent with samples.
IITA – import permit stating list of accessions transferred, endorsed by PQS prior to departure. Report at boarder PQS office.
 

Provision for return of germplasm

Bioversity – loss of samples from LTS at Bioversity ITC; sample provided by the duplication site at the request of Bioversity, giving six-months' written notice (if less than 95% certainty that one minimum plant can be regenerated per experiment).
IITA – repatriation permit to request material when needed.

Recording information during safety duplication

The following steps should be taken regularly, due to the short-term duration of conserving clonal crops:

• Updated lists of existing germplasm should be regularly sent to the owner of the germplasm (every 3-4 months in the case of IITA).
• Lists should be checked and any new material (not duplicated in the recipient genebank) should be identified.
• Depending on seedling availability at the owner’s genebank, seedlings should start to be prepared and the recipient genebank informed to start preparing the relevant documentation.

The following information should be kept up-to-date:

• Number of seedlings per accession.
• Date of production of seedling.
• Date of safety duplication.
• Name of institute holding the safety duplicate.
• Box label where the sample is placed.

References and further reading

FAO/IPGRI. 1994. Genebank standards. Food and Agriculture Organization of the United Nations, Rome and International Plant Genetic Resources Institute, Rome. Available in English, Spanish, French and Arabic.