Crop Genebank Knowledge Base

Articles

Sample processing and viability in field banks (wild rice and related genera)

Contributors to this page: T.T. Chang Genetic Resources Centre-IRRI, Philippines (Ruaraidh Hamilton, Ken McNally, Flora de Guzman, Renato Reaño, Soccie Almazan, Adelaida Alcantara, Elizabeth Naredo); WARDA, Cotonou (Ines Sánchez); UPLB-University of the Philippines at Los Baños (Teresita Borromeo).

Provides guidelines and recommendations about the best practices for the daily management of genebanks, describing the most important procedures for sample processing and viability in field genebanks for wild rice and related genera. Best practices are shown in a pale blue color with bullets. Justification for each best practice is given within brackets (…).

Cleaning propagules/seeds in field banks

Source of planting materials in field banks

Use seeds treated with additional care to assure germination and survival.

Visual inspection of plant materials

Check the materials carefully for pest or disease contamination.
Consult the health diagnosis menu for specific details about pests and diseases.

Disposal of contaminated materials

To ensure plants do not spread by seeds or rhizomes, specific measures should be followed:

Do the seed multiplication of all wild rices inside the screenhouse in pots.
Designate a disposal area (a pit about 3-4 meters deep from the surface ground) for burying discarded and burnt samples.
Provide a modified incinerator or burning facility to accommodate burning activities especially during the rainy season.
Cover all drainage canals inside the screenhouse with fine-mesh screens to further control dissemination of seeds through water.
Waste materials from the canals should be regularly hauled, burned, and buried.
If sufficient seeds are obtained, old plants should be discarded, burned and buried into the pit.
Excess planting materials (seeds, seedlings, rattooned tillers) should be collected, burned and buried after seeding, transplanting and/or replanting.
Discarded soil used in growing should be treated with herbicide and buried in the designated area.
Before filling up all the discarded materials, the disposal area should be treated with a non-selective herbicide (e.g. glyphosate).
Screenhouse staff should be advised to change their working clothes to minimize dispersal of seeds when they leave.
Hand threshing and seed cleaning should be done in a specified room in the Seed Processing Area.
All dried leaves/straws, unfilled grains, mixtures and off-types must be collected, burned and buried.
The access to screenhouses should be regulated depending on the nature/importance of the visit.

Routine monitoring for field banks

Methods and frequency

Survival rates - Check survival monthly (some germplasm that have to be maintained in a field genebank are perennial and regular monitoring is important to ensure survival).
Vigor - Record vigor monthly.
Pests and diseases - Inspect for pests and diseases monthly (this is sufficient to identify any pests or diseases and rescue the plants in case of problems).
Replacement by other weeds - Rogue plants of other species regularly and at flowering time. Check taxonomy at least once in a year.

Recording information during sample processing and routine monitoring in field banks

The following information should be recorded for each step:

Accession number (an ID number).
Genus (genus name of the plant, entered in full).
Species (species name of the plant, entered in full).
Field bank site name (a code to indicate the site of seed production).
Plot number (the plot number at the production site).
Date of monitoring (date when data is collected).
Name of staff (name of staff recording the data).
Damage [a score of 1-5 (where 5 is damaged) on amount of damage (insect, disease etc)].
Vigor [assessment of vigor of the plants on a scale of 1-5 (where 5 is high)].
Details of plants removed or destroyed (due to type mixtures or pests or diseases contamination).