Sample processing in seed banks of wild rice and related genera genetic resources

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

Seed cleaning
Seed drying


Cleaning is the removal of physical contamination from the plant material after harvesting, before it can be stored. The exposure to unfavourable conditions should be minimized for greater seed longevity in storage.

Visual inspection of seeds

IRRI staff selecting good seeds for storage to the IRRI Genebank facility (photo: IRRI)

For base collection

For active collection

Bulk sample for active collection.

For black-box safety backup storage:

For temporary storage

Often samples of wild rice do not produce sufficient material especially when there are limited incoming seeds.

Disposal of contaminated material

This is important for discarded material, either from incoming samples or after harvest. Wild rice species are classified as noxious or invasive species, subject to rigorous biosafety containment procedures during all the stages of sample handling.

Inspection and certification (purity analysis of seeds)


Certain changes in seed phenotype may occur even though the seeds remain genetically true-to-type:

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Seed drying


1st stage of drying (during cleaning)

2nd stage of drying (after cleaning)

Alternative drying

Using a moisture meter to check the moisture content of seeds (photo: IRRI)

Drying time

Moisture content before drying

Moisture content for storage

Critical moisture content

Determination of moisture content

Recording information during seed cleaning and drying

The following information should be recorded for each processing step:

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The Genebanks

The 11 CGIAR genebanks currently conserve 730,000 of cereals and grain legumes, forage crops, tree species, root and tuber crops, bananas and crop wild relatives.