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Sample processing of bread wheat, durum wheat, triticale and related cereals genetic resources

Contributors to this page: CIMMYT – Wheat, Mexico (Thomas Payne) and ICARDA, Syria (Ahmed Amri) with inputs also received from CIMMYT – Maize, Mexico (Suketoshi Taba); USDA – National Small Grains Collection, Aberdeen, Idaho, USA (Harold Bockelmann); CGN, Wageningen, The Netherlands (website) and IPK, Gatersleben, Germany (Helmut Knűpffer).

Contents:
Seed cleaning
Seed drying
Seed moisture content

Seed cleaning

Cleaning harvested seed using course sieves (photo: CIMMYT)

Cleaning is the removal of physical contamination from the plant materials after harvesting, before they can be stored.

Visual inspection of seeds

This is a quality control that must be done after harvesting the seeds.

Special treatments

Disposal of contaminated material

Inspection and certification

A seed conservation manager or curator should be in charge of the final inspection on purity of seed material (the multistage seed inspection by the genebank curator or personnel should be required to ensure the purity of the seed accession and the genetic traits present in the germplasm accessions).

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Seed drying

Methods

1st stage drying (during cleaning)

2nd stage drying (after cleaning)

Drying time

Moisture content for storage

Critical moisture content

Recording information during seed cleaning and drying

The following information should be recorded for each processing step:

TIP: In the seed storage facilities, the type and the status of a seed lot must be clearly distinguishable so that seed material cannot enter a wrong process stream or activity. Some collections use coloured labels to identify different processes within their schema of accession management. CGN The Netherlands recommends that the type and/or status of seed lots be marked by means of coloured labels, which are attached to the boxes in which the material is stored. Relevant data should be noted on the labels, thus revealing the identity of the material. In addition, the location of further information about the material and where the material is stored should also be given.

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Determination of seed moisture content

Methods

Sampling frequency

Sample size and grinding

Oven drying temperature

Recording information during determination of seed moisture content

The following information should be recorded for each processing step:

References and further reading

International Seed Testing Association ISTA. 1993. International rules for seed testing. Seed Science and Technology 21, Supplement.

Hong TD, Linington S, Ellis RH. 1996. Seed storage behaviour: a compendium. Handbooks for genebanks no 4. International Plant Genetic Resources Institute, Rome.

Probert RJ, Hay FR. 2000. Keeping seeds alive. In: Black M, Bewley JD, editors. Seed technology and its biological basis. CRC Press LLC. USA and Canada. pp. 375-404.

Thormann I, Metz T, Engels JMM. 2004. The Species Compendium (release 1.0; December 2004). [online]. Available from: http://www.bioversityinternational.org/scientific_information/Information_Sources/Species_Databases /Species_Compendium.html. Date accessed: 31 March 2010.

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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.

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