Viability of forage grass genetic resources

Contributors to this page: ILRI, Addis Ababa, Ethiopia (Jean Hanson); CIAT, Cali, Colombia (Daniel Debouck); Bioversity International/ILRI, Addis Ababa, Ethiopia (Alexandra Jorge).

Viability testing
Routine monitoring

Viability testing

Laboratory methods

Viability test methods are specific for different species. International Seed Testing Association rules should be used when available. Specific information is available for many species (see Species Compendium).

Type of test


Number of seeds and replicates

International Seed Testing Association rules should be used when available.


See the attached list with recommendations for some grass species (viability test methods are specific for different species. International Seed Testing Association rules should be used when available).

For Brachiaria seeds, scarification is done by immersing in a 2% solution of sulphuric acid for 15 minutes and washing well to remove all traces of acid before setting for germination.

A 0.2% potassium nitrate solution is also used to break dormancy in several species of tropical grasses. Seeds can be soaked in the solution overnight or the solution can be used with the germination media or incorporated into water agar.

The text for this flip book was extracted from: Rao NK, Hanson J, Dulloo ME, Ghosh K, Nowel D, Larinde M. 2006. Manual of seed handling in genebanks. Handbooks for Genebanks No. 8. Bioversity International, Rome, Italy. 147pp.


River sand that has been treated previously with steam at 100°C for two hours is recommended for grass seeds so that they can grow into strong seedlings. Seeds are usually planted in rows 3-4 cm deep and then covered with sand to 2 cm depth. The sand is kept moistened, usually twice a day with a spray. Viable seeds germinate in 6-10 days.



Duration of test


Monitoring intervals

Some species of grass seeds are very short-lived so the sampling interval should be sufficient to measure loss of viability without being so frequent as to use valuable germplasm for testing:

Recording information during viability testing

The picture above shows abnormal (left) and normal (right) grass seedlings. (photo: ILRI)

The following information must be recorded for each testing step:

Back to top

Routine monitoring


Monitoring frequency

This is set according to the minimum quantity and minimum viability of seeds below which they need to be regenerated.

Critical quantity

Critical germination level

Recording information during routine monitoring

The following information should be recorded for each step:

References and further reading

Butler JE. 1985. Germination of Buffel grass (Cenchrus ciliaris). Seed Science and Technology 13:583-591.

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.

ISTA. 2008. International Rules for Seed Testing. International Seed Testing Association. ISTA secretariat, CH-Switzerland. Available from:

Smith RL. 1979. Seed dormancy in Panicum maximum Jacq. Tropical Agriculture 56:233-239.

Thormann I, Metz T, Engels JMM. 2004. The Species Compendium (release 1.0; December 2004). [online] Available from: Date accessed: 09 April 2013.

Whiteman PC, Mendra K. 1982. Effects of storage and seed treatments on germination of Brachiaria decumbens. Seed Science and  Technology 10:233-242.

Back to top

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.