Best Practices for Safe Transfer of Maize Germplasm

Contributors to this page: CIMMYT, Mexico (Etienne Duveiller, Monica Mezzalama, Eloise Phipps, Thomas Payne, Jesper Norgaard), Independent consultant (Jesse Dubin).

In CIMMYT Mexico, ‘Rules and Regulations for the Safe Movement of wheat and maize germplasmhave been described by Dr. M. Mezzalama, Head of Seed Health Laboratory (SHL).

Since 1988 the CIMMYT SHL has been officially authorized by DGSV (Direccion General de Sanidad Vegetal) to carry out the quarantine procedures on seed introductions coming into Mexico and CIMMYT, and in April 2007 the SHL obtained accreditation under standard ISO/IEC 17025: 2005, “General requirements for testing and calibration laboratories”, as required by the Mexican government. An official DGSV inspector is assigned exclusively to CIMMYT to assist with thorough and timely seed inspection and importation.

All seed brought into CIMMYT, without exception, must be subjected to quarantine procedures in the Seed Health Laboratory.

The seed introduction procedure at CIMMYT Headquarters is summarized health flow chart


 The pathogen detection and identification flowchart is described below:

 All maize seed, both entering and leaving CIMMYT, must pass through the seed health laboratory. All seed undergoes the same set of testing procedures, although the key target pathogens vary between incoming and outgoing seed depending on relevant quarantine regulations.

CIMMYT generally uses well-established test procedures that may be found in any standard reference on seed health. The filter wash test is somewhat specialized, and the procedure are given in CIMMYT Seed Health Manual.

The tests used in CIMMYT are as follows:


Seed health testing on maize

Pathogen type(s) detected
Pathogens of importance in incoming seed
Pathogens of quarantine importance in outgoing seed **

Seed wash filter test

Fungi ( smuts)


Heterodera zeae*

Ustilago maydis

Freezing blotter test

Imperfect fungi

Acremonium maydis*

Cochliobolus spp.

Dilpodia spp.

Fusarium spp.

Lasiodiplodia theobromae

Greenhouse germination test



Burkholderia andropogonis*

Clavibacter michiganensis subsp. nebraskensis*

Pantoea stewartii*

Wheat streak mosaic virus*

Acidovorax aveanae subsp.avenae

C. michiganensis subsp. nebraskensis

P. stewartii

Maize dwarf mosaic virus

Maize chlorotic dwarf virus

Sugarcane mosaic virus




Pantoea stewartii*

Wheat streak mosaic virus*

P. stewartii

Maize dwarf mosaic virus

Maize chlorotic dwarf virus

Sugarcane mosaic virus

Downy mildew detection test

Peronosclerospora maydis*

P. philippinensis*

P. sacchari*

P. sorghi

Sclerophthora rayssiae var. zeae*

P. sorghi

* Quarantined under Norma Oficial Mexicana NOM-018-FITO-1995.
** According to information reported on importing countries requirements

References and further reading

Mezzalama M. 2012. Seed Health: Fostering the Safe Distribution of Maize and Wheat Seed: General guidelines. Third edition. Mexico, D.F.: CIMMYT. Available here (0,5 MB)

Warham EJ, Butler LD, Sutton BC. 1996. Seed Testing of Maize and Wheat: A Laboratory Guide. Mexico, D.F.: CIMMYT. 84 pp

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.