Crop Genebank Knowledge Base

Health Diagnosis

Health diagnosis of rice 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, Patria Gonzales); WARDA, Cotonou, Benin (Ines Sánchez); UPLB-University of the Philippines at Los Baños (Teresita Borromeo); CIMMYT- Global Wheat Program (Etienne Duveiller).

List of diseases of quarantine importance

Click here for more detailed outputs from the page on the safe movement of germplasm, on this site.

The list below mentions some of the diseases that were considered important worldwide, but many of them may or may not have relevance in specific countries. It also does not consider diseases of limited relevance (e.g. only important in very few countries).

Bacteria

Bacteria leaf blight (Xanthomonas oryzae pv oryzae).
Bacterial leaf streak (Xanthomonas oryzae pv oryzicola).

Nematodes

White tip (Aphelenchoides besseyi).

Fungal diseases

Bacanae and foot rot (Fusarium moniliforme).
Brown spot (Bipolaris oryzae).
Leaf scald (Microdochium oryzae).
Blast (Pyricularia oryzae).
Kernel smut (Tilletia barclayana).
Sheat rot (Sarocladium oryzae).

Options for testing procedures

Recommended methods to detect the presence of each disease:

Seed borne fungi (Blotter test).
Bacteria (seed wash assay using semi sel).
Nematode (modified Bachmann funnel method).

Testing intervals/seasons

Testing before material goes into the genebank or to the field is important to reduce transfer of diseases or pests.

Apply routine seed health test prior to storage.
Samples that do not pass the test should not be entered into the active or long-term collection. Instead they should be stored temporarily, treated if possible and scheduled for early seed multiplication with treatment.
Testing is not needed during storage (the low temperate and humidity of storage prevents the increase of pests and diseases, so no further testing is needed).

Testing prior to distribution depends on the phytosanitary requirements of the requestor’s country.

Recording information during health diagnosis

The following information should be recorded for each step:

See seed health testing data sheet (http://books.irri.org/9712200493_content.pdf).

References and further reading

ISTA. 2008. Detection of Pyricularia oryzae on Oryza sativa (Rice). International Seed Testing Association (ISTA), Bassersdorf, Switzerland. Available from: http://www.seedtest.org/upload/cms/user/7-011.pdf. Date accessed: 15 June 2010.

Mew TW, Misra JK, editors. 1994. A Manual of Rice Seed Health Testing. International Rice Research Institute, Los Banos, Languna, Philippines. Available from: http://books.irri.org/9712200493_content.pdf. Date accessed: 15 June 2010.