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module_02   Importance of seed health in seed/germplasm exchange

Seed Health Unit - operations

Rice seeds have to undergo standard steps and protocols for phytosanitary certification before they can be released for export or for field experiments.

Dry seed inspection   This is conducted in the Seed Inspection Area to ensure that seeds are clean and free of foreign material. Initial examinations are done and if live storage insects are found, seeds are fumigated immediately.

Some significant risks that can be eliminated through dry seed inspection are: 
  1. weed seed contaminants
  2. insect pests
  3. seed discoloration 
Dry seed inspection
dry seed inspection



Macro testing After dry seed inspection, the bulk of the seedlot is submitted to the laboratory for:
Macro testing - to detect teliospores of Tilletia barclayana.

Macro testing

Macro testing



Routine seed testing A working sample from the seedlot is provided to the laboratory for the following seed health tests:
  1. Blotter test – to detect seedborne fungi that respond to sporulation
  2. Modified Baermann Funnel or Sedimentation Test –  to detect or extract seedborne nematodes
  3. Seed wash assay test (using semi-selective medium) - to detect seedborne bacteria. This test is only conducted if stipulated in the Import Permit of the country of destination (an additional declaration is needed against seedborne bacteria, i.e. Pseudomonas fuscovaginae, Xanthomonas oryzae pv. oryzae
Blotter test
Set up for Nematode extraction
Set up for Nematode extraction

Seed wash assay test
Seed Wash Assay test2


Crop health monitoring All seeds are subject to crop health inspection at seedling, tillering, flowering and mature stages. IRRI maintains plots for:
  1. post-entry crop health inspection
  2. pre-export crop health inspection 
Field inspection
field inspection


Seed treatments The following treatments can be conducted on seeds:
  1. Fumigation – with phosphine at 2 g/m2 to destroy storage insects
  2. Fungicide treatment – with benomyl and macozeb to control fungal pathogens that are surface-borne on the seed and internally seed-borne
  3. Hot water treatment – 52°C to 57°C for 15 minutes after presoaking in cold water for 3 hours to control white tip (Aphelenchoides besseyi), a disease caused by nematode
  4. Sodium hydrochloride seed wash – to control kernel smut (Tilletia barclayana)


Fungicide treatment                                                                         Hot water treatment
slurry fungicide         hot water


Pre-shipment treatments To comply with ASEAN PLANTI recommendations, rice genetic material has to be subjected to the following treatments before it can be imported into the Philippines and IRRI:
  1. Fumigation – all seeds must be fumigated
  2. Fungicide treatment – all seeds must be treated with fungicide
  3. Hot water treatment - if seeds are infected by nematode


Intellectual Property Rights and Germplasm Exchange

Procedures for the transfer of PGRFA


Last Updated on Tuesday, 22 September 2009 06:20