Crop Genebank Knowledge Base

Genebank management strategies & principles

Rice

Safe transfer of rice germplasm

Contributors to this page: IRRI, Seed Health Unit, Los Baños, Philippines (Patria Gonzales, Evangeline Gonzales, Carlos Huelma, Myra Almodiel, Joel Dumlao).

Rice germplasm is under the mandate of IRRI. The Africa Rice Center works on this crop in Africa.
The following pages are grouped in the following sections:

Import and export requirements.
Technical guidelines for the safe movement of germplasm and detection of relevant pathogens and pests.
Best practices in place at IRRI.

At IRRI, The Seed Health Unit (SHU) has been designated as the Single Gateway for all incoming and outgoing rice seeds, rice grains (dehulled, polished, milled, powdered), non seed biological materials, and soil samples to and from the International Rice Research Institute.

As a Single Gateway, SHU ensures the following:

that seed health status of rice seeds, rice grains for destructive analysis, non seed biological materials, and soil samples coming into IRRI (IMPORTED) meets Philippine plant quarantine regulations and standards before releasing to IRRI scientists (POST ENTRY CLEARANCE);
that seed health status of rice seeds, rice grains for destructive analysis, non seed biological materials, and soil samples going out of IRRI (EXPORTED) meets plant quarantine regulations and standards of recipient countries (PHYTOSANITARY CERTIFICATION); and
that the intellectual property rights protocols established by IRRI in line with its agreement with the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) are complied with in all incoming and outgoing materials (rice seeds, rice grains for destructive analysis, non seed biological.

SHU approach is to conduct seed health testing on all incoming and outgoing rice seeds. In addition, the T.T. Chang Germplasm Genebank sends samples to SHU for seed health testing prior to storage.

Seed health testing activities:

1. Direct Visual Examination

Seedlots are examined for the presence of seed contaminants (i.e. storage insects, sclerotia, weed seeds, soil particles, seed of other crops, other plant parts) and seed conditions (i.e. insect-damaged seeds, discolored seeds, broken grains, smutted seeds, shriveled seeds, unfilled/partially filled seeds). Any of these seed contaminants and /or seed conditions should not be present in the seedlots. If these are observed for outgoing seedlots, the applicants will be requested to do further cleaning or will be requested to replace seeds with seeds of better quality. For incoming seedlots, SHU staff shall clean the seedlots. Corresponding documentation are done (seed contaminants and seed conditions are qualified and quantified).

2. Routine Seed Health Testing

Blotter test - conducted for the detection of seedborne fungi. The procedure is done in accordance to the International Seed Testing Association (ISTA) rules and standards.
Modified Baermann Funnel Method (Sedimentation Test) - conducted for the detection and extraction of seedborne nematodes.
Macro test - conducted for the macroscopic detection of Tilletia barclayana, kernel smut fungi of rice.

Additional declarations (if stipulated in the Import Permit of Country of Destination.)
Seed Wash Assay test using semi selective media – conducted for the detection and isolation of seedborne bacteria.

3. Other Activities

3.1 Seed Treatment

Recommended seed treatments

Seed treatments will be based on the results of seed health tests and on the requirements of the importing country. USA and India do not require chemical and physical seed treatments except fumigation. Standard treatments given to seeds are the following:

i. Hot water treatment. Presoak seed for 3 hours in tap water followed by dipping in hot water at 52-57^oC for 15 minutes and redrying to 14% MC. The hot water treatment may be followed by slurry or dusting of fungicide (Benlate) at 0.3% by seed weight as an ASEAN standardized seed treatment (1981 July 1-23, Kuala Lumpur Meeting).

ii. Fungicidal treatment. Slurry treatment with Benlate 50 WP, Dithane M45, or a combination of both at 0.3% formulated product by seed weight (0.3 g/100 g seeds). Retest for efficacy of fungicidal treatments will be done on samples that have abnormally high infection. Samples that do not respond to treatments will be rejected or applicants will be asked for replacements.

iii. Insecticidal treatment. The seeds may be treated with Diazinon at 0.5 g/100 g seeds when fumigation or hot water treatment could not be done.

Fumigation. All seeds are fumigated with Phosphine gas at 2 g/cubic meter enclosed space at 28 ^oC for 72 hours.

3.2 Crop Health Monitoring

Conducted during active growth of the crop namely: seedling stage (inspection is conducted at seedbed), maximum tillering/booting stage, flowering stage, and maturity stage, wet and dry season.

3.3 Dispatch

Seed Packages for dispatch are accompanied by required documents: Import Permit, Phytosanitary Certificate (signed by duly authorized Plant Quarantine Officer), Standard Materials Transfer Agreement, and Plant Quarantine Seal.

All of these documents are pasted outside the package and photocopies of these documents are provided and placed inside the package in addition to the list of materials.

References and further reading

Mew TW, Misra JK. 1994. A manual of Rice Seed Health Testing. IRRI, Manila, The Philippines, 114,pp.

Mew TW, Gonzales P. 2002. A handbook of Rice Seedborne Fungi. Los Baños (Philippines): IRRI, and Enfield N.H.(USA) Science Publishers Inc. 83 pp.