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Soybean Testing Services
SGS offers quick, professional, and diagnostic service to seed companies from over 43 different states and several countries.
- Standard Germination (Warm) Test
- Sand Emergence Test
- Herbicide Tolerance Tests
- Tray Cold Test
- Accelerated Aging Test
- Protein, Oil and Moisture (POM)
- Tetrazolium Test
- Varietal Purity Test or Hilum Examination
- Mechanical Purity and Noxious Examinations
- Soybean Germination and Cold Test Remarks Reference Form
- Automatic Retesting
Sand Emergence Test
Sand Emergence Test is conducted on a 400 seed sample at 25C for seven days and seedlings are evaluated in accordance with the AOSA Rules. Please submit 250 grams of seed.
This test is the best estimate of field emergence when seeds lots have mechanical damage and/or pathological problems. The sand provides uniform water uptake, facilitates root growth on damaged seedlings and tends to suppress fungal growth related to seed coat infections.
Tray Cold Test
The cold test is a vigor test that simulates cold and wet conditions that might occur in the field. Seeds are placed on a 24-ply sheet of crepe cellulose paper moistened with 10oC water, covered with ¾” of dry sand, placed in a 10oC chamber for seven days and then transferred to 25oC for four days. Seedling emergence percentages are evaluated on the eleventh day of the test.
The cold test, including variations of the above procedure, has been widely used by a number of the major soybean companies. A minimum value of 80% (or within 15% of standard germination) has been used as a standard.
One potential problem with the cold test relates to low moisture seed. If a seed sample loses moisture before cold testing, it may express artificially low cold test values. When submitting samples for testing always use sample bags with a moisture barrier. In the testing laboratory, it is important to start cold tests immediately to minimize seed sample moisture loss.
Tetrazolium Test
Tetrazolium Test is a quick viability test completed within 24 to 48 hours. Two hundred seeds are prepared and stained with tetrazolium solution and evaluated for viability.
This test tends to over-estimate germination of fungal infected seed lots. The tetrazolium test is usually not recommended if the client can wait for the completion of the standard germination test. Please submit 250 grams per seed lot.
Mechanical Purity and Noxious Examinations
Mechanical Purity and Noxious Examinations are conducted on a 500 gram sample for domestic usage and a 1,000 gram sample for exports (ISTA).
Pure seed, inert matter, other crop seed, weed seed, and noxious weed seed percentages are reported.
Soybean Germination and Cold Test Remarks Reference Form
When we evaluate warm germination tests we describe the abnormalities and fungal species present to help explain the cause of a seed quality problem. Below we have listed the most commonly observed problems and possible causes of these respective problems.
Physical / Mechanical Abnormalities
| Observed Symptom | Possible Cause |
| Short, damaged hypocotyls (SDH) | Impacts to hypocotyl/radicle |
| Insufficient roots (IR) | Impacts to radicle |
| Conductive tissue lesions (TL) | Bruising/impacts to hypocotyl |
Pathological Abnormalities
| Observed Symptom | Possible Cause |
| Decayed seedling (DS) Bacteria (BAC) |
Fungal infection caused by Phomopsis spp. Bacteria noted on 5% or more of the dead seed. |
Fungi Observed
| Species | Possible Cause |
| Rhizopus spp.(RH) | Sugar leakage from seed |
| Fusarium spp.(FU) | Field fungus - seed/seedling decay. |
| Phomopsis spp.(PH) | Field fungus - seed/seedling decay. |
| Aspergillus flavus (AF) | Storage fungus - high seed moisture. |
| Aspergillus niger (AN) | Storage fungus - high seed moisture. |
| Penicillium spp. (PE) | Storage fungus - high seed moisture. |
* Phomopsis, Fusarium, Aspergillus and Penicillium spp. are reported only when they are infecting dead seeds
Recommended References:
Seedling Evaluation Manual. SL-90. T.J. Gutormson.
Soybean Seed Health. Pm-990. D.C. McGee and R.E. Nyvall.
Automatic Retesting
We offer customers an automatic retesting option when ‘apparent’ seed quality issues occur. This retest will provide additional information on the seed lot to facilitate seed quality decisions. Currently, this service is offered on corn, soybeans, sorghum and cotton.
You, the customer, choose the thresholds that would trigger the auto-retest and MWSS sets these thresholds up for your account in our computer system. For example: if you want samples to be auto-retested when the warm germination falls between 79% and 94%, the thresholds for a warm germ test would be set at 80<=Germ<=93. Samples falling into this range receive an automatic retest. Retest threshold ranges can be applied to most germination-based tests and can be easily adjusted if your needs change.
There is no charge for setting up auto-retest thresholds and once auto-retesting is in place; your samples will be retested within 24 hours thus saving valuable time in your decision-making process. Retests are billed to your account at the same rate as the regular tests.
