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Grass & Legume Seed Testing
We focus our grass testing efforts in different species of grass and legumes like ryegrass, tall fescue, wheatgrasses, bromegrass, alfalfa, red clover, sweetclover, and white clover. We also test native grass and forbs including: bluestems, indiangrass, switchgrass, gramas, green needlegrass, western wheatgrass, coneflowers, wild flowers, native legumes, and many others.
We understand the value of accurate purity and viability tests on these sometimes difficult-to-test species.
- Mechanical Purity and All-states Noxious Weed Examinations
- Standard Germination Tests
- Undesirable Grass Seed Search (UGS)
- Tetrazolium Test
- Multi-Species Germination Remarks
Standard Germination Tests
Standard Germination Tests are conducted on a 400 seed sample and seedlings are evaluated in accordance with the Association of Official Seed Analysts (AOSA)"Rules for Testing Seeds". When we observe low germination due to ungerminated seeds, we check their viability using the tetrazolium test. We also identify fungal species and abnormalities to help explain the cause for lower viability.
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Undesirable Grass Seed Search (UGS) Undesirable Grass Seed Search (UGS) is conducted on the amount of seed normally given an All-States Noxious Weed Examination. |
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.
Multi-Species Germination Remarks: Warm Germination Test
When germination tests are evaluated, we describe the abnormalities and fungal species present to help explain the cuase of a seed quality problem. Below are listed the most commonly observed problems and possible cause of these respective problems. Tests below 90% may have the following remarks.
Seedling Abnormalities
| *Physical/Mechanical Abnormalities: Observed Symptom |
Possible Cause |
| Shredded Leaves (SL) | Impact to shoot and coleoptile |
| Short; damaged hypocotyls (SDH) | Impacts to hypocotyl/radicle |
| Insufficient Roots (IR) | Impacts to radicle |
| Stunted Shoots (SS) | Damage within or below growing point |
| No Shoots (NS) | Damage within or below growing point |
| Detached Mesocotyl (DM) | Handling or Frost Damage |
| *Physiological Abnormalities: Observed Symptom |
Possible Cause |
| Watery Hypocotyl [Clear Hypocotyls] (WH) | Physiological weakness |
| Partial Coleoptile (PC) | Aged Seed |
| *Pathological Abnormalities: Observed Symptom |
Possible Cause |
| Decayed seedling (DS) [root and hypocotyls] | Fungal infection |
| Decayed Cotyledons (DC) | Primary infection by a Fungus |
| Bacteria (BAC) | Bacteria noted on 5% or more of the dead seed |
Fungi Observed
| Rhizopus spp. (RH) | Sugar leakage from seed |
| Fusarium spp. (FU) | 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 |
| Alternaria spp. (AL) | Field weathering promotes occurence |
*Fusarium, Aspergillus and Penicillium spp. are reported only when they are infecting more than 2% dead seeds.
Recommended References:
Seed Technologist Training Manual – available at www.seedtechnology.net/publications.htm
