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Native Grass and Forb Species Testing
SGS has experience on a number of native grass and forbs including: bluestems, indiangrass, switchgrass, gramas, green needlegrass, western wheatgrass, coneflowers, wild flowers, native legumes, and many others. We realize the value and importance of accurate purity and viability tests on these sometimes difficult-to-test species. We always check the viability of all ungerminated seed using the TZ test.
- Mechanical Purity and All-States Noxious Weed Examinations
- Standard Germination Tests
- Tetrazolium Test
- Multi-Species Germination Remarks: Warm Germination Test
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 "Rules for Testing Seeds". When we observe low germination due to many ungerminated seeds, we check their viability using the tetrazolium test. We also identify fungal species and abnormalities to help determine the cause for lower 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
