Seed Vigor Index Calculator
Enter germination percentage and mean seedling length to compute the seed vigor index SVI = germination(%) × seedling length(cm) by the Abdul-Baki & Anderson method, assessing seed-batch vigor and quality.
Input Data
Results
At a glance:The seed vigor index (SVI) is a quantitative index combining 'germination rate' and 'seedling growth vigor' to assess a seed batch's vigor, most commonly the Abdul-Baki & Anderson (1973) formula: SVI = germination(%) × mean seedling length(cm). Germination rate alone only tells the proportion that can sprout, unable to distinguish 'weak seedlings that barely germinate' from 'vigorous seedlings with strong growth'; multiplying germination by mean seedling length brings in both 'quantity of germination' and 'quality (sturdiness) of seedlings'. A higher SVI means the batch not only germinates well but also grows fast and sturdy, usually with better field emergence and uniformity under stress (low temperature, drought, disease). In practice SVI compares different seed batches, evaluates storage aging, and tests seed treatments (priming, coating) and disinfection effects — an important tool for nurseries and seed quality control. Measure germination as the percentage value and seedling length commonly as root+shoot length (cm); keep the same test conditions and measurement method when comparing two batches.
Formula
Seed vigor index: SVI = germination(%) × mean seedling length(cm).
Use the numeric germination percentage (e.g. 90% uses 90).
Seedling length commonly uses mean of 'root length + shoot length' (cm).
$$SVI = G_{(\%)} \times L_{seedling\,(cm)}$$How to Use
- Run a standard germination test and record germination (%).
- At the end of the test measure mean seedling length (cm, commonly root+shoot).
- Enter both; the tool returns the seed vigor index SVI; higher SVI means a more vigorous batch.
SVI interpretation (for relative comparison)
| Situation | Feature | SVI relative |
|---|---|---|
| High-vigor new seed | High germination, sturdy seedlings | High SVI |
| High germination but weak seedlings | Sprouts but poor growth | Medium SVI |
| Aged stored seed | Both germination and length drop | Clearly low SVI |
| Low-germination batch | Most fail to sprout | Low SVI |
No fixed pass/fail threshold; compare under the same crop and test conditions. Value depends on crop and seedling-length measurement method.
Case Studies
SVI of a high-quality new seed lot
A new seed lot: germination 90%, mean seedling length 12 cm.
SVI = 90 × 12 = 1080.
High germination with sturdy seedlings, SVI 1080 — a high-vigor batch with expected uniform field emergence.
Vigor decline after one year of storage
Same lot after a year: germination drops to 80%, mean seedling length shrinks to 8 cm.
SVI = 80 × 8 = 640.
SVI fell from 1080 to 640, about a 40% drop — far larger than germination's alone (90%→80%), showing weakened seedlings accelerate vigor loss; use first or increase sowing rate.
FAQ
How does seed vigor index differ from germination rate?
Germination rate only answers 'what proportion of seeds sprout', a single dimension. SVI multiplies germination by mean seedling length, adding the dimension 'how well they grow after sprouting'. Two lots both at 90% germination, one with 12 cm seedlings and one with 8 cm, give SVI 1080 vs 720 — vigor优劣 is clear, which germination alone cannot show.
Measure root or shoot for seedling length?
The original Abdul-Baki & Anderson method often uses total seedling length 'root + shoot'; some protocols compute root-vigor and shoot-vigor indices separately. The key is a consistent standard within one test: use total length or shoot length throughout for fair comparison. This calculator accepts your mean seedling-length value; keep the measurement口径 uniform.
Is there a pass/fail threshold for SVI?
No universal fixed threshold across crops, because seedling lengths differ greatly (large-seed species have longer seedlings and naturally higher SVI). SVI's value is 'relative comparison': under the same crop and same germination-test conditions, compare SVI across batches, storage times, or treatments. For an internal standard, use your own historical high-quality batch's SVI as the baseline.
Why can SVI reflect field performance?
Field conditions often have stress like low temperature, drought, soil crusting; high-vigor seeds germinate fast, push through soil strongly, and extend roots quickly, giving better emergence and uniformity; low-vigor seeds may sprout in the lab but emerge slowly with many gaps in the field. SVI merges germination ability with seedling growth vigor, better predicting such field emergence differences, hence widely used in seed quality control.
How to improve a batch's vigor?
Vigor mainly depends on the seed's own maturity, plumpness, and storage conditions — low-temperature dry storage greatly slows aging. Pre-sowing treatments like seed priming (controlled hydration then re-drying), coating, and proper disinfection improve germination uniformity and seedling sturdiness, raising SVI. But these cannot 'revive' severely aged, very low-vigor seeds; the source is still choosing fresh, plump, high-quality seed.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.