Seed testing

Seed testing is performed in dedicated laboratories by trained and usually certified analysts. The tests are designed to evaluate the quality of the seed lot being sold. Several tests are done:

• Germination test: Reports the percentage of seed that germinated. Tests are usually made in 200 or 400 seed samples.
• Purity test: The percentage of seed described on the label that is actually found in the quantity of seed.
• TZ test: A test for viability that involves three steps: 1. preconditioning (imbibition); 2. preparation and staining (sometimes cutting the seed and then soaking the seed in a 2,3,5 triphenyl tetrazolium chloride solution); and 3. evaluation (examining the seed for a color change in the embryo).
• Weed test: Examines a sample of seed and identifies every seed that is different from the labeled seed kind.

References

The brief descriptions above are provided by Pure Harvest Software for Seed Labs. Other information about practices in the USA can be found at the following sites:

• Association of Official Seed Certifying Agencies
• Society of Commercial Seed Technologists
• Association of American Seed Control Officials (AASCO)
• Association of Official Seed Analysts