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Tag: Seed Testing Procedures

Ready for Spring?

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Photo by MARTINOPHUC from Pixabay.

Time to Test Your Seed

The Seed Laboratory is busy, and it will take at least 7 days to get test results before issuing final reports, bulk certificates, and tags. So, have your seed tested now. You don’t want to be waiting for a test when it is planting time.

A few other items to keep in mind:

  • Update your germination. If you have carryover seed, be sure the label has a germination test date that complies with the seed law.
  • Submit a Sampling Report with all samples, complete with field numbers, lot size, number of bags or totes, and tests requested.
  • Be sure you received a passed seed certification report before any tags or bulk certificates are issued.
  • Always tag or issue bulk certificates for the seed you distribute.
  • Resolve any issues about eligibility of seed source before planting.
  • Retain your tags or bulk certificate as proof of seed source for your field inspection application.

Submitting Samples to the Seed Lab

To ensure that your samples arrive in good condition use a good quality, leak-proof bag and quality packaging. For fragile seeds (like soybeans) use a sturdy box and use packing material to keep them from getting bounced around during shipping. You may want to write ‘Fragile’ on the package.

Repackaging Certified Seed Procedures

When repackaging certified seed and retesting is required, follow the procedures described in the Seed Certification Handbook, pages 18 through 19.

When repackaging certified seed and retesting is not required, a Lot Number Change Request Form must be submitted in order for certification to be valid on the repackaged lot. This form can be found on the Client Resources page: www.mncia.org/resources. Look under Certification Services, Seed Certification Program, Labeling & Transferring Seed.

For seed certified by another state, be sure to include the original certification label and analysis results showing a MN Noxious Weed Exam or All-States Noxious Weed Exam was completed. A MN Noxious Weed Exam is required on Minnesota certified seed.

The MCIA staff is available to answer any questions you have. Please contact the MCIA Office or your field supervisor.

Why We Mix and Divide

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How the Seed Laboratory Obtains Representative Seed Samples

Seed Divider
Seed divider in action.

We frequently stress the importance of obtaining a representative sample of your seed lot for testing. This includes sampling intensity and storage of the composite sample. You may not be aware it, but the components of your seed lot or composite sample can separate over time with movement or shipment.

For instance, lighter seeds of a particular kind will make their way towards the top of a sample bag during transit whereas the denser seeds will move towards the bottom. Similarly, seeds of larger size will also separate towards the top of the sample whereas smaller seeds will move toward the bottom.

This type of separation can easily be observed when opening a container of mixed nuts—you will likely notice several nuts of one kind located on the top! In addition, at the bottom of the container you will find the smaller, broken pieces of nuts, much of which would be classified as inert matter in seed testing.

So, what does all of this mean? Much like the importance in sampling of your seed lot, we want to ensure that the testing that takes place in the lab is also representative. To achieve this, we obtain the required amount of a working sub-sample for purity analysis through a process called mixing and dividing.

Prior to testing, each sample is thoroughly mixed by passing the entire sample through a calibrated divider three times. Following the third passage, sample reduction takes place through successive halving and combination of half-portions until the required minimum working weight for the particular kind is obtained.

For instance, after mixing, a 1000-gram wheat sample will be divided down to obtain a minimum of 500 grams for the noxious exam. From this noxious portion, a minimum of 100 grams will be divided out to conduct the purity analysis, in which the component percentages used for labeling are determined. Altogether, this process of mixing and dividing provides randomization of the sample while eliminating bias and it lays the foundation for subsequent tests.