There are many problems associated with testing native seed species. This is why most seed laboratories shy away from offering tests for these seeds. Problems found with testing native seed species can be broken down into the following categories:

• Identification problems
• Sampling and dividing problems
• Purity analysis problems
• Germination testing problems
• tetrazolium testing problems
• Labeling problems

Let's take a close look at each of these problem categories:

Identification Problems With Testing Native Seed Species

The problem with testing many native seed species is that the seed units haven't been properly described and classified as have the traditional agronomic crop species. Not only haven't the species' seeds been described, but many have distinct sub-species that require further description.

To compound this identification problem, analysts see weed species in native seed lots that they have never seen before and can find no plates, images or seed keys to identify them properly. The identification of these weed species becomes paramount with how extensive our seed herbarium is.

Here at the J & T Green Seed Services, collecting native seed species and their accompanying weed seeds for our herbarium has always been a priority so that we can give you the most accurate identifications in our reports as can be possible.

Sampling and Dividing Problems With Testing Native Seed Species

Sampling seed lots with any crop can be a problem, but this is compounded with native seeds. Because so many of the species have adhering appendages, they tend to clump together and hold in weed seeds within their appendages. This can make for pockets of inert material and weeds seeds that are not uniform within the seed lot. It is hard to take a proper seed sample.

Seed thiefs and triers don't work well with native seed. They are not free flowing and because of this, manual, hand sampling is often the best way to gain an accurate sample of the seed lot. This is tedious and time consuming if done properly.

On the other end, dividing submitted samples at the seed laboratory into working samples that the purity analyst works with have the same problems. The chaffy nature of the seed tend to make an accurate working sample harder to create.

Purity Analysis Problems With Testing Native Seed Species

The purity analysis of native seed lots presents many problems. It's not only the identification of crop and weed seeds. Knowing the basic seed unit and how to classify it becomes a problem depending upon which family the seed unit falls into.

Native seed species of the Asteraceae family present a particular problem. Part of the problem is that many of the seed units have attached floral remnants which are tedious to remove and classify as inert. And many lots of these species include obviously empty achenes but because the analyst can't see inside, they must be classified as pure seed but they will lower the germination percentage.

Another problem is with the grass family and the number of species that produce what is known as multiple florets. These are seed units with more than one seed, all attached together. The AOSA Rules for Testing Seed have factors to apply to these units when determining which seeds should be included as "pure seed" with common agricutural seeds, but not with all the natives.

Blowing points and procedures present a problem to the analysis of native seed. Here again, the chaffy nature of these seeds makes them clump together and flow through the seed blower as a group of seed instead separating into individual units and the air flow taking out the empty, inert seed.

Excessive chaff, inert matter, weed and other crop seed makes the purity analysis tedious and time consuming. Add to this the fact that many of our native grass species present problems with simply determining whether or not a caryopsis fills the seed unit makes for a lengthy time spent with each seed sample.

Germination Problems With Native Seed Species

Germination presents some of the toughest problems that face the analyst that tests native seed. These species are far from being what we would call "domesticated". Many species have narrow germination conditions with high percentages of dormancy making it hard to obtain a good laboratory germination.

All types and forms of dormancy can be found in the species that bridge the classification of native seed. Many species have more than one form of dormancy that has to be overcome before germination can proceed. With dormancy as an issue, the difference between laboratory germinations and germination in the field becomes exaggerated.

Two good examples of this are Indian ricegrass and crambe. Ricegrass germinates poorly in the lab and shows very high percentages of dormancy, while in the field, in contact with soil and natural conditions, it germinates well. Crambe, on the other hand, can be teased into a high germination in the laboratory by applying potassium nitrate to the germination test. But, when planted in the field, it often germinates poorly and it may take years for a good stand to be obtained.

Wide variations in the germination percentage of a seed lot can be experienced between two testing laboratories. Seed tested at different times of the year will very greatly in germination due to the cyclic nature of some of the dormancy mechanisms.

Tetrazolium Testing Problems With Native Seed Species

Tetrazolium (TZ) testing is used in the seed lab to determine the viability of dormant, ungerminated seed at the end of the germination test. Yet, there can even be problems with the TZ test when testing native seed. These problems are by far shadowed by the other testing problems with native seed though.

The main problem seen is a slower, lighter staining of some seed species due to the dormancy mechanisms that slow the rate of respiration within the seed and limit the reaction of the hydrogen ions given off by this metabolism with the TZ solution.

Along with this, analysts see variations in the staining patterns that make the test harder to evaluate with some native seed species. Analysts that perform TZ tests on native seed need to have more experience than the average seed analyst.

Labeling Problems with Native Seed

Native seed has labeling issues. These result from how do you label for dormancy to how this type of seed will be bought and sold. The seed trade has been coming to grips with these issues and they are becoming less a problem than they were when native seed first came onto the agricultural market.

Some states don't recognize the Tetrazolium test and in these states, native seed has to be sold strictly on the germination percentage achieved in the seed lab. This presents a big problem when selling native seed that have high rates of dormancy. On the other hand, a handful of western states now allow for some native species to be sold on a stand-alone tetrazolium test.

In the past few years, seed companies have taken on the practice of buying and selling native seed through using the concept of "Pure Live Seed" (PLS). This is a very good means to convey the quality of a native seed lot. Unfortunately, pure live seed is not recognized by state or Federal seed acts for labelling purposes.

PLS is the percentage purity of the seed lot multiplied by the germination (or viability) percentage, divided by 100. One can see how this gives a better indication of the quality of the seed than either the purity percentage or the germination rate. The seed industry is beginning to address these labelling problems as native seed takes a bigger share of the seed market.

J & T Green Specializes in Native Seed Testing

Our Registered Seed Technologist has over 30 years experience in testing seed. The majority of his seed testing career has been spent testing native seed. He brings this expertise to work for you when testing your seed. If you are looking for reliability in your native seed test results, turn to J & T Green Seed Services. We understand the problems that exist when testing native seed speces and have what it takes to bring quality test results to your native seed lots.