Overcoming Challenges in Seed Testing: Adapting Protocols for Accurate Results

Seed testing is not always as simple as following a set protocol; it requires meticulous attention to detail. In some cases, the initial results may not provide a clear picture, necessitating retests and the adaptation of pre-established protocols.

For instance, the standard requirements for a chickpea Tetrazolium test state that the seeds should be soaked in water and then placed in the Tetrazolium solution for 6 hours. However, there may be cases where the results are inconclusive. For example, the Tetrazolium result may be satisfactory at around 95%, but the germination test shows an abnormal percentage of 20%. But why does this occur? It is due to the inherent nature of living organisms – mother nature herself.

When such situations arise, retesting becomes necessary, along with the adaptation of protocols to gain clarity. This adaptation may involve modifying testing conditions, adjusting the soaking time of the seeds, and even altering the concentration of the chemical to allow sufficient time for metabolic activity to occur. As a result, some chickpeas may display a clear contrast between red and white colors in the TZ Testing.

This final answer provides growers and traders with the information they need to assess the quality of their product.

The Tetrazolium Test

" The introduction of the tetrazolium test (TZ) into the "world" of seed techonology in the mid-1940s was among the most important watersheds in the history of organized seed testing."  James C. Delouche, 1984

 Almost 80 years ago, the TZ test emerged as a reliable tool for the seed industry, and its relevance persists today. At Agetal, our aim is to bring clarity and offer a simplified explanation of this test. This revision clarifies the timeframe and the purpose of the TZ test, while also presenting the company's intention in a more coherent manner.


What is a Tetrazolium test?


Is a quick biochemical test that assesses the seed viability. It is done through the direct contact between the tetrazolium chemical and the surface of the living cell in the seed embryo.  it is a colour sensitive test, that is why the seed tissue would respecto thus:

  •   Seed viable = red coloration/stained
  •   Seed non-viable = No/blank coloration Unstained,
  •   Rotten tissue, non-viable


But, What is a VIABLE seed? 

A VIABLE seed is that one capable of germinating and developing into a healthy and functional plant under suitable conditions. Because of that, it is important that in the tetrazolium test all the structures involved in physiologic seedling development are well stained, meaning the tissue is alive and can lead potentially to a healthy plant.

 Some seeds may only partially stain, which can lead to an abnormal seedling. A germination test is recommended to cover this.



Why and when should it be done?

To have a quick and reliable result of the seed VIABILITY
  •  If there is an urgent need to sow the seed after being harvested, or when needs to check viability progression  after a period of storage.
  •  When storage conditions might have declined the seed viability over the time
To contrast with the result of a germination Test
  • when there are “bad” results in a germination test and the remaining seeds are fresh.
  • The seed can be dormant but still viable, in that case a tetrazolium test would be the test to proceed. If the result is good, it is necessary to break dormancy.

At any other circumstance where a very quick estimate of germination potential is required.



Discover the full potential of your seed!  Knowledge is power.



I love a sunburnt country: But, What is happening to my tropical grasses?

Dorothea McKeller, wrote I love a sunburnt country, a land of sweeping plains, of ragged mountain ranges, of droughts, and flooding rains.”

 As many farmers know, we are at the mercy of Australia’s ever changing sometimes brutal weather conditions that make up our climate. Many years of drought, fire and flooding rains have battered our pastoral areas that are dominated by C4 tropical grasses. Buffel, Rhodes Grass, Panic, Setaria, and Bluegrasses are all C4 plants.  This term refers to the pathway the plant uses to capture carbon dioxide during photosynthesis. The C4 pathway evolved in species in the wet and dry tropics.

 C4 plants evolved in and are adapted to warm or hot seasonal conditions, under moist or dry environments.  C4 grasses tend to be less frost tolerant compared with C3 species, and they generate more bulk which leads to more feed through the growing season.



Features of C4 Grasses compared to C3 Grasses
    C3 carbon pathway      Requirements     C4 carbon pathway
Cool season or year longGrowth period  Warms Season
Lower Light requirement  Higher
Lower Temperature requirement  Higher
Higher Moisture requirement  Lower
Higher Frost tolerant  Lower
Higher Feed Quality  Lower
Lower Production  Higher


With the climate anomalies being experienced by farmers in tropical regions, there have been some seed production issues. Seed viability has been lower than usual. This has been caused by cooler than normal temperatures affecting where the plant places its energy.  Tropical grasses will put a lot of energy into plant growth leading to very bulky plants which is great for feed production but in turn less energy is placed into the production of seed for the next generation.

 Wet conditions during flowering, especially for grasses is detrimental.  Tropical grasses are often self-pollinating, and pollen is extremely light, so can be easily dislodged from the floret during periods of rain, leading to a higher proportion of un-pollinated seed.

 Tropical grasses require a significant amount of light for both development of foliage and seed.  Insufficient sunlight caused by a greater frequency of cloudy days during growth and development, forces the plant to place most of its energy into keeping the vegetative parts of the plant, and therefore less energy into seed production. The inflorescence may then produce numerous seeds but with differing rates of maturity.

 All these factors will be seen during the testing of seeds in the laboratory.  Farmers and seed companies will likely see reduced germination rates and viability (Tetrazolium test) on their seed analysis certificates.


The AgEtal Team






Agricultural Cover Cropping for Beginners

What is cover cropping?

The foundation of healthy land is healthy soil. When growing single crops year in and year out, the biological activity in the soil tends to simplify, depleting the nutrients in the soil and making your crop vulnerable to pests. Cover cropping is the act of growing crops specifically to nourish the soil, rather than harvesting them for commercial activity. Cover cropping is done between standard crop cycles and can be done to manage erosion, fertility, quality, biodiversity, and pests. This is a suggested method of how to reintroduce biomass and microorganisms and biological activity into the soil. The result will be a healthier, more complex, and more robust soil ecosystem.

What should I include in my cover crop?

Cover crop mixes should include crops for biomass, nitrogen fixation, and diversity to encourage increased biological activity and ecological diversity into the system. We suggest some crops that grow fast and produce bulk biomass, like corn in the summer, and forage oat in the winter. Nitrogen depletion is also a common problem, but legumes are excellent at fixing nitrogen in soil, so be sure to include them in your cover crop. Pigeon pea and lablab are good in summer, and field peas are good in winter. Pigeon Peas are also excellent for encouraging soil microorganisms. To encourage diversity, you’ll also want crops that feed from different parts of the soil profile, and crops that attract different microorganisms. For instance, in summer, you could add sunflower and forage sorghum as a point of difference to your corn, and in winter you could add forage brassicas as a point of difference to your forage oats.

Make sure you know the quality of the seed you're using in  your cover crop. If it has low germination rates, increase the population so you still have adequate viable seed of each species. Also, be sure not to accidentally spread weeds. 

When/How do I cover crop?

  • Between your standard crop cycle, disperse your cover crop mix onto your fields.
  • Leave your cover crop to grow until the first species starts to flower.
  • Use slashing or another mechanical means to kill the crops.
  • Leave them to rot on the field.
  • Plant next seasons harvest crop on richer, healthier, and more active soil.

Would you prefer to Print or Download this form?

If you would prefer not to complete this form online, you can download or print the form.

Simply complete the form on paper, attach to your sample and post or deliver to AgEtal.

If you require testing to full ISTA methods (i.e. 4 reps instead of 2) or for OIC/BIC please use the ISTA form.

Download ISTA Form

Request for Analysis FormNew Customer Form

Accurate results
in a timely manner.


Request for Analysis.

Simply book online for all your seed and grain testing then drop off or post the sample to our lab.

Please be sure about the tests you require before submitting your Request for Analysis. *See our Cancellation Policy
Test results have a fast turnaround and are available online.

Request for your samples to be analysed in three easy steps.

Complete the
form below.
Sign & attach the receipt
to your sample.
Post or deliver the
sample to AgEtal.

Attach the form to your sample. Post or deliver the sample to AgEtal. For fast turnaround, please deliver samples before 3:30pm.

Thank you for requesting an analysis

We have received your request for analysis, don't forget to print and sign the receipt below to attach to your samples. Send or deliver your samples to our laboratory. If you have any questions, please contact us.

We will be in contact with you when your results are ready.

Print Receipt

Attach the form to your sample. Post or deliver the sample to AgEtal.

AgEtal Request Analysis

Customer Details
Accounts Payable Details
Analysis Details 1
Lab. No. (Office use only)
Analysis Details 2
Lab. No. (Office use only)
Analysis Details 3
Lab. No. (Office use only)
Analysis Details 4
Lab. No. (Office use only)
Analysis Details 5
Lab. No. (Office use only)
Analysis Details 6
Lab. No. (Office use only)
Analysis Details 7
Lab. No. (Office use only)
Analysis Details 8
Lab. No. (Office use only)
Accredited Sampler & Other

* Abbreviations: Purity = P  Germination = G  Vigour = V  Tetrazolium = Tz  |  Weed Search = WS

A booking receipt will generate when submiting this form. (a confirmation will sent to the nominated Customer email)

Test results have a fast turnaround and are available online.

Please remember to complete the final steps when you submit this form.

Sign & attach the receipt
to your sample.

(Booking Receipt)
 Post or deliver the
sample to AgEtal.

Export Information (if applicable)
Analysis Submit
Issued by Luanne Cunliffe Director Webform WAM03 01/09/21

Contact AgEtal Agricultural Testing Laboratory

Get in contact with our laboratory to book an analysis or learn more about our testing.

Phone 07 4633 3223

Courier 9/24 Carroll St Toowoomba QLD 4350

Auspost PO Box 7135 Toowoomba South 4350

Opening Hours

Monday to Friday
8:30am to 5:00pm

Saturday & Sunday
Closed to the public

Counting is done every day – after hours drop off box available.

Follow us on Social Media



Send a message

Need some more information about the laboratory services we provide, have a technical question, feedback or want to discuss an idea with us?

Select a form and forward your message. 

General Enquiry

AgEtal Contact

Send a message

Technical Questions

Agetal - Technical Questions

Technical Questions

Customer Feedback

Agetal - Customer Feedback

Customer Feedback

Subscribe to our mailing list

* indicates required