What are the Methods of Seed Testing

• Germination testing is required by law and is a good indication of the plant-producing potential of a seed lot under normal conditions.
• The seed vigor test represents the seed’s ability to develop a normal seedling under stressful environmental conditions
• There is not a standardized seed vigor test across the seed industry. Inconsistent lab vigor testing procedures make it difficult to compare results across labs.

There is strong agronomic value in a perfect corn stand emerging evenly over a 24 to 48-hour window. Having the confidence that your seed is of the highest possible quality to achieve this goal is equally important. This article will review current industry and Golden Harvest® seed quality testing standards. Interpretation of independent seed lab test results will also be explored.  

Seed testing is important to ensure that only the best quality seed lots are allowed into the marketplace. Testing provides assurance to the farmers using the products. Golden Harvest has seed testing protocols and product specifications to ensure the products shipped to customers meet or exceed these expectations.  

Standard Industry Seed Quality Testing

Multiple seed quality tests are required by the Federal Seed Act and individual state seed laws to be carried out and reported on seed bag tags. Germination and physical purity are both required to be visible on bag tags. Genetic purity testing ensures genetic purity and trait purity expression are meeting product specifications. Genetic purity results of less than 95% require bag tag labeling to be referred to as a blend. 

Germination is measured using a warm germination test, which is a standardized process adopted across the seed industry. Germination determines the plant producing potential of a seed lot. The germination capacity of a seed lot is expressed as the percentage of normal seedlings developed under favorable laboratory conditions. Germination test results are highly consistent across certified seed testing labs. 

The Association of Official Seed Analysts (AOSA) Rules for Testing Seed define the germination testing procedure that all seed providers are required to follow. Warm germination results are an essential measure of seed quality. However, they do not predict how seeds will emerge under stressful field conditions.

Golden Harvest Proprietary Seed Vigor Testing

​​​​Seed vigor tests are commonly used by seed providers and 3rd party seed testing labs to better understand the seed’s ability to germinate and grow normally under stressful soil conditions. Vigor testing is not required by federal or state laws, although it is routinely used across the seed industry to ensure the best quality seed for customers. 

Due to lack of legal requirements, vigor testing procedures are at the discretion of the seed supplier. Although the importance of predicting consistent emerging products to ensure a good customer experience has made vigor tests more common. Seed providers are developing proprietary testing methods to deliver the highest quality seed possible. Multiple vigor tests are utilized across the seed industry. However, lack of a universal testing procedure makes it difficult to compare results across labs.


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In addition to warm germination, Golden Harvest utilizes proprietary vigor tests to quantify seed vigor. In 2019, Golden Harvest introduced a novel approach to seed vigor testing. Although a vigor test cannot mimic every potential combination of environmental factors affecting field emergence, this new method is designed to mimic the imbibitional chilling stress seeds face in less than ideal field situations (Figure 2). This test is helping differentiate at both a genetic and physiological level, helping provide customers with seed lots at or above industry and independent lab seed quality standards. The Golden Harvest Vigor Test protocol was validated in actual field emergence trials and compared with 3rd party vigor tests before finalized. The Golden Harvest Vigor Test continues to be validated yearly through lab testing and against field emergence to ensure the most current and relevant testing procedures are being used.

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Low and High Seed Vigor Lab Testing Samples

The warm germination test and Golden Harvest Vigor Test are just two examples of the many tools Golden Harvest utilizes in its quality assurance program to evaluate seed quality. Golden Harvest conducts seed quality testing continuously and endeavors to provide its customers with quality seed. Development of the Golden Harvest Vigor Test is one of various technological improvements that Golden Harvest is implementing into the new state of the art Quality Control Laboratory located in Slater, Iowa. Ultimately, Golden Harvest stands behind every unit of seed to be of the best quality. 

Common Reasons for Lab Vigor Result Discrepancy:

• Improper seed sampling procedure.
  • Seed tests are only as good as the sample submitted. It is critical to pull a representative seed core sample from throughout the entire shipping container.
• Comparing results across different 3rd party labs. 
  • Not all vigor tests are equal.
• Vigor testing procedure not calibrated for genetic families.
  • Not all genetics react the same to all vigor tests. Some genetics will always score lower or higher than if a different vigor test were used. Most major companies use proprietary tests they have validated against their genetics and field data to correct for this, whereas most 3rd party labs do not have this capability.
• Non-accredited seed lab performing test.
  • Labs not following AOSA Rules for Testing Seed or operating without oversight of an accredited analyst (Registered Seed Technologist or Certified Seed Analyst) are less likely to deliver consistent results.

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