Every Seed is a living organism consisting of
- A “small plant” referred to as a embryo
- Food/energy reserves referred to as endosperm or cotyledon
Because seed is alive it has the potential to be injured, sometimes resulting in death. At the Michigan Crop Improvement Association Seed lab, seeds are tested to determine viability and vigor. MCIA offers a full service seed testing laboratory for both seed certification and the commercial seed industry. Currently on staff are two trained Registered Seed Technologists (RSTs) to accurately determine the quality of each seed lot. Seed testing is performed according to rules for testing seeds developed by AOSA, the Association of Official Seed Analysts.
Why Lab Testing?
To evaluate and verify genetic purity, quality, and contamination levels
Performed after harvest to verify no contamination from harvesting/unloading equipment
Performed at various checkpoints (bins, pre-conditioning, post-conditioning, shipping, barges)
Seed Tests Offered
Standard Warm Germination
Used to determine how seed will perform under ideal conditions. Seeds are placed on sterile media in a growth chamber set at the ideal temperature and humidity. Seeds are evaluated according to AOSA rules specifying duration of test period and classification of normal, abnormal, and dead seedlings. Results are reported as percent germination, including dormant and hard seed.
Tetrazolium (Tz) Test
The Tz test is a quick test (24 hrs) used to estimate germination and seed lot vigor. Seeds are imbibed with water and then soaked in a solution of tetrazolium chloride. As the seeds respire the tetrazolium chloride reacts changing from a clear color to a red color. Based on the staining patterns, seeds are evaluated into categories of high, medium, and low vigor or dead seed. The Tz test has proven very beneficial in determining mechanical damage in soybeans and sprouting in small grains. MCIA recommends that seedlots should have at least 80 combined high and medium vigor seeds to be considered high vigor seed. This test is available for all field crops.
Accelerated Aging (AA) Test
The AA test is as the name implies a test used to artificially age seeds by exposing them to a stressful environment allowing seed respiration levels to increase. This test can be used to predict storability of a seed lot along with determining the vigor of a seed lot. Seeds are placed in chambers of high temperatures (41 C ) and high humidity for a set period of time. After this stress period, seeds are then germinated under ideal conditions. High quality seeds will produce normal seedlings while low quality seed will deteriorate and produce abnormal or dead seedlings. MCIA recommends that AA germination levels of 80% or better be considered as high vigor seed. This vigor test is available for small grains, soybeans, corn, and dry beans.
The cold test is used to help predict how a seed might perform if planted in cool wet soils common with early spring planting. Seeds are planted in soil with exposure to fungi common in soils, placed in a cold chamber (10 C) for a set period of time, and then transferred to a chamber to grow under ideal conditions. High quality seeds will produce normal seedlings while low quality seed will be unable to survive these conditions and will produce abnormal or dead plants. MCIA recommends that Cold Test germination levels of 75% or better be considered as high quality seed. This vigor test is available for corn, soybeans, and dry beans.
Seed Purity Analysis
The purity test is a physical evaluation of a set amount of seed described by AOSA rules. It is evaluated for the percent pure seed, inert, weed seed, other crop, and other varieties. Results are used to label seed and determine if it is in compliance with certification, state, and federal regulations. MCIA also performs noxious weed seed exams for seed sales in other states or countries as requested.
Herbicide testing is offered for both Roundup and STS varieties. Seeds are tested to quantify the purity level of the genetic trait in seed lots. This test can also be used to determine the purity of conventional varieties. Testing is available for soybeans.
Seed Count Test
As planting equipment and recommendations become more specific, seed counts become more important. MCIA performs seed counts to accurately determine the number of seeds per pound, which is used to calculate the planting rate needed to obtain the desired plant population. This test is available for small grains, soybeans, corn, and dry beans.
Seed Moisture Test
This test is available for most field crops and determines the percent moisture found in the seed sample. It can be very useful for determining whether the seed is at a safe moisture level for storing.
Official results are sent when all tests are completed. For special requests, information may be obtained verbally when earlier tests are complete.
|Warm Germination||7 days*|
|Tz Test||24 hrs**|
|AA Test||12 days**|
|Cold Test||14 days|
|Seed Count||1 day|
|Herbicide Test||8 days|