Warm Germination

Each germination test consists of 400 randomly selected pure seeds. This test utilizes Top of Crepe Cellulose Paper (TC) as the media.* A treated germination test is also available to reduce fungal colonization of fungal inoculum and mycelium growth on untreated samples. Percentage of normal seedlings is reported. Additional information regarding percent of abnormal and dead seedlings, type of abnormal seedlings observed and growth characteristics are available under Raw Data on the report. This test is required by the Federal Seed Act (FSA) for labeling and shipping across state lines.

*Conducted according to Association of Official Seed Analysts (AOSA), International Seed Testing Association (ISTA) Rules for Testing or Canada Methods and Procedures (M&P) based on customer need.

Sand Germination

Each sand germination test consists of 400 randomly selected pure seeds. This test utilizes Sand on Top of Crepe Cellulose Paper (TCS or S) as the media.* Emergence through sand emulates field emergence most accurately of the available testing methods by providing uniform water uptake and suppressing seed coat colonization by Fusarium or Phomopsis spp. A treated sand germination test is also available to reduce fungal colonization of fungal inoculum and mycelium growth on untreated samples, providing a best-case scenario for maximum germination. Percentage of normal seedlings and any extended normal seedlings is reported. This test meets the Federal Seed Act (FSA) requirement for labeling and shipping across state lines.

*Conducted according to Association of Official Seed Analysts (AOSA), International Seed Testing Association (ISTA) Rules for Testing or Canada Methods and Procedures (M&P) based on customer need.

Tetrazolium

Seed is imbibed for 16 hours as a pre-conditioning step to allow easier long-sectioning of seeds and to ramp up respiration and enzyme systems. Seeds are long-sectioned using razor blades exposing the cut surface to a tetrazolium (TZ) chloride salt solution. When respiration is active, the TZ combines with Hydrogen ions to form formazan, a red insoluable pigment. Percentage of viable seed (normal staining embryos and any dormant seeds) is reported. When seed has a fungal colonization, such as Fusarium or Phomopsis spp., this test will best estimate a treated germination test.

Accelerated Aging

SoDak's recommended vigor test for soybeans. Seed is aged for 72 hours at 41°C in a high humidity regime. After aging, 200 seeds are planted on crepe cellulose paper and covered with sand. Percentage of normal seedlings is reported. Additional information regarding fungal and physical damage are available under Raw Data on the report. Results within 15% of germination is considered strong, 16-20% difference is considered moderate and greater than 30% difference is questionable.

40F or 50F Cold

Occassionally used as a vigor test for soybeans, but not recommended due to seed moisture mirgration. Each cold test consists of 200 seeds planted on chilled crepe cellulose paper to emulate a cold water uptake. The cold duration is seven days, in an aerobic environment, followed by a growth period at 77°F until 120+ Growing Degree Day (GDD) units are reached. Percentage of normal seedlings is reported. Additional remarks are under Raw Data on the report.

Herbicides

Glyphosate (GT), Glufosinate (LL), 2,4-D/Glyphosate (Enlist), Dicamba (Xtend),  Chlorosuflan (STS)

Each herbicide bioassay test is conducted on 400 seeds which imbibe the desired herbicide solution over a seven-day period. Positive and negative trait check seeds are planted on each tray to ensure accurate rate of herbicide has been applied. The percentage of trait seedlings is reported. Trait confirmation of herbicide tolerance is required by the trait or genetic license provider. 

A seedling spray over test, utilized for later maturity (group 5+) soybeans, is conducted on 200 seeds. Seedlings are grown at 25C in a peat/sand mix for seven days then sprayed using a DeVries Track sprayer. Positive and negative trait check seeds are also utilized with this method. The percentage of trait seedlings is reported. This method emulates applications to seedlings when seed imibition of the herbicide active ingredient may not be providing satisfactory results.

Herbicide Bioassay

Glyphosate (GT), Glufosinate (LL), 2,4-D/Glyphosate (Enlist), Dicamba (Xtend),  Chlorosuflan (STS)

To test conventional seed for the unintended presence of herbicide traits a bioassay, for each herbicide, is conducted on 400 seeds which imbibe the desired herbicide solution over a seven-day period. Positive and negative trait check seeds are planted on each tray to ensure accurate rate of herbicide has been applied. The percentage of trait tolerant seedlings is reported.

PCR GMO Screen

In this test, 3000 or 10000 seeds are grouped into "pools' and ground into a fine flour. DNA is extracted from ground material and tested for the presence of standard DNA sequences utilized in transgenic insertion. "Pool" size determines the ability to calculate the percent of trait tolerance based on the number of "pools" that test positive for specific biotech sequences and estimations using SeedCalc 8. An estimated purity, based on positive and negative responses and the total number of seed tested, is reported.

Purity & Noxious Weed Exam

Or Other Seed Determination (OSD), tests are conducted using Association of Official Seed Analysts (AOSA), International Seed Testing Association (ISTA) testing rules or Canada Methods & Procedures (CAN) testing methods. To meet ISTA requirements, 1000 grams should be tested. Samples are physically examined for inert, weed and crop seeds while being screened over a 10/64th slotted screen. All material falling through the 10/64th screen is regarded as inert matter. Pure seed, inert matter (broken seeds, soil, etc) and other seed are reported as percentages by weight. For AOSA rules, other crop seeds are defined as other crop seed and common weed seeds. Noxious weed seeds in specific state(s), or the entire lower 48 states, are reported as well. This exam is required for the seed label in accordance with Federal Seed Act and assures clean pure seed free of undesirable seeds.

Hilum Exam (VP)

The recommended varietal purity test for soybeans, seeds are physically examined for true type hilum color. Off-type hilum colors are weighed by color and reported.

Hypocotyl Growout

This test is conducted on 200 seeds which are grown at 25°C in a peat/sand mix and placed under intense light to promote true hypocotyl color expression in seven-day old seedlings. The percentage of Green, Purple or a combination of the two hypocotyl colors is reported. This test can help identify a mixture of varieties or tolerances to a herbicide trait.

Seed Coat Damage

This test, also known as the soak test or hypochlorite soak test, is conducted on 200 seeds. Seeds are placed in a dish with hot coffee (in place of a hypochlorite solution) for approximately 3 minutes. The brown coffee color provides a nice contrast to the soybean seed, making it easier to find damaged seed. Percentage of swollen "oblong" seeds found within three minutes of soaking is subtracted from 100. The resulting value is reported. Often seed coats or embryonic axis of soybean seeds are damaged during harvest, especially at seed moisture contents of 9-10%. This test helps assess the damage and alerts the harvester adjustments may need to be made. 

Visual Seed Defect Exam

Seeds are rated for soil flecks (non, trace or high) and visual defects. Diseased, discolored, shriveled, green, bleeding hilum and purple seed stain are common defects. Percertage of non-defected seed, and percentage of any defect(s) found, is reported.

Visual Ratings

Seeds are physically examined for the presence of any defects and rated on a scale of one to five, with one being ideal. Defects such as soil flecks, cracked seed coats, disease, discoloring, and immature seed are all considered. Rating of one, two, three, four or five is reported. Most conditioned and color-sorted samples will rate a two.