The Seed Department offers the following tests to provide additional important information about seed lots. Some tests are required for certification.
The herbicide trait bioassay test determines the percentage of seeds in a sample that are tolerant to the herbicide in question. Germinating seeds are subjected to the herbicide solution then placed on germination paper. Those that produce normal seedlings are counted as tolerant. Seedlings exhibiting malformities such as stunted roots are counted as non-tolerant. This test is useful to determine purity for the trait in question based on the presence of the gene.
- Glyphosate - Roundup Ready® canola and soybean
- Glufosinate – Liberty Link® canola
- Imidazolinone - Clearfield® canola, spring and winter wheat, rice and sunflower
Seed count is often used to calculate seeding rates of many crops. Seed count, purity and germination percentage are used to calculate the number of Pure Live Seed of a specific seed lot. For this test, the seed analyst determines the number of seeds per pound of pure seed. A purity analysis must be done at the same time. When required for certification, seed count tests are done automatically.
Occasionally, seed producers want to know what kind of other crops, if any, may be in a seed lot prior to conditioning. This knowledge can help them adjust their seed conditioning equipment for optimum performance and efficiency. In soybean, it is used to identify seeds with other hilum colors.
For certification purposes, the purity analysis of white wheat seed lots includes an examination for the presence of red wheat. Seed are soaked in a solution of potassium hydroxide (KOH) and bleach which causes the red wheat seeds to take on a darker appearance. The number of red seeds are counted and a percentage is determined.
The fluorescence test is used to determine the purity of ryegrass seedlings with fluorescent roots. The fluorescence test is performed on all samples of ryegrass for which the percentage of perennial ryegrass (Lolium perenne) and/or annual (Italian) ryegrass (Lolium multiflorum) needs to be reported. Seedlings are grown on filter paper and the number of fluorescent seedlings are determined under ultraviolet light at the end of the germination period.