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Biochemical and Molecular Techniques are utilized by many members of AOSCA in seed certification activities. This website is intended as a resource for member agencies looking for information on specific techniques. This website may be continually updated by member agencies as additional BMT’s are added, or as additional laboratories offer services to agencies. Contact the AOSCA office to request changes or additions.
The Clearfield Confirm Test is a purity test for Clearfield winter wheat seed. It is a seed-based germination assay used to determine the frequency of Clearfield tolerance in commercial wheat seed. The tolerance standard is supplied by BASF, typically in a protocol provided annually to licensees of the Clearfield production system. As of July 2011, the required tolerance to pass the Clearfield Confirm test is 92%. The herbicide treatment uses 200 micromolar imazamox in 10 millimolar phosphate buffer. Seed testing laboratories must be approved by BASF to offer the test and deliver results. Blind test samples are supplied to laboratories and must be evaluated satisfactorily to be approved by BASF.
Agencies Utilizing the Technique:
This is a test to determine the percentage of ryegrass seedlings with fluorescent roots. AOSA Rules state that a fluorescence test shall be performed on all samples of ryegrass for which the percentage of perennial ryegrass (Lolium perenne) and/or annual (Italian) ryegrass (Lolium multiflorum) is to be reported. The seedlings shall be grown on filter paper and the number of fluorescent seedlings determined under ultraviolet light at the end of the germination period. The AOSA Rules contain example calculations for properly reporting the results.
Agencies Utilizing the Technique:
This is a test for cultivar separation based on high or low seed coat peroxidase activity. This information is taken from the AOSA Rules. Analysts remove and place the dry seed coat from soybean seeds into individual test tubes or suitable containers. They add 10 drops of 0.5 percent guaiacol to each test tube. After waiting 10 minutes they add one drop of 0.1 percent hydrogen peroxide to the tube. After one minute, seeds are recorded as peroxidase positive (high peroxidase activity) if there is a reddish-brown solution; or peroxidase negative (low peroxidase activity) if there is a colorless solution in the test tube. Various sample sizes may be used for this test. Test results are to include the sample size tested. Note: Smell of guaiacol is offensive, perform test under a fume hood.
The Phenol Test is based on a color reaction between the phenol solution and the seed coat (pericarp) of the wheat seed. This test should be conducted according to the AOSA Rules for Testing Seed.
Agencies Utilizing the Technique:
PO Box 174
Fayette, MO 65248
(309) 736-0120
© AOSCA – Association of Official Seed Certifying Agencies
Association of Official Seed Certifying Agencies
3105 Research Road
Champaign, IL 61822
(309) 736-0120
© AOSCA – Association of Official Seed Certifying Agencies