Explanation of Tests
The seed laboratory provides a broad range of testing services to seed
producers and consumers and everyone in between. The laboratory is a member of
the Association of Official Seed Analysts (AOSA) and is staffed by accredited
seed analysts. It is equipped with modern testing equipment necessary to perform
test on all kinds of agricultural, vegetable, tree and flower seed.
The following is a description of the more commonly requested seed tests. If
you need information on other tests give us a call.
Purity Analysis
Determines the percentage by weight of pure seed, inert matter, other crop
seed and weed seed present in the sample. Identification is made of other crop
seed and weed seed found. This test also includes a North Dakota noxious weed
examination.
North Dakota Noxious Examination
Determines the rate of occurrence of North Dakota prohibited and restricted
weed seeds present in the sample.
USA Noxious Examination
Determines the rate of occurrence of weed seeds that are restricted or
prohibited in any state in the U.S. Use this test when preparing to label seed
for sale in a state other than North Dakota.
Germination Test
Determines the percentage of normal seedlings that develop under ideal
conditions. The percentage of hard seed or dormant seeds also determined when
present.
Tetrazolium Test (TZ)
A rapid (24 – 48 hr.) chemical viability test that can be used to predict the
results of the germination test. However, it cannot be used as a substitute for
the germination test in labeling seed.
Accelerated Aging Test (AA)
A high humidity, high temperature stress test that is an indicator of vigor
in wheat, durum, barley and soybean seed. Includes a germination test. The
accelerated aging test score should be compared to the germination test. High
vigor seed should be within about 15% of the actual germination, medium vigor
seed should be within 16 to 30% of the actual germination and low vigor seed is
so defined when the difference between the two tests is more than 30%. These
numbers are not absolutes and suggest how a lot of seed will perform under
adverse conditions.
Seed Count
Determines the number of seeds per pound of pure seed. A purity test must be
done at the same time.
Herbicide Trait Bioassay Test
(Roundup Ready® canola and soybean, Liberty® canola, Clearfield® canola and
winter wheat) This test subjects the seed to the herbicide in question to
determine the percent of the seed that has the resistant gene present.
Canadian Purity
Provides the purity information necessary to ship seed to Canada. Call for
information.
Diagnostic Lab Tests
The North Dakota State Seed Department Diagnostic Laboratory provides a wide
range of testing services designed to meet the needs of the seed industry. The
lab offers testing services in three main areas including seed health, genetic
purity, and genetic modification. The following is a brief explanation of the
types of testing services offered:
SEED HEALTH TESTS
Ascochyta Blight:
Pulse crops such as field pea, lentil, and chickpea can be affected by
Ascochyta blight. High levels of Ascochyta infected seed can cause serious yield
losses in these crops. The department offers Ascochyta testing using an
established agar plating method.
Barley Stripe Mosaic Virus:
An ELISA test is used by the department to detect the presence of BSMV in
barley seed. North Dakota requires BSMV testing on all Foundation class seed.
Bean Anthracnose:
Dry edible bean anthracnose testing determines the presence of this seed
borne pathogen. Low seed infection rates can cause serious problems in the
field. A growout method is currently used to screen for this pathogen.
Blackleg:
This is a serious fungal disease that affects canola and is spread easily by
infected seed. The department currently tests for Blackleg using a standardized
agar method.
Dome test:
This test detects dry edible bean bacterial blight pathogens present in a
particular seed lot and gives an estimate of the disease potential that exists
if such seed were planted. The dome rating number allows the grower to compare
the blight potential of different seed lots.
Loose Smut:
The department conducts testing for loose smut in barley using an established
embryo count procedure. Infection rates in barley typically correlate directly
with yield losses in the field.
Phomopsis Seed Decay:
A seedborne fungal pathogen of soybean that can cause serious problems with
seed quality. A minimum infection rate is required for seed to pass OECD
requirements.
Soybean Bacterial Blight:
This test is also a requirement for soybean seed to meet OECD specifications.
A standardized plate test is offered to detect this pathogen.
Virus Tests:
ELISA based tests for potato, soybean, and edible bean viruses are offered.
Examples of viruses currently tested by the department include: bean common
mosaic virus (BCMV), soybean mosaic virus (SMV), bean pod mottle virus (BPMV),
and most potato viruses including potato mop top virus (PMTV).
GENETIC MODIFICATION TESTS
The North Dakota State Seed Department offers genetic modification tests that
detect the presence or absence of the glyphosate resistant gene in soybean.
These tests are sometimes referred to as “GMO” or “non-GMO” tests. The
department currently conducts three types of genetic modification tests for the
detection of the glyphosate resistant gene in soybean including lateral flow
strip tests, ELISA tests, and PCR tests. An ELISA test is offered for GMO
detection in potato using leaf or tuber tissue. |
