Analytical purity
Seeds are separated from various
impurities (such as weeds, other crop seeds and inert
matter) before it gets weighed to determine the
percentage of purity of the sample. The analyst
identifies the other crop and weed seeds found in the
sample and report it to the relevant persons.
Special care is given to harmful
impurities such as noxious weeds.
Moisture content
The official method to determine moisture
content implies drying of the seeds in an oven at
specific temperatures and for various periods according
to ISTA rules. Moisture content is represented as a
percentage of the sample weight.
Germination
Germination tests determine the
percentage of normal seedlings that will develop in
ideal growing conditions. Dormant seeds are counted and
reported as a portion of the viable seed percentage. In
cases of dormancy, seed may be pre-chilled, pre-heated
or treated with either potassium nitrate of
Gibberellic
acid before the actual germination test
commences. Dormancy breaking method would depend on the
species to be tested.
The incubators used for germination tests
are designed to control heat, air, moisture and light
and comply with ISTA rules.
Tetrazolium Test
In cases where a more rapid indication of
germination potential is required, a tetrazolium test,
in which the stained seed embryos are examined, can
provide a result in a matter of days.
