Brookings, South Dakota
September 19, 2007
Wheatgrass Seed Testing
One of the more difficult purity
examinations performed in a seed laboratory is a separation of
wheatgrass species. Western Wheatgrass and Quackgrass rank in
difficulty right up with undertaking a Brassica species
seperation. Because of the difficulty of this examination, it is
very important to have your wheatgrass samples tested in a
laboratory with analysts trained and experienced in conducting
those separations.
Wheatgrass plants have a wide range of variability in the seed
size, coloration, and even angles of attachment to the rachis at
different parts of the plant panicle. Analysts are typically
trained to recognize the “average” or “typical” seed
characteristics and only through experience learn to recognize
the atypical seed that is still within the species being
examined.
At Mid-West Seed Services Inc.
we have an annual refresher training session for all of our
analysts in purity separations, seed identification, germination
procedures and tetrazolium testing. This weeklong re-training is
held in a classroom discussion format with everyone sharing the
little tips that they may have developed during the previous
testing season for identification.
Wheatgrass purity testing is very difficult and provides a new
learning experience with each new sample. The purity analysts at
Mid-West Seed Services see many different wheatgrass and wildrye
seed samples from a wide number of states. This exposure to many
similar looking species aids in keeping our eyes trained to
notice those small differences critical to correctly analyzing
your seed sample. Each of these purity samples is double-checked
by a separate RST (Registered Seed Technologist) to ensure that
your result is accurate. Because we use a team approach to all
our analyses, you receive the benefit of having two different
analysts judge and agree upon the information on your test
report.
Cool Season Grass - Tall Fescue
The method of testing our Tall Fescue samples may change in the
future!
This past year, a rules change proposal was submitted to the
AOSA/SCST membership for a vote. The rule would change the basic
methods of performing a purity analysis on Tall Fescue. The
proposed method was based upon the Uniform Blowing Method for
Kentucky Bluegrass. Instead of hand picking the empty florets
from the sample and separating the multiple units the blowing
method uses a calibrated air stream to precisely remove florets
with smaller caryopses or with no caryopses at all. Studies were
performed to demonstrate the material removed by the seed blower
was not viable seed and the purity percentages between the
current hand method and the proposed blowing method were not
significantly different.
Questions were raised about the possibility of some seed
conditioners decreasing attempts to break multiple floret units
apart and thereby sell more inert material to the consumer. This
concern and others resulted in a very close vote and the
proposal failed this past June. Interestingly enough, if the
voting method of two years ago were in effect the proposal would
have passed and gone into effect October 1 this year. Because
the two organizations made the requirements for Rules passage
more stringent with a 2/3rds majority now required instead of a
simple majority vote the proposal failed by one percentage
point.
Further studies are being performed this year, and nationwide
referee test of the procedure. Mid-West Seed Services will again
participate in these studies. We are prepared to test your seed
lot utilizing both methods if you request it. By performing both
methods you can make your own comparisons of how this rule
change may affect your inventory value. In addition, the
Oregon State Seed
Laboratory is soliciting comments from grass seed producers
and conditioners for additional input into the proposed methods
change.
For further Information on this, contact Larry Prentice,
Multi-Species Laboratory Manager, at 1-877-692-7611. |
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