(ISTA News Bulletin) No. 136, October 2008 - International Seed ...

Training and Education
ISTA Workshop reports
Centres). This latter method has many advantages
over the ISTA method, especially
regarding evaluation and speed, and therefore
also lower costs. It was thus proposed
for acceptance into the ISTA Rules. This
new and superior method convinced all the
participants.
To conclude the first day, Peter Büttner
presented the Research Centre’s Institute
for Plant Protection, and conveyed an insight
into the work of a diagnostic laboratory,
especially seed health methods.
The second day started with a presentation
about ISTA’s history and organization,
since for a third of the participants,
it was the first time that they had contact
with this organization.
Next was a demonstration, by means of
a field trial, of the differentiation between
two-rowed and six-rowed barley using morphological
traits. Not all characteristics of
a variety can be determined in the purity
analysis. Field trials are hence a good way
of determining the remaining traits.
The afternoon session started with a
cordial welcome by the President of the
Research Centre, Mr Jakob Opperer. He
emphasized the importance of development,
improvement and international harmonization
of seed testing methods, and
was proud of the opportunity to host this
important workshop at Freising.
The afternoon was then fully dedicated
to the identification, using morphological
features, of the various meadow-grass species:
annual meadow-grass (Poa annua),
common meadow-grass (P. pratensis),
rough meadow-grass (P. trivialis), wood
meadow-grass (P. nemoralis) and supina
bluegrass (P. supina). The distinction of
meadow-grasses in seed production is very
important, as P. annua and P. pratensis occur
in almost every arable field. The identification
of meadow-grass species is extremely
demanding. It requires on the one
hand staff with many years’ experience in
grass examination, and on the other good
laboratory equipment (microscope, liveimage
camera) is necessary. The morphological
traits of the lemma (veining, keeling,
form, filigree hairs) and palea (veining,
little teeth on the keels), and the filigree
hairs of the rachilla can be used. P. annua
and P. supina can only be distinguished
by means of protein electrophoresis. The
participants first had to examine simple
samples of each meadow-grass species,
and then a difficult one. They were allowed
to take the samples home for practice.
This exercise demanded high concentration,
and the participants were very glad
when the afternoon was over. A guided
tour through the greenhouses and grounds
of the Research Centre cleared everyone’s
heads and rounded off the day.
In the morning of the third day, identification
of species and varieties by means of
fluorescence (UV light) was on the agenda.
The fluorescence test can be carried out on
seeds or seedlings, depending on the species.
For oats (Avena sativa), the glume
colour under UV light is diagnostically
useful. For most varieties of Italian ryegrass
(Lolium multiflorum), the root courses
of almost all seedlings show fluorescence
under UV light, while in most varieties of
perennial ryegrass (L. perenne), root fluorescence
is rare. Moreover, hybrid forms
(L. hybridum) between the two species
show an intermediate reaction. In the case
of red fescue (Festuca rubra) and sheep
fescue (F. ovina), the roots shine respectively
either yellow-green or bluish green in
an ammonia atmosphere. When wild mustard
(Sinapis arvensis) is put on filter paper
soaked with potassium hydroxide, it can
be distinguished from rape seed (Brassica
rapa), because the filter paper surrounding
the wild mustard shows a blueish fluorescence.
The methods for identification
of yellow and white oats, wild mustard
in rape seed, red fescue and sheep fescue,
and, with reservation, the methods for perennial,
Italian and hybrid ryegrass were
demonstrated and intensively discussed.
In the afternoon, there was a visit to
a seed-processing facility of a famous
Bavarian seed company. All were very
Glume fluorescence in oat seeds.
48
Fluorescent wild mustard seeds among non-fluorescent rape seed.
Seed Testing International No. 136 October 2008