COLES
AND
WRIGLEY:
METHODS
OF
IDENTIFYING
WHEAT
CULTIVARS
501
~
~-
-.
oJ·
••
-
Fig.
1 -
Starch gel electrophoresis patterns of New
Zealand cultivars. Top to bottom: Takahe, Raven,
Kopara, Karamu, Hilgendorf, Gamenya, Arawa,
Aotea.
white)
is
reliable.
Differences
in
natural
colour
within
either
the red or the
white
group
are not
always
useful
for
identification.
Table
1 shows
the
classification
of
cultivars
as
red-grained
or
white-grained
on the basis of the 5%
NaOH
test.
Results
have
been
consistent
for each
cultivar
over a
range
of
samples
grown
at
Lincoln.
Grain
hardness
The
hardness
of the
grain,
judged
subjectively
or by
quantitative
tests, has
proved
useful
in
other
countries
for
distinguishing
five
groups
of
wheats
(very
hard, hard,
intermediate,
soft, very
soft),
though
this
characteristic
shows some
variation
caused
by
environment
and
grain
moisture
content.
Among
current
New
Zealand
wheats,
only the soft
wheat
Arawa
and the
generally
soft
Gamenya
stood
out
from the rest
in
terms
of
hardness
(Table
1).
All the
others
gave
quantitative
hardness
results
(PSI and PR)
in the range
equivalent
to
"hard",
as defined by
Wrigley
&
Shepherd
(1974),
and were signi-
ficantly
different
from
Australian
wheats
classed
as
"intermediate"
or
"very
hard".
Thus
in New
Zealand
wheat
these
quantitative
tests of
hard-
ness achieve no
more
distinction,
though
they do
provide
a more definite
measure
of
hardness
than
subjective
assessment.
Phenol
test
Table
2 shows the results of the
qualitative
phenol
tests for the
cultivars
in
certification
and
other
lines of
interest.
Each
cultivar
gave a
homogenous
reaction
except
Arawa,
one
sample
of
which
gave no
colour
change
with
phenol
solution.
This
sample
showed
the
electrophoretic
pattern
characteristic
of
Arawa,
and may repre-
sent a
second
biotype
of this
cultivar,
possibly
393,01/10.
Hilgendorf
and
.Kopara
are difficult to dis-
tinguish
by the
conventional
qualitative
phenol
test,
although
the
smaller
grain
size of
Kopara
is
often
a useful
distinction.
However,
the small
difference
in
their
phenol
reactions
can be
accentuated
by the
vacuum
phenol
tests, in
which
Kopara
(reactien
4)
darkens
more
than
Hilgen-
dorf
(reaction
2 or 3) in 1.5
hours.
The
three
tests do not
distinguish
Hilgendorf,
Karamu,
and
Takahe