The Rural Voice, 1990-08, Page 25parts. Once the cells accepted the Bt
genes, plants were regenerated from
these cultures.
"The issue now is to garner
support to assess the plants against
insects. The bottom line is an insect
bioassay. It's no good to have a pro-
tein expressed if the insects can eat it
for breakfast," maintains Crosby.
The field trials of the modified
canola plants will be carried out at the
Agriculture Canada Research Station
in Saskatoon by Dr. Martin
Earlandson, who says that questions
such as whether Bt genes will be
expressed only in the leaves or
whether root expression may be
effective against cutworms are
premature. All they want now is to
see if "levels of expression are high
enough to cause mortality or feeding
suppression," and hope to be testing
plants some time this summer.
This is the point at which all
sorts of difficulties start to enter the
picture. Apart from the basic scien-
tific questions about how effective
the Bt proteins will be against the
target insects, there are other political
and social problems which will have
to be dealt with before these plants
will ever become a viable crop
variety.
The first of these is finding
enough money to proceed with the
insect bioassays. According to
Crosby, "work could well stop"
because it has been difficult to obtain
funding for the assay part of the
project. He says that there are several
reasons for this, but the most
important one is that new funding
from the government is predicated on
joint funding from industry. However,
as there is "no industrial activity in
Canada for getting genes into plants
for insect protection," it is essentially
impossible to fulfil the criterion of
industrial participation. Without
funding for Earlandson's part of the
project, the existence of a plant with
Bt genes is nearly useless in any
practical sense.
Crosby hopes that because this
is a highly specific and ecologically
safe way of protecting the crop, any
"national funding body with the
national interest at heart" will
eventually come through with the
money.
A second problem revolves
around whether or not the inclusion
of an insecticide in a crop plant will
result in the development of resist-
ance in the pest population. Dr.
Robert Bodnaryk, an insect bio-
chemist at the Agriculture Canada
Winnipeg Research Station wonders
if the widespread exposure of insects
to Bt will not quickly lead to a
resistant strain. With "every bug and
his brother" eating the plants, any
hidden biochemical processes that the
insects might possess for detoxifying
Bt would quickly spread through the
population.
Earlandson says that resistance
is "an important question," especially
since the literature shows that pest
insects are capable of developing
resistant to Bt. However, in the case
of the Diamondback moth, he feels
that the risk of resistance buildup is
less than might be expected, because
the moth is not native to Canada.
Instead, it colonizes us every spring
and summer from the southern U.S.,
which means that the same gene pool
is not being exposed to the plants
every year, diluting any resistance
effects.
With the native Bertha
armyworm, alternative strategies may
need to be used to avoid resistance.
He outlined two alternatives that may
be used in the future. One involves
putting several insecticide genes into
the plants. The possibility of the
insects simultaneously developing
resistance to more than one Bt strain
is much more remote. A second
strategy would involve selective
deployment of the plants to areas of
high risk. Bertha armyworm usually
occurs in patchy outbreaks, and
forecasting methods could predict
which areas may be hardest hit.
Sowing resistant plants in these areas
would minimize the number of insect,
exposed to the Bt, reducing the risk of
resistance. Earlandson points out that
these will be looked at later — the
main thrust right now is to see if the
plants will even work at all.
A third area of potential trouble
lies with the public perception of
genetic recombination. There is a
general unease (that can develop into
outright mistrust and fear) in our
society about releasing genetically
altered organisms into the environ-
ment. There is a sense that they are
unnatural, mutations that will
somehow run rampant once they are
out of the lab. Dr. Crosby is very
much aware of the perception,
carefully choosing the language he
uses to describe the project, and
going out of his way to stress how
non-toxic Bt is to people and how
ecologically sound the idea is.
The final decision on whether
or not the plants can be taken out
of the lab will be made by the
Agriculture Canada regulatory
process concerning genetically altered
organisms. Crosby says that the
permit to do the field trials is cur-
rently being considered by the agency,
and he hopes permission to go ahead
will come through soon. Given the
proven safety record of the Bt proteins
and the fact that similar releases have
already taken place in the U.S. with
tobacco and tomato plants, it is highly
unlikely that the application will be
refused, or that any major public
outcry will result. It is instead the
scientific and practical aspects of this
projects that will probably determine
whether or not farmers will have a Bt
producing plant to add to their arsenal
against insect pests.0
AUGUST 1990 21