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Date:

June 18, 2002

Subject:

Biotech Crops Reducing Pesticide Use, Anti-GM Groups Losing Europe, Cancer Fighting Tomato, Potatoes, Scary Organic Food, Labeling

 

Today in AgBioView: June 19, 2002:

* Biotech aids area farming
* ANTI-GMO GROUPS LOSING EUROPEAN STRONGHOLD
* BIOTECH CROPS REDUCING PESTICIDE USE IN THE U.S. BY
MILLIONS OF POUNDS
* Tomato packs more cancer-fighting punch print
* Deconstructing potatoes
* Safety Scare Challenges Organic Food
* Re: Labeling
* FAO Web site Article
* Destiny of a transgene escape

http://www.washtimes.com/business/20020618-94494869.htm

Biotech aids area farming

THE WASHINGTON TIMES
By Tom Ramstack
June 18, 2002

Farmers in Maryland and Virginia earned at least an additional
$17.3
million last year by growing the bioengineered crops used to stock
the
shelves of grocery stores in the Washington area and elsewhere,
according
to a group that studies food policy.

The earnings resulted from greater crop production and reduced
expenses,
according to the National Center for Food and Agricultural Policy, a
Washington-based nonprofit research organization.

Maryland farmers, for example, reduced expenses by using
282,000 fewer
pounds of insecticides and herbicides. Their bioengineered crops
resist
insects and weeds without adding chemicals to them, the group
said.

In Virginia, herbicide use rose by 158,000 pounds as farmers tried
to
eradicate weeds common to their state. Without bioengineering,
the crops
would die along with the weeds.

However, production increased because new strains of
bioengineered
soybeans and cotton can survive the weedkillers and still produce
a cash
crop.

Maryland also has weeds, but they are less of a threat to the
state's corn
and soybeans.

"They have different weed problems," said Leonard Gianessi, a
senior
researcher for the food research center.

The center's figures on crop yields, revenue and herbicide use
were taken
from surveys of state agricultural extension services.

Maryland's crop commodities increased by 38.9 million pounds in
2001,
mostly because of a pest-resistant bioengineered corn called BT
corn, the
center reported. Bioengineering increased Virginia's crop yield by
3.5
million pounds, mostly for corn and cotton.

BT corn exudes a toxin that can kill the corn borer, a pest that has
devastated crops in Maryland and Pennsylvania, but is less of a
problem in
Virginia.

The increased production found in the Washington area reflects
the same
trend nationwide, where U.S. farmers earned an additional $1.5
billion
from bioengineered crops, the center reported during a
biotechnology
conference in Toronto last week.

State Agriculture Department officials in Maryland and Virginia said
they
did not keep similar records to verify the food research center's
figures.

However, the U.S. Department of Agriculture's National Agricultural
Statistics Service has recorded a steady upswing in farmers using
bioengineered crops.

In 2000, 25 percent of all corn crops planted nationwide were
bioengineered. A year later, 26 percent were bioengineered.

For soybeans, 54 percent were bioengineered in 2000; 68 percent
were one
year later.
+++++++++++++++++++++++++++++++++++++++

ANTI-GMO GROUPS LOSING EUROPEAN STRONGHOLD

The Philippine Star (Via Agnet)
June 16, 2002

LONDON - According to this story, the traditional bulwark of
anti-genetically modified organism (GMO) advocates appear to be
slipping
as Europe opened its doors to a major biotechnology research in
the United
Kingdom (UK), and as a major European food company stood its
ground
against a Europe-based international pressure group. UK Prime
Minister
Tony Blair recently backed GM food trials in Cambridge, defying
protests
launched by groups, which branded GM crops as "Frankenstein
food."

Blair pledged "to defend science against these misguided groups"
and that
these groups "will not be allowed to stand in the way of legitimate
breakthroughs."

Blair was reportedly furious at attempts made by pressure groups
to
disrupt the GM food trials. "It is completely unacceptable for people
to
try and disrupt legitimate research," Blair said.

In a related development, giant global food manufacturer Nestle
lashed out
at international pressure group Greenpeace after the latter
demanded that
Nestle, a Switzerland-based firm, stop using GM ingredients in its
food
products due to alleged health and environmental concerns.

Nestle blasted Greenpeace for its failure to come up with clear
proof that
food ingredients derived from genetically modified crops are
unsafe for
human consumption. Nestle also criticized the pressure group "for
refusing
to accept the opinion shared by international scientific bodies
worldwide
that GM crops are as safe as their conventional counterparts."

Greenpeace also came under fire from leading food
manufacturers in the
Philippines after it demanded that the companies buy their raw
materials
from Greenpeace1s list of suppliers. The Philippine companies
said the
Greenpeace proposal is more expensive and does not guarantee
availability
and consistency in the supply of raw materials.

Filipino scientists also criticized what they labeled as "scare
campaign
against GMOs."
+++++++++++++++++++++++++++++++++++++++++++

NEW STUDY DEMONSTRATES ROLE OF PLANT
BIOTECHNOLOGY IN PESTICIDE REDUCTION:
BIOTECH CROPS REDUCING PESTICIDE USE IN THE U.S. BY
MILLIONS OF POUNDS
ANNUALLY

June 18, 2002
>From a press release

ST. LOUIS -- A new study released by the National Center for Food
and
Agricultural Policy (NCFAP) shows that crops enhanced through
plant
biotechnology have resulted in a significant reduction in the use of
pesticides on American farms.

According to the study, the eight biotech crop varieties currently
grown
in the U.S. reduced pesticide use by 46 million pounds in 2001. An
analysis of 32 other biotech crop varieties still under development
indicates that, if planted, they would reduce pesticide use by 117
million
pounds per year, bringing total pesticide reduction for all biotech
crops
to 163 million pounds annually.

"This is the most comprehensive study to date and this data
clearly
demonstrates that plant biotechnology is producing a significant
reduction
in the use of pesticides on American farms," said Harvey Glick,
director
of Global Product Stewardship at Monsanto Company (NYSE:
MON). Dr. Glick
holds a Ph.D. in crop physiology and agronomy.

"We believe pesticide reduction is important because it benefits
the
environment by reducing consumption of resources, which
enhances the
sustainability of agricultural production," said Glick. "Growers need
to
use a variety of pesticides -- herbicides, insecticides and
fungicides --
to protect their crops from weeds, insects and disease that would
otherwise damage the health and yield of their crops.
Biotechnology
offers new tools to help growers meet these needs.

Monsanto is proud to be a leading provider of the crop traits that
enable
this more sustainable method of farming." The study, "Plant
Biotechnology:
Current and Potential Impact for Improving Pest Management in
U.S.
Agriculture," was released at the Biotechnology Information
Organization
(BIO) 2002 conference in Toronto, Canada. The NCFAP study is a
wide-reaching assessment of the economic and environmental
impact of
biotech crops, including a significant reduction in the use of
pesticides
on food and fiber crops.

The greatest pesticide reduction in 2001 was calculated for
herbicide-
tolerant soybeans (28.7 million pounds) and herbicide-tolerant
cotton (6.2
million pounds). Other totals for pesticide reductions for crops
currently grown in the U.S. include herbicide-tolerant corn (5.8
million
pounds), insect-resistant corn (2.6 million pounds),
insect-resistant
cotton (1.9 million pounds), and herbicide-tolerant canola (0.5
million
pounds).

"As a farmer, I know that plant biotechnology has helped me
significantly
reduce pesticide sprayings on my own farm," said Larkin Martin, a
cotton
grower in Courtland, Alabama. "Before I started planting Bt cotton
in
1996, I had to spray two to six times, depending on the season, in
order
to control worm pests. Today we average spraying less than once
per
season to control those pests. In some fields we do not spray at
all,"
she said.

"I have experienced first-hand how biotech crops are helping the
environment." Among the NCFAP study's estimates for the other
biotech crop
varieties still under development, field corn resistant to rootworm
offers
some of the greatest potential. It could replace 14 million pounds
of
insecticides used on this crop each year.

"Biotech crops are responsible for a significant and sustained
reduction
in pesticide sprayings. This reduction is better for the environment
and
better for our communities," said Glick. "We commend the authors
on this
thorough study that adds to the large number of independent
studies that
document the benefits of our products and technology."

The NCFAP study was supported initially by the Rockefeller
Foundation,
with additional grants to expand the study from Monsanto, BIO,
CropLife
America, Council for Biotechnology Information, and the Grocery
Manufacturers of America.

The complete report is available at www.ncfap.org.
+++++++++++++++++++++++++++++++++++

Tomato packs more cancer-fighting punch print

Purdue University
June 17, 2002
By Steve Tally
(765) 494-9809
tally@purdue.edu

WEST LAFAYETTE, Ind. Forget the attack of the killer tomato, this
is the
attack of the healthy tomato: A team of scientists has developed a
tomato
that contains as much as three and a half time more of the
cancer-fighting
antioxidant lycopene. It turns out that the antioxidant-rich tomato
was a
happy accident.

Scientists at Purdue University and the U.S. Department of
Agriculture's
Agricultural Research Service were working to develop tomatoes
for food
processing that were of higher quality and would ripen later.

They accomplished that, but in the process they discovered that
the new
tomatoes also had significantly more of the antioxidant than
conventional
tomatoes.

"We were quite pleasantly surprised to find the increase in
lycopene,"
says Avtar Handa (pronounced "Honda"), professor of horticulture
at
Purdue.

Although increasing the nutritional value of foods is the goal of
so-called second-generation biotechnology products, there have
been few
success stories.

"This is one of the first examples of increasing the nutritional value
of
food through biotechnology," Handa says. "In fact, it may be the
first
example of using biotechnology to increase the nutritional value of
a
fruit."

Co-discoverer Autar Mattoo, who heads the USDA Vegetable
Laboratory, says
the increase in lycopene occurred naturally in the genetically
modified
tomatoes. "The pattern for the accumulation was the same as in
the control
tomatoes," he says. "The lycopene levels increased two to 3.5
times
compared to the non-engineered tomatoes."

The research was announced this week in the June issue of
Nature
Biotechnology. A separate article on the research in Nature
Biotechnology
noted, "The findings remind us that in the 'rational' and
quantitatively
driven post-genomic era, serendipity still has a large part to play."
A
U.S. patent application has been filed on behalf of the joint owners
USDA
and the Purdue Research Foundation. The Consortium for Plant
Biotechnology
Research Inc., a USDA funded program, funded the research.
Lycopene is a
pigment that gives tomatoes their characteristic red color. It is one
of
hundreds of carotenoids that color fruits and vegetables red,
orange or
yellow. Of these pigments, the most familiar is the beta-carotene,
which
is found in carrots. In the body these pigments capture electrically
charged oxygen molecules that can damage tissue. Because of
this they are
called antioxidants. Lycopene has been the focus of much
attention since
1995, when a six-year study of nearly 48,000 men by Harvard
University
found that men who ate at least 10 servings of foods per week
containing
tomato sauce or tomatoes were 45 percent less likely to develop
prostate
cancer. The study also found that those who ate four to seven
servings per
week were 20 percent less likely to develop the cancer.

That research was published in the Journal of the National Cancer
Institute.

Subsequent research has found that lycopene also reduces the
amount of
oxidized low-density lipoprotein the so-called bad cholesterol
and
therefore may reduce the risk of heart disease.

As an antioxidant, lycopene is able to capture twice as many
oxygen ions
in the body as is beta-carotene.

"This characteristic may be responsible for lycopene's ability to
mitigate
epithelial cancers, such as breast cancer and prostate cancer,
and for its
ability to mitigate coronary artery disease," Mattoo says.

Despite the apparent benefits, it's been difficult to increase the
amount
of lycopene in the diet, says Randy Woodson, director of
Agricultural
Research Programs at Purdue.

Studies have found that taking purified antioxidants as a dietary
supplement doesn't work. In fact, one study found that giving
beta-carotene to smokers actually increased their chances of
developing
cancer.

"When you just take lycopene as a drug it doesn't have the same
effect,"
Woodson says. "There is still a lot of biology to understand before
we
know why phytonutrients in food are so much more effective than if
they
are given as supplements."

Another wrinkle is that when it comes to lycopene in tomatoes,
cooked
tomato sauces are more effective than raw tomatoes.

This may be because cooking breaks the cell walls of the tomato,
releasing
more of the lycopene. Or it may be that cooking oil allows the
lycopene to
move more easily into the body.

To develop the lycopene-rich tomato, the researchers inserted a
gene,
derived from yeast, fused to a promoter gene into tomato plants.
The
promoter gene helps turn on the yeast gene in the tomato.

"The promoter gene is like a ZIP code that tells the yeast gene
when and
where to turn on in tomato," Handa says. "For high-lycopene
tomatoes we
used a promoter that targeted expression of the introduced gene
in fruits
only."

The yeast gene itself produces an enzyme that affected the
production of
growth substances in the plants called polyamines, which are
known to help
prevent cell death.

In plant cells, polyamines help build new, beneficial compounds.

"They may stabilize membrane networks that involve longevity of
physical
structures in the cells called chromoplasts," Mattoo says.
"Because
lycopene accumulates in chromoplasts in the tomato fruit cells, in
this
case the polyamines seem to have a positive effect." The
polyamines share
a precursor with a plant hormone called ethylene that causes
ripening in
many fruits.

The researchers thought that because ripening was delayed there
must have
been a decrease in ethylene, but found the opposite was true.

"That's not how we started out thinking, but that's why we do
experiments," Mattoo says. "Now we know the change i.e.,
allowing the
accumulation of polyamines in the fruit doesn't necessarily affect
ethylene production, but ethylene action. We think the polyamines
has
changed the ethylene receptors on the cell membranes, but we
are looking
into that."

Handa says the technique used in this research might also be
used to
increase the amount of other antioxidants in foods.

"We are excited about this approach, not only because it results in
an
increase in lycopene in tomato, but because we think this
approach could
be used to increase the phytonutrient content of other fruits and
vegetables," he says.
++++++++++++++++++++++++++++++++++++

Deconstructing potatoes

Asia Intelligence Wire
By Seth Robson
June 18, 2002

Christchurch scientist Margaret Gilpin has bounced back from an
attack on
her research by anti-genetic engineering (GE) protesters, winning
a
prestigious award and heading to Florida to present her findings
to the
world's top biotechnologists.

Dr Gilpin's technique may be used one day to improve potatoes'
appearance,
nutrition, shape or quality.

There had been warnings an attack would happen. Activists,
unwilling to
accept the decision of last year's Royal Commission of Inquiry into
Genetic Modification, threatened to destroy GE crops and that is
exactly
what they did, breaking into a greenhouse at Crop and Food,
Lincoln in
January and uprooting hundreds of GE potato plants.

The irony was the plants were only used in the experiments
because they
were easy to dye. The research aimed to produce non-GE
chimeric potatoes,
ideal for growing on the organic farms championed by the
activists.

For Christchurch scientist Margaret Gilpin, who discovered the
technique
used to grow the potatoes, the attack was the biggest setback of
her short
career. The loss of the potatoes was devastating for the young
scientist,
who had recently been chosen to present her findings to the
prestigious
International Association of Plant tissue Culture and Biotechnology
Congress in Florida.

In a field where scientists world- wide are racing to keep up with
the
state-of-the-art any setback can be a killer. However, the
good-natured
mother of two has taken it in her stride and will present the results
she
has obtained so far at the conference later this month.

Last week her work received another honour when she was
awarded the FiRST
(Foundation for Research Science and Technology) South Island
scholarship.
This week she travels to Auckland to compete for the national
FiRST award
and the following week heads to Florida to present her work.

So what is it, exactly, that Dr Gilpin has discovered?

In biology a chimaera is an organism consisting of at least two
genetically different kinds of tissue.

Many old potato cultivars -- such as russet burbank and red king
edward --
are natural chimaeras and arose spontaneously as mutants.
Royal gala
apples are another natural chimaera.

The long, thin shape of russet burbanks, which are used by
McDonald's
restaurants, makes them ideal for french fries, while their rough
skin
provides good protection against disease. Dr Gilpin has found a
way to
make chimaeras deliberately.

In the past three years she has been working to create a potato
with the
skin of the purple urenika potato and the white flesh of the iwa. The
iwas
she uses have been genetically modified to have a marker gene
that shows
blue when dyed, allowing her to track her progress.

Dr Gilpin's technique may be used one day to improve
potatoes' appearance, nutrition, shape or quality.

The 31-year-old mother is at home in the laboratory or the kitchen.
She
was born in Holland to Indonesian parents and says rice is more
common
than potatoes on her table. She has had to juggle her research
with
looking after her children, Zoe, two, and Isaac, three. The science
suffers, the kids don't.

Her work has been influenced by other scientists at Crop and
Food,
especially her mentor, Tony Connor, who also had research
damaged in the
activists' raid.

My scientific heroes would be the people I work with, like Tony,
who have
been in the field for a long time and teach me things, she says.

Dr Connor believes his protege has potential to become one of
New
Zealand's great scientists, following in the footsteps of Nobel Prize
winners Ernest Rutherford and Alan MacDiarmid.

In any scientist there is that spark that might bring about an
amazing
discovery. I would hope anyone would have those successes in
their career
and hopefully Margy does, Dr Connor says.

Dr Connor says some aspects of Dr Gilpin's work are extremely
innovative
but have not been disclosed in order to protect intellectual property
rights.

In time it will be a technology that will be applied to industry. It is an
alternative approach to crop improvement that doesn't necessarily
involve
breeding or GE.

Despite the commercial potential of the work, Dr Connor finds it
laughable
when activists claim scientists like Dr Gilpin are only interested in
profit.

"If that were the case she'd be out there working for the big multi-
nationals, not working for the public good of New Zealand.

The most exciting thing is that we had this germ of an idea three to
four
years ago and it actually works. The exciting thing is how easy it is
to
do it.

Ms Gilpin says the next phase of her research will be the most
exciting.

Now we have the model system sorted out we are going to test
different
combinations of potatoes. We will be able to grow almost
unlimited
combinations of new potatoes mixing the good characteristics of
existing
and future cultivars ... and once you have done potatoes you can
apply it
to other crops. It is going to be huge.
+++++++++++++++++++++++++++++++++++++++++

http://www.futuresource.com/news/news.asp?story=i4262946255
677096000

Safety Scare Challenges Organic Food

Future Source
By Michael J. Strauss, Senior Editor-At-Large
June 18, 2002

London, June 18 (OsterDowJones) - Food safety concerns in
various parts of
the world have lured many people toward organic food, but a
scandal over
potentially dangerous organic food in Germany may change that -
with
implications for grain and poultry markets.

The scandal involves the use of animal feed made from wheat
contaminated
with a banned cancer-causing herbicide called Nitrofen. Nobody
yet knows
how the herbicide got into the wheat, but the tainted feed made its
way
from a distributor in eastern Germany to dozens of organic poultry
farms
that supply chickens and eggs to organic food retailers throughout
the
country.

Germany has been unusually dynamic in steering the farming
industry toward
more organic production. With an agriculture minister from the
Greens
party leading the drive, the government wants to make 20% of
German farm
output organic in the next decade. The scandal may wreck this
momentum if
it blunts the trend of rising demand for organic food.

It's too early to know just how consumers will react, making things
uncertain for the agricultural markets until the public response
becomes
clear.

What is known is that each new food safety alert can have major
effects on
agricultural markets as people respond, often strongly, by
changing their
buying habits. The most dramatic recent example involved bovine
spongiform
encephalopathy, or mad cow disease, a crisis that caused
European Union
beef demand to fall an estimated 10% last year. According to a
USDA
report, "the European BSE crisis gave a big push to the demand
for organic
foods."

A recent French survey showed that despite premium prices for
organic
food, demand accelerated during the recent economic slowdown
as the BSE
crisis and other food safety issues were still major concerns.

Many people feel positive toward organic food because it is
generally
produced on a smaller scale than non-organic food, and they
perceive it as
healthier to eat and less prone to the kind of safety problems that
would
periodically generate health concerns about non-organic products.

Some researchers have argued these perceptions aren't entirely
accurate,
but organic food has never been ensnared in food safety scandals
until now
and this has helped reinforce the public's favorable view of it.

In short, organic food has become a food of refuge for many
people
concerned with food safety - just as some investors buy gold in
times of
political turmoil.

So the German scandal could be a turning point. No doubt many
eyes will be
on the consumer reaction and its impact, and this impact could
grow as
there are more developments in the scandal. One new twist is that
the
tainted wheat may have come into contact with wheat sold for other
organic
products - and not just in Germany. A French organic flour miller
has said
six metric tons of wheat it bought from the same German supplier
may have
been affected by the herbicide.

So far, German authorities have convinced the European Union
they are
taking all the right steps to contain the problem, and this has
staved off
a feared E.U. ban on exports of German organic food.

Whether that's positive or negative for organic food demand
remains to be
seen, since past food safety crises have shown that decisions on
whether
or how to respond can sway consumer behavior in unpredictable
ways.

A ban can be seen as limiting the problem, so people may feel
that organic
food that is still sold is safe. But a ban can also be seen as official
confirmation that organic food is subject to safety problems just
like
non-organic food, which would remove a factor behind its growing
sales.
Taking no action might leave the public uncertain about whether
the
problem is being adequately addressed.

If consumers who buy organic food do start wavering, new
questions arise.
Will there be new foods of refuge? For how long? And in how
narrow or
broad a geographic area? The answers may be clues to which
agricultural
markets will gain and which will lose as the German scandal
continues to
play itself out.
---
Michael J. Strauss, OsterDowJones Commodity News, 44 20
7979 5767
mstrauss@osterdowjones.com
+++++++++++++++++++++++++++++++++++++

From: vkonaje@zuari.co.in
Date: Mon, 17 Jun 2002 09:28:29 +0530
Subject: Re: Labeling

Hi all,

I agree with Sam Johnston. I believe the consumers should
ultimately have
the right to decide what is good for them.....and as far as the pro
and
anti-biotech groups are concerned, I believe both parties should
take a
more responsible line when approaching the issue.

What I mean to say is that, when it comes to
pharmaceuticals/biotech
drugs, most of these groups will like to see the customers do the
talking.
Curiously, the "for and against" confusion does not seem to exist
there,
even though the basic issues remain the same. Has anybody out
there
thought why people don't mind injecting themselves with biotech
drugs but
why they are so finicky when it comes to GM foods? I believe part of
the
fault lies with the ag-biotech industry itself, since it has failed to
de-mystify ag-biotech and clearly communicate this to the
consumers,
giving rise to irrational fears. Remember that it is the consumers'
preferences which ultimately shape the policies adopted by the
government.

There is another point that has to be noted. In case of biotech in
drugs,
the big pharma companies seem to have accepted biotech as the
way
forwardto better finding better solutions to health problems,
whereas in
ag-biotech there may be some contention between the agro-chem
companies
and the ag-biotech companies. When viewpoints in the area
converge (which
I am sure it will ultimately), I'm sure ag-biotech will be on firmer
ground.

Vinay

Disclaimer:- please note that all views expressed by me either in
this
mail or any previous mail does not constitute views of any
organisation/company. The views expressed here are solely mine.
++++++++++++++++++++++++++++++++++++++

Subject: FAO Web site Article
From: Don.Ferguson@fas.usda.gov
Date: Tue, 18 Jun 2002 12:21:11 -0400

You may wish to either flag or perhaps reproduce from the --
www.fao.org
--- web site; a focus on the issues piece entitled "A Harvest of
Silence".

(article found at

http://www.fao.org/worldfoodsummit/english/newsroom/focus/focu
s7.htm)

And to quote: "Efforts ot boost the economy of one of
Guatamalla's
poorest regions through cash cropping threateens the culture and
genetic
diversity of the Maya".

Perhaps your readers would like to comment.
+++++++++++++++++++++++++++++++++++++++

From: "Lu changming"
Subject: Destiny of a transgene escape
Date: Thu, 20 Jun 2002 00:06:20 +0900

Theoretical and Applied Genetics
Online First (2002)
DOI 10.1007/s00122-001-0856-2
Springer-Verlag 2002

Destiny of a transgene escape from Brassica napus into Brassica
rapa
C. M. Lu1, M. Kato1, and F. Kakihara1

(1) Laboratory of Plant Breeding, Faculty of Agriculture, Ehime
University, Matsuyama, Japan

Communicated by H.C. Becker

Abstract. Transgenic Brassica napus can be easily crossed with
wild
Brassica rapa. The spread of the transgene to wild species has
aroused the
general concern about its effect on ecological and agricultural
systems.
This paper was designated, by means of population genetics, to
study the
fate of a transgene escape from B. napus to B. rapa. Three
models were
proposed to survey the change in gene frequency during
successive
backcross processes by considering selection pressures against
aneuploids,
against herbicide-susceptible individuals, and by considering A-C
intergenomic recombination and the effect of genetic drift. The
transmission rate of an A-chromosome gene through an individual
to the
next generation was 50%, irrespective of the chromosome
number; while that
of a C-chromosome transgene varied from 8.7% to 39.9%,
depending on the
chromosome number of the individual used in the backcross.
Without
spraying herbicide, the frequency of an A-chromosome gene was
50% in the
BC1 generation, and decreased by 50% with the advance of each
backcross
generation; that of a C-chromosome gene was around 39.9% in
BC1, 7.7% in
BC2, 1.2% in BC3 and 0.1% in the BC4 generation. Under the
selection
pressure against herbicide-susceptible individuals, the frequency
of a
transgene reached a stable value of about 5.5% within six
generations of
successive backcrossings. The effect of genetic drift and
intergenomic
exchange on gene transmission rate was discussed. It is
suggested that the
transgene integrated on a C-chromosome (or better on a
cytoplasm genome)
is safer than that on an A-chromosome. The transgenic cultivars
should be
cultivated rotationally by year(s) with other non-transgenic varieties
in
order to reduce the transfer of the transgene to wild B. rapa
species.

Keywords. Transgenic Brassica napus - Brassica rapa -
Backcross progenies
- Simulation - Ecological risk