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2-Plants: UK report on GMO research

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TITLE:  Genetically Modified Organisms Research
SOURCE: Department for Environment Food and Rural Affairs, UK
DATE:   Dec 24, 2002

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Genetically Modified Organisms Research


The report represents the combined final reports of two separate Defra 
monitoring contracts run between 1994-1997 and 1997-2000. See also ACRE's 
Advice on this publication [see below].

* A summary of the final report is available below.
* The full report is available for downloading and printing as follows:
* low-quality version intended for reading on-screen (880kb)
* high-quality version intended for printing (4.5MB)



In 1994 the National Institute of Agricultural Botany (NIAB) and the 
Laboratory of the Government Chemist (LGC) were commissioned by the 
Department of the Environment, Transport and the Regions (DETR) to monitor 
the first agricultural releases of genetically modified (GM) oilseed rape 
(OSR) for a three year period. Subsequently NIAB received a second contract 
in 1997 to continue monitoring releases of GM OSR including all the 
previously studied sites and any new sites over 1ha. The contracts also 
required NIAB to conduct studies of monitoring methods and of the flow of 
transgenes to crops and wild relatives. The monitoring terminated at the 
end of 2000.

The first crops monitored were seed production crops sown in spring 1995 
and 1996. Two 5ha areas of GM winter OSR sown in the autumns of 1995 and 
1996, were also monitored. The seed production crops monitored were for the 
production of the Plant Genetics System (PGS) GM hybrid oilseed rape and 
consisted of a GM male-sterile female parent line, interplanted with a 
pollinator containing a male fertility restorer gene, and both lines 
containing the Bar marker transgene conferring tolerance to the herbicide 
glufosinate-ammonium. The winter rape areas were PGS trials containing a 
mixture of GM and non-GM parent lines and hybrids. The transformations were 
similar to those in the spring rape.

>From 1997 several new sites containing trials or crops of glufosinate (Bar 
and Pat genes) and glyphosate tolerant transgenic varieties were monitored. 
In 1998, several sites growing a high laurate transgenic spring OSR variety 
were included in the monitoring study. In 1999 the monitoring included the 
two first Farm Scale Evaluation (FSE) trials of GM OSR and provided an 
opportunity to study gene flow between two large adjacent blocks of spring 
OSR at these sites. By the year 2000, a total of 11 sites that had grown GM 
OSR were being monitored. All sites continued to be monitored in the years 
following the GM OSR crop or trial until the end of 2000.

The monitoring programme studied the characteristics of herbicide-tolerant 
transgenic rape which were most likely to effect the crop, the cultivated 
and the non-cultivated environment. These characteristics were assumed to 
be the same as those of non-transgenic rape, namely dispersal into and 
colonisation of these environments and gene flow into other crops, feral 
populations and wild crucifers. The following factors were studied and 
comparisons made between the behaviour of transgenic OSR and conventional 
OSR where possible.

Intra-specific gene flow

Gene flow was monitored from GM OSR crops to adjacent crops, OSR volunteers 
and feral rape populations.

No intra-specific gene flow was detected at any of the sites monitored 
between 1994 and 1997. During this time none of the GM release sites were 
near to other synchronously flowering oilseed rape crops. No gene flow was 
detected to OSR volunteers and feral OSR growing near the GM releases 
monitored at any of the sites during this period.

In the period 1998 to 2000 gene flow was detected from GM trials into 
adjacent OSR crops. At one of the FSE sites gene flow decreased rapidly 
with distance from the pollen source. However at both FSE sites, levels of 
herbicide-tolerance in excess of 0.5% were found in some samples taken at 
100m from the source while at one FSE site levels of herbicide-tolerance in 
excess of 0.5% were found in some samples taken at 200m, though the overall 
trend was for gene flow to decrease with distance. These could have 
resulted from several factors including, adventitious GM material in the 
original seed batch of Hyola 401, the possible presence of male-sterile 
individuals, weather conditions or a combination of these and other unknown 

Gene flow was also measured from 2 GM trials into adjacent fields of OSR in 
2000. Gene flow levels were found to be substantially higher into a 
varietal association than a conventional variety, due to the male sterile 
component of these systems. Levels up to 3.2% herbicide tolerance were 
found at the edge of one field of the varietal association Gemini, at 105m 
distance from a small block of transgenic herbicide tolerant OSR. By 
contrast when a transgenic herbicide tolerant trial pollinated a 
neighbouring conventional crop of the variety Apex, at a different site, 
maximum levels of outcrossing at 100m were 0.2%. However at most sampling 
points less than 0.1% herbicide tolerance was found 70m from the pollen 

Inter-specific gene flow

Gene flow was monitored between GM OSR and related cruciferous species. In 
the first three years of the contract (1994 to 1997) a wider range of 
crucifers was monitored including Capsella bursa-pastoris (shepherd's 
purse) and Sisymbrium officinale (hedge mustard). When the contract was 
renewed in 1997 it was considered that resources should be concentrated on 
species considered to be important candidates for hybridisation with OSR. 
The species that continued to be monitored were Brassica rapa (wild 
turnip), Raphanus raphanistrum (wild radish), Sinapis arvensis (charlock) 
and Sinapis alba (white mustard).

No gene flow was detected from OSR into the related species examined in 
this study during the period 1994 to 1997. Between 1997 and 2000 
hybridisation was detected with B.rapa. One site was examined where weedy 
B.rapa occurred in an agricultural field. Hybridisation frequencies varied 
between plants and were between 0.0% and 48.5%. When seeds were germinated 
from hybrid mother plants, some evidence of backcrossing in the direction 
of both parents (B.napus and B.rapa) was also found. Backcrossing to 
B.napus plants was identified by their ploidy level, however back-crossing 
to B.rapa plants could not always be determined by their ploidy level as in 
many cases this was the same as or very similar to the ploidy level of 
B.rapa. The co-existence of the B rapa populations with B napus crops and 
the numbers of hybrids found, suggested that gene flow has been occurring 
for some time between these populations.

Seed dispersal

Seed dispersal was usually associated with spillage and distribution by 
agricultural machinery, particularly combine harvesters. In the contract 
from 1994 to 1997, it was found that some combine harvesters were not 
cleaned after the harvesting of the GM crop, and the crop harvested 
subsequently flushed out the GM rape seed onto the ground causing 
contamination of this field .

GM OSR volunteers found in fields were generally controlled in the same way 
as conventional volunteers. Outside the cultivated area establishment and 
survival of seedlings was very poor, and few feral transgenic OSR plants 
survived to maturity.

Persistence of transgenic OSR volunteers

The persistence of transgenic OSR volunteers was compared to existing data 
and observations of non-transgenic volunteers. The numbers of GM OSR winter 
and spring volunteers were generally low in subsequent crops. The presence 
of a herbicide-tolerance transgene or high laurate transgene did not appear 
to increase the weediness or persistence of volunteer OSR in this study.

Feral Oilseed Rape

Only one feral OSR population was found to persist for more than one year 
at any of the sites being monitored. The herbicide-tolerance Bar gene was 
not detected in any of the feral OSR plants so that effects on weediness 
and persistence of these populations could not be assessed.

Development of optimal methodology for monitoring

A practical, effective and economical combination of monitoring methodology 
was developed to cover all the above aspects of monitoring. This included 
familiarity with the species and sites involved, combined with phenotypic 
and genotypic testing for the presence of the transgene. The combination of 
methods used ensured that any major impacts of the GM plants on the 
agricultural and local environment occurring at each site were likely to be 


The high levels of isolation from other OSR crops flowering synchronously, 
and the relatively small GM pollen sources and low levels of cruciferous 
weeds present at the sites, limited potential gene flow at the sites 
monitored in the first 3-year contract (1994 to 1997). Larger trials or 
crops released during the second 3-year contract (1998 to 2000) and the 
closer proximity of pollen receptive crops and related wild species allowed 
greater opportunities for gene flow to be studied. The results from these 
larger trials and crops indicate that commercial scale releases of GM OSR 
in the future could pollinate other crops and B.rapa, the levels of cross 
pollination depending on the environmental, varietal and agronomic factors 
prevailing at the time. There may be a need to review isolation 
requirements in keeping with current legislation on contamination 
thresholds in crops, in light of this research. Page published 24 December 
2002; last modified 30 December, 2002


ACRE - Advisory Committee on Releases to the Environment  

ACRE Advice

Monitoring large scale releases of genetically modified crops (EPG 1/5/84). 
Incorporating report on project EPG 1/5/30: monitoring releases of 
genetically modified crop plants
Advice of the Advisory Committee on Releases to the Environment
under Section 124 of the Environmental Protection Act 1990

ACRE was asked to review the final report of the monitoring of large scale 
releases of GM oil seed rape grown between 1994 and 2000. The report 
represents the combined final reports of two separate DEFRA monitoring 
contracts run between 1994-1997 and 1997-2000. The final report is 
available at

The report considers inter- and intra-specific gene flow by means of cross 
pollination and also seed dispersal and the persistence of volunteers. The 
research reported was not deliberately designed to investigate gene flow 
but took advantage of the results from a programme of monitoring of a 
series of approved releases of OSR between 1994 and 2000. Monitoring was 
undertaken at 11 field-scale experimental release sites in total.

The report is divided into several sections including details of methods 
and sites used, gene flow between crops, gene flow between species - 
including a specific study of gene flow to weedy Brassica rapa, feral and 
volunteer rape and conclusions.

The main findings of the report include:

Gene flow between GM and adjacent conventional oil seed rape crops

The occurrence of cross pollination decreased rapidly over a distance of a 
few metres but was detected at a levels of 0.5% at 250m at one site. Higher 
levels of out crossing were detected when the GM crops was grown near a 
varietal association crop. The report concludes that "the results presented 
show different situations can give very different results under natural 
field conditions".

Feral and Volunteer oilseed rape

The incidence of transgenic volunteers at sites was monitored for several 
(up to five) years. The number of volunteers that were detected was 
variable. In one incidence transgenic oil seed rape volunteers persisted 
until 2000 at least from a crop harvested in 1996. GM volunteers appear no 
more persistent than non-GM volunteers. A low level of gene flow was 
detected from GM oil seed rape to feral rape growing nearby (up to 20m). 
The report concludes that transgenes can persist in volunteers and feral 
populations but the level of occurrence is low and the transgenes did not 
appear to persist.

Interspecific gene flow

Gene flow between GM oil seed rape and Brassica rapa was detected at a site 
where a small amount of B. rapa was deliberately sown alongside a GM crop, 
and at another site where GM oil seed rape was sown in an area where weedy 
B. rapa was a known problem. The report concludes that where B. rapa and 
oil seed rape (B. napus) are grown together, gene flow will occur. Cross-
pollination between oil seed rape and other wild relatives was not detected.

ACRE's advice

ACRE considered the results of the monitoring carefully. ACRE's risk 
assessment of GM oil seed rape has always assumed some gene-flow will occur 
and that this does not in itself constitute a risk to human health or the 
environment. It was concluded that the extent of gene flow observed in the 
monitoring between GM oil seed rape and adjacent crops, feral oil seed rape 
and wild relatives was entirely within expectations. The persistence of GM 
volunteers and feral oil seed rape plants were also entirely within 

ACRE members were content that the results of the monitoring were 
consistent with the existing risk assessment and no further action was 
necessary. ACRE welcomed the immediate publication of the monitoring report.


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