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 www.defra.gov.uk/environment/gm/research/epg-1-5-84.htm.
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 expectations.
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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