GM Rape fails to perform as study reveals erroneous basis for UK fieldscale trials

( the address of this page is www.btinternet.com/~nlpwessex/Documents/gmrapetrials.htm )

17 April 2000

A study recently published in 'Aspects of Applied Biology' [1] has produced some interesting findings in relation to transgenic oilseed rape varieties developed by Aventis, the principal commercial participant in the UK's controversial fieldscale trials for GM crops.

Carried out under the European Commission's FACTT Project (Familiarisation and Acceptance of Crops incorporating Transgenic Technology) [2] the paper examines the agronomic performance of transgenic rape varieties tolerant to the herbicide glufosinate-ammonium ('Liberty') and developed by Plant Genetic Systems, a subsidiary of AgrEvo/Aventis. The study confirms that:

• compared to conventional rape hybrids mean yields from the transgenic varieties were lower.
• compared to conventional rape hybrids yields of the transgenic varieties showed a higher degree of variability.
• the transgenic varieties usually produced reduced financial returns when treated with herbicides compared to when receiving no herbicide treatment at all (any small increases in yield derived from weed control were usually insufficient to cover the extra cost of the herbicide, including glufosinate-ammonium).

It is this latter finding which is perhaps the most extraordinary. Because the authors also refer to much earlier research indicating similar findings in relation to oilseed rape, the study appears to confirm that many farmers may have been applying herbicides to their rape crops unnecessarily for years. This situation would indicate that they would be financially better off applying no herbicide at all.

If this conclusion is correct it has important implications for the UK national fieldscale trials for herbicide tolerant transgenic oilseed rape. It means that looking at comparisons of biodiversity impact between glufosinate-ammonium and conventional spray regimes is the wrong test. The correct test would be to compare biodiversity impact between glufosinate-ammonium and 'no-herbicide' spray regimes. It is unlikely that glufosinate-ammonium would provide equal biodiversity in such a test.

The following additional observations in relation to the study may be helpful:

• The field trials detailed here were carried out in the UK over two seasons at four sites involving both winter and spring oilseed rape (although results from the latter appear not to be included)
• The non-herbicide tolerant varieties were selected from the HGCA funded Recommended Lists
• The herbicide trials on the transgenic varieties included:
  
  i) Conventional herbicides using either soil residual (metazachlor) or contact (benazolin/clopyralid/cycloxydim) herbicides
  ii) A herbicide programme (unspecified) based on glufosinate-ammonium
  iii) Untreated controls

• When tested in 1998 on transgenic varieties metazachlor gave on average the 'most consistent' margin over herbicide costs of minus £13.50 per hectare (i.e the farmer would still be £13.50 per hectare worse off than if he had not sprayed any herbicide at all).
• The mean margin over herbicide for glufosinate-ammonium treatments in 1998 was "just under £1/ha worse than metazachlor", the current industry standard residual herbicide (note: this figure seems to conflict slightly with a related one given elsewhere in the study - see below).
• Meaned across variety and site, glufosinate-ammonium gave a negative margin over herbicide response of minus £16/ha for 1997 and minus £13/ha for 1998 (with the exception of metazachlor in 1998 the other herbicides produced considerably worse responses).
• all of the other herbicide treatments tested were ones which are currently applied to UK winter oilseed rape. These gave negative margins over herbicide ranging from minus £13/ha to minus £99/ha, "showing that the benefits of weed control in oilseed rape are not consistent".
• No account was taken in the trials when calculating margin over herbicide costs of the extra premium price that is likely to apply to the transgenic seed (this premium is essential if the breeder is to recover the substantial additional cost of developing such varieties).
• Nonetheless the authors conclude that the performance of these transgenic varieties "will need to be greater than that seen in these trials, when compared to open pollinators and conventional hybrids, to offset the likely higher seed cost of the herbicide tolerant crops."
• At several sites even negative yield responses were seen following the application of all the herbicides (i.e including glufosinate-ammonium), and "may have been as a result of transient phytotoxicity of the herbicides to the rape plants" (ie the application of herbicides actually reduced yields, not just financial margins).

Although not strongly emphasised by the authors in their conclusions, the general findings of this paper indicate that it is usually not in farmers' financial interests to apply any of these herbicides to oilseed rape. Except perhaps in situations of abnormal weed infestation farmers would be financially better off spraying no herbicide at all.

The authors do, however, acknowledge that some of the study's findings support "inconsistencies previously reported in the response of oilseed rape to herbicide use". In making this statement they refer to a paper published in 1990. Whilst we have not had an opportunity to review that paper the implication would seem to be that some or many farmers may have been applying herbicides to oilseed rape unnecessarily and without any financial benefit to themselves (in fact probably the opposite) for the last ten years or more.

How could such a situation have come about? There are a number of factors to take into account:

• firstly all these chemicals kill weeds. As far as that goal is concerned the farmer would usually see for himself that the product he had bought was doing its job.
• however, this study indicates that these weed killers can also check the growth of the crop.
• because few, if any, farmers would be adventurous enough to grow their own control crop with no weed killer applied they would not be aware of any inadequate or even negative effect on yield response derived from the use of such herbicides (it seems likely that in the case of negative yield response any positive effect arising from the removal of weed competition is negated by the loss in vigour of the crop as a result of the temporary phytotoxicity of the herbicide treatment). In either case the farmer would be unlikely to be aware that the cost of the herbicide programme is not recovered.
• it is likely that the main people, if any, aware of this situation would be research scientists at the herbicide manufacturers. It would certainly not be in the financial interests of the companies' concerned to emphasise this point to their field advisers or farmer customers (who, as long as the weeds continued to die, would most likely believe they were following an optimum financial route).

If, therefore, this study demonstrates that the best financial option for farmers is usually to apply no herbicide at all to their rape crops then it is the 'no herbicide' scenario which should be used as the principal control in the UK biodiversity fieldscale trials and NOT a comparison against conventional herbicide applications.

It is not apparent that the current biodiversity fieldscale trials are intended to focus on crop yield data collection. Without this data it is not possible to scientifically assess the optimum enviro-economic scenario for weed control in oilseed rape crops - an issue (albeit not the most fundamental) whose resolution lies close to the heart of the current controversy concerning the proposed introduction of transgenic crops in the UK.

Given the economic findings of this particular paper it is questionable whether the UK fieldscale trials on transgenic rape should be going ahead at all.

If, as appears to be already established here, NOT spraying any herbicide on such crops is likely to give both higher biodiversity (weeds are not killed) and higher financial returns to farmers, then these herbicide resistant transgenic varieties serve no useful purpose.

Meanwhile the environmental genetic pollution caused by any continuing fieldscale trials associated with them will have been generated for no gain whatsoever (already the first multiple herbicide-tolerant transgenic gene-flow has been discovered in other UK oilseed rape trials, with the likelihood that this is going to cause significant husbandry problems for farmers).

NATURAL LAW PARTY WESSEX
nlpwessex@bigfoot.com
www.btinternet.com/~nlpwessex

[1]
Aspects of Applied Biology 55, 1999
Production and Protection of Combinable Break Crops

The Familiarisation and Acceptance of Crops incorporating Transgenic Technology (FACTT). 
A summary of UK trials.  
By M R GREEN   ADAS High Mowthorpe, Duggleby, Malton, North Yorkshire, YO17 8BP, UK
and ELAINE J BOOTH   SAC, Craibstone Estate, Bucksburn Aberdeen, AB21 9YA, UK

[2]
FACTT (Familiarisation and Acceptance of Crops incorporating Transgenic Technology) is a body funded by the European Commission and partner organisations in the agricultural sector. Plant Genetic Systems (Belgium), a subsidiary of European biotechnology and agro-chemical company AgrEvo (now Aventis), is the co-ordinator of FACTT.   FACTT has a total budget of 3.6 ECU of which 1.6 million is provided by the Commission.

Partners in the UK are SAC, ADAS, Arable Research Centres (ARC) and the National Institute of Agricultural Botany (NIAB). The Home Grown Cereals Authority (HGCA) provides co-ordination of the UK programme.

FACTT can be contacted in the UK through Dr Paul Meakin, Home Grown Cereals Authority, 020 520 3975 or email paul.meakin@hgca.com who is also able to provide a copy of the paper.

GM rape heading for agronomic scrap heap? - May 2001

Fundamental scientific conceptual errors in the development of recombinant DNA technology

For more information from the FACTT project on transgenic oilseed varieties click here

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Why millions of acres of underperforming GM crops are being grown in the USA

Return to NLP Wessex GM page