GMW: GM potatoes - Soil Association briefing

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GMW: GM potatoes - Soil Association briefing

" GM WATCH " <info

Thu, 24 Aug 2006 21:18:29 +0100

 

 

 

 

 

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http://www.gmwatrch.org

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From Gundula Azeez:

 

Dear all,

 

There has been a sudden interest in GM potatoes, with coverage in the

papers and on the news last night about BASF's proposed trials next year

Please find here a briefing of the issues, including the risk of

contamination of non-GM potatoes.

 

In summary:

- potatoes are a staple food, generally considered wholesome. There can

be no market for GM potatoes in the UK. They were rejected by major

food companies in the US in 2002, including McDonalds McCain's, Burger

King and Pringles. This morning, the British Retail Consortium said UK

supermarkets won't be stocking them

- these blight resistant varieties offer little environmental benefit

as only 1,300t of the 12,000t of pesticide applied each year to potatoes

in the UK is fungicides

- any contamination would be serious as it would result in whole

potatoes being GMOs

- the direct risk of GM contamination of normal non-GM food crops via

cross-pollination would be less with GM potatoes than the risk from GM

cereals or oilseed crops, as potatoes are tubers, not seed. But, as

Defra have acknowledged, there is risk of contamination in later years

via

potato 'volunteers'

- a plot-scale study found a very high rate of cross-pollination, with

31% of plants being hybrids 1km from a GM variety. Normal farm-scale

fields would pose a much higher risk of cross-fertilisation.

- moreover, blight resistant varieties like this GM variety pose a much

higher risk of GM contamination, as the flowering heads are likely to

be left much longer

- there are major health concerns with GM pototoes. Two animal feeding

trials, one funded by the UK Government, have found that GM potatoes

cause lesions in the gut of animals

- GM potatoes are completely unnecessary. With cnventional breeding of

existing potato varieties, non-GM blight resistant varieties are

currently being developed and trialled by the organic sector

 

(See attached file: GMbriefing23, Summary risks of GM potatoes.doc)

 

The subject was covered on Channel 4 news yesterday (audience 1

million), with a live interview of myself and Professor Chris Leaver

at Oxford

University. Here is a link to the report and interview.

 

Shortcut to:

http://www.channel4.com/news/special-reports/special-reports-storypage.jsp?id=30\

93

 

I understand that there will be a 60 day public consultation period,

before Defra make their final decision on approving the trials.

 

Regards

Gundula Azeez

 

Policy manager

Soil Association

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Briefing:

Summary of the risks of GM potatoes

 

Below is information on the risks of GM potatoes. This includes a

summary from the report by the National Pollen Research Unit and other

information on the risks of GM contamination of normal non-GM crops.

Also

evidence of health problems.

 

SUMMARY

*there would be no market for GM potatoes in the UK

*the major food retailers rejected GM potatoes in the US in 2002,

including McDonalds, Burger King, McCain's and Pringles. The British

Retail

Consortium has said UK supermarkets won't be stocking GM potatoes.

*given that potatoes are a staple food, consumed fresh, and considered

wholesome, there would be little or no desire to eat them

*any contamination would be much more serious as it would result in

whole potatoes being GMOs, as opposed to some GM presence in a

quantity of

grain

*with potatoes, there is less direct risk of contamination of non-GM

crops via cross-pollination than with GM grain and oilseed crops, as

potatoes are tubers, not seeds

*however, there is still a risk of contamination from cross-pollination

in later years via potato volunteers

*cross-pollination seems to be much greater when the GM and non-GM

varieties are different and when the main pollinator is the pollen

beetle,

which travels far

*a study found the cross-pollination level was 31% at 1km from the GM

crop

*blight resistant GM potato varieties pose much more of a risk of

contamination as the flowering tops are less likely to be removed

*the NPRU has recommended a separation distance of 500m

*there are major health concerns, as two animal feeding trials, one

funded by the UK Government, found GM potatoes cause lesions in the

gut of

animals

 

1. General

Potatoes are a staple food in the UK, and the fourth largest staple

food in the world. Originally from South America, they have been

grown in

the UK for 300 years. Each person eats about 100kg per year,

equivalent to 820 medium-sized potatoes. Potatoes are also used for

industrial

purposes, as a source of starch. The total area of potato production

in the UK was 137,000t in 2005, of which 1,805t were organic (1.3% of

the total area). Many varieties are grown in the UK.

 

2. Scientific evidence on the risks of contamination

The NPRU report on pollen dispersal reviewed the scientific literature

on pollen transfer ( " Pollen dispersal in the crops maize, oil seed

rape, sugar beet and wheat " , by Dr Treu and Prof. Emberlin, January 2000,

commissioned by the Soil Association):

 

*the NPRU recommended a separation distance of 500m (in contrast with

the proposal by Defra in August 2006 of no separation, their

`co-existence' paper)

*potatoes are an annual plant. The commercial crop is produced from

'seed' tubers, not true seeds. There are no sizeable seed producing

areas in the UK.

*potatoes both self- and cross-pollinate. Cross-pollination rates are

estimated to range from 0-20%

*cross-pollination is mainly by insects, mainly bumblebees - which tend

to travel short distances, but can be by pollen beetles - which can fly

far. The pollen beetle is " very common " in England

*potatoes pose a relatively low risk of cross-pollination because (i)

potatoes are not grown from seeds but from tubers, which are clones of

individuals of the desired variety, and (ii) the harvested crop is the

tuber which is not affected by any cross-pollination

*however, potatoes produce volunteers, called 'ground keepers', and

these pose a risk of GM contamination of non-GM crops in following years.

*importantly, the risk of cross-fertilisation is increased if (i) the

GM and non-GM varieties are different but flower at the same time; (ii)

if the varieties are blight resistant as the GM crop is more likely to

be left flowering; or (iii) when the main pollinator is the pollen

beetle, not bumblebees

*many varieties rarely produce berries as they are male sterile, but

several modern varieties can produce very large numbers, each containing

400 seeds

*seed can survive seven years in southern England. When seeds grow,

they mature into full potato plants, producing normal tubers, in the

second year

*one study (Skogsmyr, 1994) found very high rates of cross-pollination

between a GM variety (a version of Desiree) and a different non-GM

variety (Stina), of 36% at 100m and 31% at 1km. This indicates that

still

considerable rates of cross-pollination would be occurring at greater

distances. These high rates were attributed to the fact that higher

levels of cross-pollination often occur between different varieties in

outbreeding plants, and because the main pollinator in this case was

probably the pollen beetle.

*two other studies found low levels of cross-pollination. It was

assumed that this was partially because the main pollinator was

bumblebees.

In one study (McPartlan and Dale, 1994), the rates were 2% at 3m and

0.017% at 10m; the low rate was probably also because the GM and non-GM

varieties were the same (Desiree). In the other (Tynan et al, 1990),

the rate was 0.05% at 4.5m; a `wild type' variety was used; the low rate

of cross-pollination was probably also because the GM and non-GM

varieties appeared to have a different flowering time.

*but these rates are probably considerable underestimates as these

three studies were all only on a research plot scale, not using

agricultural scale fields which would normally produce much higher

rates of

cross-pollination

*'relic' potato plants from earlier crops can be found and persist on

tips, waste grounds and fields

*potatoes are not interfertile with other crop or wild species

 

Defra has also considered the contamination risks from GM potato crops

:

*the main risk of GM potatoes is from cross-pollination of non-GM crops

and GM volunteers appearing in later seasons: " the recipient plant will

… produce GM hyrids, which means that GM volunteers may be created. It

is possible that over time there could be some limited GM transfer

between farms via the development and persistence of GM volunteers. "

Comment

The NPRU says " the role of the pollen beetle in long distance

distribution of potato pollen is in need of further research " .

Further research

into the significance of wind pollination in long range dispersal is

also suggested.

 

2. Agricultural practices affecting the risk of GM contamination

*many different potato varieties are grown in the UK

*potatoes flower at similar times to the time when the tubers are being

produced

*to prevent fungal 'blight' damage to the plant from affecting the

growth of the potato tubers, farmers usually defoliate the plants,

removing

the flowering heads and green leaves (done with acids or, among organic

farmers, mechanically or with flame-weeders). This is done at

flowering or soon after. So, flowering is common, even if not present

in most

fields and generally only for short periods.

*after the defoliation, the crop is left for a few weeks to let the

potato skins 'set'

*however, the defoliation itself affects tuber growth, so farmers

prefer to leave the green tops if they can. They are therefore more

likely

to leave the flowers if the varieties are blight resistant. This means

that blight resistant GM varieties pose a higher risk of flowering

presence, cross-pollinating and producing seed

*volunteers are usually controlled with herbicides but, according to

Defra, " it is not possible to guarantee the complete elimination of

volunteers "

*also, not every potato tuber will be removed from the ground

 

3. Organic potato production techniques

Organic farmers primarily control crop pests and disease with natural

processes, including healthy soils, crop rotations and by encouraging

natural predators. Blight in potatoes is one of the very few crop

diseases where such management techniques are not wholly effective, and

instead late blight in organic farming is controlled by copper sprays.

Copper is a naturally occurring element and many soils are deficient

in it.

The amounts used are limited to 6kg/ha per year and it does not build

up in the soil, due to the crop rotations. The copper is sprayed onto

the plant's leaves and does not end up in the potatoes, unlike the

pesticides used in non-organic farming which are found in a quarter of

potatoes and may pose a risk to human health.

 

4. Development of GM potato varieties

The German chemicals group BASF has developed a blight resistant GM

potato. It is currently trialling them in Germany, Netherlands and

Sweden

and has applied to Defra for approval to carry out two 1ha trials in

the England in spring 2007 (one in Derbyshire and one in

Cambridgeshire).

After 3-4 years, they intend to seek permission to grow and sell the

potatoes in Britain. The potatoes contain two genes from a wild Mexican

potato. According to BASF, the GM variety would reduce the number of

fungicide sprays from about 15 per season to just a couple. These would

be the first GM trials in the UK since the end of the farm-scale trails

in 2003. BASF has also applied for EU approval for a potato that is

rich in a type of starch used in the paper industry; it hopes for

approval later this year.

 

GM potatoes are unnecessary and are unlikely to deliver significant

environmental benefits. Only 1,300t of the 12,000t of pesticide used on

potatoes in the UK are fungicides, so it seems that at most they could

reduce pesticide use by 10%.

 

Conventional breeding of existing varieties is making progress in

developing blight resistant varieties. These are being developed and

trialled for use in organic farming. Using old Hungarian varieties,

Sarpo

Mirea and Axona, potato grower Dr David Shaw has developed blight

resistant red varieties with a high dry content, suitable for chips and

baking, and he is looking into a variety suitable for salads.

 

4. Commercial experience of GM potatoes

In the US, attempts at selling GM potatoes failed after being rejected

by major food companies, including McDonald's, Burger King, McCain's

and Pringles. There are no GM potatoes sold in the US now. On the radio

programme, Farming Today, on 24 August 2005, Andrew Opie of the British

Retail Consortium, representing supermarkets, said, " We won't be

stocking GM potatoes for the conceivable future ... The fact is people

remain

suspicious of GM " .

 

5. Health problems with GM potatoes

There is a major concern that GM potatoes pose a risk to human health.

There are many serious concerns about GMOs in general, most of which

would apply to GM potatoes. However, there is a particular concern with

GM potatoes as for several years there has been evidence indicating

that they could cause haemorrhages.

 

Feeding trials by two scientific teams found that GM potatoes cause

lesions in the gut wall of rats and mice . Both studies were

published in

scientific journals. One was a controlled UK Government funded study,

peer reviewed and published in the Lancet, the most respectable medical

journal, in October 1999 (Ewen and Pusztai, 1999). The editor said the

paper " deserved further scientific attention. "

 

The biotechnology industry reacted very aggressively and tried to

mobilise the scientific community to undermine the credibility of the

work.

However, no further work has been undertaken since which could in any

way suggest that the finding was wrong. Moreover, the credibility of

the findings is supported by the fact that similar effects have been

found with GM tomatoes in two US feeding trials, which found that GM

tomatoes cause lesions in the gut wall of rats.

 

GA, 24.8.2006, GMbriefing23

 

 

 

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