BMELV coexistence research programme

“A distance of 150 metres should be enough to ensure that the 0.9% labelling threshold is observed for the harvest taken as a whole.”

In January 2008 the Bundestag passed a new genetic engineering law. It stipulates that farmers who grow genetically modified maize must allow a minimum separation distance of 150 metres between GM crops and conventional fields. This distance ruling serves to comply with the 0.9% labelling threshold prescribed by the EU. These distances have been established on the basis of findings from the research programme on safeguarding coexistence initiated by the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV). GMO Safety spoke to Gerhard Rühl of the Julius Kühn Institute (JKI) in Braunschweig, coordinator of the research programme, which is designed to run for several years.

Dr Gerhard Rühl, coordinator of the BMVEL research programme on safeguarding the coexistence of GM and GM-free crops and protecting biodiversity; Julius Kühn Institute (JKI)

GMO Safety: The Bundestag has just passed the new Genetic Engineering Act. This year for the first time we have rules of good agricultural practice for the cultivation of GM maize. On the basis of your findings so far, do you think that the distance ruling stipulated in the act is reasonable?

Gerhard Rühl: In view of the current arrangement, a distance of 150 metres should be enough to ensure that the 0.9% labelling threshold is observed for the harvest taken as a whole. This can be inferred from the data which we have been gathering since 2005.

GMO Safety: What do you mean by the ‘current arrangement’?

Gerhard Rühl: There is still no threshold for acceptable GMO contamination in seed. This means that in making our recommendations, we are assuming that seed contains no GMO traces. If a seed threshold were to be set in the future (a value of between 0.1 and 0.5% is currently under discussion), it would naturally limit the scope for further GMO presence during cultivation. Only a specific percentage could then be permitted to enter crops in addition to the seed threshold to ensure that the 0.9% labelling threshold was not exceeded. In these circumstances the findings would have to be re-evaluated.

GMO Safety: If 150 metres is regarded as safe for conventional farming, why do the rules on good farming practice specify a distance of 300 metres from organic farms? Is this a case of double standards?

Gerhard Rühl: There is actually no legal basis for the 300 metre separation distance from organically farmed land. There is only one labelling threshold set by the EU, and that is 0.9 percent. The ruling is really a concession to organic farmers. You mustn’t forget that organic farmers use zero tolerance of GMO inputs as a sales argument. Three hundred metres was chosen in an attempt to approximate this as closely as possible. It is a purely political decision.

GMO Safety: A report for the Federal Agency for Nature Conservation (BfN) from May 2007 revealed that significantly more pollen reaches a distance of 100 metres that was previously assumed. How significant is this for outcrossing and determining separation rules?

Gerhard Rühl: The report focussed mainly on pollen drift, which is of course the basis for outcrossing. However, when interpreting pollen drift data with regard to possible outcrossing events, we should not overlook the importance of pollen fitness and competition between local and foreign pollen. Pollen which has been in the air for a long time no longer has the competitive ability of freshly shed pollen; it may even be no longer viable and is therefore less likely to result in an incrossing event. So when we designed the trials, we decided that although it is interesting to know how far pollen drifts, from the point of view of coexistence it is only of theoretical interest. We have to record the actual outcrossing. Whether a pollen grain actually lands on a maize flower and leads to successful fertilisation is the only decisive factor as far as coexistence is concerned. Ultimately it also forms the basis for possible liability vis-à-vis neighbouring farms, which the coexistence rulings are designed to eliminate as far as possible.

GMO Safety: How do you take into account the dependence of pollen drift on climatic conditions when testing separation distance rules?

Gerhard Rühl: We carry out our outcrossing studies under ‘worst-case’ conditions. This means that the fields are arranged in the direction of the prevailing wind and we always use varietal pairs which flower more or less at the same time. This particular pattern will of course not occur very often in practice. But since the aim of coexistence measures is to generally safeguard the coexistence of different cultivation methods, the field trials are carried out under the most unfavourable conditions possible. We are very fortunate that the German weather service sets up and monitors a weather station in each of our fields. Wind direction, wind speed, temperature, air humidity, precipitation and sunshine are all recorded during the flowering period. This is hugely important to us for evaluating and assessing the trials. We need to know the climatic conditions on the field itself. In 2005 we experienced extremely windy conditions; constant wind at the right speed from the ‘desired’ direction. In this first trial year we recorded a very high rate of incrossing far into the crop. This surprised us because we hadn’t expected it based on the literature. But that is precisely why we conduct field trials over several years and at several different sites; it enables us to record extreme conditions like this, estimate the likelihood of their occurrence and make allowances for them when formulating rules of good agricultural practice.

GMO Safety: Thank you for talking to us.

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