"We have 60 years’ experience of propagating wheat seed."
Several genetically modified wheat lines are currently being tested in a field trial on the site of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) in Gatersleben. The IPK also has one of the world’s largest gene banks. Well over a hundred thousand plant specimens, including wheat, have been stored there for years. Every summer, a proportion is planted in the field and propagated. Does the GM wheat trial represent a threat to the gene bank’s work? – GMO Safety spoke to the head of the gene bank, Prof. Andreas Graner.
On 23 November 2006 the Federal Office of Consumer Protection and Food Safety (BVL) (the German authority responsible) approved the release trial of GM wheat lines with a modified protein composition.
As a self-pollinator, wheat generally fertilises itself with its own pollen inside the floret. This means that from a purely biological perspective, outcrossings are unlikely, which means a spread of the transgenic DNA is also unlikely. Nevertheless, the trial field has been set up 500 metres away from the gene bank’s wheat propagation plots. As we have just learnt, the BVL recommended that the gene bank move its wheat propagation plots as a precaution.
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GMO Safety: You are in charge of the gene bank at the IPK in Gatersleben. What are the tasks of the gene bank and how important is it? Andreas Graner: The gene bank’s role is to conserve, supply and document plant genetic resources. The gene bank plays an important role in preventing gene erosion, i.e. preventing cultivated plants and their wild relatives from dying out. GMO Safety: Which cultivated plants do you do this for? Andreas Graner: We deal primarily with agricultural crops and horticultural plants and their wild relatives. We have over 3000 different species in our gene bank from more than 750 botanical genera. As regards species diversity we are probably the most complex gene bank in the world. With a stock of 150,000 specimens from over 3000 species we are also one of the largest. Even more plant specimens are stored at the Wawilow Institute in Russia. GMO Safety: Some of these specimens are regularly planted in the field and propagated. This is necessary for obtaining seeds from the different strains. How many specimens are planted out and how many samples are cultivated per year? Andreas Graner: This varies a lot from species to species and depends to a large extent on the shelf life of the seeds. The average is around 20 years. This means that each year we need to plant five per cent of our collection in the field or in the greenhouse for propagation purposes. That equates to around 7500 specimens. |
GMO Safety: When these specimens are propagated in the field you have to make sure that they do not mix. Can you rule this out and what measures do you take to prevent it happening?
Andreas Graner: For a start we use agronomical measures – for instance, in the cereals assortment we don’t plant the different wheat specimens next to each other; we alternate them with barley. This “disjunctive” cultivation method was established in Gatersleben years ago. It enables us to avoid cross-fertilization to a large extent – in this case in wheat and barley. We can also ensure that when it comes to harvesting we differentiate clearly between harvested material from neighbouring plots and keep it separate. Cross-fertilizing species are planted on isolation plots with a minimum distance of 250 metres between them. This separation distance prevents e.g. pollen from different rye populations from being mixed by the wind. And for the third group – cross-fertilizing species that are pollinated by insects – we cultivate the plants in small greenhouses. The fronts and backs are covered with an insect-proof gauze. We have 170 of these greenhouses that are full every year during the growing season.
GMO Safety: Do you check whether you are actually achieving your aim of avoiding cross-contamination?
Andreas Graner: Yes. And there are other measures that we take as part of our conservation management. For instance, the propagation plots are regularly monitored by the curators and assortment managers during the growing season in the summer months. This means that the material is checked for authenticity using certain morphological characteristics, e.g. changes to flower colour or leaf position. Any deviations caused by e.g. cross-fertilisation or mixed seed, can be spotted.
GMO Safety: Do you really find all the deviant plants?
Andreas Graner: For instance, if by chance a seed from the previous years’ plantings is left in the soil and germinates, this plant will not correspond to the material that we want to propagate. When such deviant plants emerge they are removed by the assortment managers – just like weeds. The descriptor characteristics used are described in detail in a list. In addition, a few years ago we introduced detailed tests using DNA markers specifically for wheat. Control specimens were used to compare wheat varieties, some of which had been propagated up to 20 times over recent decades. We established that in all the cases we investigated the end specimen was still identical to the original specimen – even after 20 propagations. So we found no deviations. This is surely an indication that our assortment managers are doing their job well.
GMO Safety: The IPK has a large number of agricultural and plant research projects. Some of the plants developed in these projects must surely be used in field experiments, such as the current trials with genetically modified wheat lines. Does this lead to particular risks for the gene bank’s propagation plots?
Andreas Graner: The number of release trials on the IPK site is manageable – not least because of the administrative work involved. They do not pose a risk to the gene bank. As part of our quality management we have taken a number of measures to avoid potential outcrossings or cross-contamination with the gene bank material. In the case of this latest trial, we are respecting a separation distance of 500 metres between the trial and the gene bank’s wheat propagation plots. This distance is sufficient to prevent any cross-fertilisation through pollen transfer. If we didn’t do this we would not be able to conserve the genetic authenticity of the 30,000 wheat specimens that we have in the gene bank. In Gatersleben we have been propagating wheat specimens using disjunctive cultivation methods for 60 years. We use plots measuring two square metres laid out like a chess board with wheat – barley – wheat - barley... If there were any significant cross-pollination in wheat, the material that we have in the gene bank today would be nothing like the material we collected in the past.
GMO Safety: When approving the release trial for genetically modified wheat, the Federal Office of Consumer Protection and Food Safety recommended that the gene bank move the propagation plots for wheat. Leaving aside the question of whether this is necessary – is it in fact possible?
Andreas Graner: From our point of view it is virtually impossible. It would mean that we would have to set up the gene bank at a different site, at least for the propagation period in the summer months. And where should this site be – one kilometre away or ten? There is no scientific justification for the "correct" distance. And logistically it would be impossible – or at least only possible at great effort and expense. We would have to rent fields and then transport the 65 or so people involved with the gene bank propagations there every day during the summer months, and transport the harvested seeds back to IPK. With such a small release trial – we are talking about around a 11.000 individual plants – and, in my view, the absence of any residual risk, moving the propagation sites would be an impracticable and unjustifiable step.
GMO Safety: Thank you for talking to us.
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