Potential of GM potatoes for sustainable potato cultivation

After a two-year scientific field trial with genetically modified potatoes, researchers have concluded that potatoes with multiple resistance to potato diseases can make our potato growing much more sustainable. Both in 2011 and 2012, genetically modified potatoes showed greatly decreased susceptibility to Phytophthora infestans.

Potato cultivation here has been threatened for decades by a potato disease caused by the fungal blight Phytophthora infestans. In the wet summer of 2012, potato growers had to spray more than 20 times in order to keep this blight under control. That means not only ecological and social pressure, but also costs for Belgian farmers estimated at approximately 55 million euros (for the purchase and application of products, lost revenues and losses during the storage of the potatoes).

Cultivation of sustainable, resistant potatoes is expected to be able to reduce fungicide usage in this crop sector by 80%. Potato growers can also benefit financially, even though the resistant plant stocks will be more expensive. The farmers will also not have to be ready with their spraying equipment at a moment’s notice, which will reduce stress levels. The researchers also predict a positive effect for those potato growers who do not elect to use sustainable, resistant potatoes: the greater the acreage of sustainable and resistant potatoes planted, the less chance Phytophthora will get to reproduce.

In the scientific field trials in Wetteren, twenty-six different genetically modified strains of potatoes were tested in 2011 and 2012, each containing one to three genes for natural resistance that come from wild relatives of our cultivated potatoes. They were compared against susceptible reference varieties such as Désirée, Bintje, Nicola, Agria and Innovator, and against the non-susceptible reference varieties Bionica, Toluca and Sarpo-Mira. The genetically modified potatoes scored better than the non-susceptible varieties Bionica and Toluca that are used in biocultivation. The results of the field trials are to be published in an international scientific journal.

The natural resistance genes (some of which still contained a xenogenetic selection marker) were inserted in the middle-late variety Désirée. Lines that contain only natural resistance genes and no genetic material from other species are referred to as ‘cisgenic’. The potato plants tested in the field were test lines that will not be used commercially. In order to progress towards genuine development of more sustainable potato cultivation, good combinations of resistance genes will now have to be inserted into varieties such as Bintje that are interesting for Belgian farmers. It will still be several years before potatoes such as these are available for new field trials.