Swiss Researchers Test Cisgenic Potato Line To Reduce Late Blight Pressure

Agroscope has begun a field trial in Zurich-Reckenholz to test a cisgenic potato line developed for resistance to late blight, one of the most significant diseases affecting potato production worldwide.

The trial, authorised by Switzerland’s Federal Office for the Environment, involves the cultivation of potato line P49 27 at Agroscope’s Protected Site. The line was developed at the University of Wageningen and contains the Rpi-chc1 resistance gene from the wild potato Solanum chacoense.

Because the resistance gene originates from a potato species and no foreign DNA is used, Agroscope describes the line as cisgenic. The research forms part of National Research Programme 84 and is intended to support further work on potato varieties with improved disease resistance, as well as greater tolerance to drought and heat.

According to Agroscope, potato cultivation in Switzerland has become increasingly difficult. Over the past decade, around 1,000 Swiss farms have stopped growing potatoes, with the agency citing more frequent disease and pest pressure, tighter restrictions on plant-protection products, and more common extreme weather events such as heatwaves and prolonged wet conditions.

The current trial is also linked to the international CRISPS project, which studies genome-edited potato cultivars as well as cisgenic varieties. Agroscope is working with research partners in the Netherlands and Sweden on the varieties Innovator and Erika, which are important for Switzerland, as well as Désirée, used as a research standard.

Over the next few years, the project aims to repair existing resistance genes or deliberately switch off susceptibility genes in these varieties before testing the resulting plants in the field.

Agroscope said conventional potato breeding is increasingly reaching its limits, as it can take more than 20 years and may not be able to keep pace with new pathogens or rapid environmental change. New breeding methods such as CRISPR-Cas are being studied as a way to develop natural traits more precisely and more quickly, without the inclusion of foreign DNA.