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Gene stacking aids in breeding natural blight resistance

The team from Ghent University, VIB and the Institute for Agricultural and Fisheries Research (ILVO), and their Dutch colleagues from Wageningen University and Research Centre have published the results of their field trial with genetically modified potatoes. The trial, which ran in 2011-12 in Wetteren, armed the potatoes with at least one and up to three natural resistance genes against blight caused by the fungus Phytophthora infestans. Researchers found that only a stack of several genes provides good resistance to the disease.

The field trials showed the tested genes each have a different contribution to resistance, but in the end, only a stack of several genes provides good resistance.

The resistance gene from Solanum venturii had the highest individual contribution to the resistance in field trials, but the best result came from the plants carrying a combination of resistance genes from Solanum venturii, Solanum stoloniferum and Solanum bulbocastanum.

Researchers concluded that future breeding efforts will have to focus on bringing together a wide combination of natural resistance genes in new varieties: at least three, but four or five would be even better. The resistance genes must also be sufficiently different. And for sustainable resistance management, it is important to strategically change the combination of genes in the new varieties.

Research is ongoing in both the Netherlands and Flanders, building on the results of the field trials. Ghent University, VIB and ILVO are now working together to develop a durable resistant Bintje potato. The Bintje is very popular because of its taste and processing qualities, but it is also very sensitive to Phytophthora.

Ghent University and VIB ILVO hope to run the first field trials on this variety in 2017 or 2018.