SLU news

Potatoes without potato blight soon on the market

Published: 21 August 2014

Potato late blight is one of the most combated pests in Sweden. Ulrika Carlson Nilsson at SLU leads the work to develop potato varieties that taste good and are long-term resistance to late blight. It would mean a lot for organic potato production if successful.

For a long time researchers and plant breeders struggled to develop potatoes that are resistant to late blight that cause major crop losses each year. Late blight is caused by the microorganism Phytophthora infestans.

New strategy for long-term resistance
Since Phytophthora infestans is a master in adapting to different circumstances, it is difficult to produce a potato that is resistant over longer times. New resistant potato varieties are often getting susceptible to infestation after some years.

At the Department of Plant Breeding, SLU, Ulrika Carlson-Nilsson is leading a project where the strategy is to combine several resistance genes from wild species with existing varieties to create cultivars with more durable resistance.

The advantage of this strategy is that the pest-causing microorganism gets several kinds of resistance to tussle with. To the online magazine Extrakt, Ulrika says:

– In that way we can get a potato in which the resistance is “sustainable” for a longer period of time. When a variety carries several resistance genes, it works a bit like a backup, it will be another defence that the fungus must "outsmart" once broken the first down.

Taste is also important
There are several things to take into account, sustainable resistance is of course important, but the new variety will also provide good yields, be good looking and not at least taste good. It can be difficult to get all the pieces in the same potato. The wild potato varieties that have desirable resistance genes can simultaneously carry genes for bad-tasting small potatoes.

In Borgeby, southwest Skåne, successful field trials have been made where crossbreeds have coped without spraying against late blight in four growing seasons.

In the interview in Extrakt, Ulrika Carlson-Nilsson is optimistic and hopes that the first potato varieties can go from breeding to be ready for market in a few years. She says:

- We see materials that have good resistance even after several years of cultivation in our field trials, so we are confident that we are on the right path.

Also good for conventional farming
The goal of the project is to develop breeding materials that can be used in efforts to produce new Swedish potato varieties suitable for organic cultivation. But these varieties will make great use even in conventional farming that is in need of finding alternatives to chemical pesticides.