Fighting late blight: what does it take to bring a resistant potato variety to market?

Bringing new potato varieties to the marketplace is very much a combined effort. Seed breeders work closely with growers to develop desirable agronomic traits, and with the wider supply chain for those crucial characteristics such as dry matter distribution, sugar formation, and storability.

In parallel, the work of researchers across the globe informs breeders about blight and the genetic basis for varietal resistance.

The role of research

The James Hutton Institute in Scotland is one such research body and currently has projects covering everything from pathogen diversity, evolution, and phenotyping to host resistance and IPM.

The knowledge gleaned from these projects, together with in-house research, inform the work of seed breeders like Agrico which has around 220,000 potato varieties starting 10 years of trials each year. And this is before growers, like the UK’s Nick Taylor, start on-farm commercial trials.

Dr. David Cooke, research leader in Cell and Molecular Sciences at the James Hutton Institute is involved in strengthening the industry’s understanding of pathogen populations and how to best use inherent resistance to control late blight in the field as part of an IPM strategy.

Cooke explains: "Varietal resistance doesn't play as big a part in crop protection programs as it really should. It's a form of protection that lasts; from the seed tubers right through to harvest and beyond. We are so reliant on fungicides yet the pressure to reduce these inputs is mounting, not least from the pathogen itself." "Late blight’s ability to reproduce both sexually and asexually means there’s tremendous variability within the population and it’s that variability that gives the pathogen its potential to resist fungicide activity – as we saw back in 2017 with the 37_A2 lineage and fluazinam."

Sjefke Allefs, director of Agrico Research added : "From the gene pool, we select parents which, by combination, we hope will give offspring clones that meet the market demands, and then we make crosses – about 500 each year."

Know your enemy

It is why his work within the Fight Against Blight and Euroblight projects is so important. In 2020, 90 UK growers (FAB scouts) submitted nearly 700 genetic samples of late blight to the team at the James Hutton Institute for analysis.

Together with samples gathered across the continent, researchers can track the evolution, spread, and population growth of different genotypes.

Read the full story in Potato Pro