While great progress has been made in understanding the existential threat posed to Scotland’s world-class seed potato industry by potato cyst nematodes (PCN), the jury is still out on whether this is keeping up with the growing scale of the challenge.
That was the update on a multi-million pound project into the pest given to the country’s potato growers last week at a major conference in Dundee.
With Scottish-grown seed underpinning the UK’s £6 billion potato supply chain, projections that the area of land infected by the pest could double every six to seven years – threatening to wipe out seed production totally by 2050 – a major research project was launched in 2021 to look at ways of combating the rise of the pest.
Highlighting the scale of the problem at the conference held by the SAC Association of Potato Producers (SACAPP) in Dundee last week, project lead Dr James Price of the James Hutton Institute outlined a series of measures which had identified as being key to addressing the problem.
Initially backed by £2.3 million of Scottish Government funding, growers heard that the project, currently halfway through its five-year run, aimed to halt the spread of PCN – including the virulent pallid strain which is spreading fast through the country’s seed-growing heartland.
Dr Price said that the measures identified included a thorough economic assessment of the economic value of the potato sector –and the impact which PCN could have on this – to help assess the effectiveness of different control options and to create an effective decision support system to back this up.
“The development of markers for genetic resistance to PCN along with the introduction of new genes from wild potato varieties into pre-breeding programmes should help ensure the viability of long-term resistance, especially when used in conjunction with new accelerated breeding techniques,” said Dr Price.
He also said that getting new varieties which were acceptable to both supermarket buyers and growers would play a key role in addressing the problem as many of the varieties currently favoured by buyers were not resistant to pallida.
Dr Price said: “We also need to understand the difference between resistance and tolerance for while resistant varieties can be fantastic at reducing the problem, this can sometimes be at the cost of yield.”
But he added that new varieties which are both resistant and tolerant were beginning to gain acceptance by buyers, offering a good opportunity for growers.
Addressing groundkeepers and volunteer potatoes was another important issue, he said, with non-resistant varieties resulting in further multiplication of PCN numbers while resistant groundkeepers could, he speculated, see that resistance challenged.
However, he admitted that while progress was being made, it was less clear if this was keeping up with the growing challenges presented by the pest which continues to tighten its stranglehold on the industry.
An economic modelling tool which could predict the range of scenarios which the industry could face in the future was presented by leading agricultural economist Professor Steven Thomson.
The outcomes of different scenarios and the effect they could have on the industry could be tested by computer modelling which is set to be made available online soon and should help growers judge the effect on profitability, and also to allow policymakers to look at the wider economic consequences of a range of changes to the potato industry.
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