Nene Potatoes

The potato business people want to be involved with

Next Genration at SASA and Gentech in December


In December the focus was on seed in Scotland. We started at SASA (Science and Advice for Scottish Agriculture).

The first person we heard from was Sandra Goodfellow. She spoke about the divisions of SASA: seed, varieties and pesticides, potato and plant health. She told us about what SASA does: acting as a certifying authority for seed potatoes, providing scientific support for ministers, inspector training for the growing crop and tuber, producing initial propagation material ‘nuclear stock’ meaning that all seed potatoes originate from SASA and the potato export liaison. She explained that SASA are involved in all aspects of the seed process from SASA microplants, through commercial micropropagation, minituber production, prebasic field crops, basic field crops and marketing. For example they test for PCN, have growing crop and tuber inspections.

Next we heard from John Elliot who spoke about the importance of seed potatoes to Scotland, with Scotland being the second biggest seed potato exporter to non EU countries in Europe, after Holland. He spoke about the ideal climate in Scotland, with the weather meaning they do not get many aphids during the growing season and so suffer from fewer viruses.

He told us about the field requirements for Scottish seed. There needs to be pest freedom of land (never had wart disease and found to be PCN free pre to planting), the rotation interval needs to be seven years for pre basic and five for basic, there is a separation requirement meaning that PC crops must be grown on dedicated farms that can only grow S or PB and all seed farms must plant E or better, not once grown ware.

He went on to explain that Scottish seed is white label (prebasic or basic seed) recognised by the EU as high quality. Scotland is a Community grade area, meaning they cannot produce blue label seed. Above Aberdeen is higher grade pre basic due to being cooler. Scottish seed is free from many important pests and diseases and all stages of production are monitored by Government officials. He commented that in Holland this is run by a commercial organisation not Government so is there a potential for influence by trade?

There are several plant health controls in Scotland. Scotland is free from several important diseases found in other countries such as brown rot, ring rot and Dickeya. SASA has ware crop inspections for ring rot as more than 4% virus can destroy the seed crop if it is nearby, there is a statutory nil tolerance for Dickeya in seed and ware crops and there is a gentleman’s agreement to not bring non-Scottish seed into Scotland as this would pose a significant threat to Scottish seed. Also, Scotland have separated virus Y,A and leaf roll from ‘total virus’ I the EU, meaning they are treated more harshly. This is something that could be added to in terms of more diseases if need be.

We were told about seed classification and the new harmonised EU scheme which was started in 2009. However, as different countries have different priorities, for example due to individual disease problems, a final decision was not made until December 2013 and the scheme was finally introduced at GCI in 2015.

The old scheme allowed ten generations whereas the new scheme only allows seven. He explained the new scheme: Nuclear (microplants/mini tubers), pre basic (up to four field generations), EU grade S (up to five generations), EU grade SE (up to six generations) and EU grade E (up to seven generations). He told is that if you are buying seed for seed it is only voluntary to have the field generation on the label and it may be a commercial decision to protect if it is only field generation four. However if the generation number is not on the label SASA will assume the highest generation, so five for S for example which affects how many times it can be grown as S before it becomes SE.

The average generation of seed is five and no clonal multiplication is allowed as in Holland, where they loop back to increase field generations. Class names and tolerances have been harmonised since summer 2015, or at least they were meant to be.

John then spoke about the nuclear stock, explaining that there are around 800 varieties stored and that virtually all Scottish seed is derived from their laboratory. Microplants then go on from this laboratory to licenced laboratories who make microtubers.

There are six licenced places in Scotland who multiply microplant material and produce minitubers in protected, pest and disease free environment. The microplants are grown on peat, hydroponics or aeroponics. The majority use peat now as it gives a better skin finish. The peat is steam sterilised, tested for PCN and only used once. All PBTC crops are monitored at SASA in post control field plots and tubers are sampled for background diseased presence.

He told us that pre basic and basic crops are inspected at least twice by Government officials, usually in July. All plants in every PBFG1 crop are inspected. The pass rate of seed at the class entered is 95%, with 4% downgraded and less than 1% rejected. They have a field grow out inspection which is a two year programme where the seed is monitored for trueness to varietal type.

Marketing is only allowed after inspection and unlike most other export countries they have strict minimum tolerance. If being exported they inspect to whichever country has tighter regulations. There is a minimum number of bags per tonne to be inspected but the inspector can look at as many as they want to. Before being inspected the seed needs to be sealed in bags with the white label on. There are new security marks on this, a UV light will glow SASA which enables the label to act as an EU plant passport.

He told us more on the seed export, which goes all over the world and is traded on the high health status of Scottish seed. He said that two thirds of the seed goes to Egypt and that they deal with quite specialised North African and Mediterranean countries.

He also spoke about the Seed Potato Unified Database System (SPUDS) which covers all stages of the certification process from soil sampling to tuber inspections, allowing full traceability. He said the system provides both the rigour and flexibility needed to continue to meet seed supply chain needs. Growers can access their own crops through mySPUDS.

Next we went to see the soil sampling area. Here, two people process 200 samples a day. They are testing PCN for Scottish fields, which would be a pointless task in England due to PCN levels.

We were told about the process whereby a grower sends a map of their fields to SASA, an inspector visits to collect the sample, the sample is tested and a certificate is issued to say if PCN is found or not found and if found, the quarantine measures. One PCN positive will take out a 4ha block. 

We were shown the process of testing the soil from the drying cabinets through the extracting carousel, sieving and rotating every 45 seconds, blasting water onto the soil for the cysts to go through, the cysts on the filter paper, into the tube, beads and buffer added, smashed to release DNA and visually examined.

We then went to see Pathology. We were told about the different roles such as disease diagnosis, training Government inspectors, monitoring seed tuber health and research into tuber diseases.  

After this we went to Virology where there were discussions on Leaf roll and Mosaics. We were told that lead roll systems are less frequently found in Scotland now but mosaics are still found and that for leaf roll aphid needs to be feeding for longer whereas mosaic they only need a short visit. An inspector notifies SASA even if they only find one leaf in a field. We were told they also look at the insects spreading the viruses and use suction traps to collect them.

After our tours we heard from Greig Cahill on quarantine diseases. He first spoke about brown rot where he said to look for lightening leaves, stem bacterial ouse, vascular tissue brown and bacterial ouse.

After this he spoke about Ring rot. He said that it is a very big problem in Poland and is more prevalent than brown rot but there has never been ring rot or brown rot in the potato system in Scotland. He said to look for leaf curling and white ends, wilt, tuber being glassy, then browning and then hollows/rots out.

Blackleg was spoken about next, where he talked about it being the major cause of seed downgrading and rejections in Northern Europe and that Dickeya has become major cause of blackleg and soft rots in Europe. He told us that blackleg increases with field generations and that Blackleg caused by Pectobacterium citrosepticium is biggest challenge.

There is a three year Scottish government and AHDB project on blackleg/ soft rot. This is looking into how and when early generations become infected, movement within fields, movement within plants, population changes over time, disease modelling and sulphuric acid effectiveness.

Greig spent some time talking about Dickeya Solana which he said is one of the newest pathogens having been found in 2005/6, first found in England in 2007 and Scotland in 2009. He said that in less than five years it has become the prominent reason for Blackleg in many EU countries but is yet to establish in Scotland. It is a seed borne disease but it is not in the seed to start with, it comes from the environment but which one? Plant to plant spreading is inefficient but it is easily transferred from infected to healthy seed during grading. There was a zero tolerance on all Dickeya species in Scotland in the seed potato classification system from 2010. There are various other controls such as it being illegal to plant infected seed potatoes in Scotland.

We then visited the stored variety collections before hearing from Rob Burns, AHDB Head of seed and exports. He spoke about the Safe Haven Scheme to guarantee freedom from Ring rot, Brown rot and Scotland Dickeya.

After Rob, Claire Hodge spoke about knowledge exchange and campaigns on Blight, Blackleg, aphids and virus. Sophie Lock also spoke and covered the variety database.

We stayed overnight in Dundee where we had discussions over Dinner with Jim Cruikshank, Ian Toth, Alistair Redpath, Alistair Melrose and Russ Kelsey. They shared stories and urged the group to get involved in wider industry activities. They stressed how their own involvement over the years in levy board campaigns and committees helped forge them ahead in business.

On the second day in Scotland we visited Gentech; the Dundee based micro-propagation and mini-tuber facility. We were given a tour around the site by facility manager Nigel Ebbelwhite and Chief Executive of Cygnet Plant Breeders, Alistair Redpath.

We saw how the methods used for rapid production of large quantities of virus free pre basic seed and the very steady hands involved. We saw the process from the tube to minitubers and were told that it is five years before the seed is planted commercially.

We then went on to a farm visit at Rob Doig, Caithness Potatoes where we were led by Stephen Hole, sales and logistics manager.

Discussions were held on the seed industry being an interesting and diverse sector that depends on expertise and the volatile market. He also spoke about areas such as it taking three weeks for seed to get to Egypt and the refrigerated containers being plugged into ships.