Maintaining quality from seed grower to farm

05.04.2018

Potato agronomists are optimistic about the year ahead, with potato seed anticipated to be of a high standard for the 2018 season.

However, with some seed varieties forecast to be in short supply, maintaining quality from the seed supplier to the farm will be key, as Potato Review investigates.

Andy Steven, agronomist at Agrovista, advises on over 1,500 ha of potato seed crops in the north of Scotland.

“There are many challenges to growing quality potato seed, which aren’t too different from that of a ware grower,” he says. “The aim is to achieve tuber quality of a high standard, which includes a good clean skin finish and no visual signs of disease. Seed quality is also maintained with the help of good storage facilities to ensure a dry crop and cold storage to control seed dormancy before delivery.”

However, he adds that to achieve a good quality potato seed, there are a number of challenges to negotiate, starting with good land selection.

“Most seed growers will be working on long rotations of between seven to ten years, in order to minimise disease pressures. If you can start with a good field that has a low pest and disease burden, then it makes ongoing management during the lifecycle of the seed crop easier.

“However, virgin land is increasingly difficult to find, and growers are having to go further and further afield, which can make the cost of production more expensive,” he adds.

Mr Steven explains that seed growers will typically start inspecting prospective fields in the Autumn to establish the history of the land and adds that the wet weather often seen in many key seed-growing areas, can increase pressure on the crop.

“Scotland had a year’s worth of rainfall between June and December last year, making ground conditions wet and increasing the risk from diseases such as black leg and blight.

“As a result of last year’s wet weather, only a small amount of ploughing has been done to date, so there’s still a lot of ground preparation required before planting starts in April,” he says.

However, Mr Steven warns that it’s important not to feel under pressure to get land turned over before its ready. “Patience and care are vital to ensure that soil preparation is done at the right time without creating compaction, either on the surface or deeper within the soil profile, which can then have an impact on yield,” he says.

Ultimately, the relationship between the seed grower and the buyer is one of the most important elements in growing healthy potato seed. “It’s vital for the buyer and grower to talk to each other about expectations of the season, and how the crop is developing,” he adds.

Meeting market demand

Mike Inglis, technical manager at Albert Bartlett, describes the selection process for sourcing quality potato seed for their growers across the UK and Jersey.

“Our main priority when procuring seed is the assessment for disease during the growing crop and after harvest. We have a low threshold for skin diseases, particularly powdery scab, black scurf, black dot and silver scurf, as these can cause secondary infection in the daughter crops.

“Once the crop has been cleared for quality purposes, we then carefully select the grower the seed is best suited to, to ensure the quality is matched with the right end market. This joined-up approach is vital, and we can’t afford to get it wrong,” he explains.

Mr Inglis adds that this level of care doesn’t stop once the seed reaches the farm gate.

“Once on-farm it’s vital that the seed is stored correctly until planting to maximise the potential yield. The correct temperature is key, as is good airflow,” he says.

“Use of a proven seed treatment is also important to prevent disease wherever possible. A number of our growers will use products such as Rhino (flutolanil) once the seed is on-farm, applying just before or after Christmas,” he says. “This can be a beneficial and cost-effective option against soil borne Rhizoctonia.

“Producing quality seed is at the centre of the potato industry, therefore it’s paramount we continue to maintain the high standards of seed quality right up until planting,” he says.

Maintaining seed quality on-farm

John Sarup, potato specialist at SPUD Agronomy, explains that the wet summer and protracted harvest last season, led to oversized tubers and fewer tonnes of the traditional seed sizes of 35mm through to 55mm.

However, he adds that most professional growers have been able to counter any negative effects through careful handling, and attention to detail at storage.

Here are Mr Sarup’s top tips for ensuring potato seed quality is maintained once on-farm:

• Unload the seed carefully avoiding any bumps and bangs
• Place the seed bags in an airy, frost-free environment, preferably on pallets, leaving space between them
• Inspect three bags at random for quality control, take pictures and notify the seed supplier if you have any initial concerns
• Decant the seed into boxes and report any further concerns to the supplier within 48 hours of delivery
• Aim to remove any condensation and keep as dry and cool as possible until planting
• Before planting, wash a sample of the tubers and assess the need for further seed treatments
• Carry out several tuber counts to enable accurate planting
• Always plant cool seed into warm soil