Turning potato seed boxes just as the seed eye opens could help boost tuber numbers in seed crops, Andrew Manfield, a Yorkshire seed potato grower, has found in initial trials.

“We need to produce the maximum amount of tubers within the contract specification in as little time as possible. But we can’t just keep piling on inputs to increase tuber numbers because of cost, so we need to find clever ways of boosting tuber numbers to increase our monetary output, while keeping costs as low as possible,” he told the SAC Association of Potato Producers Conference.

Tuber numbers could be increased by looking at nutrition, controlling diseases, optimising seed spacings and seed populations, creating good seed-beds, and manipulating seed pieces, he suggested.

Avoiding apical dominance was critical, he continued. “If we don’t get all the eyes to open, it means we get fewer stems, and therefore fewer tubers.”

One solution tested by Mr Manfield was to use a box turner manufactured by Dutch company Wifo, which is fork-lift mounted rather than being a static machine.

“The little bit of damage you inflict by turning the boxes just as the eyes open a millimetre or two, is sufficient to cause other eyes on the tuber to open. Typically you do this two or three times before planting.

“In a trial at our farm, across four replicates of Innovator, there was a trend for increased tuber numbers, which was encouraging.

“In Holland they have found not all varieties respond the same, and there are clearly issues with spread of diseases, such as powdery scab and bacterial diseases, so you would have to be selective about the stocks you would choose.

“But it is something we will do more, and as the the machine has other uses including being a regular box tippler, and being able to fill 1.25t bags, there isn’t any net effect of investing if you choose the right piece of kit.”

• Read more from the SAC Association of Potato Producers Conference