Unlike other common varieties of potatoes, clean, virus-reduced Jersey Royal seed is not available 'off the shelf'.
The Jersey Royal has to manage all of its own seed stocks, and in order to create a rolling 9,000 tonne seed stock it has taken 6 years to develop.
In 2008 The Jersey Royal Company took the decision to bring the whole process of seed regeneration in-house. This started by selecting several tubers from particularly good seed grown in the Island that was sent to SASA to be 'cleaned' of virus.
The process starts with a single tuber that has a v-shaped notch cut out which contains one of the potato's eyes. This eye is propagated under high care laboratory conditions to form a seedling that grows rapidly.
The speed of growth means that the virus held in the cells of the mother tuber cannot migrate up the stem as quickly as the growth of the seedling, and as such the stem can be cut at nodes higher up the seedling that are 'virus-free'. In practice, this has to be carried out several times over a 6 - 12 month period repeatedly cutting the stem from previous cutting until virus free seedlings are produced.
Each virus free cutting can then grow to five nodes and produce five cuttings, and so the multiplication process at this stage is five-fold over roughly a 5 week timeline.
Cuttings are planted as seedlings into seedling trays and grown under controlled conditions until they reach a mature plant after 4 - 5 months. Each seedling will produce approximately 4 - 5 mini tubers. The mini tubers are harvested in July / August and then stored through the dormant period, ready for planting out in open fields the following spring.