The Meristem Programme ensures quality

Our professional multiplicationprogram forms the basis of our potato quality

The Danish Meristem Programme was established to ensure that a completely disease-free material is used for professional multiplying of seed potatoes. Furthermore, obligated replacement as a continuing process will ensure that only this disease-free material will be used.

In short, the Meristem Programme is about developing meristem tubers from a few growth cells in a potato sprout to be used for multiplying seed potatoes. As opposed to this the traditional cloned multiplication is based on single tubers where the risk of disease particles is much bigger than by meristem breeding.

The Danish Meristem Programme

In 1977, Denmark abandoned the traditional cloned multiplication (selection of healthy variety typical single tubers for multiplication) and gradually started producing potato tubers via meristem breeding. In 1986, the Meristem Programme was completely implemented for all professional seed potato growing in Denmark.

A meristem is the few outermost growth cells of a potato sprout, that is few 1/10 millimetres. Disease particles are spread in potato tubers and sprouts but they do not get to these outermost cells. The potato meristem is cut with a scalpel under a microscope and is put on a growth medium in glass test tubes. Here the meristem grows to a small potato plant – the meristem plant.

The company Vitroform in Denmark does the fabrication of meristems and the multiplication until meristem plants. During this stage the meristem and the meristem plants are sent to several examinations in SASA in Scotland  to ensure that they are completely disease-free and genetically genuine.

The meristem plants are sent back to Vitroform where every single meristem plant is cut into 10-12 meristem cuttings. These will be put into glass test tubes again to produce meristem plants or they can be planted directly into pots in insect-proof net houses to produce the first tubers – the meristem tubers.

The breeding material for the prebasic grower

The meristem tubers are delivered to the prebasic growers (PB growers). The first year, the meristem tubers are planted to grow/breed class PB1; PB1 can grow to class PB2 – and like this, the prebasic growers can grow up to 4 generations/classes at the same time. That is:

  • Meristem tubers to PB1
  • PB1 to PB2
  • PB2 to PB3
  • PB3 to PB4

Breeding these different classes takes place at the same time in a closed system. PB1 to PB4 are the breeding classes, and when tubers from one of these classes from the prebasic grower are sold to other seed potato growers it is done in one of the sales classes PB or S.

The sales classes PB or S are determined by the virus content (Virus Y and Leaf Roll) at the winter testing where the PB has 0 % virus.

Basic grower with own breeding

The PB material is sold to basic growers, that is seed potato growers who grow  the class PB class S, S to class SE, SE to class E and E to class A. Our basic growers can therefore grow several classes at the same time. The seed material must be PB material or seed material from own breeding.

Basic grower without own breeding

This group of growers must every year buy the seed material of class E or higher and can then grow/breed the following class E or for breeding class A. At the winter test class E must not contain more virus that 2 % and class A no more virus than 8 %. When there is more virus than 8 % the party/lot will be rejected as seed potatoes. The down classification to a lower class for the basic grower therefore takes place at an overstepping of the virus boundaries of 2 % and 8 % virus at the winter test.