Some plant species cross-pollinate easily, or even require cross pollination in order to produce seeds and fruit. In cross pollination, the flower’s pistils are fertilised with pollen from other plant individuals with different genetic make-ups, and the resulting seeds have a combined genome from the mother and father plants. The seeds therefore differ from the species that we want to preserve. For this reason, the varieties of these plant species are not preserved as seeds, but as growing plants, from which cuttings, grafts, runners, etc. are taken.
Other reasons not to preserve plant species as seeds can be, for example, the fact that the plant is not good at producing growable seeds, or that their seeds only survive for a short amount of time.
Plant species that are preserved vegetatively are fruit, berries, perennial plants, certain spices and herbs, roses, some trees and bushes, and a selection of vegetables including asparagus, Jerusalem artichokes, shallots and rhubarb.
The Nordic countries have national programmes to preserve their genetic resources in accordance with the Convention on Biological Diversity or the Rio Convention. The bodies responsible for preservation in the Nordic region vary, depending on whether it is seed or vegetatively-propagated plant material. NordGen preserves the seed-propagated plant species in a central seed vault. The vegetatively-propagated plant species are preserved by each individual Nordic country, in central collections and in local clonal archives located in, for example, open-air museums, rural museums, institutions and universities.
NordGen is responsible for storing and disseminating documentation about Nordic plants that are vegetatively propagated. This information is accessible to everyone, primarily through NordGen’s website and a web-based database called SESTO. Information and knowledge are also disseminated through written documents, lectures, exhibitions, symposia and in contact with authorities and politicians.