Here we go. An expression which makes one (not only one:)) totally exhausted. We all know that the term ‘Kultur’- ‘culture’ has its origin in the Latin ‘colere/ cultura- cultivation’ and that this term’s correlations with agriculture (nomen omen) are out of any question.
Whilst the noun ‘Saat” (seed-s) rather poses no problems to translators, its combination with ‘Kultur’ really does.
While searching for possible solutions being useful for the translation of the first part of the compound noun I found such expressions as: culture seeds/ cultural seeds and last, but NOT the least – cultured seeds.
Moreover, Kultursaat’ is also “ein Verein” in Germany, but this is not the point in this discussion.
Kultursaat as an organization:
http://www.kultursaat.org/

We cannot rely on the translations of ‘linguee’ for two reasons: First of all they “could be wrong” (a comment in case of translations that have not finally been verified or might be questioned) and in fact- they are wrong, except for ‘Kultursaat’ as an organization- that one is not translated.
What we could take into consideration ( it is only a proposal)is the term 'cultured' even though it is rarely used, but- as I think- it relates to something ‘artificially grown’. (see the explanation in the references and in the dictionary)

http://www.dict.cc/german-english/Kultur.html

In the reference text (also available in PDF format) there is a sentence:
In 2007, Kultursaat (cultural seeds), a no-profit Association of Central European Biodynamic plant breeders, set up a gene bank for the collection and in-situ maintenance of open pollinated varieties. More than 800 OP varietieswere bought from all over Europe as the sense was they would likely be taken off seed lists in the near future.
(This project was co-funded by the German federal program for organic farming)
LINK to the text:

http://www.soilassociation.org/LinkClick.aspx?fileticket=0k3...

What is meant, is the ‘non-profit Association’, but the term has been translated; so the translator did want to provide some insight into the meaning of the German term and- to some degree- he might have been right in doing so.

Finally- ‘züchten” and ‘cultivate/ breed’ makes me think that in this particular context there are similarities towards the discussed ‘Kultursaat’.