What is landrace cannabis?
A landrace is a domesticated, locally adapted, traditional variety of Cannabis that has developed over time through adaptation to its natural and cultural environment along with being isolated from other populations of the species.
Specimens of a landrace tend to be genetically very similar, though much more diverse than members of hybrid and IBL populations. Some heirlooms and modern hybrids originate from attempts to make landraces more consistent through selective breeding, however, stabilising a landrace may result in the genetic resource of a landrace being lost through cross and inbreeding.
Landraces are distinct from ancestral wild-type Cannabis. Not all landraces derive from ancient stock largely unmodified by human breeding interests. In a number of cases, domesticated cannabis escaped in sufficient numbers in an area to breed feral populations that, through evolutionary pressure, can form new landraces in only a few centuries.
In other cases, simple failure to maintain breeding regimens can do the same. For example, selectively bred cultivars can become new landraces when loosely selective reproduction is applied.
Increasing adoption of and reliance upon modern, purposefully selected plant strains, considered improved – "scientifically bred to be uniform and stable" – has led to a reduction in biodiversity.
The majority of the genetic diversity in a given domesticated species lies in landraces and other traditionally used varieties, they can be considered "reservoirs of genetic resources".
What are the characteristics that define a landrace?
General features that characterise a landrace may include:
Particular and recognizable characteristics or properties that may be dynamic.
It is genetically adapted to and able to withstand the conditions of the local environment including climate, disease and pests - even cultural practices.
It is not the product of formal (governmental, organizational, or private) breeding programs, and may lack systematic selection, development and improvement by breeders.
It is maintained and fostered less deliberately than a formal "strain", with its genetic isolation principally a matter of geography acting upon human culture and it's transmission across a given area.
It has a historical origin in a specific geographic area, will usually have its own local name(s).
A landrace will show high stability of yield, even under adverse conditions, but a moderate yield level, even under carefully managed conditions.
At the level of genetic testing, its heredity will show a degree of integrity, but still some genetic heterogeneity (i.e. genetic diversity).
Note, not all cultivars agreed to be landraces exhibit all possible landrace characteristics.
What does the word ‘landrace’ mean?
The word landrace literally means 'country-breed' (German: Landrasse) and close cognates of it are found in various Germanic languages. Equivalents are found in several other languages, notably ‘Bheldia’ as a term to describe Cannabis landraces from the Maghreb..
The term was first defined (in German) by Kurt von Rümker in 1908, and more clearly described (in Dutch) in 1909 by U. J. Mansholt, who wrote that landraces have better "stability of their characteristics" and "resistance capacity to tolerate adverse influences" but lower production capacity than cultivars, and are apt to change genetically when moved to another environment. H. Kiessling added in 1912 that a landrace is a mixture of phenotypic forms despite relative outward uniformity, and a great adaptability to its natural and human environment. The word entered non-academic English in the early 1930s, by way of the Danish Landrace pig, a particular breed of lop-eared swine.
A landrace native to, or produced for a long time (e.g. 100 years or longer) within the agricultural system in which it is found is referred to as an autochthonous landrace, while an introduced one is termed an allochthonous landrace.