Seedsman Blog
landrace heirloom
Home » Landrace vs Heirloom Cannabis

Landrace vs Heirloom Cannabis

Landrace, just the mention of the word, is known to grab any cannaseurs attention and conjures up visions of rare cannabis gene pools pristinely preserved in exotic locations, free from man’s intervention and located more than a wind-blow away from any modern hybrid.

It’s often asked if landrace varieties still exist or if they have been bred out of existence due to cross-pollination from modern hybrids being introduced to local gene pools. We need to have clear definitions to understand what we are looking for.

What is a Landrace Strain?

A landrace is a plant variety which has adapted to its local environment and can be considered the oldest type of crop cultivars. Landraces originally started from wild populations and, over time and generations, have developed a distinct identity.

Natural selection by climatic conditions in South and Central Asia initiated the divergence in wild cannabis populations, with phytochemical divergence being driven further by domestication. Landraces have adapted to best suit their local climate, with water availability, soil type, and ripening time influencing them.

These populations are maintained by wild open pollination or by local farmers saving seeds. As a domesticated crop, the gene pool of landraces is significantly wider and more diverse than a commercial variety while maintaining a distinct identity. An enhanced genetic diversity assists in maintaining crop health and vigour across generations, making it more adaptable and resilient to new environmental pressures such as pests, drought or flooding. 

Wild-type var. himalayensis growing in the Azad Kashmir region. Credit: Landrace Warden

Does Landrace Mean Wild-Type? 

When it comes to wild-type cannabis, the only true location that can make claim to wild-type cannabis, pre-domestication, is the Tibetan plateau and surrounding area, the true origins of ancestral cannabis where it diverged from hops over 25 million years ago, long before homosapiens came into existence. 

Distribution of collected herbarium specimens of wild-type himalayensis and wild-type asperrima. 
Green triangles: var. himalayensis.
Red circles: var. asperrima.

Wild-type variety ‘himalayensis’, also known as the primordial source of drug cannabis lines, and wild-type variety asperrima, also known as ‘wild-type Asian hemp’ are the only cannabinoid-rich cannabis populations on the planet that can make the claim to being free from man’s intervention.

CBD dominant wild-type varieties C. sativa var. spontanea and C. ruderalis, taxa assigned to the population of wild-type plants growing near Saratov, Russia, and found wild across Kazakhstan, are also worth mentioning for historical note, though less than 1% of these populations have THC dominant phenotypes, in contrast to more than half of wild-type ‘himalayensis’.

Landrace variety in Kalat, Balochistan.
This landrace variety has developed extreme drought resistance from years of adaption to the local environment. Credit: Landrace Warden

Once transported worldwide and planted in a new location, varieties change and adapt to new environmental inputs. Epigenetic changes across generations allow for a new distinct identity to be created in the new location. Through these changes, landraces like ‘Panama Red’ and ‘Malawi Gold’ have evolved, transported by man, then generationally adapted to the new location. Different gene pools and breeding lines may be introduced in the new location to increase resilience or adaption of the crop. These combinations, over time, create a unique identity that forms a landrace.

What is an Heirloom Cannabis Strain?

Heirloom varieties have a more distinct phenotype and less genetic variability than landrace, resulting from man’s selection and refinement for desired traits and expressions. Heirlooms are typically maintained by open pollination, but unlike a landrace, an heirlooms identity is not connected to any particular geographical location. Best thought of as varieties that have stood the test of time and been shared among gardeners and collectors for preferred traits.

Any combination of genetics can be used to create an heirloom. For example, ‘White Widow’, ‘Blue Dream or ‘Cheese’ could all be classed as heirloom cannabis varieties.

The gene pool allows for more consistency of the desired expression by limiting genetic variables, making the variety more demanding in its environmental requirements and less able to adapt to new stressors than a landrace. 

Seedsman Blue Dream

Heirlooms Gone Wild

A recent study in Serbia comparing wild-type hemp plants with EU industrial hemp cultivars and US CBD production cultivars found that overall the essential oil from wild-type plants was significantly different in its chemical profile and bioactivity compared to registered hemp cultivars.

Wild-type hemp plants consistently had higher levels of THC than registered varieties, a greater antimicrobial activity against Staphylococcus susp. aureus, Enterococcus faecalis, and G−Yersinia enterocolitica, Salmonella enterica subsp. enterica, and yeasts Candida albicans and Candida tropicalis, and one select pheno-type even producing higher levels of CBD in its essential oil than that of the US CBD production cultivar. 

Hindu Kush landrace with re-wilded traits.Credit: Landrace Warden

Man’s Influence on Landraces

Debate often centres around the definition of a true landrace and the extent of man’s involvement in the process.

While climatic changes can be a source of re-distribution of seeds to new areas, man has played a significant role in developing landraces. Classic landrace varieties like Panama Red, Colombian Gold and Mexican Zacateca all started with man selecting seeds to take across the ocean where these new varieties evolved from interacting and adapting to local environments.

It is often said that we are losing landraces, and while it is true many of the world’s historic cannabis cultivation regions since the 1970s have seen hybrids introduced, at the same time, new landraces will emerge. The very word implies that constant evolution is an integral part of what a landrace is. 

Towards an Evolved Concept of Landrace

Researchers in Spain have now proposed a more inclusive definition of landrace, where conventional or modern breeding techniques can be used in traditional or new agricultural environments within a defined ecogeographical area and under the influence of the local human culture. Unconscious, conscious selection, and breeder-assisted technology could be used in a mixed selection system which could be established to develop evolved landraces.

An evolved concept of Landrace

Wild-type populations are an excellent source for strengthening the genetic basis and accumulation of desirable variation, which has been lost due to selection pressures and adaptation in modern cultivars.

Landraces have co-evolved alongside man with strong ties to local culture and agriculture and will continue to do so.

While overall horticultural quality and harvest of improved hybrids have increased yearly, this improvement has been accompanied by a reduction in allelic diversity. Association mapping and genomic prediction studies can be used to identify novel sources for resistance to abiotic and biotic stresses by identifying alleles for enhancing yield and abiotic stress adaptation, thus raising the productivity and stability of crops in vulnerable environments. 

References:

Cultivation information, and media is given for those of our clients who live in countries where cannabis cultivation is decriminalised or legal, or to those that operate within a licensed model. We encourage all readers to be aware of their local laws and to ensure they do not break them.

Kyle Esplin