Landrace cannabis

Definition

Landrace cannabis is a cultivated cannabis population that has evolved over time in a specific geographic region, shaped by local environmental conditions and human cultural practices. Cannabis landraces are genetically diverse and locally adapted, often valued for unique traits such as flavour, resilience or suitability for traditional uses. [1] [2] [3]

Characteristics

There are differences between authoritative sources on the specific criteria which describe landraces, although there is broad consensus about the existence and utility of the classification. Individual criteria may be weighted differently depending on a given source's focus (e.g., governmental regulation, biological sciences, agribusiness, anthropology and culture, environmental conservation, home-growing and breeding, etc.). Additionally, not all populations agreed to be landraces exhibit every characteristic of a landrace.[5]

General features that characterize a landrace may include:

It is morphologically distinctive and identifiable (i.e., has particular and recognizable characteristics or properties) yet remains "dynamic".[5][12]

It is genetically adapted to and has a reputation for being able to withstand the conditions of the local environment including climate, disease and pests even cultural practices.[5][12]

It is not the product of formal (governmental, organizational, or private) breeding programs and may lack systematic selection, development and improvement by breeders.[2][4][5][13]

It is maintained and fostered less deliberately than a standardized breed/cultivar, with its genetic isolation principally a matter of geography acting upon whatever plants that happened to be brought by humans to a given area.[2]

It has a historical origin in a specific geographic area, will usually have its own local name(s) and will often be classified according to intended purpose.[5][12][13]

Where yield can be measured, a landrace will show high stability of yield, even under adverse conditions, but a moderate yield level, even under carefully managed conditions.[7]

At the level of genetic testing, its heredity will show a degree of integrity, but still some genetic heterogeneity (i.e. genetic diversity).[5][12][13][14]

Terminology

Historically, the term “landrace” was coined in the early 20th century (von Rümker, 1908) to distinguish traditional farmer varieties from modern, uniform cultivars. Early definitions focused on populations that had evolved without formal breeding programs and were selected primarily by farmers through traditional practices. [1] [3] [4]

Over time, however, scholars recognised that landraces are not static or relic-like. They are dynamic populations, constantly evolving due to natural selection in local environments, ongoing seed exchange among farmers and occasional introgression from other cultivars or hybrids.

Zeven (1998) emphasized that landraces continuously “contaminate” each other through gene flow, leading to gradual adaptation and genetic shifts rather than fixed, pure lines. [4]

Modern scholarship, notably that of Casañas et al. (2017), has further expanded the concept. They argue that landraces can legitimately incorporate modern breeding techniques as long as they remain tied to local adaptation, cultural practices and farmer participation. [1]

Casañas et al. propose:

“Landraces consist of cultivated varieties that have evolved and may continue evolving, using conventional or modern breeding techniques, in traditional or new agricultural environments within a defined ecogeographical area and under the influence of local human culture.” [1]

Autochtonous and Allochtonous landraces

A landrace native to, or produced for a long time within the agricultural system in which it is found is referred to as an autochthonous landrace, while a more recently introduced one is termed an allochthonous landrace.[7][5][9]

Within academic agronomy, the term autochthonous landrace is sometimes used with a more technical, productivity-related definition, synthesized by A. C. Zeven from previous definitions beginning with Mansholt's: "an autochthonous landrace is a variety with a high capacity to tolerate biotic and abiotic stress, resulting in a high yield stability and an intermediate yield level under a low input agricultural system."[7]

Landraces vs. Cultivars vs. Hybrids

In cannabis nomenclature, these terms are often confused or used interchangeably, though they describe fundamentally different genetic categories: Landraces are populations that have evolved through natural and human selection in specific geographic regions over extended periods, maintaining genetic diversity while exhibiting local adaptation. They represent dynamic gene pools rather than fixed genetic lines.[1][2]

Cultivars (cultivated varieties) are plants that have been intentionally selected and bred for specific traits, resulting in relatively uniform populations. Modern cannabis cultivars are typically stabilized through selective breeding programs to express consistent characteristics across generations.[Citation needed]

Hybrids are the result of intentional crosses between distinct parental lines, whether between different landraces, between cultivars, or between landraces and cultivars. First-generation hybrids (F1) often exhibit hybrid vigor but subsequent generations may show significant phenotypic variation.[Citation needed]

The distinction becomes particularly important in cannabis conservation and authentication efforts. A landrace population grown in its region of origin differs fundamentally from the same population grown elsewhere (which may be termed an heirloom or preserved line) and from stabilized cultivars derived from that landrace.[2]

Biodiversity and Conservation

A significant proportion of farmers around the world grow landrace crops.[4] However, as industrialized agriculture spreads, cultivars, which are selectively bred for high yield, rapid growth, disease/drought resistance, and other commercial production values, are supplanting landraces, putting more and more of them at risk of extinction.[citation needed]

In 1927 at the International Agricultural Congress, organized by the predecessor of the FAO, an extensive discussion was held on the need to conserve landraces. A recommendation that members organize nation-by-nation landrace conservation did not succeed in leading to widespread conservation efforts.[7]

Landraces are often free from many intellectual property and other regulatory encumbrances. However, in some jurisdictions, a focus on their production may result in missing out on some benefits afforded to producers of genetically selected and homogenous organisms, including breeders' rights legislation, easier availability of loans and other business services, even the right to share seed or stock with others, depending on how favorable the laws in the area are to high-yield agribusiness interests.[8]

As Regine Andersen of the Fridtjof Nansen Institute (Norway) and the Farmers' Rights Project puts it, "Agricultural biodiversity is being eroded. This trend is putting at risk the ability of future generations to feed themselves. In order to reverse the trend, new policies must be implemented worldwide. The irony of the matter is that the poorest farmers are the stewards of genetic diversity."[8] Protecting farmer interests and protecting biodiversity is at the heart of the International Treaty on Plant Genetic Resources for Food and Agriculture (the "Plant Treaty" for short), under the Food and Agriculture Organization of the United Nations (FAO), though its concerns are not exclusively limited to landraces.[8]

Landraces played a basic role in the development of the standardized breeds but are today threatened by the market success of the standardized breeds. In developing countries, landraces still play an important role, especially in traditional production systems.[6]

In cannabis, landrace conservation faces unique challenges due to the plant's history under prohibition [Citation needed]. Many traditional growing regions have experienced eradication campaigns, habitat loss through development and genetic contamination from introduced hybrid varieties [Citation needed]. Unlike food crops, cannabis landraces often lack formal documentation [Citation needed], relying instead on oral tradition and farmer knowledge that is increasingly at risk as younger generations move away from traditional agriculture [Citation needed].

Cannabis landraces played a basic role in the development of the standardized strains available today [Citation needed], but are threatened by the market success of those standardized strains. In developing countries, landraces still play an important role, especially in traditional production systems.[6]

In situ and ex situ landrace conservation

Three approaches have been used to conserve plant landraces:

In situ where the landrace is grown and conserved by farmers on farms.
Ex situ where the landrace is conserved in an artificial environment such as a gene-bank, using controls such as laminated packets kept frozen at −18 °C (0 °F).
Ex situ where the landrace is grown and reproduced in small numbers by enthusiasts, either outdoors or outdoors.

As the amount of agricultural land dedicated to growing landrace crops declines, such as in the example of wheat landraces in the Fertile Crescent, landraces can become extinct in cultivation. Therefore ex situ landrace conservation practices are considered a way to avoid losing the genetic diversity completely. Research published in 2020 suggested that existing ways of cataloging diversity within ex situ genebanks fall short of cataloging the appropriate information for landrace crops.[10]

An in situ conservation effort to save the Berrettina di Lungavilla squash landrace made use of participatory plant breeding practices in order to incorporate the local community into the work.[11]

Landrace Cannabis Growing Regions

Click here to see a curated, easy to browse list of landrace growing regions.

References

[1] Casañas, F., Simó, J., Casals, J., & Prohens, J. (2017). Toward an evolved concept of landrace. Frontiers in Plant Science, 8, 145. doi: 10.3389/fpls.2017.00145

[2] Clarke, R. C., & Merlin, M. D. (2013). Cannabis: Evolution and Ethnobotany. University of California Press.

[3] von Rümker, K. (1908). Die systematische Einteilung und Benennung der Getreidesorten für praktische Zwecke. Jahrbuch der Deutschen Landwirtschaftsgesellschaft, 23, 137–167.

[4] Zeven, A. C. (1998). Landraces: a review of definitions and classifications. Euphytica, 104(2), 127–139. doi: 10.1023/A:1018683119237

[5] Camacho Villa, Taina Carolina; Maxted, Nigel; Scholten, Maria; Ford-Lloyd, Brian (December 2005). "Defining and Identifying Crop Landraces". Plant Genetic Resources. 3 (3): 373–384. Bibcode:2005PGRCU...3..373V. doi:10.1079/PGR200591. S2CID 5234510.

[6] Commission on Genetic Resources for Food and Agriculture. "Glossary of Selected Terms" (PDF). In Vivo Conservation of Animal Genetic Resources. FAO Animal Production and Health Guidelines. UN Food and Agriculture Organization. pp. xv–xx. ISSN 1810-0708

[7] Zeven, A. C. (1998). "Landraces: A Review of Definitions and classifications". Euphytica. 104 (2): 127–139. doi:10.1023/A:1018683119237. S2CID 20631394.

[8] Andersen, Regine (April 2010). "An Issue of Survival". Development & Cooperation. Internationale Weiterbildung und Entwicklung.

[9] "Section B. Landraces: B.1. Introduction" (PDF). Resource Book for the Preparation of National Plans for Conservation of Crop Wild Relatives and Landraces. Food and Agriculture Organization of the United Nations. 2014.

[10] Ramirez-Villegas, Julian; Khoury, Colin K.; Achicanoy, Harold A.; Mendez, Andres C.; Diaz, Maria Victoria; Sosa, Chrystian C.; Debouck, Daniel G.; Kehel, Zakaria; Guarino, Luigi (2020). "A gap analysis modelling framework to prioritize collecting for ex situ conservation of crop landraces". Diversity and Distributions. 26 (6): 730–742. Bibcode:2020DivDi..26..730R. doi:10.1111/ddi.13046. hdl:10568/108131. ISSN 1366-9516. JSTOR 26914952. S2CID 216486179.

[11] Andreani, L.; Camerini, G.; Delogu, C.; Fibiani, M.; Lo Scalzo, R.; Manelli, E. (2022-03-01). "How to save a landrace from extinction: the example of a winter squash landrace (Cucurbita maxima Duchesne) in Northern Italy (Lungavilla-Pavia)". Genetic Resources and Crop Evolution. 69 (3): 1163–1178. Bibcode:2022GRCEv..69.1163A. doi:10.1007/s10722-021-01294-2. ISSN 1573-5109. S2CID 244432667.

[12] Harlan, Jack R. (1975). Crops and Man. Madison, Wisconsin: American Society of Agronomy and Crop Science Society of America. ISBN 0-89118-032-X.

[13] Friis-Hansen, Esbern; Sthapit, Bhuwon, eds. (2000). Participatory Approaches to the Conservation and Use of Plant Genetic Resources. Rome, Italy: International Plant Genetic Resources Institute. p. 199. ISBN 978-92-9043-444-3.

[14] Harlan, Jack R. (1971). "Agricultural Origins: Centers and Noncenters: Agriculture May Originate in Discrete Centers or Evolve Over Vast Areas Without Definable Centers". Science. 174 (4008): 468–474. doi:10.1126/science.174.4008.468. JSTOR 1733521. PMID 17745730. S2CID 24239918.