Landrace cannabis

A landrace is a cultivated plant population that has evolved over time in a specific geographic region, shaped by local environmental conditions and human cultural practices. Landraces are genetically diverse and locally adapted, often valued for unique traits such as flavor, resilience, or suitability for traditional uses. [1] [3] [4]

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 cultivars agreed to be landraces exhibit every characteristic of a landrace.[5]

General features that characterize a landrace may include:

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][18]

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]

The terms autochthonous and allochthonous are most often applied to plants, with animals more often being referred to as indigenous or native. Examples of references in sources to long-term local landraces of livestock include constructions such as "indigenous landraces of sheep",[19] and "Leicester Longwool sheep were bred to the native landraces of the region".[20] Some usage of autochthonous does occur in reference to livestock, e.g. "autochthonous races of cattle such as the Asturian mountain cattle – Ratina and Casina – and Tudanca cattle."[21]

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 and 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.[9]

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."[9] 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.[9]

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] Specimens within an animal landrace tend to be genetically similar, though more diverse than members of a standardized or formal breed.[2]

In situ and ex situ landrace conservation

Two approaches have been used to conserve plant landraces:[10][22]

   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).

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.[22]

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.[23]

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.