Landrace conservation

Part of a series on

Conservation

Potatoes of Chiloé on show at Castro in 2008. Named landraces of the island were counted between 1928 and 1969.

Cannabis conservation·Grow-out priorities·Populations

Threat Categories

Extinction

Genetic Threats

Genetic erosion·Genetic contamination·Introgression·Gene flow·Hybridisation·Population bottleneck·Genetic drift·Inbreeding depression

Habitat & Environmental Threats

Habitat loss

Eradication Tracking & Analysis

Eradication·Herbicide spraying of cannabis·Herbicide spraying in Mexico·Herbicide spraying in the United States·Herbicide spraying in Colombia·Herbicide spraying in Belize·Herbicide spraying in South Africa·US eradication abroad·Yukthiya·Cannabis eradication in Kirivong·Cannabis eradication in Fiji·Campaigns by country

International Enforcement

Cannabis prohibition·US eradication abroad·INCB

Legal & Policy

Farmers' rights·Access and benefit-sharing·Intellectual property·Single Convention on Narcotic Drugs·1988 Convention·Cannabis legalisation movement

Population Assessment

Minimum viable population·Population viability analysis·Effective population size

Conservation Monitoring

Population monitoring·Genetic monitoring

Conservation Methods - Ex Situ

Ex situ conservation·Gene bank·Cryopreservation·In vitro conservation·Core collection·Seed storage

Conservation Methods - In Situ

In situ conservation·On-farm conservation·Genetic reserve·Community seed bank·Feral and ruderal populations

Genetic Conservation

Germplasm·Genetic resources·Crop wild relative·Conservation genetics

Sampling & Collection

Germplasm collecting·Germplasm sampling

Preservation Strategies

Conservation prioritisation·Complementary conservation

Recovery & Restoration

Reintroduction·Genetic rescue

Conservation Science

Landrace conservation

Portal·Category

Landrace conservation is the keeping of crop landraces in cultivation and in stored samples. In practice it mostly means on-farm conservation by the people who grow a landrace or seed storage in gene banks.^: 7 Landraces go on changing under farmers and the environment, which leads some authors to prefer "preserving" or "maintaining" to conservation in the strict sense.^: 46 Data on how many have been lost are few and seldom rigorously quantified.^: 11

In European studies from 2010 to early 2024, tomato and common bean were the species most often named as keywords.^: 2712 Cannabis enters this work as hemp in the national landrace inventories of Romania and Russia.^{: 139–140: 150–151} Robert Clarke and Mark Merlin held of the plant that "the vast majority of landraces may already be extinct". They give no count.^: 318

Early proposals

E. von Proskowetz and F. Schindler proposed a discussion of landrace conservation at an agricultural and forestry congress in Vienna in 1890, and landrace conservation was raised again in 1906. The International Agricultural Congress at Rome recommended in 1927 that participants organise it in their own countries by growing landraces on farms and in school plots. Only Austria made a start, and the organisation there broke down after a few years. In 1936 Harlan and Martini argued for conserving landraces in North America.^: 127 From the end of the 19th century large numbers of accessions went into American and Soviet collections, the latter through researchers led by Nikolai Vavilov.^: 128

Plant genetic resources have historically been conserved mainly in stores. On-farm conservation was proposed later as a way to keep a complex of populations evolving.^: 6 The plant treaty of 2001 asks parties to survey and inventory their resources and to support the efforts of farmers to conserve them on the farm.^: 4–5 In a European volume they edited in 2009, Valeria Negri, Nigel Maxted and Merja Veteläinen count breeding value, food security and local culture among the reasons to keep landraces.^: 2–4 Anton Zeven compared landraces to monuments, regional dress and folk songs as cultural heritage.^: 128

What is being kept

Main article: Landrace Cannabis

Tania Carolina Camacho Villa and colleagues argued in 2005 that conservation had been held back by the lack of an accepted definition, since an inventory needs one and changes can be recognised only against an inventory. Their working definition describes a "dynamic population(s) of a cultivated plant" with a historical origin and a distinct identity, lacking formal crop improvement, often genetically diverse, locally adapted and tied to traditional farming. Not every landrace has every feature. A definition from a European task force adds a close link to "the uses, knowledge, habits, dialects, and celebrations" of the people who developed the crop and still grow it.^: 9 On that definition a landrace brought in from elsewhere would not qualify even once locally adapted, since the people growing it did not develop it. Negri and colleagues say that treating such populations as landraces at anyone's disposal raises questions of farmers' rights.^: 9–10 Zeven concluded in 1998 that a landrace is too complex for an all-embracing definition and judged that the intensity of selection on one "will have varied from nil to quite strong selection".^: 136–137

For Negri and colleagues the aim of landrace conservation is the full range of diversity within a landrace. Because landraces are variable populations of a crop taxon, they hold that the IUCN Red List categories, built for whole taxa, would not be effective in their usual sense.^: 16

Because landraces keep changing, Maxted, Veteläinen and Negri prefer to speak of "preserving" or "maintaining" diversity in the field, with storage as a back-up.^: 46 Francesc Casañas and colleagues object that definitions excluding formal breeding would turn landraces into "museum relics". Pierre-Arnaud Chouvy warns against a landrace being "musealized" through strict conservation.

Inventories and names

Maxted, Veteläinen and Negri treat an inventory as the first step. As far as they knew in 2009, no country had a complete national inventory of its landraces.^: 45–46 In their view genotyping every landrace would be impractical, so inventories use names and expert knowledge in its place.^: 46–47 Farmers may use one name for genetically distinct populations and several names for one population. A potato landrace of the Nordic countries has up to 18 documented names.^: 10–11 Variety names could not stand in for diversity in common bean in Romania.^: 141

A European survey published in 2022 found 19,335 georeferenced cultivation sites and over 4,500 landrace names, in 141 herbaceous and 48 tree species. One landrace can carry several names, and some countries and crops are missing.^: 2715

Measuring loss

Main article: Genetic erosion

Negri and colleagues wrote in 2009 that few data exist on landrace extinction or genetic erosion, that objective evidence is "largely absent" and that assessment is mostly anecdotal or based on names. Examples include counts of named potato landraces on Chiloé, from 200 in 1928 to 35 or 40 in 1969, and farmers in Ethiopia naming 26 tetraploid wheat landraces of which six remained available. They concluded that landraces are highly threatened and that without immediate action "complete extinction is the only possible conclusion".^{: 11–12, 16} Maize landraces in central Italy showed introgression from hybrids with no sign of erosion, while a study of rice landraces in South and Southeast Asia detected no significant reduction.^: 15 The editors asked for genetic time series, setting stored samples against fresh ones from the same localities.^: 316

Negri and colleagues attribute losses to the replacement of landraces by bred cultivars, to seed law and to the loss of the people who grow them.^: 12–14 Bred cultivars spread because they yield more under high inputs. Wheat in Europe went from about 1.2 to 4 tonnes a hectare from the early 1900s, with about half of the rise credited to breeding.^{: 3, 12} Registration in European variety catalogues requires a variety to be distinct, uniform and stable. The editors hold that the stability requirement goes against the nature of a landrace.^{: 2723: 309} In central Italy, where 427 landraces were found on farms, Negri wrote that social problems seem to be the main cause of erosion.

On farms and in gardens

Main article: In situ conservation

Bere barley ready to harvest in 2008, with unripe green patches of other varieties. Local groups in Scotland support bere as a landrace tied to its territory.

Negri and colleagues widened Maxted's 1997 definition of on-farm conservation to the management of local crop varieties by farmers within their own farming systems, because in Italy many landraces are grown with modern techniques and in other countries with few inputs.^: 7 A study of 27 crops on five continents found considerable diversity still kept on farms, much of it through many small farms following different strategies. In the European Union the people keeping landraces include single farmers and gardeners, producers' consortia, seed networks, small seed companies and public authorities. Lorenzo Raggi, Giorgia Spataro and Negri consider single farmers and gardeners the main actors, though most of them are unknown.^{: 2717–2720} Growers keep landraces for adaptation, family habit, taste and price. Products with a mark of origin can be particularly lucrative, and emmer wheat from Monteleone di Spoleto carries one.^{: 2715–2716}

Commission Directive 2008/62/EC lets landraces and old varieties under threat of erosion be registered as conservation varieties, with their seed sold in limited amounts in their region of origin. The European Union's common catalogue of varieties held 412 conservation varieties of agricultural species and 193 of vegetables in 2022, far below the number of known landraces in the assessment of Raggi and colleagues.^{: 2723–2724, 2728} Negri and colleagues thought it unlikely in 2009 that a directive mainly concerned with seed trading would preserve all the diversity then maintained.^: 14

The editors of the 2009 volume wrote that on-farm work in Europe depended on particular researchers and single projects.^: 307 Raggi and colleagues still called it "patchy" and poorly coordinated in 2024.^: 2727 Zeven thought it somewhat exaggerated to say that landraces and farmers need each other to survive, since a farmer may easily switch from one landrace to another.^: 136–137 A review by Mauricio Bellon and colleagues found little evidence that interventions in support of on-farm conservation did more than farmers were already doing.

Stored samples

Main article: Ex situ conservation

The editors of the 2009 volume held that keeping all landrace diversity on farms is unlikely ever to be possible and that a stored back-up is therefore critical. Gene banks also often give users easier access.^: 316 In March 2009 the European catalogue EURISCO listed 234,447 landrace accessions, 36 per cent of its total. The editors say that the number cannot show whether the holdings reflect diversity in the field. Negri and colleagues call the collections almost random.^{: 307–308: 16} A modelling study of common bean in the Americas found that collections represent 78.5 per cent of the predicted range of its Andean gene pool and 98.2 per cent of the Mesoamerican one.

At the Vavilov Institute, some wheat populations regrown as mixtures lost components over time.^: 151 Bellon and colleagues describe stored samples as "frozen snapshots" of each population at the time of collecting.

Cannabis in the landrace literature

The west building of the Vavilov Institute in Saint Petersburg in 2010. Its collection keeps many Russian landraces that are no longer grown.

Landraces of Cannabis sativa were noted in ten villages of six Romanian counties between 2000 and 2008. Silvia Strajeru and colleagues judged fibre crops the worst placed, and an old hemp variety was found in cultivation in 2008 at Groșii Țibleșului in Maramureș County.^: 139–140 Cultivated hemp in Russia forms Northern and Mid-Russian groups, both perhaps developed from local weedy forms. The northernmost landraces are short, early-ripening and suitable only for oil. Tamara Smekalova counts hemp among the crops whose growing is practically lost. Many Russian landraces survive in the Vavilov Institute's collection, though some have been lost there.^: 150–151 A Finnish call for landraces in 2006 asked for hemp along with cereals and forages.^: 72 The resource book of Maxted and colleagues names Cannabis sativa in a list of European crop databases. In November 2026, 30 of the 97 cannabis accessions at the Suceava Genebank in Romania had the status of landrace or traditional cultivar, along with all 106 at INRA Maroc.

Clarke and Merlin held that the majority of traditional landraces are no longer grown and named prohibition, neglect and economic priorities among the routes of loss. They give no count for this or for their statement on extinction.^: 317–318 John McPartland and Ernest Small wrote that Central and South Asian landraces "face extinction through introgressive hybridization". Fatima Bachir and colleagues described Moroccan varieties as contaminated and rapidly disappearing, while Chouvy holds that kif remains distinct. Genetic time series of the kind the 2009 editors ask for need dated samples from known localities.^: 316 Public passport data for cannabis accessions were absent or of low quality when Matthew Welling and colleagues reviewed them in 2016. Bachir and colleagues suggest sampling herbaria to work out the history of Moroccan cannabis. In the Rif Mountains, Chouvy and Kenza Afsahi reported in 2014 that growers had begun to call kif by names such as beldiya, from the Arabic for countryside or local, as hybrids spread.

McPartland and Small put the threat down to foreign seed and crossing. Clarke and Merlin quote a list by Watson and Clarke that includes suppression and eradication.^: 318 Chouvy and Afsahi found it "not clear what role forced eradication might have played" in the Rif's turn to hybrids. Morocco's law of 2021 requires growers to use certified seed.^: 1173 A press report of March 2024 said that the national agency, ANRAC, had authorised a first supervised trial of the local variety in the Al Hoceima region, with wider growing dependent on tests; the agency had not yet confirmed it. By August 2024 the agency had authorised seed of the variety for 106 cooperatives. Chouvy calls an appellation of origin the best available form of intellectual property for Moroccan hashish and the kif landrace, though the illegality of the product makes such protection problematic for now, less so for the landrace than for the resin.

Clarke and Merlin held that indigenous farmers who maintain local landraces preserve genetic diversity and that limited traditional hemp production at lower latitudes relies mostly on landraces.^{: 317, 319} The reviews by Welling and colleagues, Clarke and Merlin and McPartland and Small describe no on-farm project set up for cannabis, which does not show that no local effort exists. Other reasons given for and against conserving cannabis are treated under cannabis conservation.

See also

• Cannabis conservation
• Community seed bank
• Complementary conservation
• Ex situ conservation
• Farmers' rights
• Gene bank
• Genetic contamination
• Genetic erosion
• Germplasm
• In situ conservation
• Landrace Cannabis
• On-farm conservation