Talk:Ex situ conservation

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Discussion for: Ex situ conservation • View • Links • Related changes

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Page scope

Ex situ conservation covers keeping cannabis away from its source population: why it is done, how long stored seed lasts, how an accession is regrown, the keeping of living plants, tissue and pollen, losses from collections and the law on holding cannabis. The material itself and the published list of collections belong to Germplasm; the facility and its operating standards to Gene bank; how many plants an accession needs to keep its variation to Effective population size; the measurement of variation to Genetic diversity; the seed lots of each accession to Help:Seed lots.

Data verification

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Discussion

Sources

• FAO, Genebank Standards for Plant Genetic Resources for Food and Agriculture (revised edition, 2014): p. 4 on field gene banks; glossary, pp. 163–165, on ex situ conservation, stored pollen, long-term conservation, orthodox seeds and regeneration.
• Toole, Toole and Nelson (1960), USDA Technical Bulletin 1215: four lots of hemp seed stored for five and a half to eight years in controlled and uncontrolled conditions.
• Small and Brookes (2012), Journal of Natural Fibers 9: 240–255: a 66-month factorial trial of four temperatures and three moisture contents on five forms of cannabis.
• Parihar and colleagues (2014), The Indian Journal of Agricultural Sciences 84: 1303–1309: 36 months at five moisture contents and three temperatures; orthodox storage behaviour.
• Cockson and colleagues (2025), Agrosystems, Geosciences & Environment 8: e70129: hemp seed at 6 to 14 per cent moisture and four temperatures over 24 months.
• Welling and colleagues (2016), Frontiers in Plant Science 7: 1113: losses from collections, regrowing, seed storage, the barriers to a physical core collection.
• McPartland and Small (2020), PhytoKeys 144: 81–112: in situ conservation and seed banks for the drug-type landraces.
• The reports on the Vavilov Institute collection in the Journal of the International Hemp Association: Lemeshev and colleagues (1994, 1995), Kutuzova and colleagues (1996, 1998) and Clarke (1998).
• Schwartz, Smart and Stansell (January 2024), Cornell Hemp factsheet; Stansell and Gordon, the USDA-ARS page on the hemp collection; ARS project 8060-21000-030-000-D; the GRIN-Global crop page for hemp.
• Adamek and colleagues (2022), The Plant Genome 15: e20169: differences between parts of one plant, and producers' reports of decline in clonal lines.
• Uchendu and colleagues (2019), Downey and colleagues (2021), Dolce and Schaller (2026): freezing of shoot tips, nodal explants and axillary buds.
• Monthony and colleagues (2021) and Zarei and colleagues (2022): encapsulated buds and nodal segments. Gaudet and colleagues (2020): pollen in liquid nitrogen.
• The Single Convention on Narcotic Drugs, 1961, articles 1, 4 and 33. 21 U.S.C. 802(16), 21 CFR 1301.13 and 1301.18, 7 U.S.C. 1639o and its amendment by Pub. L. 119-37, section 781. 91 Federal Register 22714.

How long stored seed lasts

Welling and colleagues cite Small and Brookes (2012) and Parihar and colleagues (2014) together for storage of up to 66 months. The 66 months are Small and Brookes's; Parihar and colleagues stored seed for 36 months. Toole and colleagues had reported more than eight years in a bulletin Welling and colleagues do not cite.

The Vavilov Institute reports give shorter periods than the trials: about five years in the 1994 report, and three to four years before germination falls below 80 per cent in the 1995 report.

The longest cannabis storage trial in these sources runs for about eight years. The FAO period for long-term storage, several decades or more, is a general figure and does not name cannabis.

Freezing

The published freezing studies on cannabis concern pollen, shoot tips, nodal explants and axillary buds of named cultivars or commercial genotypes. Welling and colleagues propose the freezing of seed; none of these studies tests it, and none uses a landrace population. The six months for encapsulated axillary buds are those of Lata and colleagues (2009), as given in the review by Monthony and colleagues.

United States law

The hemp definition quoted by the Geneva collection is the one in force from 2018; the amended text of 7 U.S.C. 1639o counts total THC and takes effect 365 days after 12 November 2025. The Schedule III order of 28 April 2026 covers marijuana in a product approved by the Food and Drug Administration or subject to a state medical marijuana licence. A wider proposal to move marijuana to Schedule III was set for a hearing in 2026; see United States.

The Cornell and USDA pages on the Geneva collection do not say what is done with an accession that tests above 0.3 per cent THC.

Terms

• Gene bank is written as two words; FAO writes "genebank".
• Regrowing, regeneration and grow-out name the same step. FAO's definition of regeneration uses "grow-out".
• Hemp in the sources on the Geneva collection is a legal category set by THC content. In the older storage studies it means fibre or seed cultivars.