The encyclopedia and open conservation database for landrace cannabis populations, their genetics and the traditional knowledge that sustains them.
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Filter by collection year, classification, priority or provenance, and select a marker for accession details. Every figure on this card describes the accessions currently shown. A further 213 documented accessions carry no coordinates yet and cannot be mapped.
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Cooper 1486 herbarium specimen, Chalimarphé (1914)
Cooper 1486 is a herbarium accession of Cannabis sativa collected on sand by a stream at a place its label gives as Chalimarphé Timpu, in Bhutan, at 7,000 feet on 11 July 1914 by R. E. Cooper. The label calls the plant a dwarf variety. The Royal Botanic Garden Edinburgh holds the sheet as E00150672.
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Sex determination in cannabis
Sex determination in cannabis is the genetic and developmental process that establishes whether a Cannabis plant develops as male, female, or, in some cultivated forms, monoecious. Cannabis is normally dioecious: pollen-bearing (male) and seed-bearing (female) flowers form on separate individuals, and sex is set by a pair of heteromorphic sex chromosomes. Females carry two X chromosomes (XX) and males an X and a Y (XY), so the male is the heterogametic sex and the Y is transmitted only through pollen.
Chromosomal sex, fixed at fertilisation, is distinct from sex expression: the male or female character of the flowers a plant actually produces. Sex expression is labile: hormonal, chemical and environmental signals can shift a plant toward the opposite sex's flowers without altering its chromosomes, and a genetically female (XX) plant induced to shed pollen transmits only X-bearing gametes.
The distinction is central to cannabis cultivation and breeding. Because cannabinoids accumulate chiefly in the unpollinated female inflorescence, drug-type and cannabinoid-hemp crops are grown as all-female stands; monoecious cultivars underpin uniform fibre and seed hemp; and reliable early identification of a plant's chromosomal sex, before flowers appear, is a routine breeding and roguing task. For dioecious landrace populations, the obligate outcrossing that dioecy enforces also shapes mating structure and the maintenance of genetic diversity. read more →
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