Characterisation of Cannabis accessions with regard to cannabinoid content in relation to other plant characters 

Euphytica 62: 187-200, 1992 

E.P.M. de Meijer, H.J. van der Kamp & F. A. van Eeuwijk

Summary 

Ninety seven Cannabis accessions were evaluated for cannabinoid content and non-chemical plant characters. Variation within populations for cannabinoid content, and consistency of chemical characters at the population level were investigated. The relationship between chemical and other plant characters was very limited. Leaflet width and phenological data can be used for a rough prediction of the chemical phenotype on a population level. Various combinations of cannabinoid content and other economic plant characters were observed, thus a breeding programme will not be hampered by strict linkage. For a selection programme a direct analysis of cannabinoids will be inevitable.

 Introduction  

The presence of stimulants in Cannabis has attracted a lot of scientific attention in the past decades. Several theories have been proposed for the biological function of the cannabinoid containing resin for the plant itself. A relation was suggested with antibiotic activity (Krejci, 1970) and drought and heat tolerance (Schultes, 1970). Warm, dry and windy conditions were believed to induce a higher density of resin glands where the biosynthesis of cannabinoids takes place. Murari et al. (1983) estimated higher contents of cannabinoids in the same varieties when grown in a continental climate than in a maritime climate.  

The presence of psychoactive components is considered as an important reason for the decline of fibre hemp cultivation in the course of the 20th century (Bredemann et al., 1957; Dempsey, 1975). Due to legislation, hemp cultivation is prohibited in many countries. Only in France, Eastern Europe, the former USSR and China cultivation of fibre hemp is still continued. In the former USSR a low content of psychoactive compounds is one of the priorities in hemp breeding (Virovets et al., 1987; Gorskhova et al., 1988). In the context of the Dutch National Hemp Programme a collection of Cannabis accessions was established (de Meijer & van Soest, 1992). Selected accessions of this collection will be used in a breeding programme. In addition to the existing fibre hemp cultivars other Cannabis strains may provide desired characters such as a long vegetative growth, and resistance to pests and diseases. However, the psychoactive potency of new cultivars should be below acceptable levels. Therefore a screening for cannabinoid content is part of the evaluation of newly introduced accessions. A relation between cannabinoid content and easily visible plant characters would allow an indirect recognition of accessions with respect to psychoactive potency. Close linkage of cannabinoid content and agronomic characters would have an impact on the breeding programme.

The relation between chemical and morphological or physiological parameters was therefore evaluated.