Establishing Canada’s cannabis gene bank
By Owen Van Cauwenberghe and Barry Shelp
By Owen Van Cauwenberghe and Barry Shelp
If cannabis is to truly become a medicine, the starting materials must be predictable and stable, and meet safety and efficacy claims expected for pharmaceuticals. Perhaps the time has come to develop a cannabis germplasm repository (CGR) in Canada to enable access to genetically and phenotypically diverse resources of cannabis from across the globe, facilitating the genetic improvement of cannabis for specific end-use applications and agronomic/horticultural traits.
Modern cannabis cultivars have the unfavourable tendency to produce male flowers and unwanted seed, are increasingly finicky about growing conditions, susceptible to pests and disease, and generally difficult to grow.
Levels of the major cannabinoids, THC and CBD, are not by themselves good indicators of medical outcomes, and minor cannabinoids and other compounds are likely to significantly influence human health. Developing new cultivars with varying profiles of major and minor metabolites could enhance our understanding of the plant and the cause/effect relationship between dosing and medical outcome, and result in improved product offerings.
Through breeding, complementary genotypes with favourable alleles or genetic attributes lacking in others are crossed to produce a plant or population that can be selected to be better than the parents. A collection of diverse genetic materials is the foundation of plant improvement, providing the complementary alleles missing in commercial cultivars.
Genetic improvements through plant breeding require genetic diversity to produce a favourable phenotype or plant characteristic. Although favourable alleles for important traits can exist among the cannabis plants on the planet, they may not be available in the cultivars currently available to domestic breeders.
To date, cannabis scientists and industry breeders in Canada do not benefit from the approximately 10 cannabis germplasm collections currently in Europe, Russia and Asia, and significant losses of genetic material have likely occurred due to conservation efforts outside of the natural habitat and to genetic erosion. Allowing the legal and unrestricted transfer among countries of genetic materials remaining, as well as the collection of new genetically diverse populations of seeds, are crucial for long term economic viability and innovation.
The cannabis genetic resources currently available in collections have not been comprehensively catalogued, so a global evaluation and availability assessment is warranted. Landraces and seed-propagated populations maintained by farmers without significant breeding or selection in geographically-distinct areas can contain significant genetic variability for important traits not currently available in domestic plant materials.
Sexual reproduction and propagation through seed is the simplest and most conventional method of cultivating cannabis. Seeds derived from mating a diverse population of male and female plants produce genetically diverse progeny that can vary favourably for plant size, flower size, terpene composition, or other selection criteria. The ease of producing and storing seed, compared to clonal propagation of genetic stocks, can also facilitate access to many large, genetically diverse populations, which can be stored, shared and propagated economically.
To realize the full potential for developing and delivering high-quality, cannabis-derived medicines and other products in the global marketplace, the acquisition, preservation and evaluation of germplasm should be considered a key component of future plans for cannabis. The greatest advances in breeding can be made by accessing seed-propagated landraces and ancestral populations, creating large segregating populations to recover sometimes rare genetic combinations, and selecting a small percentage of elite plants with the best genetics and attributes.
Given the importance of genetic diversity to ensure longevity of Canada’s cannabis industry, a task force should be established to create a plan for comprehensive and methodical assessment of the benefits of a CGR. Interested parties, including academic, government, industry, legal and medical communities should be invited to join. National leadership must be also involved because regulatory and legal obstacles to developing a core collection of cannabis resources may exist within and among countries, and ultimately the ease of access to diverse genetic resources in other countries will be influenced by the recent signing of the International Treaty on Plant Genetic Resources for Food and Agriculture. It may be reasonable to adopt germplasm or seed-bank systems already established for other agricultural crops; however, different global regulatory and legal implications for drug-type cannabis resources require a system that collaborates at the provincial, national and international levels of governments and practices.
Guidelines or criteria must be established to ensure that both the quality and utility of the materials are well understood and can be catalogued in a meaningful manner.
This article was originally published in Greenhouse Canada, a sister publication of Grow Opportunity.
Owen Van Cauwenberghe, PhD, and Barry Shelp, PhD, are officers of Bio Therapeutic Molecules Inc. of Guelph, Ont., and expert advisors for MMGenetics. Shelp is also professor emeritus at the University of Guelph, and VP of plant biology for MedC Bio. Van Cauwenberghe is also president and director of MedC Bio. He can be reached at firstname.lastname@example.org.