The Cannabis cultivation industry has increasingly utilized technologies from modern agriculture. Since 2015, Dark Heart Nursery has implemented tissue culture micropropagation to generate mother stock plants for our Nursery.

Tissue culture micropropagation is the production of plants in sterile containers containing nutrient media. These plants are sub-cultured over a period of time, multiplying their numbers indefinitely. When desired, plants exit the micropropagation cycle and are ‘hardened off’- acclimatized to living outside of the tissue culture environment. Micropropagation is widely used in crops such as grapes, hops, sweet potato, and also in flowers such as orchids, roses, and chrysanthemums for both mass production and as part of pathogen eradication programs.

Cannabis plants are host to a large number of bacteria, viruses, and fungi that live on the plant surface (exogenous) and within the plant circulatory system (endogenous). Harmful microbes such as HpLVd, Botrytis, Aspergillus, Pseudomonas, Salmonella, and E. coli are potential Cannabis contaminants. State Cannabis regulations increasingly include testing for microbe contamination of Cannabis products in addition to pesticide content.

One benefit of tissue culture micropropagation is the removal and/or vast reduction of both exogenous and endogenous bacteria and fungi that make up the Cannabis microbiome. Plants entering our micropropagation system are topically sterilized before inoculation into tissue culture. Any microbes that survive treatment continue to grow in culture as unwanted contamination. Contaminated containers are identified and removed from the population, leaving a population of sterile plants. Once established, tissue culture production facilities maintain low contamination rates by continuous aseptic transfer. The ‘vigor’ associated with micropropagated plants is partially due to this reduction of contaminants.

Tissue culture is an excellent way to ‘rejuvenate’ old genetics. Much of the ‘genetic drift’ from clonal cut propagation is speculated to be a pathogen load that is causing inconsistencies in plants, not genetic variation of source material. ‘Genetic drift’ is a term for genetic variation in a sexually reproducing population, and cannot contribute to asexual clonal propagation. Plants from tissue culture have been observed to grow vigorously after micropropagation, with increased internode production.

Tissue culture micropropagation allows for a sterile growing environment without the use of herbicide/pesticides. As concerns over use of pesticides such as Imidacloprid, Myclobutanil, Paclobutrazol, and other systemics increase, micropropagation is seen as a popular opportunity to mass-produce Cannabis plants without worry of infestation with thrips, whiteflies, aphids, and other pests.

Every year new Cannabis cultivars enter the market. As grower’s genetic libraries grow, they must balance the need to maintain diverse plant selection while also scaling production. Tissue culture has emerged as a promising solution to long-term storage needs. Once established in culture, maintenance of a strain in tissue culture is a fraction of the labor of maintaining an equivalent mother plant. Having a tissue culture repository of genetics is also a useful contingency in the case of fire, disease outbreak, or other catastrophic loss to a grower.

Cannabis Tissue culture continues to evolve in its role in commercial cannabis production. By utilizing tissue culture micropropagation, growers can be ensured elite disease-free plants can be produced for years.

In conclusion, Tissue Culture Micropropagation:

– An agricultural technology used for mass production of plants

– Free of microbial disease and pests

– ‘Rejuvenates’ old mother stock material

– Pesticide free

– Useful for long-term genetic storage

To find out more about tissue culture services, contact lab@darkheartnursery.com