Cannabis: Another step towards efficient production
A cultivation technique, called micropropagation, would facilitate the production of cannabis.
As nurseries and garden centers fill up with spring landscaping plants, home gardeners owe a lot to a technique called micropropagation, which has been shown to be beneficial for many plants, and cannabis could join them, thanks to the work of scientists. researchers from UConn’s College of Agriculture.
Micropropagation and cannabis
Micropropagation is a technique used to grow large quantities of new plants from fewer “mother” plants, resulting in clones with the same predictable qualities. The cannabis industry (Cannabis sativa), however, has been largely excluded from this beneficial technique, as this species of plant is extremely difficult to micropropagate.
UConn researchers, including Associate Professor Jessica Lubell-Brand, Ph.D. student Lauren Kurtz and Professor Mark Brand, Department of Plant Science and Landscape Architecture, have addressed some of the challenges of micropropagation of hemp by cannabis. Their method was recently published in HortTechnology.
Currently, the commercial cannabis industry relies on other propagation techniques, such as collecting seeds or taking carefully planned cuttings from stock “mother” plants. These methods require a lot of space and maintenance, as several specimens from each row of mother plants must be kept in case of epidemics or plant death.
Careful control of the culture
“Micropropagation produces many more clones than other methods. Since it is not based on seeds, the clones are uniform and they will function the same as the mother plant. Tissue culture plants also have the advantage of being disease free, they often show increased vigor and you can grow a lot more in less space, ”Lubell-Brand explains.
Plants in tissue culture depend on the grower to take on the role of nature to provide the right balance of nutrients and growth hormones in the growing media, to regulate temperature and light. For some plants, micropropagation is easy to achieve, where the explants placed in the culture medium multiply easily. For others, like cannabis, the process requires a bit of refining to ensure the production of large numbers of healthy plants.
“Cannabis doesn’t really want to be part of tissue culture. This research is trying to understand the most important need of the plant according to Lubell-Brand.
Difficult first steps
Recognizing the potential to help meet the needs of the rapidly growing medical cannabis industry, the researchers set out to answer this question and decipher the needs of cannabis in tissue culture. The process requires a lot of trial and error, explains Lubell-Brand.
“We start the cultivation using shoots from plants grown in a greenhouse. Then we subculture them and if we suspect that something is missing, for example, that the plant is not getting what it needs, we experiment with nutrients like calcium, magnesium, phosphorus and nitrogen to try to increase the duration of their growth in culture. ”
According to Lubell-Brand, one of the problems with micropropagation of hemp is the hyperhydricity of the shoots: when the shoots are saturated with water, they become brittle and do not grow well. Lubell-Brand explains that by adjusting the medium during the first six weeks of culture while also using ventilated vessels to increase airflow, they were able to avoid hyperhydricity.
Equipment that is already available
“In addition to creating large amounts of parent plant clones, micropropagated plants will most likely show improved growth vigor compared to conventional stem-propagated plants,” she says.
In the medical cannabis industry, consistency and reliability of cultures are highly sought after, and micropropagation could offer both. For growers to get started with the micropropagation technique, certain equipment is required, such as an autoclave and a laminar flow bench to ensure a sterile environment. However, for operations already using tissue culture techniques, the equipment is the same, Lubell-Brand explains.
Kurtz believes the research has been met with some enthusiasm: “Tissue culture is not so well developed for cannabis in the literature. People are aware of the complications, problems and failures, so people have been quite receptive to our work. ”
Much progress is still needed
Lubell-Brand said research is continuing, with Kurtz planning further studies to refine the process, such as determining the optimal time for rooting and how long the shoots can stay in culture.
The cultivars the researchers are working with are cannabidol (CBD) cultivars devoid of psychoactive amounts of tetrahydrocannabinol (THC), but their micropropagation technique can also be applied to THC-dominant cultivars. Someday, perhaps not so far in the future, the majority of cannabis can be micropropagated using tissue culture, although Lubell-Brand says there is still room for improvement.
“Despite our best efforts, it is still not easy to grow cannabis in tissue culture. However, now we can multiply the shoots, root shoots and get them from the lab to the greenhouse, which is a step forward. ”