Growing from clones has its obvious advantages, but which strains have the quickest strike rate and does it really make a difference where the cutting is taken from the mother? Soft Secrets investigates…
You know the feeling; the NYE hangover has just about disappeared, Christmas is a dim and distant memory and the jars are beginning to run low. That harvest you were sure would last you well into the New Year has dwindled fast! It’s time to get your grow on… and quickly.
When you want to get going in a hurry, clones are the answer. No messing around sexing your plants, just get them rooted out and bang them into flower for a speedy crop. When time is of the essence, every day counts and high success rates are vital. So, which strain roots the quickest? And, does the position that the cutting is taken from the mother plant affect the speed of rooting?
Luckily for us (and for you) a friend of ours had asked himself exactly the same question and, in the pursuit of homogenising clones for pharmaceutical cannabis, has conducted just such an experiment…
The Summary… AKA The Short and Sweet Version
The ultimate aim of these experiments was to improve the propagation step of medicinal Cannabis for its production and selection in breeding programs. Cannabis sativa L. gives standardised clone production, showing fast, healthy and homogenous root growth within a short period of time and aeroponic propagation enabled us to generate cuttings ready for transplant in just 14 days. It is hoped that Horticulturalists and Breeders will now have another applicable tool to evaluate the growth of roots in cuttings and a new reproducible method to obtain clones for standardised medicinal production of marijuana.
This experiment has shown a difference in rooting between different strains of Cannabis and between the positions of where the cutting was taken from the mother plant. Despite the satisfactory and clear results we obtained, it should be noted that further research should be carried out to evaluate the impact of the mother plant age and to find out the best suitable transplantation substrate for the clones obtained in an aeroponic propagator according to cannabinoid production i.e. what technique leads to the greatest cannabinoid production? An improvement of this clonal propagation technique can then be expected and could be part of a standardised production of Cannabis sativa L.production for future pharmaceutical applications.
It was decided to carry out the research in an X-Stream aeroponic propagator as aeroponic propagation systems reliably provide high success rates with uniform root development and is a very efficient system in which to observe root initiation; as the cuttings remain suspended in the air.
It is also very easy to use and the cuttings can then be transplanted on to any kind of substrate. Accordingly, we ran the research trial for stalk position on the mother plant, combined with strain difference in two batches (2 x 90 cuttings).
Get Ready For The Science… AKA The Full Story…
We hope that this research will help to improve Cannabis production lines for medicinal use in order to have standardized and suitable drugs for patients. An aeroponic propagation system will be set up. Then an analysis will be done on asexual propagation techniques (i.e. taking cuttings and developing clones) to show how efficient it can be. Moreover, beyond its efficiency as a propagation technique, it can be use to obtain selected healthy plants, free of pathogens and as a tool for breeding in a mass selection program.
Cannabis sativa L. is a single plant with monotypic characteristics. Among this species it can be said there are hundreds of subspecies derived from its geographical origin. There are literally hundreds of subspecies (or strains) of cannabis. The original one “Sativa” and the second distinguish as “Indica”. The therapeutic properties of Cannabis and its psychotropic substance related to the production of cannabis are Δ9 -THC (Delta9 -Tetrahydrocannabinol) and CBD (Cannabidiol) which are the two main cannabinoids; Δ9 -THC has psychotropic activity, while the CBD does not.
Therefore in the pharmaceutical industry it is recognized that Cannabis is a medicine for its chemical compounds which are cannabinoids. To obtain a medicine, synthesized or natural, it has to be reproducible as identical in chemical amount for every patch of production. When it is a synthesized molecule this is not a problem, but when it comes from a plant material this is not so evident.
Cannabis sativa L. is – historically – usually grown from seed for its fibre purposes, however this is not the most suitable method for therapeutic purposes as the percentage of cannabinoids is less uniform in plants growing from seed than the one growing from vegetative propagation. And, variation of cannabinoids
can be found into the same subspecies (or strain) of cannabis which is related to environmental condition and genotype variation in the same family from one to another. That is why therapeutic cannabis has to be propagated by asexual method, especially cuttings, because of its reliability and efficiency to obtain identical plants to the one selected for its cannabinoids content.
In 1954 researchers M.A Khan and W.C Hall conducted an experiment that showed for the propagation of sugar cane that a variability of success existed in rooting among cuttings taken from the same mother plant according to its position on the plant (top, middle or bottom). And variability of strike rates is present between subspecies (or strains) of the same plant species.
This experiment will try to define if there is a relevant difference in Cannabis sativa L. between cuttings taken from different parts of a mother plant: top, middle and bottom.
In correlation with the position of the cutting on the stock plant we will attempt to find out the different strike rates of different Cannabis subspecies (strains) to be able to optimize the propagation step of therapeutic Cannabis production.
To sum up; what gives the best results, cuttings taken from the top, middle or bottom of the mother plant? And, which strain roots the best, Sativa, Indica or a Sativa / Indica cross?
Materials and Methods: How Did We Do It?
The cuttings were cut just above the 4th nodes starting from the top of the branch and then the leaves were removed. The cuttings were then placed in 50mm plastic mesh pots and held in place with a black neoprene collar that keeps the stem suspended above the water tank; where sprinklers are running constantly to water the cuttings and maintain a humid atmosphere. Each cutting was placed randomly in a Nutriculture X-Stream Aeroponic propagator.
The environmental parameters were set as follows:
Light luminosity = 1200 Lux,
Relative humidity = 100%,
Air temperature = 25° C,
Water temperature = 23°C,
pH = 5.8,
Electrical Conductivity = 0.8 mS/cm.
Regarding fertilizer; the experiment used a hydroponic nutrient widely available across the whole of Europe – Canna Aqua. The tank of the X-Stream aeroponic propagator was filled and we added nutrients at the following ratios: 30 litres of tap water (pH = 7.8) + 25ml of Canna Aqua A and B + 6 ml of pH down (to achieve a near neutral pH of 5.8). All of these environmental parameters were the same during the entire experiment.
The trial was done in the X-stream propagator with a capacity of 105 cuttings. Different significant subspecies (strains) of genotypes were needed therefore the following three representative subspecies (strains) were chosen:
V1: Power Plant (mostly Sativa: original South African strain),
V2: Early Queen (Hybrid Sativa/Indica: Early Pearl x Early Girl x Super Skunk)
V3: The Doctor (mostly Indica: Great White Shark x South Indian x Super Skunk)
These three mother plants were grown in 20L containers filled with organic soil. The photoperiod for the mothers was set to 18 hours of 600 watt artificial light – High Pressure Sodium (HPS) – and 6 hours of darkness.