December 30, 2024
One of the greatest challenges facing cannabis cultivators is the demand for new and exotic genetics. While some “legacy genetics” will always have a place at facilities with the expertise and ability to maintain mother/stock plants, demand at the consumer level is ever present as newer “hype” strains become sought after. Nowadays, cultivators have different options for sourcing genetics that completely eliminate the need to maintain or dedicate vegetative space for stock plants and traditional cloning methods. Whether through “True” F1 seeds or genetics derived from tissue culture, many genetic options are available.
One of the downsides to this approach is that operators may limit themselves to what genetics happen to be available at the time and also having the same genetics as many other growers within the same region. Finally, trialing of genetics should be carried out in specific environments as one strains may grow well in one situation but not as well in another. In this review we will briefly discuss the importance of trialing and also pheno-hunting through new genetics to find something unique that best suits your environment.
Traditional Breeding
In previous discussions (Cannabis Breeding: Challenges and Future Potential), we talked about how traditional breeding approaches have utilized the tremendous amount of genetic diversity within cannabis plants to create some incredibly unique strains. Also, with exhaustive analytical date on the parental lines used, finding new strains can be made slightly more predictable. For example, Figure 1 displays two parental lines used in a recent phenohunting project. This particular cross was chosen for the purpose of finding a strain that tests high in THC regardless of yield. Both Reserva Privada and Wedding Cake are two strains known to test high in total THC percentage (THCA x 0.877) + THC derivatives) therefore, the F1 polyhybrid seed population derived from this cross would expect to test high as well.
As seen in Figure 2, plant architecture from this particular cross was unsurprisingly very similar to the parental lines used. In this example, we started with 30 – F1 seeds for trialing in an indoor controlled environment. Phenotype selections to continue from the veg through flower cycle were made based on rooting, vegetative vigor, plant architecture in flower, and other agronomic traits eventually leading to the 10 selections displayed here. Ultimately however, the goal of this particular cross was to commercialize a new strain that tested high in THC therefore, analytical data would be critical.
Importance of Analytics and Reproducibility
In order to verify a trait such as cannabinoid content, robust analytical data is needed. Each facility may have different criteria for the final selection of a strain based on a particular trait. Again, using total THC percentage as an example, multiple rounds of (minimum of three) should be used to verify the potential outcome. Different environmental conditions based on season or simply cycle to cycle variation should be accounted for. Figure 3 displays analytical data from a cannabis testing lab on three different harvest cycles during the selection process. In this case, each round of testing was very similar for overall total THC percentage indicating this particular phenotype performs well in this environment and ultimately met the criteria for final selection.
Another consideration to be made during these types of phenohunting is that ultimately multiple “phenotypes” can be selected for commercialization. These particular F1 populations are not genetically identical unlike “stable F1 populations” that are now being offered from various commercial companies. The example outlined above is an example of how effective a traditional phenohunt can be with reliable genetics that have been vetted thoroughly. Not all such trails are as straight forward as the one described here and, in some cases, unexpected results can also lead to interesting discoveries.
New Trait Discovery
Due to the heterozygous nature of cannabis, new unexpected positive results are also possible when crossing different parental lines. For example, Figure 4 displays a cross between the parental lines of White Widow and Bio Jesus. Both of these particular strains are known to test high in total THC percentage (>25%) and also yield well (+50 g/sqft). From this cross, a commercial selection was ultimately made from phenotype D20 which consistently tested above 25% total THC (as described above) and also had similar yield results when compared to the parental lines. More surprisingly however, multiple phenotypes displayed greater anthocyanin content leading to more purple in finished flower especially when compared to the parental lines (Figure 4). While this particular trait may be more beneficial to overall bag appeal at the consumer level (see previous discussion; Anthocyanins: Putting the Purple Into Perspective), it is an unintended observation made in this particular environment that also led to commercialization of different phenotypes.
Importance of Trialing
Ultimately, how a particular strain performs in a particular environment must be trialed and repeated multiple times. If a strain grows well in one facility it doesn’t necessarily guarantee it will grow well in another. Environmental conditions such as light, temperature, and humidity play a major role in over cannabinoid content and yield and these factors can vary wildly from facility to facility. Also, a very open question in the cannabis world remains as to whether or not a proven strain that does well in an indoor setting, will also perform well in an outdoor setting. Again, trialing is key and will ultimately determine strain performance.
Conclusions
Regardless of the source from which a facility acquires genetics, trialing is still an important step in the process to determine commercialization. In environments such as a greenhouse, this would be especially important considering seasonal variation in DLI and temperature, among others, things that could influence performance. Another important note to make is that trialing does not require a lot of dedicated space. Even in a high production setting, valuable information can be learned from strategic and well thought out trial of new genetics.
As always, if you have any questions or comments about the topics presented, please reach out to DDH for assistance. If you are interested in setting up your own trailing let us know and we can help with the design and implementation of such studies.
