Breeder’s Corner: Mindful Seed Selection

The majority of dispensaries today in Oregon consider THC percentages before any other criteria when deciding which products to stock. It’s a sad state of affairs, to be sure. Most customers—usually buyers at dispensaries—primarily look at those THC potency test numbers as the main indicator of topshelf bud. Unfortunately, this situation means that a lot of really fine, well-cared-for cannabis varieties, with fantastic terpene and cannabinoid profiles, are not finding the shelf space they deserve. The worst part is the potential to lose these genetics over time as breeders and producers focus on high THC content. If the survival of the cannabis farm depends on high THC flowers, then the cannabis “arms race” has already begun.

Luther Burbank
Luther Burbank. Image

I often wonder what direction my hero Luther Burbank, botanical visionary, would have taken cannabis if he had a field of it to work with. Burbank was a wizard at bringing out valuable traits that others never noticed. He would scour fields of thousands to find the ones that would carry on the next generation. He brought the world the russet potato, the Shasta daisy, the Alberta peach and the plumcot, a white blackberry, a spineless cactus and about 800 other unique nuts, fruits, flowers and vegetables. Burbank was criticized for his lack of scientific method because he kept few notes—yet his eye for the unique and his passion for breeding led him to amazing success.

The cannabis plant is poised to undergo a revolution in its breeding. The plant’s genome has a large amount of variation simply because it has been cultivated and acclimatized in diverse places around the world. This variation stretches from wild Russian ruderalis (auto-flower) to tropical, narrow leaf varieties, to the wide leaf hash plants of the Kush Mountains that were developed over centuries for hashish production. This variation gives today’s breeders an extra large palette of potential to create their masterpieces. By using modern tools like gas chromatography, along with terpene and genetic testing, breeders who have clear goals and patience will, sooner than later, bring the world new and unique variations. Exciting times, folks!

Experienced plant breeders understand that while selecting for one trait, it is important to watch all the other traits, too. For example, when I was selecting for an early outdoor harvest years ago, I was inadvertently selecting for short stature—a trait that was never apparent until the shift from guerilla-grown to garden-/farm-grown occurred with the legalization of medical cannabis. So, be aware that some traits may be linked to other traits.

First generation, or F1 (for filial 1) hybrids from unrelated parent stock typically create uniform offspring. When that F1 is taken to the F2 and F3 generations, variations in offspring surface. At this point, you want to select the best and ignore the rest. To do that, there are four main tools to use: your eyes, your nose, your microscope, and your testing results.

Male selection is just as important as female selection. Finding the best pollen donors among your population is key. Those male flower parts can, and should, be lab-tested if your trait targets include terpenes or cannabinoids.

breeders corner, marijuana breeding, cannabis seeds, Reames
Small start close-up. Image: Richard Reames

Cloning of plants while in the vegetative state, both male and female, can help because the best window for seed production may pass before you realize that you have a superior plant that should be selected as a genetic contributor. By selecting several of the best examples generation after generation, while keeping all growing conditions exactly the same, eventually a true breeding cultivar can be produced.

The main reason folks prefer clones over seedlings is the fact that cannabis is dioecious (requires male and female plants for breeding) and it takes a few months to visually determine sexual expression. One alternative is to get a genetic test for sex identity. This can be done when the plant is a small seedling. The test is performed using a qPCR (quantitative polymerase chain reaction) operated by a trained technician. Hopefully the price of this testing will come down as more businesses offer it.

Breeders should always pay close attention to any outbreaks of mold, russet mites, powdery mildew, or plant viruses and note which ones, if any, show immunity or resistance. These are important genetics to conserve and could be the silver lining to issues that arise during cultivation.

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Richard Reames is a father, husband and author of two books. His claim to fame comes from his work shaping living trees into artistic and functional items. Richard studied horticulture in college and has grown cannabis since 1983. He operates a seed and genetic improvement company.