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Have you heard the term “breeding” when referring to new strains of cannabis? Maybe you’ve met a marijuana breeder, someone who understands the science behind creating new cannabis strains. But what do new strains of marijuana mean to the average individual? The goal of breeding a new strain is to produce a medical marijuana product that targets certain genetic characteristics such as relieving pain or boosting energy. Or you’re mixing genes to create a more potent sativa or indica cannabis strain with a mellow high for recreational users.

Here’s a peek at the science behind creating new cannabis strains for medical or recreational marijuana use. First, let’s explain what a breeder is and what he or she does.

What do breeders do?

Imagine if you will a cannabis expert with in-depth knowledge of all the available cannabis strains and their potency, their chemical makeup (e.g., percentage of cannabinoids), and how they make a person feel. Now imagine how someone with that knowledge who understands how to breed strains together to create a new version with never-seen characteristics, usually the best traits from both parents.

Just like you have rose breeders who create such stunning plant strains as “Crimson Shower” or “Gold Medal,” you also have experts who breed for disease resistance and other attributes. If you want a German Shepherd puppy that won’t develop hip dysplasia later in life, go to a reputable breeder who has bred that condition out of his gene pool.

A cannabis breeder’s main goal is to create a new cannabis strain with targeted traits to offer something new and different for either medical marijuana patients or recreational use patrons. A marijuana breeder has a specific purpose in mind, usually to improve and diversify existing strains.

Characteristics of a good cannabis breeder

What you would most expect in an expert weed breeder is good judgment and a master of his or her senses. A master breeder needs to recognize what traits to breed for in the strain to be marketable, not just those he personally likes. She also needs a heightened sense of sight, smell, and even touch. Most breeding is done by sight to assess the particular traits of each strain, and smell and touch also play a role in helping a master breeder know which plants to include and which to exclude.

Finally, a master breeder has years of experience. He’s painstakingly learned the necessary knowledge and honed the required skills to breed cannabis strains into a viable new plant.

Breeders must be patient because the process is long

First, a breeder carefully chooses two “ideal” plants, selected for specific characteristics that would complement each other in a single strain. These are the parent plants and they provide the crossings that create the first generation.

The first generation comprises many seedlings, and again the breeder must carefully choose the ones that best resemble the characteristics or traits she wants. At this point, the breeder has a weighty decision to make: should he inbreed first generation plants to create more or should he crossbreed again with the parents to refine the character traits?

Once he’s decided, he breeds the second generation. He repeats this process for each successive generation, either inbreeding or crossbreeding until the fourth generation when character traits are more stable.

Specific traits breeders look for in a new strain

As mentioned earlier, breeders look for marijuana strains’ chemical differences and specific traits when deciding which strains to cross and breed new ones. Here are the basic traits a breeder looks for when choosing parents to crossbreed.

  • Disease and pest resistance. Growers highly prize plants that can resist common pests and diseases. The more resistant they are, the hardier they’ll be, which leads to the next trait.
  • Hardiness. Plants need to survive in all kinds of environments. Since breeders can’t select perfect growing conditions for their strains, they need to make sure their strain is hardy enough to withstand all climates.
  • Vigorous. The more vigorous a plant is, the better it grows. Breeders look for a vigorous plant that grows bigger than others and produces higher yields.
  • Maturity rate. How long it takes a plant to grow and produce fiber, flower, or seeds is key for knowing when it’s best to harvest. Growers want consistency in maturity rate to project their potential yield.
  • Calyx-to-leaf ratio. The colas are the main buds of the plants which make up the calyx-to-leaf ratio. For example, if your plants have a 1:1 ratio, that’s not very good. A 2:1 ratio is better, but still not good. If you can produce a 4:1 or 5:1 calyx-to-leaf ratio, that’s a good yield. Breeders shoot for between a 7:1 to 10:1 for an excellent yield.
  • Flowers. It’s all about the following flower traits when breeding new cannabis strains:
    • Shape, color, and size of calyx
    • Cannabinoid profile such as the percentage of each and their durability
    • The flavor and durability of aroma
    • The quantity and quality of resin and its persistence
    • Th length of drying and curing periods
  • Size. Breeders today are very interested in the size of each plant. Especially if you have indoor grows, you can’t have a sativa plant that grows to amazing heights; it would outgrow any grow tent and cause problems.
  • Productivity and potency. Both traits are important for growers who want to meet or exceed market demands. Potency refers to the focus on cannabinoids; for example, medical marijuana focuses on CBD rather than THC. As more growers join this competitive market, breeders who can create highly productive and potent strains are the most successful.

What are master breeders’ best practices?

A master breeder manages for the following best practices of breeding cannabis strains.

  • Specialized selection. Breeding just any two strains is certainly not a best practice. Genetic selection is the basis for any breeding program. Master breeders analyze each plant’s genetic patterns and how they’re expressed in generation after generation.
  • Selected pollination. Breeders who control their pollination environments are masters. They only allow pollination by plants selected to pass on their genetics to the next generation. They carefully manage the entire pollination process.
  • Sample size and alternatives. Sample size matters. For example, if a breeder has the financial resources and growing space to select the best plant out of 1,000 samples, you’ll get a more specialized plant than if you picked the best out of 10 samples. Not all breeders have these resources, so they choose an alternative trait such as vigor, which is easily identifiable in the first generation at the seedling stage.

What are breeding methods?

Master growers have an array of methods for breeding their new cannabis strains.

  • Crossbreeding. This is the most common method of breeding. You simply cross two different strains you’ve chosen based on their specific traits.
  • Inbreeding. After you’ve already crossbred two strains, you select the best two offspring (first generation) and cross them with each other to strengthen their desirable traits.
  • Backcrossing. Choose a stable generation (e.g., fourth generation) and backcross it with one of the parent plants to strengthen particular traits you find more desirable. A subset of backcrossing is recurrent backcrossing when you continue to backcross a child with a parent to solidify desirable traits.
  • Trait fixing crossing. Let’s say you have two cannabis strains that strongly display the same trait. You crossbreed these two highly similar plants to increase the frequency of its genetic expression in future generations.
  • Selfing. This is when a breeder takes cuttings or self-pollinates a particular plant to increase its stability and reduce its genetic diversity.

Final thoughts about breeding

Breeders focus on a wide variety of reasons for crossing strains. The following prompt master breeders to select genetic traits and begin the breeding process:

  • Improve on, or at least solidify, the traits of a strain. Particularly when trying to create viable strains for the marketplace, this is a big reason for breeding. For example, breeders may try to breed strains that offer a more potent CBD for medical marijuana purposes.
  • Create an entirely new strain. Some breeders may seek to create a new strain with a specific genetic potency. Either for recreational use consumers or medical marijuana patients, high potency strains can make a difference in their experience.
  • Recreating a lost strain. Much like the scientists in Jurassic Park, some breeders try the daunting task of reviving a lost strain that, for whatever reason, went extinct. They’ll select and cross current strains to try to replicate something from the past. This is usually restricted to labs with the right equipment and breeders who don’t mind the hard work and repetition.
  • Create a new strain suited to a specific climate. As states around the US legalize either medical marijuana or both medical and recreational, breeders are crossing strains in an attempt to create new strains that grow specifically in a certain climate, whether that’s hot, cold, dry, or wet. Certain strains, because of their genetic makeup, grow best in certain climates, and breeders are creating strains that can even grow in harsh climates.
  • Increase certain cannabinoids. CBD is in big demand for medical marijuana, and breeders are working to creating strains rich in it. Once more states legalize medical marijuana, the impetus will be on research facilities to determine the best mix of cannabinoids to treat specific diseases, disorders, chronic pain, and more. However, this is a long and involved process of research and lengthy breeding cycles to create the perfect strain.

It can take years to create a specific strain. Any plant you’re trying to improve on or genetically engineer a new strain takes a long and involved cycle of analyzing, selecting, crossing, rejecting those that don’t meet your standards, and continuing to cross for the best strain possible. It can take up to four generations to create a stable plant with the genetic traits you’re aiming for and one that is the closest to the ideal. The result, however, could be a medical marijuana strain that eliminates seizures for epilepsy patients, giving them a whole new quality of life they’ve never experienced. That’s one reason breeders do what they do.

Christopher Wright

Meet Christopher Wright, aka Blue, successful radio host and creator of Cannabis Talk 101. As well as CEO of Cannabis Talk Network. For over a decade now, Chris has had his hands in all faucets of the Cannabis Industry. From medicinal marijuana dispensaries and cultivations to controversial cannabis activism, Chris is a pioneer for the cannabis movement.