Primary Components of a Breeding Program

Marijuana Horticulture

by Jorge Cervantes

Develop a vision or a breeding goal

Every breeding program should begin by developing a breeding goal. Why are you trying to make seeds? What are you trying to accomplish by mating these sets of parents? You might be trying to make a seed population that represents the traits of an ideal, or mostly ideal plant you have previously selected. In the case of the latter, you might be trying to add new traits to your mostly ideal plant and incorporate these new traits into a new seed line. Some may just want some seeds to plant for next year’s crop. Think of your breeding goal as your final destination; the breeding process is the roadmap or route t get to that goal.

Find or Create Variability

Finding variable seedlots these days is certainly not a difficult task, because very few breeders take the time to stabilize or fix certain traits within a given breeding population prior to release. Your starting seed stock likely represents a range of variation for most traits, depending on the source of your initial starting material. The sad reality is that most of the seed industry today focuses more on creating seed for sale than soon developing improved or even uniform plant stock. As a breeder looking for germ plasm to work with, this leaves unstable populations with ample variation for future selection. If searching for variation, this could be considered a good thing. However, since true breeding stable plants are what breeders look for when choosing stock for their own breeding, this is a hindrance as well. It is much easier to breed with true breeding plants because one can see patterns emerging in a predictable manner in subsequent generations, and thus expect reliable, consistent results when hybridizing known true-breeding parents. This can only be achieved if the breeder is using true-breeding starting parent stock. Due to the lack of commercially available true-breeding stock to work with, serious breeders must stabilize their initial breeding stock before beginning the hybridizing or outcrossing phases of their breeding programs.

Grow and Evaluate

Do just as it says. The more plants you grow, the more variations you will see. I am repeatedly surprised and even amazed to see new expression of traits when growing this fabulous species. Cannabis is an extremely variable and polymorphic species, many traits have numerous possible expressions. Growing varied seed stocks of different heritage (and many of each population) ensures the breeder a wide array of phenotypes and combinations of traits for future selection.

Choosing from as many plants as possible is always preferable; having a wide and diverse starting stock assures the highest chances of finding what you might be looking for. When selecting from just a few seeds, it’s not possible to assure all plants will be vigorous or show the traits of interest even if they are seeds of known quality. Breeders must weed through large populations of potential plants, and “rogue out” the undesirable individuals. In any breeding program, off-types which d not suit the goal should be removed from the breeding populations.

Some recessive traits, especially those controlled by multiple genes (polygenic traits), have the potential for phenotypes that are only apparent in 1 in 100 or even 1 in 1000 plants. Unless growing many individuals, the breeder has a very ow likelihood of discovering these phenotypes. All other things being equal, the breeder who grows the most plants has the greatest possibility of finding the best breeding candidates. Testing the final product is a crucial part of the evaluation process, so get out that bong r those rolling papers and put all your hard work to the test!

Screen, Select, and Apply Selection Pressures

To paraphrase one f the great breeders of the 20th century, select only plants that closely match your goal, and reject all others. This is an important rule to follow if your future generations are to gradually approach your goal.

Breeders select plants for future breeding on the basis of their desirable characteristics. There is no “right” or “correct” ranking of priority for selecting one trait over another; this is purely based on what traits are most important to the breeder. For indoor cultivation, these include short, squat, bushy growth; large, densely formed buds; discernible taste or particular flavors and aromas; high THC content and quality of high (long lasting, soaring, sedative); and resistance to specific insects r diseases. It’s a good general rule to look for pants with overall vigor and good health.

Sometimes, we find a plant that is almost ideal in every respect, but has some negative trait that is undesirable. For example, the breeder may select a highly potent plant that produces exceptionally aromatic or flavorful flowers but is tall and lanky and difficult to grow indoors under artificial light.

Post-harvest selection requires either partial seeding of each plant (only seeds from the most potent plants are sown for successive generations) or keeping cone copies of each and every plant, for future seed production use once post harvest evaluations are done.

Commercialize

This is an optional part of a breeding program. Some people breed to create a variety tat suits their specific growing environment and smoking tastes, without ever intending to profit from the sale of their work. They just want reliable seeds for their own planting and future use. Some are of the opposite extreme; they make seeds exclusively to sell. These “breeders” do very little breeding. We refer to them as seed makers.

Because cannabis is a species under attack from various governments and other evil forces around the world, true breeders with goals and intentions other than financial are solely needed to protect the genetic resources cannabis has left. Years of persecution from governments and greedy seed-making practices without improvement or preservation have led to a genetic bottleneck, a narrowing of the potentially available breeding stock. Now more than ever, ethical breeding should be of utmost concern to cannabis enthusiasts. The species desperately needs breeders who are willing to improve populations in their possession, all the while preserving valuable genetic resources for future generations of breeders.

Sam the Skunkman, a great ally of cannabis, says we all stand on the shoulders of those who have come before us. We can build upon the improvements our ancestors have made to landraces and wild populations, but we can only work with what they have left us. Selections and advancements come at a cost t genetic variability. Breeders often reduce variability by narrowing the gene pool of that particular population as a consequence of fixing traits. The best breeders strive t advance and improve a given variety or population while preserving the variation present for the traits not under selection, which may prove valuable for future breeders and growers.