These seeds—now a hybrid of the two parent strains—will be grown on their own, outside of the breeding environment.
To do this, you need a male of one strain to pollinate a female of the other. Once pollinated, the female will then produce seeds that express the genes of both the male and female plant. Those seeds will be harvested and grown separately, and voilà: You have created a hybrid.
When the seeds are mature, they are harvested and stratified (or dried). “The secondary process of maturation happens after the plant is dead, and the seed needs to be stratified before it will germinate,” says Pennington. “In general, harvest for flower takes place three to four weeks before harvest for seed.”
How to Breed Cannabis Plants
Cannabis plants can be either male or female. Cannabis consumers are mainly concerned with female plants, because only females produce the sticky buds that we all know and love. But male cannabis plants are important for the breeding process, as they are needed to pollinate the bud-producing females.
Backcrossing is a practice where a breeder will cross-pollinate the new strain with itself or a parent—essentially, inbreeding the strain. This makes the strain more homozygous, and strengthens its genetics and desirable characteristics, and also ensures that those genes continue to pass down from generation to generation.
Lemon Skunk also tends to grow extremely tall and has loose buds, whereas Super Silver Haze grows smaller and has denser buds. Through selecting specific phenotypes, a breeder can pick one that has the attributes they want to keep. In this case, a phenotype that has the structure and bud density of Super Silver Haze and the flavors and aromas of Lemon Skunk.
After two parent strains are selected for breeding, a male and several females are put into a breeding chamber to contain the pollen. A breeding chamber can be as simple as an enclosed environment with plastic sheeting on the sides, or a specially designed sterile environment for large-scale breeding.
However, if an F1 hybrid cultivar is bred with an F1 hybrid cultivar from a different genetic line, a polyhybrid is formed. F1 hybrids already possess varying genetic traits from both parent strains, meaning polyhybrids are even more diverse and unpredictable in the traits they possess. Creating polyhybrids is a great breeding method as it allows you to combine unique traits from a wide spectrum of cultivars. Although, as you can imagine, these strains are quite unstable and heterozygous. It takes some solid work to stabilise these varieties and ensure that their offspring are more uniform.
It’s vital to document everything you do when breeding cannabis, especially during the more complex process of creating polyhybrid strains. It’s easy to mix up genetics and lose track of which male you bred with which female, and what strain each of them is. It’s best to label every plant individually so they can be easily identified. It’s also a good idea to create a spreadsheet or draw out a flowchart on a whiteboard to keep track of every cross you’ve made with each individual plant. Add dates beside every documented task to help you estimate waiting periods accurately.
SMALL SCALE BREEDING OPTIONS
Before further breeding experiments, it’s no harm to practice collecting pollen and making seeds first. Breeding from a reliable batch is a good introduction to cannabis breeding.
Similarly, filial breeding can be complicated. Honestly, it’s far too demanding for the first time home breeder. By crossing a pair of F1s (first generation) the resulting progeny is the F2 (second generation). Unfortunately, these seeds will be far less stable and far more difficult to work with than the previous F1 generation.