Choosing Parent Stock
When selecting specific plants for breeding, it is important to look at as many relevant data points as you can to identify standout candidates. This includes the data points gathered from the plant as it grows and flowers, as well as those from the plant as a seed maker. A good seed maker is a plant whose seed-making abilities are desirable.
Seed making traits are predictable, just like other phenotypical variations. To help predict which plants will be best, it helps to have as much data as possible. Before breeding, consider a plant’s morphology (how it grows), morphogenesis (formation and traits of the flower) and seed-making efficacy. It’s also important to know if a plant’s most desired traits breed dominantly or recessively.
Expressions to look for when making seeds:
Length of ripening time, from pollination to seed
Color and consistency of seed
Uniform ripening (some plants will ripen more quickly in certain areas)
Overall seed yields
Fertility of the plant (ability to receive pollen)
Traits to consider:
Cannabinoids (presence, diversity & concentration)
Terpenes (presence, diversity & concentration)
Bract development (density, form, large bracts, bract sets & foxtailing*)
Trichome development & density per sq. millimeter
Trichome quality (formation, color & size)
Depth of flower development
Development & onset of flower ripening phase
Efficiency & yield
*There is desirable and undesirable foxtailing. It is considered desirable as long as the foxtails are just as frosty as the primary bud. Genetics that do not ripen well can also foxtail, but these outer bracts are undesirable, as they are not nearly as potent or as high quality as the rest of the bud. If all aspects of the bud, including the foxtails, are equally ripe, then it’s desirable.
Expressions to look for during the harvest window:
Presentation from nugs at mid & lower canopy
How a plant grows in different systems
Terpene development (some terpenes develop late, others peak early)
Terpene changes (typically, sweeter flavors develop early; sour & gassy develop later)
Color changes (Anthocyanin presentation)
Subjective flower effects
Extraction window (when are the trichomes best for the end game of the extractor)
Certain fast flowering varieties lose visual appeal after ripening quickly, while some longer flowering varieties maintain visual appeal through a long flowering window.
Some extractors like to harvest earlier for “prettier,” white extract, while some varieties allow for a longer harvest window while maintaining this quality.
Advantages to Breeding with Female Plants:
Female plants allow for a much larger set of data points to use in your selection, including the majority of flower expressions and proper testing for cannabinoids and terpenes.
Another advantage when breeding with two female plants is you can choose which parent will be the pollen donor and which will be the pollen recipient. Often, one will make much more visually-desirable seeds than the other.
Having the option to choose which parent receives the pollen can often be helpful because fertility and quality of seed production has a wide range.