Breeding and genetics: developing your own strains

Cannabis breeding enables the development of unique strains with desired characteristics:

**Breeding basics:**

*Mendelian inheritance:*

- Dominant and recessive traits

- F1, F2, F3 generations

- Understanding genetic splitting

- Phenotype vs. genotype

- Predictable inheritance patterns

*Cannabis-specific genetics:*

- Dioecious plant (male/female)

- X/Y chromosome system

- Complex trait inheritance

- Polygenic traits

- Environmental gene interactions

**Basic breeding concepts:**

*P1 generation (parents):*

- Select original breeding animals

- Complementary traits

- Favour known genetics

- Health and vitality

- Documented origin

*F1 generation (first cross):*

- Hybrid vigour possible

- Uniform but not stable

- Best characteristics of both parents

- High variation in F2

- Commercial production

*F2 generation (F1 x F1):*

- High genetic splitting

- Selection possibilities

- Isolate desired traits

- Large populations necessary

- Basis for stabilisation

**Selection criteria:**

*Morphological traits:*

- Growth habit and structure

- Leaf shape and colour

- Internode spacing

- Branching pattern

- Overall appearance

*Flowering characteristics:*

- Flowering time and duration

- Bud structure and density

- Resin production

- Calyx-to-leaf ratio

- Finishing characteristics

*Chemical profiles:*

- THC/CBD ratios

- Terpene profiles

- Total potency

- Cannabinoid diversity

- Stability of the profiles

*Cultivation properties:*

- Disease resistance

- Stress tolerance

- Nutrient efficiency

- Yield per unit time

- Processing properties

**Pollen collection and storage:**

*Male plant identification:*

- Early sex determination

- Pollen sac development

- Isolation before opening

- Timing critical

- Ensure purity

*Pollen harvest:*

- Collect mature pollen bags

- Drying at room temperature

- Sieving for purity

- Clean working method

- Avoid contamination

*Pollen storage:*

- Dry, cool conditions

- Airtight containers

- Freezer storage possible

- Rice/silica for dryness

- Labelling with date

**Controlled pollination

*Isolation techniques:*

- Separate rooms/tents

- Temporal separation

- Plastic bags over branches

- Precise control

- Avoid cross-contamination

*Pollination methods:*

- Brush for precise application

- Pollen-water suspension

- Direct pollen application

- Multiple applications

- Documentation important

*Timing of pollination:*

- 2-3 weeks in flower

- Fresh, receptive pistils

- Several pollination dates

- Weather-dependent outdoor

- Wait for optimal conditions

**Seed development:**

*Maturation process:*

- 4-6 weeks after pollination

- Calyx swells

- Seed colour develops

- Check hardness and ripeness

- Patience for complete ripening

*Seed harvest:*

- Fully ripe seeds

- Dark and hard

- Clean extraction

- Drying before storage

- Quality grading

**Population management:**

*Large population sizes:*

- Minimum 50 plants