🧬 Cannabis Breeding Generations Guide

Understanding F1, F2, S1, S2, BX1, BX2 and their applications

F1 Generation

First Filial Generation

50% A + 50% B

Parent A

Parent B

F1 Hybrid

🎯 Key Characteristics:

Maximum Vigor

Uniform Plants

Hybrid Strength

Disease Resistance

High Yields

Don't Breed True

✅ Advantages:

Maximum hybrid vigor
Consistent F1 offspring
Often exceed both parents
Great for production
Disease resistance

❌ Disadvantages:

Seeds don't breed true
F2 will be highly variable
Need to remake cross each time
Require parent maintenance

F2 Generation

F1 × F1 Cross

Wild Variation

F1 Plant

F2 Chaos

🎯 Key Characteristics:

High Variation

Trait Segregation

Phenotype Hunt

Hidden Traits

Selection Material

Breeding Gold

✅ Advantages:

Maximum genetic diversity
Hidden traits appear
Great for phenotype hunting
Selection opportunities
Novel combinations

❌ Disadvantages:

Highly unpredictable
Many poor performers
Need large populations
Time intensive selection

S1 Generation

Selfed Generation 1

Plant × Itself

Female Plant

Same Plant (Reversed)

S1 Seeds

🎯 Key Characteristics:

70% Similar

Inbred Effects

Feminized Seeds

Genetic Preservation

Quick Process

Some Variation

✅ Advantages:

Preserve exact genetics
Only need one plant
Fast - one generation
Feminized seeds
70% plants very similar

❌ Disadvantages:

Inbreeding depression
Reduced vigor
Hidden problems surface
Potential hermies

S2 Generation

S1 × S1 Cross

More Inbred

S1 Plant

S2 Seeds

🎯 Key Characteristics:

85% Similar

More Inbreeding

Greater Uniformity

Reduced Vigor

Stability

Risk of Problems

✅ Advantages:

Higher uniformity
More trait consistency
Stable genetics
Predictable offspring
Line development

❌ Disadvantages:

Significant vigor loss
Higher risk of defects
Smaller plants
Fertility issues

BX1 Generation

First Backcross

75% A + 25% B

F1 Hybrid

Parent A

BX1

🎯 Key Characteristics:

75% Target Parent

Good Vigor

Target Traits

Some Variation

Progressive

Professional

✅ Advantages:

Maintains good vigor
Target specific traits
Progressive improvement
Professional method
Controlled selection

❌ Disadvantages:

Takes multiple generations
Need parent plants
Still 25% variation
Complex planning

BX2 Generation

Second Backcross

87.5% A + 12.5% B

BX1 Plant

Parent A

BX2

🎯 Key Characteristics:

87.5% Target

High Similarity

Near Stability

Good Vigor

Fine Tuning

Almost There

✅ Advantages:

Very similar to target
Stable enough for most uses
Maintains vigor
Predictable results
Commercial quality

❌ Disadvantages:

Still some variation
Long time investment
Parent dependency
May want BX3

⏰ Breeding Timeline Flow

P1 Generation (Parents)

Start with two stable parent plants with desired traits

Example: OG Kush (Parent A) × Blue Dream (Parent B)

F1 Generation

Cross the parents - maximum hybrid vigor, uniform plants

Result: F1 hybrids with 50% OG + 50% Blue Dream genetics

Choose Your Path

Decision point: F2 for hunting, S1 for preservation, or BX for targeting

F2 = chaos hunt, S1 = preserve F1, BX1 = target OG traits

Generation 2+

Continue based on goals: stabilize, hunt, or refine

F3/S2/BX2 depending on strategy chosen

📊 Generation Comparison Matrix

Generation	Genetics	Vigor	Stability	Time	Best For	Population Size
F1	50% A + 50% B	Maximum	Uniform F1s	1 gen	Production	20-30
F2	Wild variation	Variable	Very low	2 gen	Hunting	50-100+
S1	Plant × itself	Reduced	70% similar	1 gen	Preservation	15-25
S2	More inbred	Lower	85% similar	2 gen	Stabilization	10-20
BX1	75% A + 25% B	Good	Medium	2 gen	Targeting	30-50
BX2	87.5% A + 12.5% B