🧬 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
✅ Advantages:
  • Maximum hybrid vigor
  • Consistent F1 offspring
  • Often exceed both parents
  • Great for production
  • Disease resistance
❌ Disadvantages:
  • More Diverse Offspring
F2 Generation
F1 × F1 Cross
Wild Variation
F1 Plant
×
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
×
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

1
P1 Generation (Parents)
Start with two stable parent plants with desired traits
Example: OG Kush (Parent A) × Blue Dream (Parent B)
2
F1 Generation
Cross the parents - maximum hybrid vigor, uniform plants
Result: F1 hybrids with 50% OG + 50% Blue Dream genetics
3
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
4
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