Heritability and Environmental Influence in Cannabis Explained

Reading time: approx. 9–10 minutes

What does heritability mean?

Heritability describes how much of a trait is determined by genetics compared to environmental and random influences.

Key clarifications:

• Heritability does not measure quality
• Heritability is not a fixed value
• Heritability always depends on environmental context

A genetically stable trait can still appear different.

Genetics define the range, environment defines expression

Genetics set the possible range. Environment determines where within that range expression occurs.

• Structure may be consistent while size varies
• Leaf traits remain recognizable but flexible
• Development speed responds to conditions

Why identical lines may look different

Environmental factors influencing expression include:

• Light intensity and spectrum
• Temperature and airflow
• Substrate and nutrient availability
• Timing of observation and selection

These differences do not imply genetic instability.

Distinguishing environment from instability

• Instability means inconsistent results under comparable conditions
• Genetic drift alters genetic composition itself
• Environmental variation alters expression only

See also: Genetic Drift Explained

Testing heritability in practice

• Repeated observations under similar conditions
• Multiple individuals from the same line
• Comparisons across generations

This directly connects to Phenotype Hunting and Stability Testing.

Why stability is not uniformity

Stable lines do not produce identical outcomes, but predictable variation.

• Variation within limits is normal
• Consistent outliers matter
• Stability is statistical, not visual

For the broader framework, see Understanding Stable Cannabis Lines.

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