Genetic Bottleneck

A genetic bottleneck occurs when a cannabis population undergoes a sharp reduction in genetic diversity, typically due to selective breeding focused on narrow trait targets, small founding populations, or repeated inbreeding cycles. This phenomenon is common in commercial cultivation, where breeders may stabilize desirable phenotypes by crossing a limited number of parent plants across multiple generations. While bottlenecks can accelerate the fixation of desired traits like potency or flavor, they simultaneously reduce overall genetic variation and can increase the expression of recessive deleterious alleles. Understanding bottlenecks is important for long-term breeding programs, as severely reduced diversity may limit future breeding flexibility and resilience to environmental stress or disease pressure.

Breeders monitoring for genetic bottlenecks often employ diversity assessments and outcrossing strategies to maintain phenotypic flexibility in foundation stock. Intentional population management—such as expanding breeding pools or introducing genetic material from unrelated lines—helps counteract unwanted bottleneck effects while preserving stabilized cultivars.