Pure Line Breeding

Pure line breeding refers to the intentional selection and propagation of cannabis plants from a single, genetically uniform parent or a highly stable genetic background across multiple generations. Breeders working in this category typically self-pollinate plants or cross genetically identical or near-identical individuals to establish homozygous traits and eliminate genetic variation. This approach differs from hybrid breeding, where distinct parent lines are crossed to combine different genetic backgrounds. Pure line cultivation requires careful record-keeping and controlled breeding conditions to maintain consistency across seed generations. The resulting seed stocks are often described as "true-breeding" when offspring reliably express the same phenotypic traits as their parents.

Pure line breeding is foundational for stabilizing desirable traits—such as terpene profiles, plant structure, or cannabinoid ratios—and creating predictable seed stocks. Breeders use this method to establish mother plants and breeding stock that can serve as reliable parents for future crosses or commercial cultivation.