Gas Chromatography Phenotyping

Gas chromatography (GC) phenotyping is an analytical method that separates and identifies volatile compounds in cannabis samples, particularly terpenes and other aromatic molecules. By vaporizing a sample and passing it through a specialized column, GC detects individual compounds and their relative abundance, producing a chemical fingerprint unique to each plant or batch. This technique has become a standard tool in cannabis breeding and quality assessment, allowing breeders to correlate chemical profiles with observed plant traits and environmental responses. GC data differs from sensory evaluation alone, providing objective, reproducible measurements that can be compared across generations and growing conditions. Many modern seed banks and research programs now archive GC profiles alongside phenotypic notes to document genetic stability and terpene expression patterns.

Breeders use GC phenotyping to select for consistent terpene profiles, track monoterpene and sesquiterpene ratios across offspring, and verify genetic purity in stabilized lines. By pairing GC results with observable traits—growth rate, morphology, flowering time—breeders build correlative data that informs selection decisions and helps predict offspring chemistry before flowering.