Anthocyanins

Anthocyanins are water-soluble pigments responsible for purple, blue, and red coloration in cannabis plant tissues, including flowers, leaves, and sometimes stems. These compounds are distinct from terpenes—they do not contribute aroma—but are often observed alongside specific genetic backgrounds and environmental conditions, particularly cool temperatures. Anthocyanin expression is commonly associated with indica-dominant and hybrid lineages, though expression varies widely even within cultivars carrying the same genetic markers. Breeders working in ornamental and specialty cannabis programs frequently select for high anthocyanin phenotypes to achieve desirable visual traits. Environmental factors such as phosphorus availability, UV exposure, and nighttime temperatures significantly influence pigment intensity and hue.

Breeders use anthocyanin expression as a visual selection marker in early-generation phenotyping. High-anthocyanin phenotypes are often stabilized in F2 and F3 lines for aesthetic breeding goals, though pigmentation alone does not indicate cannabinoid or terpene profiles.