Systemic Acquired Resistance

Systemic Acquired Resistance (SAR) refers to a plant-wide immune response triggered when a localized infection or stress event activates defense mechanisms across the entire organism. In cannabis breeding and cultivation research, SAR describes how pathogen exposure in one tissue can prime defensive compounds—including certain terpenes and phenolic compounds—throughout the plant. Breeders and researchers monitor SAR-related traits because enhanced systemic immunity may reduce susceptibility to secondary infections during growth cycles. Documentation of SAR responses in cannabis genetics remains limited compared to model plants, though breeding programs increasingly select for lineages demonstrating robust immune priming. Understanding SAR mechanisms helps inform cultivation strategies and informs selection criteria in long-term breeding projects.

Breeders working in disease-resistance categories often cross-reference SAR-related phenotypes when selecting parent plants, as systemic immunity can reduce fungal and bacterial pressure without external inputs. Selection for vigorous, stress-responsive genetics may inadvertently favor lines with stronger acquired resistance traits.