Stress Tolerance Heat

Heat tolerance in cannabis refers to a plant's genetic capacity to maintain growth and development under elevated temperature conditions, typically above 28–30°C (82–86°F). This trait is influenced by multiple genetic factors affecting photosynthetic efficiency, stomatal regulation, and cellular stress-response pathways. Lineage records frequently report heat tolerance in cultivars originating from equatorial and subtropical regions, where environmental selection has favored thermal resilience. Breeders distinguish between acute heat stress (short-term spikes) and chronic heat exposure (sustained warmth), as genotypes respond differently to each. Understanding heat tolerance is particularly relevant for outdoor cultivation in warm climates and indoor environments where temperature management may fluctuate.

Breeders working in hot climates or targeting heat-resilient cultivars typically screen parental lines for maintained vigor, leaf integrity, and reduced heat-stress phenotypes under controlled conditions. Heat-tolerant genetics are crossed to preserve this trait while introducing desirable secondary characteristics, making it a key selection criterion in tropical and Mediterranean breeding program