Vapor Pressure Deficit Response

Vapor Pressure Deficit (VPD) Response refers to a plant's genetic capacity to regulate transpiration and stomatal function under varying humidity and temperature conditions. Cannabis cultivars show measurable differences in how efficiently they manage water loss when VPD fluctuates—a trait influenced by leaf surface morphology, stomatal density, and cuticle thickness. Plants with strong VPD resilience maintain stable photosynthetic rates across broader environmental ranges, while sensitive genotypes may experience stress or reduced growth in high-VPD conditions (hot, dry air) or low-VPD conditions (cool, humid air). This heritable trait is particularly relevant in controlled environment agriculture, where breeders select for cultivars that thrive under specific climate profiles.

Breeders working in indoor and outdoor production systems increasingly prioritize VPD-responsive genetics to reduce crop losses from environmental stress and improve resource efficiency. Cultivars bred for consistent performance across variable humidity zones command attention in breeding programs targeting commercial stability.