Variation in Hydric Response of Two Industrial Hemp Varieties (Cannabis sativa) to Induced Water Stress

Information on industrial hemp (Cannabis sativa) water use and stress is sparse. We studied impact in two essential-oil cultivars (‘Wife’ ‘Cherry’) prompted by anecdotal differences growth use. In a greenhouse setting, we measured relations, use, growth, essential oil (CBD-cannabidiol THC-delta-9 tetrahydrocannabinol) concentrations. Water did not significantly affect THC CBD concentrations, but both responded to reducing transpiration through notably different mechanisms. ‘Cherry’ had more anisohydric behavior, maintaining high stomatal conductance (Gs) negative leaf potential until root zone depletion triggered partial afternoon closure moderate stress, resulting lower flower yield. By contrast, water-stressed ‘Wife’ rapidly defoliated half its area balance with less applied so maintained Gs yield par well-watered plants, suggesting for deficit irrigation conserve reduce post-harvest vegetation management. Differences translated provisionally suggested crop coefficients of 1 1.3–1.5 ‘Wife’, further research needed. Because genetically diverse, cultivar naming conventions are currently lax, germplasm screening needed determine the extent which either conservative or water-stress defoliation response found larger population cultivars.