Season‐long characterization of high‐cannabinoid hemp (Cannabis sativa L.) reveals variation in cannabinoid accumulation, flowering time, and disease resistance
de Meijer | E. P. M | K. M | C. J | J. P | S. G | J. A | M. A | M. R. G | X.-Y
To replicate and extend work in the existing literature, the objectives of the replicated field trials involving 30 high-CBD cultivars in this experiment were to: Assess variation in cultivar height and growth rate throughout the growing season; Evaluate genetic segregation for chemotype in cultivars; Quantify variation in flowering time within and between cultivars; Model cannabinoid accumulation by cultivar using a time series of shoot tip samples; Rate cultivars for susceptibility to powdery mildew; and Quantify yield components by cultivar including biomass yield and cannabinoid content in stripped biomass. Value Formula Growth rate (Weekn height − Weekn−1 height)/# days between measurements Total cannabinoid % CBDA % + CBD % + THCA % + Δ9-THC % + CBGA % + CBG % + CBCA % + CBC % + THCVA % + THCV % + CBDVA % + CBDV % + CBN% Total CBD % CBD % + (CBDA %0.877) Total THC % Δ9-THC % + (THCA %0.877) Total CBG % CBG % + (CBGA %0.878) Total CBC % CBC % + (CBCA %0.877) Total THCV % THCV % + (THCVA %0.867) Total CBDV % CBDV % + (CBDVA %0.867) % Dry matter total dry biomass/total wet biomass100% % Floral tissue dry floral biomass/total dry biomass100% CBD yield per plant dry floral biomass% CBD in biomass subsample Biomass:Shoot ratio % CBD in biomass sample/% CBD in last shoot sample CBD:THC ratio Total CBD %/(Total THC % + 1.013CBN %) 2.4 Flowering surveys All plants were rated weekly for evidence of flowering. Group 1 2 3 4 5 3.2 Chemotype and cannabinoid ratios Several of the cultivars in the trial were segregating at the B locus and produced the expected CBD:THC ratios (Table 5; Table S2). For some cultivars, disease severity by cultivar varied by site: ‘NY Cherry’ had no signs of powdery mildew in the Ithaca trial, but nearly 20% mean leaf area with powdery mildew in the Geneva trial. Cultivar, but not site, had a significant effect on the CBD:THC ratio.