Industrial hemp is increasingly grown and harvested for its cannabinoids of pharmaceutical interest. These compounds are generally obtained from plants harvested at maturity but not all cannabinoids are present or abundant during the last stage of hemp development. This study examined intraspecific cannabinoid variability during ontogenic development of hemp to identify growth stages and cultivars that optimize production of specific compounds. The cannabinoid content of twelve commercial industrial hemp (Cannabis sativa L. subsp. sativa) cultivars at three growth stages (i.e., flowering, grain filling and maturity) was determined by high performance liquid chromatography in an experimental field in Cocagne, New Brunswick, Canada. Most cannabinoids in acidic or neutral form were more abundant at maturity. However, cannabigerolic acid, a precursor to all acidic and neutral forms of cannabinoids mentioned in our study, was more abundant during the grain-filling stage. In contrast, cannabichromene was associated with the flowering stage and found in greater abundances in grain cultivars than in dual-purpose cultivars. The cultivar Katani exhibited higher concentrations of most cannabinoids while the cultivars Ferimon, Altair and Anka exhibited higher concentrations of cannabinoid acidic precursors. The current study could help optimize the targeted production of cannabinoids at specific growth stages and to identify the chemical phenotype of different hemp cultivars.

工业大麻因其具有药用价值的大麻素而越来越多地种植和收获。这些化合物通常从成熟时收获的植物中获得，但并非所有大麻素在大麻发育的最后阶段都存在或丰富。这项研究检查了大麻个体发育过程中的种内大麻素变异性，以确定优化特定化合物生产的生长阶段和栽培品种。十二种商业工业大麻（Cannabis sativa L. subsp. sativa ）的大麻素含量）在三个生长阶段（即开花、灌浆和成熟）的栽培品种在加拿大新不伦瑞克省科卡涅的一个试验田中通过高效液相色谱法测定。大多数酸性或中性大麻素在成熟时更丰富。然而，大麻二酚酸是我们研究中提到的所有酸性和中性大麻素的前体，在籽粒灌浆阶段更为丰富。相比之下，大麻素与开花期有关，并且在谷物品种中的丰度高于双重用途品种。品种 Katani 表现出较高浓度的大多数大麻素，而品种 Ferimon、Altair 和 Anka 表现出较高浓度的大麻素酸性前体。