Effect of Hormonal Treatments on Cannabinoid Content Levels in Female Hemp (Cannabis sativa L.) Inflorescences

The diverse hormonal treatments applied to hemp (<i>Cannabis sativa</i> L.) carry significant implications for cultivation, and yield optimization across a range of applications, including fiber, seed, oil production, and the enhancement of medicinal compounds. However, there is no evidence concerning the long-term consequences of hormonal treatment. To determine the connection between the effects of hormonal treatment and cannabinoid accumulation, hemp plants were treated with γ-aminobutyric acid (GABA), abscisic acid (ABA), and salicylic acid (SA) to investigate their effects on gene expression and cannabinoid content levels in female inflorescences at 3 days and 4 weeks after treatment. The treatments influenced the transcript levels of five key cannabinoid biosynthesis genes, with 1.0 mM GABA significantly increasing <i>OAC</i>, <i>THCAS</i>, and <i>CBCAS</i> transcripts within 48 to 72 h. Additionally, 1.0 mM GABA led to a significant increase in tetrahydrocannabinol content by day three and significant increases in total cannabidiol and cannabinoid by week four. In addition, both ABA and SA induced transient, dose-dependent increases or decreases in gene expressions, but cannabinoid accumulation at 4 weeks showed no significant changes compared to the control. These results provide valuable insights for hormonal application in cultivation and the development of traits that enhance cannabinoid production in cannabis cultivation, which could significantly contribute to optimizing industrial applications.