Cannabis is a short day (SD) photoperiodic flowering plant whose inflorescences produce valuable medicines. At least two loci have been identified in cannabis which are responsible for the SD photoperiodic flowering response and consequently the autoflowering or fast flowering phenotypes. Yet, the specific functional genes within these loci have not been identified. In SD plants, CONSTANS, which is enhanced by critical daylength gated proteins that are expressed during short days, acts as a bifunctional regulator of flower inhibition or genesis by regulating FT (florigen). These genes are downstream of phytochrome, which may be activated by horticultural lighting conditions: red (R, 660nm) to far red (FR, 700+nm) wavelength ratios. This study demonstrates that gene expression can be manipulated using high and low R:FR ratios, and characterizes the expression levels of CONSTANS, FT, PRR37, and SOC1 in cannabis over the first 14 short days. It also demonstrates the resulting effect on cannabinoid production and biomass yields. Finally, differential expression analyses (DESeq) were performed on leaf tissues before and after the initiation of short days to identify CDL gated putative enhancers of flowering. Future research may include co-IP of CsCONSTANS interactors as well as DESeq in the developing floral meristem. Understanding CDL-gated enhancers and repressors of CONSTANS in cannabis may reveal key regulators of floral initiation and yield potential.

Learning Objectives:

• Understanding CDL-gated positive enhancers of flowering will:
• Yield genes that are predictive of performance
• Help to clarify the conserved mechanisms of flowering in SD plants 
• Clarify the incomplete dominance of the autoflowering allele and photoperiod phenotypes