Discovery of a novel hemp branching mutant

Cannabis (Cannabis sativa L.) is a unique crop producing cannabinoids, including Δ9-tetrahydrocannabinolic acid and cannabidiolic acid, which can transform into Δ9-tetrahydrocannabinol (THC) and cannabidiol through decarboxylation, but it is largely prohibited or strictly regulated in most countries because of the psychoactive effects of THC on humans. However, there has recently been increasing interest in cannabis because of clinical research, thus suggesting it has therapeutic effects. Because of its physiological properties and limited accessibility, ensuring homozygosity in cannabis is challenging. Most cannabis plants that are currently sold are hybrids. The SupwerowomanS1 cultivar was used to develop a new cultivar, document genetic variation, and identify a novel hemp mutant following self-pollination during polyploid breeding. A mutant with fewer axillary stems than SuperwomanS1 and round floral organs with many sugar leaves (like rosette leaves) was identified. A quantitative real-time PCR analysis indicated the expression levels of the main genes regulating axillary bud formation (SHOOT MERISTEMLESS, LATERAL SUPPRESSOR, REVOLUTA, WUSCHEL) were higher in the mutant than in SuperwomanS1. These findings may be relevant to hemp breeding and cultivation.