GENE EXPRESSION MARKERS FOR PREDICTIVE CANNABIS BREEDING THROUGH GAMMA RADIATION-INDUCED MUTAGENESIS

Enhancing cannabis varieties through plant breeding plays a pivotal role in meeting market demands. Identifying gene markers associated with THC and CBD synthesis could streamline the early selection process within a plant breeding program. To assess the efficiency of radiation-induced breeding of the Thai ‘Hang Kra Rog’ marijuana, two methods of radiation exposure are employed: exposing young seedlings to low doses of radiation and exposing seeds to high doses of radiation. The expression of the THCAs gene in seedlings exposed to 20 Gy and 40 Gy increased to 4.0 and 2.5 times as high as control, respectively. Seeds exposed to 200 Gy of gamma radiation exhibited a substantial increase in THCAs gene expression compared to control (2.4 times as high). Meanwhile, no evidence of CBDAs gene expression was observed. In chemical analysis using HPLC, seedlings exposed to a dose of 40 Gy showed a THC content of 3.9%, which was higher than control (2.8%). This trend was similar to the group of seeds irradiated with 200 Gy, which had a THC content of 2.7%, also higher than control (2.3%). Meanwhile, no detectable CBD presence was observed. There is a correlation between THCAs and CBDAs gene expression and their respective cannabinoid concentrations. In conclusion, the study outlines its potential contribution to cannabis breeding practices. Gamma radiation exposure is an effective method for inducing mutations in cannabis breeding. The gene expression markers can be used to predict cannabinoid profiles and support the selection of desirable traits of cannabis.