Sex reversal in female cannabis plants as a in response to male flowering promoters

Abstract

Cannabis sativa is a widely studied species and is currently accepted worldwide due to its medicinal properties, especially those conferred to the CBD phytocannabinoid, which is synthesized mainly in the globular trichomes of female flowers. Males are undesirable and rare in commercial plantations; however, they are necessary for breeding programs. This research aimed to evaluate sexual reversion methods in female cannabis plants as a preliminary stage of a plant breeding program. A completely randomized design with eight treatments and four repetitions was used. The treatments consisted of protocols for the sexual reversion of female plants through drip application and foliar spraying of Silver Thiosulfate (STS), Aminoethoxy-vinyl-glycine (AVG), 1-Methylcyclopropene (1-MCP), and Gibberellic acid (AG3), plus a control treatment without application. Male flower production was evaluated in female cannabis plants, and pollen viability in male flowers was determined. The AVG treatments applied to the apex by dripping, and the AG3 applied to the foliage in the form of a spray influenced the sexual reversion of female plants and produced a total of 132 and 32 male flowers, respectively, without difference between them (P=0.08383). For AVG dripping, only male flowers were observed at the apex, where the application was made directly. Moreover, STS and 1-MCP did not induce the production of male flowers. The pollen from male plants treated with AG3 in spray, and AVG dripping showed high viability (>50%), contrary to the low viability observed in plants treated with AGC applied in spray. The plants treated with AG3 (spray) were higher due to the elongation of the internodes. The AVG and AG3 compounds are effective in the sexual reversion of female cannabis and generate male flowers with viable pollen.