Format: ORAL

Ainhoa Riera-Begue1, Matteo Toscani1, Jiaqi Shi1, Susanne Schilling1 and Rainer Melzer1

School of Biology and Environmental Science, University College Dublin, Dublin, Ireland

Cannabis sativa is mainly a dioecious plant, which means that female and male flowers develop on separate individuals. This crop presents high sexual dimorphism, as we can see biochemical, vegetative and reproductive differences between the two sexes. C. sativa has a XY sex determination system: female have two X chromosomes and male plants carry an X and a Y chromosome; but the sexual system of this crop is much more complex, as the sex is not only determined genetically, but also by environmental and hormonal factors. While the developmental processes of male and female Cannabis sativa flowers clearly involves the orchestrated activation of numerous genes, it is conceivable that one or two key genes act as molecular switches for sex determination. The aim of our research is to understand how genes, phytohormones and environmental conditions interrelate and contribute to sex determination in hemp. Utilising transcriptomics analysis, we have pinpointed potential candidate genes on the sex chromosomes apparently associated with both female and male functional development in Cannabis sativa. Among those candidates are transcription factors with homologs know to be involved in reproductive development and sex determination. We have also developed a PCR-based method to determine sex genotype and establish genotype-phenotype relationships. Our results indicate that sex determination is established very early during Cannabis development by a network of gene regulatory proteins, and that the genetic basis of sex determination is robust across different cultivars and chemotypes.