Progress in the study of dioecy in Mexican cycad species and its implications for conservation

Abstract Dioecy is a system of sexual reproduction in plants, characterized by the spatial separation of reproductive structures into different individuals. This system is thought to have evolved to reduce the adverse effects of inbreeding that can occur in hermaphroditic ancestors. Although significant progress has been made recently in understanding this phenomenon, the mechanisms of sex determination in plants remain largely unexplored. These mechanisms may have a genetic, physiological, or epigenetic basis, which has been a focus of interest in cycads, a plant group with a strong association with dioecy. Cycads are threatened plants that exhibit a long period of sexual maturity, making it difficult to determine their sex at an early age, which hinders conservation efforts. In this review, we outline the research history on finding effective methods for early sex identification in cycads, with an emphasis on Mexican cycads. Additionally, we include a discussion by presenting genetic data for the endemic Mexican species Ceratozamia mexicana Brongn., Zamia furfuracea L. f., and Zamia inermis Vovides, J.D. Rees & Vázquez‐Torres. We also discuss how sex identification could aid in developing effective conservation plans for these critical species, many of which are recognized by the IUCN (International Union for Conservation of Nature) and federal norms in Mexico.