Plant Growth Regulators Use in the In Vitro Culture of Agave Species

Agave species possess substantial cultural, ecological, and economic significance, particularly in Mexico, where they are traditionally utilized for food, fiber, and beverages. Their industrial relevance has expanded to include bioenergy, nutraceuticals, and sustainable agriculture. However, conventional propagation methods are constrained by long life cycles, low seed germination rates, and susceptibility to phytopathogens. In vitro culture has emerged as a pivotal biotechnological strategy for clonal propagation, germplasm conservation, and physiological enhancement. This review presents a critical synthesis of plant growth regulators (PGRs) employed in agave micropropagation, emphasizing their roles in organogenesis, somatic embryogenesis, shoot proliferation, and rooting. Classical PGRs such as 6-benzylaminopurine (BAP), benzyladenine (BA), 2,4-dichlorophenoxyacetic acid (2,4-D), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA) are widely utilized, with BA + 2,4-D and BA + IAA combinations demonstrating high efficiency in embryogenic callus induction and shoot multiplication. Additionally, non-traditional regulators such as abscisic acid (ABA) and putrescine (Put) have been shown to affect embryo maturation. This review synthesizes recent studies on agave in vitro culture protocols, identifies trends in PGR use, and highlights key research gaps. These insights reveal opportunities for innovation and underscore the need for species-specific optimization and molecular validation to improve reproducibility and scalability.