Management of Auxin-Cytokinin Interactions to Improve Micropropagation Protocol of Henequen (Agave fourcroydes Lem.)

Henequen (Agave fourcroydes Lem.) is a high value plant species both for agricultural and ecological uses. The species is very well known worldwide by the quality of its fiber that is widely used for industrial purposes. This species is propagated at a large scale by asexual methods but current propagation technologies are not satisfying the grower’s demands. A. fourcroydes has been cultivated n vitro but it has shown some recalcitrant behaviour during the multiplication and rooting stages. The combination of 6-benzylamynopurine (BAP) (0.75 mg L-1) and indolebutyric acid (IBA) (1.0 mg L-1) instead of 2,4-dichlorophenoxyacetic acid (2,4-D) significantly improved explant survival and shooting during the establishment of n vitro young shoots. Combining thidiazuron (TDZ) (0.5 or 0.75 mg L-1) with BAP (1.0 mg L-1) and IBA (1.0 mg L-1) in the basal medium increased the multiplication rate of henequen and significantly speeded out bud dormancy breaking. To improve rooting of the micropropagated shoots, the addition of IBA and naphthylacetic acid (NAA) was tested. The best rooting efficiency was obtained when the basal medium was supplemented with 0.5 or 0.75 mg L-1 of NAA, giving 100% of rooted explants and an average of 9.40 and 11.55 roots per explants, respectively. Over 94% of micropropagated plants survived the ex vitro weaning step and no morphological disorders were observed in any of the plants. Modification of plant growth regulators composition in the medium was a key factor to improve the efficiency of the micropropagation technology of henequen. El henequén (Agave fourcroydes Lem.) es una especie vegetal de gran valor agrícola y ecológico conocida mundialmente por la calidad de su fibra usada con fines industriales. Esta especie se propaga a gran escala por métodos asexuales, pero las tecnologías de propagación actuales no son capaces de satisfacer la demanda de los productores. A. fourcroydes ha sido propagado n vitro pero muestra comportamiento recalcitrante durante las fases de multiplicación y enraizamiento. En este estudio se demostró que la combinación de 6-benzilaminopurina (BAP) (0.75 mg L-1) y ácido indolbutírico (IBA) (1.0 mg L-1), en lugar de ácido 2,4-diclorofenoxiacético (2,4-D), mejoró significativamente la supervivencia de los explantes y la brotación durante la fase de establecimiento n vitro a partir de brotes jóvenes. La combinación de thidiazuron (TDZ) (0.5 ó 0.75 mg L-1) con BAP (1.0 mg L-1) e IBA (1.0 mg L-1) en el medio basal inc