In Vitro Propagation of Threatened Agave Species Using a Two-Stage System.

Agaves are plants with multiple possibilities of use and are naturally tolerant to low water availability conditions and high temperatures. This makes them species of great interest in the context of the necessary substitution of crops due to climate change. Unfortunately, the overexploitation of wild specimens has endangered many species of the genus that have not been domesticated or cultivated intensively. In vitro mass culture and propagation techniques have emerged as a very efficient option to produce agave plants that can be used without damage to the natural populations. A protocol is presented here for the in vitro micropropagation of agaves in a two-stage process. In the first step, clusters of slightly differentiated shoots are generated from stem segments cultivated on a semisolid medium added with cytokinin. In a second step, these shoot clusters are cultured in temporary immersion bioreactors where they grow and complete their differentiation, and then the shoots are rooted and transferred to soil. This protocol has been successfully applied to several threatened species of the Agave genus.

Micropropagation of Yucca Species.

Yuccas are plants adapted to arid and semiarid regions and have been used as source of food and raw materials and for ornamental purposes. Lately, the interest in this genus has grown due to the presence of potential useful compounds such as saponins and polyphenolics. However, they present very low reproductive rates and virtually all the plants used are wild individuals; as consequence, their natural populations have been depleted. We present an efficient method to establish in vitro cultures of Yucca species starting with seeds and then obtaining shoots from the seedling meristems using cytokinins and auxins. These shoots can be rooted and transferred to soil or can be used as explants for another multiplication cycle. Hence, it is necessary to acquire seeds just once to establish a large-scale micropropagation protocol.