MICROPROPAGATION OF Opuntia velutina: A SPECIES USED AS VEGETABLE CACTUS

Abstract

Prickly pear cactus (Opuntia ficus-indica) has gained prominence in the 21st century due to its growth characteristics, uses and nutritional and phytochemical properties, which has boosted interest in related species such as the wild nopalillo (Opuntia velutina), used as a vegetable cactus. Despite its use, there is a lack of data on its ecology, physiology and genetics, making it necessary to develop efficient propagation systems such as micropropagation. This study established a protocol for micropropagation of O. velutina. For explant establishment and shoot induction, areolas were immersed in commercial sodium hypochlorite (NaClO) at different concentrations (0-15 %) and immersion times (5-15 min) and then placed on basic Murashige and Skoog (MS) medium. In the multiplication phase, the MS medium was supplemented with different concentrations (0.5-1.5 mg L^-1) of 6-benzyladenine (BA), kinetin (Kin), indolacetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D). For shoot elongation and rooting, Kin (0.5, 1, 1.5 mg L-1) was combined with IAA and 2,4-D (1.5, 1, 0.5 mg L^-1), and for acclimation five peat:perlite ratios (1:0, 0:1, 1:1, 2:1 and 1:2) were evaluated. The highest percentages of established explants (70.8 %) and shoot induction (66.7 %) were observed after 5 min in 5 % NaClO. Treatment with 1.5 mg L^-1 of BA produced the largest number of shoots and shoot-forming capacity (7.06). Explants with the longest shoots (26.82 mm) and highest rooting response (8.26) were obtained with 0.5 mg L^-1 Kin and 1.5 mg L^-1 IAA, significantly outperforming the control. In acclimatization, the 1:1 peat:perlite mixture promoted the highest survival (80 %). The micropropagation protocol developed in this study represents a biotechnological tool for large-scale multiplication of O. velutina that could be used in reintroduction programs and commercial exploitation of the species.