Improved propagation of vanilla (Vanilla planifolia Jacks. ex Andrews) using a temporary immersion system

Here, we evaluated the efficiency of shoot multiplication of Vanilla planifolia Jacks. ex Andrews using solid medium, partial immersion, and a temporary immersion system (TIS) to improve micropropagation in this species. Clusters of shoots were cultivated in vitro using Murashige and Skoog (MS) medium supplemented with 9.55 μM benzyladenine (BA) and 100 mL L^?1 coconut water. For the TIS, a RITA^® system was used and three immersion frequencies were evaluated (every 4, 8, and 12 h) with an immersion time of 2 min. After 30-d culture, the TIS produced the maximum multiplication rate (14.27 shoots per explant) when using an immersion frequency of 2 min every 4 h, followed by the partial immersion system (8.64 shoots per explant), and solid medium (5.80 shoots per explant). Next, the effect of the volume of culture medium per explant was also evaluated for TIS. The most suitable volume of culture medium for shoot formation was 25 mL per explant, which increased the rate of multiplication to 17.54 shoots per explant. Root initiation was 90% successful in TIS using half-strength MS medium supplemented with 0.44 μM naphthaleneacetic acid (NAA) and an immersion frequency of 2 min every 4 h. With this system, the shoot multiplication rate increased threefold compared to that obtained with solid medium. In addition, this system produced good results for the transplantation and acclimation (90% of survival) of in vitro-derived plants. These results offer new options for large-scale micropropagation of vanilla.