Morphogenic characterization of vanilla (Vanilla planifolia Andrews) for propagation

Abstract

Introduction. Vanilla (Vanilla planifolia Andrews) is an orchid that is commercially grown for the production van, a flavoring substance that is used mainly in the food industry and as a cosmetic. Although the demand has motivated its cultivation, there is little availability of vigorous seed and free which has been a limited. Temporary immersion systems have been shown to be efficient. For their massive micropropagation but studies of time, immersion, frequency and optimal volume have not yet been established in the proliferation of shoots in Temporary Immersion Bioreactors (BIT), furthermore, a morphogenic pathway that guarantees genetic stability and optimization during the micropropagation process is unknown. Objective. Morphogenic characterization of vanilla (Vanilla planifolia Andrews) in a BIT. Materials and methods. Three experiments were carried out, each with 3 treatments. For the first experiment, the immersion time considered the  treatments of 5, 10 and 15 min, in the second experiment 3 frequencies were evaluated at times of 6, 12 and 18 hours and in the third experiment were considered 20, 30 and 40 ml/ explant as volume of culture medium. For the differents treatments used 5 repetitions, with an experimental unit of 10 explants and stem segments with 3 axillary buds. The culture medium consisted of Murashige Skoog (MS) salts supplemented with 1 mg.L^-1 of BA and 1 g.L^-1 of casein. The photoperiod was adjusted to 16 light hours, with a temperature of 27°C±3 and a relative humidity of 80%. Results. Statistical differences (p<0,05) were obtained with respect to the evaluated times, frequency of immersion and the volume per explant. A period of 15 minutes it was determined as the best immersion time, 6 hours as the immersion frequency and 40 ml as the volume of medium per explant. When comparing the development response, the BIT system exceeded the semisolid medium 1.8 times in the number of shoots and 4 times in the increase in fresh weight. In addition, 36 shoots were obtained per explant in BIT, while in the culture system in semi-solid medium, a multiplication rate of 20 shoots per explant. Conclusions. By using the BIT system, the micropropagation mechanism of V. planifolia was optimized compared to the semi-solid culture medium in the direct organogenic route, which was proved with the formation of preformed shoots and adventitious shoots.