FIGURE 24.2 Different plants used as stake in traditional vanilla plantation (a) “piti” (Gliricidia maculata), (b) “purau” (Hibiscus tiliaceus), (c) “pignon d’Inde” (Jatropha curcas), (d) “aute” (Hibiscus rosa-sinensis), and (e) “nono” (Morinda citrifolia).
The traditional type of cultivation is the one most currently used. In this system, vanilla is in fact associated with other species such as food crops or fruits. In 1995, the average size of traditional vanilla plantations was about 3000 m² and the average age of the producers was over 50 years old. This traditional type of cultivation displays many constraints for the farmer. The plots are generally very sloppy and far from the house. It is regularly necessary to cut the branches of the stake tree to maintain constant shade, neither too intense, nor too weak, in order to preserve the development and bloom of vanilla plants. Finally, the vanilla plants can compete with the stake tree for water and its nutritive requirements. This will hamper the development of vanilla plantations.Owing to this, some producers using the “traditional way” choose techniques involving the use of a shade house. Of course, they maintain their natural plantation and expect the first harvest through their new “shade house” plantation. It is therefore likely that, in forthcoming years, the quantity of ripe vanilla from traditional cultures will decrease due to the desertion of “traditional plantations.”
The Under Shade House Culture
In recent years, vanilla plantations have been set up in shade houses in order to increase its production. Shade is ensured by insect-proof canvas thus avoiding virus transmission through insect vectors (Figure 24.3). The stake is generally made of concrete, and therefore is not in competition with the vanilla plant for the compost supply, which can be easily controlled. The production per hectare is strongly increased and daily work is less intensive. According to traditional plantations, the geographical location of shade houses must be taken into account. Ventilation plays an important role for shade houses. It is preferable to build a shade house on the coast on the sheltered side of the island. This facilitates ventilation and diminishes risks of fungal disease. The soil must always be drained and slightly sloped.
FIGURE 24.3 (a) Vanilla plant under shade house, two years after plantation; (b) vanilla plants flowering, under shade house, second year of production.
This new method of culture is more productive and facilitates the task of farmers; however, the cultural technique, traditional, or under a shade house, has little influence on the aromatic composition of the vanilla beans. Healthy vanilla vines will give high-quality beans whatever the cultural technique used.
Production and Agricultural Value
French Polynesia was once among the big vanilla producers. Between the years 1900 and 1960 more than 100 tons of ripe vanilla beans were produced per annum (Figure 24.4). The production dropped during the 1960s, following the installation of the Center of Nuclear Experimentation of the Pacific, which attracted many Polynesian people (Petard, 1986). Since the 1990s, the production of vanilla is making a come back, and is averaging 35 tons of ripe vanilla per annum. However, the production remains subjected to the weather. The cyclone of 1998 generated a drop in production by 16 tons in 1999. High temperatures in 2005 also had a negative impact on the production of 2006. In order to raise vanilla production in French Polynesia, governmental programs were set up to enhance its cultivation.
FIGURE 24.4 Evolution of the exportation of vanilla since 1905 and detail of the production and of the exportation of ripe and cured vanilla during the last 18 years.
The Service du Développement Rural (SDR), a public service in charge of the agricultural productions and livestock in French Polynesia, originally in charge of the “vanilla program” developed a cultivation system under shade houses and techniques of composting. In order to popularize these innovations, the Polynesian government established the Etablissement Vanille de Tahiti (EVT, Figure 24.5) in 2003. This public establishment with commercial interest was mandated to restimulate the production of vanilla in French Polynesia, in the archipelago of the Leeward Islands, where a “traditional way” had been maintained. In addition, the culture of vanilla “under shade house” has been developed in the other French Polynesian islands.
FIGURE 24.5 Logo for Etablissement Vanille de Tahiti.
This program is primarily devoted to human resource management. The aim is to increase the income of farmers and perpetuate their production.
The EVT assists growers through the sale and installation of shade houses and the supply of virus-free certified cuttings of vanilla. It ensures training and provides technical support on cultivation and sanitary control to the farmers.
The Sanitary Control
Cuttings sold to the farmers with the installation of shade houses are certified to be virus-free. The sanitary certification of these vines consists in the repeated controls of the cutting sources in the nurseries of the EVT, using ELISA detection of three types of viruses (Potyviruses, Cucumber mosaic virus, and Cymbidium mosaic virus) (Richard et al., 2009). Cuttings are collected only on vines in which no virus was detected over the past 9 months. At planting, a map of the new plantation is established with indication of the origin of each cutting (nursery, cutting source name, and location). At 3–4 months after planting of the cuttings, an ELISA test for the detection of the three viruses is carried out in the newly planted shade house in order to check if contamination did not occur during planting.
The Research and Development Department
As a priority, the EVT laboratory has undertaken research to characterize the traditional vanilla vines for their yield, their aromatic and lipidic composition, and their genome (see Chapter 13); in order to select the best cultivars and then create new varieties to be proposed to the farmers. The objectives were also to set up an “Appellation of Origin” “Vanille de Tahiti.” This would enable consumers and industrialists, to have a better visibility of the quality of Tahitian vanilla.