Vanilla

Vanilla has been cultivated in French Polynesia since the nineteenth century. Tahitian vanilla, the genuine black gold of French Polynesia, is cultivated for its famous beans, which develop an intense fragrance of anise notes (see Chapter 13). The vanilla plantations are mainly located in the archipelago of the Society Island (Figure 24.1). The surface dedicated to vanilla production covers 306 ha (SDR, 1995). The island of Tahaa is also called the “Vanilla Island.” The island has a land area of 88 km² and harbored 573 vanilla producers in 2002. Its nearby islands, Raiatea and Huahine, comprised 206 and 300 vanilla producers (census of the SRD, 2002). Vanilla is also widely cultivated throughout French Polynesia. From Tahiti and its sister island Moorea (10.3 ha of vanilla production) to the Marquesas Islands (2.4 ha), the Tahitian people meticulously cultivate their invaluable Tahitian vanilla. Vanilla is cultivated by two techniques: the first one known as the “traditional way” and the second called the “under shade house technique.”

FIGURE 24.1 Map of French Polynesia. The Society Islands (Iles de la Société), where vanilla production is the most important, are circled in black.

Traditional Way of Cultivation

The traditional way of cultivation has been used for several generations, where the vanilla vine is planted at the base of a tree. The tree provides stake and shade for the climbing orchid. The vanilla plantation is generally located on a hillside, within a cleared forest, chosen for its high content in organic matter (Wong, 1999). The plantation is sloped, below wooden trees to benefit the humus generated by the trees at the top. If the ground is flat, the soil needs to be drained, digging channels to clear up the excess of water. The choice of the stake is important that it must protect the vanilla from the heat of the sun or wind and not compete for water supply and compost. The two favorite stakes are the “piti” (Gliricidia maculata) and the “pignon d’Inde” (Jatropha curcas) (Figures 24.2a and c). Gliricidia is a leguminous plant, which does not compete with vanilla for nitrogen supply. It grows quickly and requires frequent pruning. Jatropha requires less pruning to limit its growth, as leaves fall naturally during the dry season when flower induction occurs in vanilla. Thus, it does not need pruning. Other natural stakes are also used—the “purau” (Hibiscus tiliaceus), the “aute” (Hibiscus rosa-sinensis), or the “nono” (Morinda citrifolia) (Figures 24.2b, d, and e).

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.

Since the installation of new plantations under shade houses (20 ha including 16 in the Leeward Islands and 4 ha in the Windward Islands) by the EVT and despite the relative decline of traditional culture, the production should increase over the next few years to reach an estimated production of 60 tons of ripe vanilla.

The agricultural value of vanilla in French Polynesia, more precisely the value of marketed vanilla mature beans, has strongly increased since 2000, starting from 65 million Pacific Francs (547,000 euros) in 2000 to 116 million in 2006 (972,100 euros). This agricultural value of ripe vanilla represents 2% of the total Polynesian agricultural value.

After a peak in 2004, the average price of a kilogram of ripe vanilla beans drew back to the level originally observed of 4000–5000 FcfP (33–42 euros/43–54 USD). Export prices of a kilogram of cured vanilla hovered around 22,000 FcfP (184 euros/236 USD) (Figure 24.6). This price is much higher than that of other cultivated vanillas, including Bourbon vanilla. This is due to the aromatic quality of the Tahitian vanilla, which is very rich in flavor and thus has become a top-of-the-range product, in particular, in pastry products and catering.

FIGURE 24.6 Evolution of the mean price of a kilogram of ripe vanilla and of exported cured vanilla beans.