The scientists of the Subtropical Plant Research Academy in Fujian Province were the first to focus on research on vanilla in mainland China. Their early works played a role in the foundation of vanilla research and industrial development in China. Meanwhile, their works initiated and promoted the industrial development of vanilla in China. As regards planting, they researched and established a model of intensive planting in artificial shade houses, which has been widely adopted in commercial vanilla planting in China. The research team published 36 papers, and edited and published the first monograph on vanilla, Vanilla Planting, in China.
The Chinese Academy of Tropical Agricultural Sciences (the South China Academy of Tropical Crops before 1994) was also the first to focus on vanilla research. Its team of scientists is the main force in the field of vanilla research in the region of Hainan Province. Its research work directly promotes and supports the industrial development of vanilla in Hainan Province. At the same time, it provides references for scientific research and the industrial development of vanilla in the region of Yunnan Province. It published over 30 research papers about vanilla, and organized and edited national agricultural standards for vanilla in China.
Several organizations are engaged in vanilla research in Yunnan Province. These are mainly the Flavors & Fragrances Research Institute and the College of Plant Protection at Yunnan Agricultural University, the Tropical Crop Research Academy in Yunnan Province, the Kunming Botany Research Institute of Chinese Academy of Science, and so on. A research team in Yunnan Agricultural University has done a good deal of work, especially in pest and disease control for vanilla, and published a monograph on Pest and Disease in Vanilla.
Some corporations that plant and manufacture vanilla, especially the vanilla manufacturing corporations in Hainan Province, have also done some research work.
Present Situation Commercial Varieties and Genetic Resources
Vanilla planifolia has been introduced and commercially planted in China. A few other introduced and native wild vanillas are used only for scientific research. The main commercial varieties and genetic resources are as follows:
V. planifolia Andr.: introduced from Indonesia (1960) and Sri Lanka (1962); Vanilla somai Hayata: Taiwanese vanilla distributed in Taiwan in China; Vanilla shenzhenica Z.J. Liu and S.C. Chen: found in Shenzhen, South China.
It is akin to Vanilla somai Hayata (Liu et al., 2007); Vanilla siamensis Rolfe ex Downie: known as “Big Vanilla,” distributed in Guangxi Province and the Xishuangbanna and Hekou areas in Yunnan Province. A relative correlation exists between V. shenzhenica Z.J. Liu & S.C. Chen and V. somai Hayata. A natural population distributed in the Yachang orchid nature protection region in Leye County, Baise city in northwestern Guangxi Province is the biggest of the wild Big Vanilla group known so far at the highest latitude and the highest altitude (east longitude 106°19′13″, north latitude 24°48′56″) (Chen et al., 2007).
The Main Growing Regions and Their Climatic Characteristics
Hainan Province and Xishuangbanna in Yunnan Province are major regions in China, and are appropriate for vanilla planting and production. Xishuangbanna, which includes three counties, Jinghong, Mengla, and Menghai, is located in southern Yunnan, E99°55′–101°50′, N21°10′–22°40′, altitude 475–2429 m. This place lies on the northern edge of the eastern and southern Asian tropical region, with tropical and subtropical climate regions, multiple climate types, and complicated terrain. The tropical climate area in Xishuangbanna covers about 400 ha that are located below 800 m altitude, which represents only 20.4% of its area. Total annual precipitation is between 977 and 1655 mm. The annual mean temperature in Xishuangbanna has been 18.3–22.4°C for many years, and the average temperature of the coldest month (January) is 12.0–16.1°C.
Hainan Island lies between north latitude 18°10′ and 20°10′, and east longitude 108°37′ and 110°03′. It is part of the oceanic tropical monsoon climate, which is suitable for vanilla cultivation. Under the influence of the tropical monsoon climate and the terrain, the climate in Hainan is warm in the south and cold in the north, dry in the east and moist in the west. The annual mean atmospheric temperature is 23–25°C in most parts of the province. The average atmospheric temperature in January is 17–21°C. Annual mean precipitation varies between 958 and 2148 mm in parts of Hainan Island, and it is one of the highest of the regions of the same latitude. But it is not evenly distributed, being dry in the east and moist in the west, highest in the middle, higher in the east, northeast and north, lower in the southwest, and lowest in the west. Typhoons frequently hit Hainan Island during the June–October period, and the number of strong wind days per year is around 4.7–6.8.
On the whole, vanilla is more suitable for cultivation in Hainan Island than in Yunnan Province.
Different Cultivation Systems
In this method, the climbing stakes for the vanilla are made with bricks of 240 mm × 115 mm × 53 mm. Bricks are placed in groups of three, forming a triangle, and each layer of bricks is rotated by a certain angle relative to the previous. In this way, a hollow brick stake is built: the buried part of the stake should measure 0.5 m, the height above ground is 1.5 m, and the space between poles is 2 m. Then substrates should be filled into the empty space of the hollow stakes, and vanilla seedlings planted around the poles. This method was adopted in a 1 ha plantation in Xishuangbanna, and 8.25 kg of fruit were harvested from 100 m² of vanilla plants. The method proved effective for vanilla cultivation, but the vines finally became entangled, which influenced the growth, pruning, pollination, and harvesting of the vanilla. The method was therefore replaced by the one described in the next section.
Nylon netting with a 50–70% shading degree is used for the shade house, which is 2.5 m high. The stakes can be made of cement (15 cm × 15 cm × 2 m), wood, stone, or bamboo. The height above the ground for stakes should be 1.5 m. The field is divided into ridges: each ridge is 1.3 m wide, and the space between ridges is 0.35 m. Stakes are fixed along the middle of the ridges, with a space of 2 m between each stake on the same ridge. The poles on the same ridge are connected with steel bars, iron strings, or other types of strings. Vanilla seedlings are then planted longitudinally along both sides of each pole. All the shade houses in the vanilla plantations in Hainan and Xishuangbanna have adopted this method, which means full use can be made of the land, and the vanilla is easy to manage and convenient for handling. The disadvantage is that the cost is too high.