Vetiveria zizanioides which is commonly found in nature grows in various conditions and adapts suitably to those conditions. The grass produces a number of inflorescences and performs cross pollination every year. Cross pollination makes the plant stronger in many ways, especially in terms of genetic components as well as tolerance to diseases and to critical climatic factors of the areas. However, cross pollination can induce mutation, particularly with those in which the roots are extracted for volatile oils. Mutation would result in a reduction or fluctuation of the quantity of volatile substances contained in the roots.
       The leaf of Vetiveria zizanioides  is 45-90 (100) cm. long and 0.6-0.9 (1.2) cm. wide. The upper surface of the blade is curved and the apex is flat and dark green. The texture is smooth and waxy. The lower surface of the blade is pale white. When holding the leaf against the sunlight, we can see a septum clearly, especially at the base and middle of the blade. The midrib which is hidden in the blade is not big or clearly seen.
       Vetiveria zizanioides at one year of age can produce the roots penetrating more than 1 metre deep. This somehow, depends on the conditions of the soil and health of the grass. The roots will be longest if the grass is grown in loose clay soil with good water drainage potential.

Vetiveria nemoralis A. Camus

       Vetiveria nemoralis or local vetiveria has a limited scope of distribution. It is found only in Southeast Asia covering the countries of Thailand, Laos, Cambodia, Vietnam and Malaysia. Moreover, there are no records of its uses.
       Vetiveria nemoralis is commonly found in dry areas or in soil conditions with good water drainage potential in every region of Thailand, especially in dipterocarp forests. However, there are only a few in the South. This species grows well in areas both with strong and moderate sunlight. The tip of the clump bends over the ground like lemongrass; it is not erect like that of Vetiveria zizanioides. In some areas, the grass grows densely in the same manner as a ground cover plant which claws over a vast area, for example in the area of Huai Kha Kang Wildlife Reserve in Uthai Thani Province. Vetiveria nemoralis that grows in dipterocarp forests is always affected by forest fires. Although the dry leaves serve as good fuel, the bottom of the clump is very dense, thus preventing the grass from being easily damaged by fires. The grass is also capable of producing new leaves rapidly after a fire.
       The leaf of Vetiveria nemoralis is 35-60 (80) cm. long and 0.4-0.6 (0.8) cm. wide and is pale green in colour. The upper surface of the blade flaps with a triangular ridge. The texture is coarse and a little bit waxy. The lower surface has the same colour as the upper surface but paler. When holding the leaf against the sunlight, we cannot see the septum. However, the midrib which is hardened and ridge-like can be seen clearly.
       At the same age, the roots of Vetiveria nemoralis are comparatively shorter than those of Vetiveria zizanioides. Generally, the roots of one-year-old vetiver can be as deep as 80-100 cm.
       The inflorescence of Vetiveria nemoralis appears in many colours which is an ordinary feature of local ecotypes. Uthai Thani and Nakhon Phanom ecotypes, particularly with a creamy white and purple-scarlet-backed flower-pecker, are found extensively growing.

Table 1. Comparing the Differences between Vetiveria Zizanioides and Vetiveria Nemoralis

Samples of 28 Ecotypes in Thailand (According to the List of the Land Development Department)

Collection of Ecotypes and Comparative Study of Growth in Various Conditions

       The grass which is currently claimed to be useful for conservation of soil, water as well as other natural resources around the world is Vetiveria zizanioides from India. The World Bank has been promoting and disseminating this ecotype to many countries, including Thailand. Early 1992 during which the Land Development Department was at the same time conducting a research on utilizing vetiver grass for soil and water conservation, botanists discovered that vetiver grass which is commonly found in every region of Thailand belong to 2 species : Vetiveria zizanioides and Vetiveria nemoralis. After the discovery, they started collecting all the ecotypes from different sources throughout the country and selecting certain ecotypes according to the ecosystems which are different with respect to physical conditions of the area, such as altitude, soil texture, water drainage capacity etc. The collection and selection was based on the hypothesis that vetiver grass grown in different area conditions are different in the characteristics defined for each particular ecotype as well as in the ability to adapt to the environment. The process was aimed at choosing suitable ecotypes that match with certain groups of soil e.g. loose soil, sandy soil, clay etc. After that, they would be named after the province where they were found. If a certain ecotype was located at more than one place, its name would be followed by a number. Number 1 indicates that the ecotype was found in the uplands whereas number 2 marks that it was found in the lowlands. For example, there are Kamphaeng Phet 1 and 2. However, there is an exception for the ones that were located only in the lowland areas. In this case, the number would run in order starting from 1. For example, there are Songkhla 1,2 and 3.
       From the selection, there are altogether 28 interesting ecotypes which were used in the comparative study. Among these, 17 belong to the Vetiveria nemoralis specie and 11 belong to Vetiveria zizanioides specie (including Sri Lanka ecotype). All these ecotypes were experimented at 12 locations all over the country which included the Land Development Stations in Mae Hong Son, Chiang Mai, Phetchaburi, Kamphaeng Phet, Khon Kaen, Roi Et, Nakhon Ratchasima, Rayong, Ratchaburi, and Satun Provinces, as well as at the Khao Hin Sorn Royal Development Study Centre in Chachoengsao Province and at the Pikun Thong Royal Development Study Centre in Narathiwat Province. The comparative study encompassed tillering and measuring of the clump diameter and height at 90 days after planting in the rainy season. As a result of the experiments, 10 ecotypes were found to grow suitably in sandy soil, loose clay soil and laterite soil as follows :

A.  Vetiveria Nemoralis

       4)       Roi Et : grows well in sandy soil; produces 26 culms per clump; each clump is dense and erect with a diameter of 7 cm. and a height of 70 cm.; the leaf is green; the spikelet is brown and can be seen about half a month after planting.
       5)       Ratchaburi : grows well in areas ranging from sandy soil to loose clay soil; produces 32 culms per clump; each clump is dense and erect with a diameter of 12 cm. and a height of 110 cm.; the leaf is light green while the leaf sheath is brown; the spikelet appears after one month of planting; gives good fresh weight.
       6)       Prachuap Khiri Khan : grows well in loose clay soil and laterite soil; produces 26 culms per clump; each clump is dense with a diameter of 14 cm. and a height of 112 cm.; the shoot is big and erect; the leaf is thick and dark green while the grooved base is white and the leaf sheath is creamy white; the spikelet is purple and the inflorescence is small; the spikelet yields at a slow pace or sometimes has a scarce chance; in some areas there appears even no single spikelet in the first 2 years.

B.  Vetiveria Zizanioides

       3)       Surat Thani : grows well in loose clay soil and laterite soil; produces 22 culms per clump; each clump is loose and broadly tufted with a diameter of 13 cm. and a height of 108 cm.; the shoot is plump; the internode rapidly elongates; the leaf is light green while the lower surface is white; the spikelet is reddish purple and can be seen after one month of planting.
       4)       Songkhla 3 : grows well in areas ranging from loose clay soil to laterite soil; produces 24 culms per clump; each clump is loose with a diameter of 13 cm. and a height of 112 cm.; the shoot is round and plump; the internode fastly elongates; the leaf is light green while the lower surface is white; the spikelet is reddish purple and starts yielding about one and a half months after planting.
       In conclusion, all the 10 ecotypes are classified into 6 ecotypes belonging to Vetiveria nemoralis species and 4 ecotypes belonging to Vetiveria zizanioides species. Vetiveria nemoralis ecotypes sprout new tillers better than Vetiveria zizanioides ecotypes on an average of 30 and 18 culms per clump respectively. Although the clump diameters of both species are not different with an average of 12 cm. each, the height of Vetiveria zizanioides clump is greater than that of Vetiveria nemoralis on an average of 104 and 99 cm. respectively.

Suitable Vetiver Ecotypes for Different Area Conditions

Sandy Soil
- Vetiveria nemoralis : 4 ecotypes which are Nakhon Sawan, Kamphaeng Phet 1, Roi Et and Ratchaburi
- Vetiveria zizanioides : 2 ecotypes which are Kamphaeng Phet 2 and Songkhla 3
Loose Clay Soil
- Vetiveria nemoralis : 5 ecotypes which are Loei, Nakhon Sawan, Kamphaeng Phet 1, Ratchaburi and Prachuap Khiri Khan
- Vetiveria zizanioides : 2 ecotypes which are Surat Thani and Songkhla 3
Laterite Soil
- Vetiveria nemoralis : 2 ecotypes which are Loei and Prachuap Khiri Khan
- Vetiveria zizanioides : 4 ecotypes which are Sri Lanka, Kamphaeng Phet 2, Surat Thani and Songkhla 3

Other Ecotypes

       Collection of vetiver ecotypes is carried out not only by the Land Development Department but also by other agencies such as the Highland Soil Development Office which operates the Highland Agricultural Project and Department of Public Welfare. The hilltribe people, especially the Karen tribe, have long been cultivating and utilizing Mae La Noi and Pang Mapha ecotypes which belong to Vetiveria zizanioides species for making herbal products. These ecotypes have large culms and a tall clump similar to Mae Hong Son ecotype which has been collected from Khun Yuam District that lies at an altitude of about 1,479 m. above mean sea level.
       At the Doi Tung Development Project, vetiver ecotypes were collected from various locations such as Pimai District of Ayutthaya Province and Surat Thani Province. Although this Surat Thani ecotype grown in the project area shares the same name as the ecotype collected from Phra Saeng District of Surat Thani Province by the Department of Land Development, it was imported originally from Indonesia and obtained from the Rubber Research Centre in Surat Thani. The study conducted at the Project focused on the use of the vetiver roots in making herbs and extracting volatile oils.
       For experimentation in highland areas which are under the cool climate condition with cloudy sky in the rainy season and smog in the dry season such as in Pang Tong area, it was found that the indigenous ecotypes of Khun Yuam District and Mae Hong Son Province demonstrated a favorable growth and a resistance to the rotten base and leaf blast diseases. However, Sri Lanka ecotype was not resistant to such diseases; it was easily infected unlike the indigenous ecotype. The cause was understood to be the poor health of the grass due to little exposure to sunlight. Therefore, the suitable ecotypes for highland areas are the local ones such as Mae Hong Son, Mae La Noi, Pang Mapha etc.

Imported Ecotypes

       According to the historical records, a number of exotic ecotypes were imported into Thailand. The Indonesia ecotypes were introduced here by the Food and Agricultural Organization (FAO) and were propagated by means of tissue culture at the Department of Botanics, Faculty of Science, Kasetsart University for planting in the project area in Chaiyaphum Province in 1991. Before this, the Land Development Department obtained Sri Lanka ecotypes and planted them at the Land Development Station Region 6, Chiang Mai Province. Afterwards in early 1992, the Khao Kor Reforestation Project procured India ecotypes from Bangalore and distributed for further use to the Doi Tung Development Project in Chiang Rai Province and the Land Development Station in Phetchabun Province. Then in April of the same year when a conference on vetiver grass was held in Kuala Lumpur, Malaysia, many agencies such as the Royal Highland Agricultural Project obtained Taiping ecotypes from Dr. P.K. Yoon in Malaysia. About the same period, the Office of the Royal Development Projects Board (RDPB) ordered some India ecotypes from New Delhi and forwarded them to the Land Development Department. These ecotypes were further propagated and dispatched to 20 Propagation Stations throughout the country under the code DLD EXT.09 which indicated that they were granted by His Majesty the King.
       Also, as an outcome of the trip led by the Director-General of the Land Development Department to observe nature farming at Ohito Farm in Japan, Japan ecotypes were then imported into Thailand and kept at the Land Development Station in Ratchaburi Province. Moreover, the Brazil ecotypes entered Thailand through the assistance of the World Bank and the coordination of Dr. Veerachai Na Nakorn. Then towards the end of 1993, Dr. R.G. Grimshaw from the World Bank provided a number of Vetiveria zizanioides native ecotypes from South America, Latin America and the Pacific to the Royal Highland Agricultural Project which were taken care of and propagated by the Highland Soil Development Office under the Land Development Department. These ecotypes involved those from Brazil, Guatemala and Fiji. Besides, in early 1995, Dr. Paul Truong from Australia gave Monto ecotypes which have no seeds to the Land Development Department.
       Nevertheless, there has been no report of a comparative study of the imported ecotypes concerning their suitability for cultivating in Thailand. But the interest in the utilization of imported ecotypes belonging to Vetiveria zizanioides species focuses on the aromatic attribute of the roots from which volatile oils can be extracted to make aromatic herbs, as well as pest repellent substances. To maximize the benefits in this respect, local wisdom which promotes the application of a simple technique to grow and take out roots should be introduced. In Tak and Mae Hong Son Provinces of the Northern Region, the Karen tribal people apply a local simple technique of planting  vetiver on rows of large bamboo tubes each with a diameter of 6 inches and a length of 1 metre. Once vetiver tillers grow and fill the tubes, they produce a long and clean root system. The other method is to plant in large plastic bags which has been carried out by Thailand Institute of Scientific and Technological Research. At present, a comparative study is being conducted between the imported ecotypes and those introduced by the Land Development Department.

Naming of Ecotypes

       Vetiver ecotypes have been collected from various sources and are named after the places they are found e.g. districts and provinces. However, a problem arises with regards to proper use of titles after the names according to the actual principle of naming in the field of plant taxonomy.  Such problem is whether to use the words 'species', 'variety', 'clone', locality' or 'ecotype'.
       If categorized by species, the vetiver grass found in Thailand belong to only 2 species: Vetiveria zizanioides and Vetiveria nemoralis. However, to classify based on the details in terms of phenotype which is different according to the area or ecological system, the conferences on the vetiver project organized by the Office of the Royal Development Projects Board, first in Chiang Rai by the end of 1993 and second in Phetchaburi by mid of 1994, concluded that the word 'ecotype' should be used. In addition, regarding the calling of 'vetiver' by adding the word 'grass' after it which can induce the problem in the practice and extension work, the officials from the Department of Agricultural Extension suggested that the word 'grass' should be omitted. This was because the farmers had bad impression with the word 'grass' which, to them, always caused trouble by acting like weed. They were afraid that vetiver would become a weed like other kinds of grass such as Pennisetum polystachyon Schulf., Thin Napie, Star grass, Signal grass, Setaria grass and Ruzi grass which were generally promoted to be used for animal grazing. For this reason, they were thus not interested in growing vetiver on their lands.
       In terms of the study on its distribution in the form of weed as well as the possibility of being a host for diseases, insects and other weeds, there has been an exchange of information between the academics in the field such as those from Botanic and Weed Science Division of the Department of Agriculture and the study is underway.

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