Study on the Genetic Diversity of Vetiver grass (Vetiveria zizanioides)

摘要

Using the materials of 13 ecotypes of vetiver grass ( Vetiveria zizanioides) from 8 countries, the genetic relationships of them were analyzed by means of RAPD molecular makers. The results showed that a total of 220 reproducible RAPD fragments were produced using 18 random primers. 186 fragments (84.55% of the total observed) were polymorphic, which indicated that there were very high genetic diversity and conspicuous genetic differentiation within 13 ecotypes of vetiver grass. Through the results of Neighbor-Joining (NJ) cluster analysis, 13 ecotypes of vetiver grass were mainly divided into 2 groups. One included 7 ecotypes, I.e. Sunshine, Zomba, Domesticated type, Wild type, Capitol, Lilongwe and Malaysia, which was strongly supported by bootstrap value (100%), reflecting very close relationships of these ecotypes. Except Capitol, this group shared an earlier earing trait to some extent, in which the relationships between Domesticated type and Wild type were closer, and their bootstrap value was 82%. In addition, it was recorded that Domesticated type was an introduced ecotype from India or Indonesia 50 years ago, and Wild type was a natural population distributed in Wuchuan town of Guangdong province in China. Based on the result of RAPD analysis, we know that Domesticated type and Wild type have closer relationships and nearer genetic distance (0.018). Therefore, we speculate that Wild type of China was probably derived from India or Indonesia through natural or introduced approaches. Another group included Huffman, Paritbuntar, Kandy and Karnataka, which was weakly supported by bootstrap value (58%). These ecotypes all shared the trait of lower earing rate in earing stage. Meanwhile, the NJ dendrogram also showed that Monto and Sabak beinam respectively formed different group by itself, and there was an evident genetic differentiation between these 2 ecotypes and others. However, the reasons are not clear now and the further studies should be performed afterward. It is clear that the study will be able to provide a theoretical evidence for the selection and the breeding of vetiver grass varieties with excellent characters.