Discovery Of The New Species—Fagopyrum Hailuogou J.R. Shao&Q. Zhang, And The Evidences For Phylogenetic Status

Buckwheat belongs to Polygonaceae, Fagopyrum Mill, annual or perennial dicotyledonous plants. It is one of the important cereal and medicine plants. China, as one of the origins of this species has plenty of resources, especially in the south of China, such as Sichuan, Yunnan, Guizhou and Tibet. Until now, there are totally26species,2subspecies and4variety species in the world, which were found and reported. This study identified one new species of buckwheat found in Hailuogou, Luding, Sichuan and the phylogenetic status of this species was confirmed by the morphological characters, karyotype analysis and the molecular method. The name of the new species was Fagopyrum hailuogou J. R. Shao&Q. Zhang and the research results are as follows:1.The field exploration showed:Fagopyrum hailuogou located in the Hailuogou scenic spot, Tibetan Autonomous Prefecture of Garze, Sichuan and the latitude of Fagopyrum hailuogou was limited within2900-3100m and its distribution was so narrow and special. The horizon distance between the species and the glacier ranged from50-200m. It was always found on the humus, around the humid district.2. We described the morphological characters of Fagopyrum hailuogou and some known species. Moreover, the skin of the buckwheat could be classified into3types:the fruit with smooth skin, protuberance or netted stripe. The fruit of Fagopyrum hailuogou belongs the first type, original species.3. The karyotype of Fagopyrum hailuogou was firstly reported in this study. The chromosome number of Fagopyrum hailuogou is16, belonging to diploid. Karytypic formulae was2n=2x=16.4. The molecular evolutionary trees were constructed based on the ITS and matK sequences, classifying the14taxa of buckwheat. From the trees, all the species were divided into2branches. The first branch involved Fagopyrum hailuogou and the other involved the rest species.5. From the constructed trees, the Fagopyrum hailuogou was far from others with relatively further distance. It was supposed that Fagopyrum hailuogou was the most original species in buckwheat and maybe it was the transitive species from Polygonaceae to Fagopyrum with its special evolutionary way. We named it Fagopyrum hailuogou J. R. Shao&Q. Zhang.6. Hailuogou has its specific geography background because it is the eastern margin of Qinghai-Tibet Plateau, belonging to the sub-humid climate. In the area with special latitude, Fagopyrum hailuogou keeps many original characteristics to adapt to the environment from the coldness of the glacier and separation of mountain regions. Therefore, Fagopyrum hailuogou is so important plant materials for the origins of Fagopyrum species.