Morphological Diversity And Karyotype Analysis Of Parthenium Hysterophorus L.

Parthenium hysterophorus L., a Parthenium species of Compositae, is the annual herb. Theoriginal habitat is North America and Mexico. It widely distributes in the global tropicalregions and sub-tropical regions. Nowadays it has invaded Yunnan, Guizhou, Guangxi,Guangdong, Hainan, Hong Kong, Fujian, Taiwan, Shandong and Jiangxi provinces in China.Its fecundity is strong, and has caused serious harm to human health, biodiversity, agricultureand animal husbandry. In order to explore the genetic diversity of Parthenium hysterophorusat the level of morphology and cytology, morphological markers and karyotype analysis wereapplied to research morphological diversity and karyotype differentiation of multiplepopulations in Hainan, Yunnan and Guangxi. The invasion mechanism of Partheniumhysterophorus was discussed and the research fundamental materials were supplied to preventand control it. The main results were as follows:1. Compared the changes in the morphological characteristics of different populations. Theresults showed that five morphological characteristics existed variations in the differentpopulations. The coefficient of variation was from6%to61%, and the highest value wasstem diameter.2. Principal component analysis of five morphological characteristics showed that thecontribution rates about plant height, stem diameter and the number of branches were22.64%,21.63%,20.88%. These included about65.16%contents of the morphologicalmarkers. Plant height, stem diameter and the number of branches were become theimportant principal components of Parthenium hysterophorus morphologicalcharacteristics.3. Chromosome karyotype changes in different geographic areas were researched, theresults showed that18populations were diploid, and chromosome numbers were2n=32or2n=34.4. There were four kinds of karyotype, including1A,2A,1B, and2B. These populationswere divided into four classes by karyotype features cluster analysis. Euclidean distancecoefficient of Qiaojia and Luzhai was lowest. It indicated karyotype differentiation waslowest, and the genetic distance was nearest. However Euclidean distance coefficient ofLiuzhou population was greater differentiation than others. It indicated the genetic distancewas further. This result was not fully consistent with the geographic distribution.5. In accordance with the degree of genetic differentiation and adaptability by descending order, it was from Hainan Provence, Yunnan Provence to Guangxi Provence. SoParthenium hysterophorus population in Hainan was higher invasive and ecologicaladaptability. This region is the main area of prevention and control in the future.6. By the results of the comparative morphological characteristics cluster analysis andkaryotype features cluster analysis, both showed a certain degree of differentiation anddiversity. According to the genetic differentiation and geographic distribution was notentirely consistent, speculated the main invasion route of Parthenium hysterophorus maybe human spread.