![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
Understanding distribution and diversity of invasive weeds is essential for the development of efficient control measures against it. In the present study, inter-simple sequence repeat (ISSR) markers were used to assess the biogeographic relationships among populations of the invasive Crofton weed (Ageratina adenophora (Spreng.)) during 2004–2006 in China. A total of 100 ISSR primers with di-, tri-, tetra- and penta-nucleotide repeats were screened, from which 20 polymorphic and informative primers were selected. Amplification of the 20 primers generated a total of 479 polymorphic bands among the 64 weed populations, and a high level of genetic diversity (H E = 0.1541 ± 0.0193) was detected in A. adenophora. Neighbor-joining (NJ) cluster analysis based on genetic distances among populations grouped the populations according to their geographical origin, i.e. (1) populations of southwestern Guizhou, (2) populations of Liangshan city in Sichuan, (3) populations of western Guizhou, (4) Guangxi populations plus Chongqing populations, (5) populations of southern Yunnan, and (6) populations of Yangtze River Valleys in Sichuan plus populations of western Yunnan. A significant positive correlation between geographical and genetic distance was detected by the Mantel test (r = 0.183, p = 0.0012). Based on the divergence relationships revealed by ISSR markers, it was assumed that A. adenophora mainly dispersed through wind and water in China.
Acknowledgements
We thank Dr Dapeng Zhang from Sustainable Perennial Crops Laboratory, Agricultural Research Service, USDA and Prof. Dr Imtiaz Ali Khan from NWFP Agricultural University Peshawar, NWFP, Pakistan, for reviewing and editing the original manuscript. We also thank Dr Dan Johnson from University of Lethbridge, Alberta, Canada, Dr Zhengyue Li from Yunnan Agriculture University, China, and Mr Lambert Motilal from the Cocoa Research Unit, The University of West Indies, Trinidad and Tobago, for their valuable comments on the manuscript. This research was funded by the National Basic Research and Development Program, China (Grant No. 2002CB111400 and 2006CB100204).