紫茎泽兰群体遗传多样性及遗传结构的AFLP分析

紫茎泽兰是我国最为严重的入侵物种之一。本研究以中国境内的紫茎泽兰为材料，用AFLP方法研究了其群体遗传多样性及遗传分化。用筛选出的3对荧光引物，对5个地区62个群体进行AFLP分析，共扩增出490条带，其中多态性带328条，群体的遗传多样性较高(P = 66.9%，H = 0.171，I = 0.268)，主要存在于群体内，群体间的遗传分化系数Fst为0.287。AMOVA分析表明，在地区水平紫茎泽兰的遗传分化主要存地区内，群体内遗传分化占 70.25%，群体间遗传分化占21.71%，地区间的遗传分化仅占8.04%。UPGMA聚类分析结果表明，62个地理群体主要分为四大类群，并且有明显的地缘关系。Sigmaplot分析表明海拔是影响紫茎泽兰遗传多样性主要地理因子。Mantel检验表明遗传距离与地理距离成正相关(r = 0.34)，但也有例外。由此推断风媒传播可能是紫茎泽兰的主要传播方式，水媒传播可能是紫茎泽兰的另一主要传播途径；随着紫茎泽向东、向北扩散，新入侵地区的遗传多样性逐步降低。

AFLP Analysis on Genetic Diversity and Genetic Structure of Eupatorium adenophorum Populations in China

Eupatorium adenophorum (Crofton weed) is one of the most widespread invasive species in China. Its genetic diversity and population structure in China were analyzed by amplified fragment length polymorphism (AFLP). Three primer pairs were selected for the analysis and 490 bands were produced from 62 E. adenophorum populations of 5 major geographic areas in China, of which 328 bands showed polymorphic (P was 59.4%). Diversity levels of populations were relatively high, mean expected heterozygosity (H) was 0.154, mean Shannon index (I ) was 0.241. At the regional level, the AMOVA indicated that about 70.25% variations in the data set were from genotypic variations within populations, 8.04% variations due to regional differences, and the remaining 21.71% due to differences among populations within the provincial regions. Cluster analysis based on the UPGMA method grouped the majority of the 62 E. adenophorum populations into four main clusters, which correspond with their geographic regions. It is concluded that E. adenophorum spread mainly by wind or water and its genetic diversity level in newly invaded area is lower than that in former invaded areas.