应用ITS序列及SSR标记分析核桃与铁核桃亲缘关系

核桃与铁核桃是我国核桃属两个主要栽培种，而后者又是我国特有种，关于两个种在植物分类学上的归属问题一直存在争议。该研究分别以核桃与铁核桃的5个居群为试材，采用ITS序列多态性分析及SSR分子标记技术，从分子水平上讨论了两个种的亲缘关系。结果显示两个种的ITS序列仅出现了一个碱基差异，序列高度相似。SSR标记共扩出了65个等位基因，其中三家村居群与其宗居群的遗传距离最近,为0.119，遗传距离最远的为MN居群与HS居群，为0.522。种间居群遗传距离与种内遗传距离相近，种间差异不明显。这一结果说明两个种应为不同的地理生态型。

Application of ITS sequence and SSR markers to study the relationship between Juglans regia and Juglans sigillata

Juglans regia L. and J. sigillata Dode. are two mainly-cultivated walnut species in China, and the later is a u-nique species distributed in the southwest China. Furthermore, the argument about relationship of the two species remains undetermined. Five populations of J. regia and J. sigillata were chosen to investigate their relationship with ITS and SSR markers. Result of ITS sequence only detected 1 nucleotide difference between the two species. Based on 65 alleles generated with SSR, genetic distance between populations was calculated. The closest genetic distance was 0.119 found between SJC and QZ population, and the furthest distance was 0. 552 found between MN and HS population. The genetic distance between intra-species was similar to that between inter-species, and the difference between two species was quite small and was not significant. Those results suggested that the two species might be different eco-types, which provided a scientific reference for revealing the evolutional and genetic relationship and genetic characteristics of walnut plants.