Genetic diversity and phylogenetic relationships of the endangered species Vaccinium sieboldii and Vaccinium ciliatum (Ericaceae)

摘要

The edible berry species Vaccinium sieboldii, Vaccinium ciliatum, and Vaccinium oldhami are deciduous shrubs found growing at low altitudes in Japan. They are classified in the same section. Of these, the former two species are listed as endangered species. The present status of these two species was surveyed. V. sieboldii was found in a very limited range, 65 km wide, in central Japan. Many plants are thought to have been lost because of habitat destruction in the past 50 years. Loss of pine forests from pine-wilt disease is thought to be a major threat to this species. In contrast, V. ciliatum was found over a range of more than 300 km in western Japan. Habitats of both species were heavily fragmented. The genetic diversity and phylogenetic relationships of the three species were studied using nine simple-sequence repeat loci. V. sieboldii and V. ciliatum have a close genetic relationship, although their present growth ranges are widely separated. Despite its limited growth range and the limited number of remaining plants, the genetic diversity of V. sieboldii is similar to that of another endangered species, V. ciliatum, and that of the widely grown species, V. oldhami. Seven populations of the former two species were used to create population-based dendrograms. They were separated into three groups: three populations of V. sieboldii, two mountainous populations of V. ciliatum, and two coastal populations of V. ciliatum. The separation was supported by high bootstrap values. Isolation factors of the two population groups in V. ciliatum are discussed.