Genetic infiltration from cultivated Japanese wax tree （Toxicodendron succedaneum （L.） Kuntze） into the closely related native wax tree, ‘Yama-haze’ （Toxicodendron sylvestre （Siebold et Zucc.） Kuntze） that accompanied the widespread introduction of the Japanese wax industry

Abstract

In the middle of the 18th century, with the rise of the Japanese wax industry, cultivation of the Japanese wax tree, ʻHazenokiʼ, originally brought from Kyushu, developed on a large scale in the Kanto region and westward. In the Kimino area, Wakayama Prefecture, where large-scale cultivation of ʻHazenokiʼ was conducted, genetic infiltration from cultivated ʻHazenokiʼ into a closely related wild species, ʻYama-hazeʼ, may have occurred. In this work, RAPD-PCR and cluster analysis of ʻHazenokiʼ and ʻYama-hazeʼ collected in this area were conducted to investigate the impact of the new industry on the genetic diversity of the closely related wild species. The results suggested that interbreeding between ʻHazenokiʼ and ʻYama-hazeʼ was progressing in this area and that typical ʻYama-hazeʼ had already disappeared. The study also showed that the rate of genetic infiltration is increasing as the Japanese wax industry declines and ʻHazenokiʼ orchards are no longer managed, and that economic coniferous forests may act as a barrier to genetic infiltration in ʻHazenokiʼ and ʻYama-hazeʼ whose pollen and seeds are transported by small birds.