Identification of <i>Thujopsis dolabrata</i> var. <i>hondae</i> clones and their distribution across plantations in Ishikawa prefecture

<i>Thujopsis dolabrata</i> var. <i>hondae</i>, known as “ate”, is the prefectural tree of Ishikawa. The species has been planted in the form of rooted cuttings or saplings created by layering since at least the 1800s. Such historical planting has led to the development of more than 20 vegetatively propagated local cultivars, but these cultivars have not been classified precisely. Understanding the clones that constitute each cultivar and the genetic relationships between clones is essential when undertaking genetic management of plantations and planning future breeding. In this study, we identified clones of cultivars used for <i>T. dolabrata</i> var. <i>hondae</i> plantations in Ishikawa Prefecture using 12 microsatellite markers, and examined the genetic relationships between clones and the distribution of clones across plantations. We analyzed 224 individuals from three local cultivars, ma-ate, kusa-ate and eso-ate, to act as a reference to identify the cultivars from which the clones in plantations originated, and 180 individuals from 35 plantations. The 180 individuals from plantations were separated into 14 clones, of which 6 accounted for 93.3% of the sampled individuals. The ma-ate cultivar used in plantations consisted of multiple, genetically related clones. In contrast, the clones of the kusa-ate and eso-ate cultivars in plantations were almost fixed. In the southern part of the prefecture, there were only two clones, whereas in the northern part, all 14 clones were present; this reflects the facts that clonal forestry involving this species has developed in the northern area and that a few clones have been selected and spread into the southern area.本达罗汉柏（*Thujopsis dolabrata* var. *hondae*），俗称"ate"，系石川县县树。至少自19世纪起，人们便通过扦插育苗或压条育苗的方式培育该物种苗木并开展栽植。这类长期的历史栽植活动催生了20余个无性繁殖的地方栽培品种，但目前尚未对这些品种进行精准分类。明确构成各栽培品种的无性系（clone）以及无性系间的遗传关系，对于人工林的遗传管理与未来育种规划而言至关重要。本研究利用12个微卫星（microsatellite）标记，对石川县本达罗汉柏人工林所用栽培品种的无性系进行鉴定，并分析了无性系间的遗传关系以及无性系在各人工林中的分布情况。为鉴定人工林无性系的起源栽培品种，我们选取了来自ma-ate、kusa-ate与eso-ate三个地方栽培品种的224份个体作为参考群体，并对35个人工林的180份个体进行了分析。本次分析的180份人工林个体共划分为14个无性系，其中6个无性系的样本量占总采样个体的93.3%。人工林所使用的ma-ate栽培品种包含多个遗传关系相近的无性系；与之相反，人工林中kusa-ate与eso-ate栽培品种的无性系则几乎固定。该县南部仅存在2个无性系，而北部则分布有全部14个无性系；这一现象反映出，该物种的无性系造林技术在北部地区得到了发展，且仅有少数无性系被选育并推广至南部地区。