Beijing Advanced Innovation Center for Tree Breeding by Molecular Design. National Engineering Laboratory for Tree Breeding, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Technology, Beijing Forestry University, 100083, Beijing, People's Republic of China.
Guangdong Provincial Key Laboratory of Bio-control for the Forest Disease and Pest, Guangdong Academy of Forestry, 510520, Guangzhou, People's Republic of China.
Sci Rep. 2017 Oct 23;7(1):13814. doi: 10.1038/s41598-017-13219-0.
Large ex situ germplasm collections of plants generally contain significant diversity. A set of 700 well-conserved Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) clones from six provinces in southern China in the ex situ gene bank of Longshan State Forest, was analyzed using 21 simple sequence repeat markers, with the aim of assessing the genetic diversity of these germplasm resources. Genetic analysis revealed extensive genetic variation among the accessions, with an average of 8.31 alleles per locus and a mean Shannon index of 1.331. Excluding loci with null alleles, we obtained a low level of genetic differentiation among provinces, consistent with the interpopulation genetic variation (1%). Three clusters were identified by STRUCTURE, which did not match the individuals' geographical provenances. Ten traits related to growth and wood properties were quantified in these individuals, and there was substantial variation in all traits across individuals, these provide a potential source of variation for genetic improvement of the Chinese fir. Screening large collections for multiple-trait selective breeding programs is laborious and expensive; a core collection of 300 accessions, representative of the germplasm, was established, based on genotypic and phenotypic data. The identified small, but diverse, collections will be useful for further genome-wide association studies.
大型植物离体种质资源库通常包含丰富的多样性。本研究对来自中国南方六个省份的龙山林场离体基因库中保存完好的 700 个杉木（Cunninghamia lanceolata（Lamb.）Hook）无性系进行了分析，共使用了 21 个简单序列重复标记，旨在评估这些种质资源的遗传多样性。遗传分析表明，供试无性系间存在广泛的遗传变异，平均每个位点有 8.31 个等位基因，平均 Shannon 指数为 1.331。排除无等位基因的位点后，各省间的遗传分化程度较低，与种群间遗传变异（1%）一致。STRUCTURE 分析鉴定了 3 个聚类，与个体的地理起源不匹配。在这些个体中，定量测定了与生长和木材特性相关的 10 个性状，个体间所有性状均存在较大变异，这为杉木的遗传改良提供了潜在的变异来源。对大型群体进行多性状选择育种计划的筛选既费力又昂贵；本研究根据基因型和表型数据，建立了一个由 300 个代表种质的核心群体。鉴定出的小型、多样化的群体将有助于进一步的全基因组关联研究。
