Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China.
Shanghai OE Biotech. Co., Ltd, Shanghai, China.
Sci Rep. 2019 Nov 14;9(1):16855. doi: 10.1038/s41598-019-53399-5.
Ramie is an important natural fiber crop, and the fiber yield and its related traits are the most valuable traits in ramie production. However, the genetic basis for these traits is still poorly understood, which has dramatically hindered the breeding of high yield in this fiber crop. Herein, a high-density genetic map with 6,433 markers spanning 2476.5 cM was constructed using a population derived from two parents, cultivated ramie Zhongsizhu 1 (ZSZ1) and its wild progenitor B. nivea var. tenacissima (BNT). The fiber yield (FY) and its four related traits-stem diameter (SD) and length (SL), stem bark weight (BW) and thickness (BT)-were performed for quantitative trait locus (QTL) analysis, resulting in a total of 47 QTLs identified. Forty QTLs were mapped into 12 genomic regions, thus forming 12 QTL clusters. Among 47 QTLs, there were 14 QTLs whose wild allele from BNT was beneficial. Interestingly, all QTLs in Cluster 10 displayed overdominance, indicating that the region of this cluster was likely heterotic loci. In addition, four fiber yield-related genes underwent positive selection were found either to fall into the FY-related QTL regions or to be near to the identified QTLs. The dissection of FY and FY-related traits not only improved our understanding to the genetic basis of these traits, but also provided new insights into the domestication of FY in ramie. The identification of many QTLs and the discovery of beneficial alleles from wild species provided a basis for the improvement of yield traits in ramie breeding.
苎麻是一种重要的天然纤维作物，纤维产量及其相关性状是苎麻生产中最有价值的性状。然而，这些性状的遗传基础仍知之甚少，这极大地阻碍了该纤维作物的高产育种。在此，利用来源于两个亲本，栽培种中丝 1 号（ZSZ1）及其野生近缘种白叶野麻（BNT）的群体，构建了一张包含 6433 个标记、覆盖 2476.5cM 的高密度遗传图谱。对纤维产量（FY）及其四个相关性状-茎直径（SD）和长度（SL）、茎皮重（BW）和厚度（BT）进行了数量性状基因座（QTL）分析，共鉴定出 47 个 QTL。40 个 QTL 被定位到 12 个基因组区域，从而形成 12 个 QTL 簇。在 47 个 QTL 中，有 14 个 QTL 的野生型等位基因来自 BNT 是有益的。有趣的是，第 10 个聚类中的所有 QTL 都表现出超显性，表明该聚类区域可能是杂种优势位点。此外，还发现了四个与纤维产量相关的基因，它们经历了正向选择，要么落入 FY 相关的 QTL 区域，要么靠近鉴定出的 QTL。FY 和 FY 相关性状的剖析不仅提高了我们对这些性状遗传基础的认识，也为苎麻 FY 的驯化提供了新的见解。许多 QTL 的鉴定和来自野生种的有益等位基因的发现为苎麻产量性状的改良提供了基础。
