Table2.XLSX

Plant height (PH), branch initiation height (BIH), and stem diameter (SD) are three stem-related traits that play crucial roles in plant architecture and lodging resistance. Herein, we show one doubled haploid (DH) population obtained from a cross between Y689 (one Capsella bursa-pastoris derived Brassica napus intertribal introgression) and Westar (B. napus cultivar) that these traits were significantly positively correlated with one another and with flowering time (FT). Based on a high-density SNP map, a total of 102 additive quantitative trait loci (QTL) were identified across six environments. Seventy-two consensus QTL and 49 unique QTL were identified using a two-round strategy of QTL meta-analysis. Notably, a total of 19 major QTL, including 11 novel ones, were detected for these traits, which comprised two QTL clusters on chromosomes A02 and A07. Conditional QTL mapping was performed to preliminarily evaluate the genetic basis (pleiotropy or tight linkage) of the co-localized QTL. In addition, QTL by environment interactions (QEI) mapping was performed to verify the additive QTL and estimate the QEI effect. In the genomic regions of all major QTL, orthologs of the genes involved in phytohormone biosynthesis, phytohormone signaling, flower development, and cell differentiation in Arabidopsis were proposed as candidate genes. Of these, BnaA02g02560, an ortholog of Arabidopsis GASA4, was suggested as a candidate gene for PH, SD, and FT; and BnaA02g08490, an ortholog of Arabidopsis GNL, was associated with PH, BIH and FT. These results provide useful information for further genetic studies on stem-related traits and plant growth adaptation.

株高（Plant height, PH）、分枝始节高度（branch initiation height, BIH）与茎粗（stem diameter, SD）是三类与茎秆相关的性状，在植物株型构建与抗倒伏性调控中发挥关键作用。本研究构建了1个由Y689（一份源自荠菜（Capsella bursa-pastoris）衍生的芥菜型油菜（Brassica napus）族间渐渗系）与Westar（芥菜型油菜栽培品种）杂交得到的双单倍体（doubled haploid, DH）群体，该群体中上述性状彼此间以及与开花时间（flowering time, FT）均呈显著正相关。基于高密度单核苷酸多态性（single nucleotide polymorphism, SNP）遗传图谱，本研究在6个环境中共鉴定到102个加性数量性状位点（additive quantitative trait loci, QTL）。通过两轮QTL元分析策略，最终获得72个一致性QTL与49个特异性QTL。值得注意的是，本研究共检测到19个主效QTL，其中包含11个新发现的QTL，这些位点在A02与A07染色体上形成2个QTL簇。本研究开展了条件QTL定位，以初步解析共定位QTL的遗传基础（多效性或紧密连锁）。此外，本研究通过数量性状位点-环境互作（QTL by environment interactions, QEI）定位，验证了加性QTL并估算其环境互作效应。在所有主效QTL的基因组区域内，我们预测到拟南芥（Arabidopsis）中参与植物激素生物合成、植物激素信号转导、花发育与细胞分化的基因的同源基因作为候选基因。其中，拟南芥GASA4的同源基因BnaA02g02560被提议作为调控株高、茎粗与开花时间的候选基因；拟南芥GNL的同源基因BnaA02g08490则与株高、分枝始节高度及开花时间相关。本研究结果为后续茎秆相关性状的遗传研究与植物生长适应性研究提供了有价值的参考信息。