Suitable flowering time can improve fiber yield and quality, which is of great significance for jute biological breeding. In this study, 242 jute accessions were planted in Fujian for 2 consecutive years, and 244,593 SNPs distributed in jute genome were used for genome-wide association analysis of flowering time. A total of 19 candidate intervals (P < 0.0001) were identified by using GLM and FaST-LMM and were significantly associated with flowering time, with phenotypic variation explained (PVE) ranging from 5.8 to 18.61%. Six stable intervals that were repeatedly detected in different environments were further identified by the linkage disequilibrium heatmap. The most likely 7 candidate genes involved to flowering time were further predicted according to the gene functional annotations. Notably, functional analysis of the candidate gene CcPRR7 of the major loci qFT-3–1, a key factor in circadian rhythm in the photoperiodic pathway, was evaluated by linkage, haplotype, and transgenic analysis. β-glucuronidase (GUS) and luciferase (LUC) activity assay of the promoters with two specific haplotypes confirmed that the flowering time can be controlled by regulating the expression of CcPRR7. The model of CcPRR7 involved in the photoperiod regulation pathway under different photoperiods was proposed. These findings provide insights into genetic loci and genes for molecular marker-assisted selection in jute and valuable information for genetically engineering PRR7 homologs in plants.

合适的开花时间可以提高纤维产量和品质，对黄麻生物育种具有重要意义。本研究在福建连续2年种植242份黄麻材料，利用黄麻基因组中分布的244,593个SNP进行开花时间的全基因组关联分析。 使用 GLM 和 FaST-LMM共识别出 19 个候选区间（P < 0.0001），并且与开花时间显着相关，表型变异解释（PVE）范围为 5.8% 至 18.61%。通过连锁不平衡热图进一步识别了在不同环境中重复检测到的六个稳定区间。根据基因功能注释，进一步预测了最有可能与开花时间相关的7个候选基因。值得注意的是，通过连锁、单倍型和转基因分析评估了主要位点qFT-3-1的候选基因CcPRR7的功能分析，qFT-3-1 是光周期途径中昼夜节律的关键因素。对两种特定单倍型启动子的β-葡萄糖醛酸酶（GUS）和荧光素酶（LUC）活性测定证实，可以通过调节CcPRR7的表达来控制开花时间。提出了CcPRR7在不同光周期下参与光周期调节途径的模型。这些发现为黄麻分子标记辅助选择的遗传位点和基因提供了见解，并为植物中的 PRR7 同源物基因工程提供了宝贵的信息。