Rose is a highly significant ornamental plant with substantial edible and medicinal value, cultivated worldwide primarily for perfume production. Recently, Rosa yangii, a new species found in northwestern Yunnan, China, has drawn attention due to its strong sweet scented flowers. In this study, the floral components of R. yangii were extracted at different flowering stages using solid phase micro extraction (SPME) and analyzed through gas chromatography–mass spectrometry (GC–MS). A total of 131 volatile organic compounds (VOCs) were detected from R. yangii, including 69 odor compounds. The production and release of floral VOCs were the highest during the initial-open stage, making it the most suitable time for harvesting as a significant number of floral components were synthesized and preserved. The analysis of the odor activity values (OAV) highlighted several key aromatic ingredients of R. yangii, such as eugenol, methyleugenol, benzeneacetaldehyde and phenylethylalcohol, heptanal, decanal, (E)-2-hexen-1-yl acetate, caryophyllene, and others. Metabolome and time-order gene co-expression networks (TO-GCN) revealed that VOCs and benzenoids/phenylpropanoids, along with associated genes, played a pivotal role in the overall floral regulatory network of R. yangii. MYB and bHLH were identified as the essential regulatory factors governing the regulation of eugenol synthase (EGS) and isoeugenol synthase (IGS), consequently influencing the sweet scent of R. yangii. The findings of this study provide a scientific foundation for enhancing fragrance through molecular breeding of ornamental plants. Furthermore, the study facilitated the development and utilization of this new plant’s essential oil material in various industries, including food storage, aromatherapy, cosmetic, and perfumery.

Rose is one of the most important ornamental and economic plants in the world.  Modern rose cultivars are primarily tetraploid, and during meiosis, they may exhibit double reduction or preferential chromosome pairing.  Therefore, the construction of a high density genetic map of tetraploid rose is both challenging and instructive.  In this study, a tetraploid rose population was used to conduct a genetic analysis using genome sequencing.  A total of 17 382 single nucleotide polymorphism (SNP) markers were selected from 2 308 042 detected SNPs.  Combined with 440 previously developed simple sequence repeats (SSR) and amplified fragment length polymorphism (AFLP) markers, a marker dosage of 6 885 high quality markers was successfully assigned by GATK software in the tetraploid model.  These markers were used in the construction of a high density genetic map, containing the expected seven linkage groups with 6 842 markers, a total map length of 1 158.9 cM, and an average inter-marker distance of 0.18 cM.  Quantitative trait locus (QTL) analysis was subsequently performed to characterize the genetic architecture of petal number and flower diameter.  One major QTL (qpnum-3-1) was detected for petal number in three consecutive years, which explained 20.18–22.11% of the variation in petal number.  Four QTLs were detected for flower diameter; the main locus, qfdia-2-2, was identified in two consecutive years.  Our results will benefit the molecular marker-assisted breeding of modern rose cultivars.  In addition, this study provides a guide for the genetic and QTL analysis of autotetraploid plants using sequencing-based genotyping methods.