The red-flowered strawberry is a novel ornamental plant. This study aimed to assess the genetic diversity among ornamental strawberry germplasm resources. In this investigation, 17 red-flowered strawberry germplasms and 1 white-flowered strawberry germplasm were analyzed for genetic diversity and genetic relationships using a combination of phenotypic data, inter-simple sequence repeats (ISSR), and conserved DNA-derived polymorphism (CDDP) molecular markers. The results indicated that the 18 strawberry germplasms exhibited significant variability and genetic diversity at both phenotypic and molecular levels. The clustering results revealed notable differences between phenotypic clustering and molecular marker clustering, while the ISSR and CDDP markers grouped into broadly similar clusters. We further consolidated the ISSR and CDDP marker data to conduct the cluster analysis and population structure analysis of the 18 strawberry germplasms. The cluster analysis classified these germplasms into four clusters at a genetic similarity coefficient of 0.77. The population structure analysis categorized the germplasms into three groups, with 88.89% exhibiting a Q value ≥ 0.6, and 11.11% demonstrating a Q value < 0.6. This finding suggests that the genetic background of the 18 strawberry germplasms is relatively homogeneous. Notably, ‘Summer Breeze-Rose’ and ‘Summer Breeze-Cherry’ possess relatively complex genetic backgrounds (Q < 0.6). Furthermore, the floral, foliar, and plant traits of both germplasms display significant ornamental value and can serve as vital resources for the development and utilization of ornamental strawberries, as well as for the selection and breeding of new varieties.

Red-flowered strawberry possesses both ornamental and edible value, but its short single-flower lifespan severely limits its ornamental potential. In this study, petals of the red-flowered strawberry cultivar ‘140’ were collected at five developmental stages (large bud, half-bloom, full-bloom, initial withering, and withered) to systematically analyze the senescence process from morphological characteristics, physiological, and ethylene-related gene expression perspectives. The results showed that the epidermal cell breakage rate increased continuously during petal senescence, with lower epidermal cells consistently exhibiting higher breakage rates than the upper epidermal cells. Moisture content decreased progressively, while relative electrolyte leakage, malondialdehyde, hydrogen peroxide, and superoxide anion contents increased continuously. Superoxide dismutase, peroxidase, and catalase activities, as well as glutathione content, exhibited unimodal responses, peaking at different stages. Both ethylene and abscisic acid contents increased and then decreased, with ethylene showing greater amplitude and faster rate of change. The ethylene biosynthesis gene FaACO1 and signaling genes FaETR1, FaETR2, FaEIN2, FaEIN7, FaERF13, and FaERF118 were significantly upregulated at full-bloom or initial withering stages, with FaERF118 showing the highest and continuously increasing expression. These findings indicate that water loss, membrane lipid peroxidation, and reactive oxygen species accumulation synergistically drive petal senescence, with the ethylene signaling pathway playing a key regulatory role.

Red-flowered strawberries possess both floral and foliage ornamental characteristics, making them highly promising as landscape groundcovers and potted ornamental plants. To establish a standardized ornamental evaluation system and screen for superior germplasm, this study used 18 strawberry accessions from China and abroad as experimental materials. Twelve core ornamental indicators were selected across three dimensions: flowering period, morphological traits, and disease resistance. The Analytic Hierarchy Process (AHP) was employed to construct a multi-level ornamental value evaluation model. The results indicate the following weight rankings across the constraint layers: morphological traits (60.66%) > flowering period (27.71%) > disease resistance (11.63%). Among these, flower color (21.96%), plant flowering period (16.41%), corolla diameter (15.69%), and single-flower flowering duration (11.30%) were the core indicators determining ornamental value. The comprehensive score rankings showed that the accessions ‘140’, ‘Pink Panda’, ‘Summer Breeze-Cherry’, and ‘Summer Breeze-Rose’ exhibited the best overall ornamental performance. These accessions feature vibrant flower colors, a prolonged flowering period, abundant blooms, and good disease resistance. ‘Frisan’ and ‘246’ had the lowest composite scores, exhibiting significant shortcomings in ornamental traits. The AHP-based evaluation system established in this study provides a quantitative tool for ornamental trait assessment in red-flowered strawberries. The four elite accessions identifed using this system—‘140’, ‘Pink Panda’, ‘Summer Breeze-Cherry’, and ‘Summer Breeze-Rose’—can serve as priority candidates for protected landscape applications and container gardening in subtropical southern China.