Morphological diversity and inheritance of chrysanthemum seeds in open pollination

Chrysanthemum is a globally popular ornamental crop. Seed propagation through hybridization is typically used for breeding new commercial cultivars. Achieving sufficient seed production is critical for the development and selection of new varieties. To date, research on chrysanthemum has mainly focused on studying the ornamental traits of plants, whereas morphological diversity research on the seed traits of the plants remains limited. In this study, we analyzed the phenotypic characteristics of four seed traits in seven chrysanthemum parent plants (designated C1–C7) and their progeny under open-pollination conditions. The traits examined included seed length (SL), seed width (SW), 100-seed weight (SWh) and the average number of seeds per inflorescence (ASPI). Among these, ASPI exhibited the highest coefficient of variation (CV) across both parent plants (0.41) and progeny generations (ranging from 0.32 to 0.62), indicating significant variability. By contrast, SL and SW displayed the lowest CVs (0.06 and 0.07, respectively) across all generations. According to correlation analyses, traits between parents were similar to those between progeny populations. SL highly significantly and positively correlated with SW (correlation coefficients: 0.97 in parents, 0.47 in progeny) and ASPI (0.91 in parents, 0.17 in progeny). ASPI emerged as the most variable and unstable trait under open-pollination conditions. This study provides valuable insights into the phenotypic variation of seed traits in chrysanthemums, offering a foundation for identifying high-seed set germplasm resources. These findings can support future research and innovation in chrysanthemum breeding techniques, accelerating the development of new cultivars with desirable traits.