Phenotypic Variation, Yield-Related Traits, and Interannual Phenotypic Responses of Forage Bermudagrass Derived from a Hybrid Population
Abstract
Context: Forage bermudagrass (Cynodon dactylon) is widely used in warm-season livestock production systems because of its high productivity and adaptability. However, systematic evaluation of forage-type germplasm remains limited, restricting the identification of superior breeding materials. Aims: This study aimed to evaluate phenotypic variation, identify key yield-related traits, and identify high-performing forage bermudagrass germplasm with contrasting interannual phenotypic responses derived from a ‘Wrangler’ × ‘CD-21’ hybrid population. Methods: Two evaluation populations were established. A single-genotype population of 621 individuals was used to assess plant and canopy height variation, whereas 16 representative entries were evaluated for biomass yield and major agronomic traits during 2024–2025. Frequency distribution, principal component, correlation, and path analyses were conducted. Key results: Stem height and canopy height showed unimodal, approximately normal distributions, indicating continuous phenotypic variation and supporting their characterization as quantitative traits. Biomass yield was positively associated with stem height (r = 0.79), canopy height (r = 0.82), and internode length (r = 0.63). Path analysis indicated that stem height had the largest estimated direct effect (β = 0.45) on biomass yield within the proposed path model. Multivariate analyses revealed distinct phenotypic differences among entries and years, allowing classification into high-performing, environmentally responsive, and leaf-structure efficient groups. Conclusions: Stem height, canopy height, and internode length were identified as key traits associated with forage biomass production. Integrating multivariate and path analyses effectively differentiated forage bermudagrass germplasm based on yield performance and agronomic traits. Implications: The identified germplasm and trait relationships provide useful information for further breeding evaluation and selection decisions and support the development of improved forage bermudagrass cultivars.