Evaluating herbicide resistance and cold tolerance in interspecific F1 hybrids of Zoysia Japonica and Zoysia Matrella using NDVI and percentage green cover

Excessive application of synthetic herbicides in turfgrass raises environmental concerns, including the development of herbicide-resistant populations. Although herbicide-resistance is a challenge in agronomic crops, it offers a promising weed management strategy in Zoysia turfgrass, reducing herbicide usage, manual weeding, and ecological impacts. Developing herbicide-resistant Zoysia grass cultivars is vital for expanding and managing Zoysia lawns in diverse environments. This study screens herbicide-resistant and cold-tolerant Zoysia grass using multispectral image analysis for efficient resistance assessments. Artificial cross-pollination between cold-tolerant Zoysia matrella (San208) and herbicide-resistant Zoysia japonica, produced 30 F1 hybrid individuals. A 0.545% working solution of glufosinate ammonium (18% SL basta ®) was applied to 56-day-old F1 individuals under controlled conditions in the greenhouse. Multispectral sensors captured images to assess growth, vigor, and herbicide response and cold tolerance through Percentage Green Cover (GCP) and NDVI-based evaluations. Within 40 days post-herbicide application, 50% of the hybrid plants perished, and one did not survive the winter of 2023. GCP and NDVI of F1 hybrid plants differed significantly (p ≤ 0.0001). At the study end, four out of 30 F1 hybrids demonstrated superior cold tolerance and herbicide resistance. Cold tolerance in F1 hybrids may be inherited from Z.matrella (San208), while herbicide resistance was derived from Z.japonica. Multispectral image analysis effectively screened Zoysia grass under herbicide and low-temperature stresses. Further F2 generation development and molecular genetic studies will refine selection strategies for optimizing Zoysia grass under these stresses. These findings enhance Zoysia breeding programs by integrating genetic advancements and phenotyping technologies for enhanced turfgrass resilience.