Endophyte Viability in Grass Seeds: Storage Conditions Affecting Survival and Control Methods

Research has evaluated the efficacy of various methods for eliminating endophytes from grass seeds, as well as changes in endophyte viability during seed storage under different conditions, indicating significant variation in different procedures and cultivars. Chemical seed treatment (tebuconazole and thiram) completely eliminated viable fungal mycelia, leaving no trace in any tested cultivar. Non-chemical methods, such as drying and microwave treatment, only partially reduced mycelial viability by 30.3% and 33.1%, respectively, with no statistically significant difference between them. A significant positive correlation was observed between the initial mycelial viability and its reduction. Lolium perenne cv. Vigor showed no impact from non-chemical methods, while Festuca rubra cv. Anielka exhibited the greatest reduction (79% after microwave treatment). Seed storage also impacted endophyte survival. Storage at +7 °C, +23 °C, and −20 °C reduced viability by 27.4%, 31.7%, and 37.3%, respectively. Positive correlations existed between initial viability and post-storage reductions. Similarly to elimination methods, cv. Vigor showed resistance to storage conditions. However, −20 °C storage proved least favorable for endophyte survival, particularly for Festuca pratensis cv. Artema, cv. Anielka, and Festuca ovina cv. Jolka. To maintain the viability of beneficial endophytes during seed storage, we must carefully control storage conditions, especially ambient temperature.