Viability of seed and endophyte (Neotyphodium occultans) in annual ryegrass (Lolium rigidum) when buried and in long term storage

The viability of seed and fungal endophyte was examined in Lolium rigidum (Gaud.) seed buried for up to 18 months, and in seed that was stored at ambient room temperature for up to 8 years. Months buried had a significant effect on seed and endophyte viability, while burial depth had no effect. Mean seed viability for the first 6 months of burial was 92% and after 12 and 18 months had declined to a mean of 67%. Viable endophyte decreased to 12% after 4 months and continued declining to 6% after 18 months burial. A significant interaction was found between length of seed storage and the origin (state) from which seed was collected. Victorian seed lots had lower germination than those from the other states of Australia. Mean germination for seed stored up to 8 years remained relatively high at 81%. Viable endophyte was negatively affected by length of storage, where viability declined considerably in seed stored for 3 or more years. Mean endophyte viability in seed stored for 4 to 8 years was < 5%. Seed-borne endophyte infection rates were significantly lower in seed of recent years relative to seed collected up to 8 years ago.