Pyrrolizidine alkaloid levels in tall fescue seed as influenced by seed age, location, and variety [Festuca arundinacea, Acremonium coenophialum, Epichloe typhina, summer syndrome, tall fescue toxicity]

Tall fescue (Festuca arundinacea Schreb.) long has had a reputation as a poor-quality forage because of an assortment of toxicological problems experienced by animals grazing this species. Summer syndrome toxicity is associated with a seed-transmitted endophytic fungus (Epichloe typhina (Fr.) Tul., Acremonium coenophialum Morgan-Jones and W. Gams) which, in turn, is associated with pyrrolizidine alkaloid accumulation, especially N-formyl and N-acetyl loline. The objectives of this study were 1) to assay the major seed-producing areas and varieties in the U. S. for loline alkaloids and 2) to investigate the effect of age of seed at planting on loline alkaloid levels of seed harvested from these stands. Seed lots of the Kentucky varieties 'Kentucky 31' and 'Kenwell' contained much higher levels of loline alkaloids than the Oregon varieties 'Alta' and 'Fawn.' Certified 'Kenhy' seed produced from stands sown with recently harvested foundation seed high in loline alkaloid content tended to have much higher levels than seed produced by stands sown with seed stored 2 years or more. Differences between varieties and seed production areas are more likely due to cultural practices, length of seed storage, or historical factors than to strict genetic or location effects. The lower loline alkaloid levels resulting from establishment with 2-year-old seed is attributed to impersistence of the endophyte. Results suggest that other unknown factor(s) may contribute to a total loss of loline alkaloid accumulation capacity in seed only 3 months old.