Factors Affecting the Alkaloid Content of Tall Fescue (Festuca arundinacea Schreb.)1

The alkaloid content of tall fescue (Festuca arundinacea Schreb.) was investigated in seed and different stages of maturity during plant growth from seed to mature plants by paper and thin‐layer chromatography. Eleven alkaloids were found in a selection of Ky 31. No alkaloids were found in seed of Alta, Goar, or NK 36, whereas 3 alkaloids were present in seed of ‘Kenwell’ and ‘Ky 31’. The initial rate of alkaloid synthesis was much higher in Ky 31 than in ‘Alta’. In young seedlings of both varieties perloline, the predominate alkaloid, was detected in the seed and roots as early or earlier than in the shoot. Leaves from mature plants, contained 44% as much perloline and 61% as much total alkaloid as stems. Significant differences occurred in alkaloid content among and within varieties, and among various plant parts. Potassium and phosphorus greatly reduced perloline whereas nitrogen increased perloline synthesis. Perloline and total alkaloid content were reduced as the plant approached maturity. Pasture plants contained the largest concentration of alkaloids, whereas alkaloid content was drastically reduced when the plant material was field‐cured as hay.