Evaluation location: Washington, United States
Alkaloid analysis was performed by the Dragondorf assay. Leaf tissue (100mg FW) at flowering was homogenized with 1mL 70% Isopropyl Alcohol for 5 minutes. Then 100?L of this extracted solution was applied directly to Whatman no.1 filter paper. When the alcohol had evaporated 100?L of Dragondorff reagent was added and allowed to dry. The size and intensity of the reaction can be qualitatively measured on a 0-5 scale. A presumed `sweet type?, for example PI 326277, had no reaction (light tan spot), while the presumed `bitter type?, for example PI 660724, produced an orange reaction. Note: Leaf extracts are less reactive than seed extracts.