Radicle emergence test predicts longevity (half viability period, p ₅₀) of leek seed lots

This study was carried out to test whether a single radicle emergence count (RE) can be used for predicting longevity in leek seed lots. Experiments were carried out on eight commercial leek seed lots with normal germination percentages above 75%. Single radicle emergence counts (2 mm) were performed after 120 hours of germination (20°C, dark, between papers). Seed longevity was determined by hermetic storage at 45°C with 20% seed moisture content over 96 hours. Twelve subsamples were taken out of controlled storage after 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88 and 96 hours and seed survival curves were constructed on radicle germination tests. Half viability period, p ₅₀, was calculated for each lot. The RE percentages in leek seed lots ranged between 75 and 94% after 120 hours, while p ₅₀ values ranged from 25.9 to 77.4 hours. Regression between RE of 120 hours and p ₅₀ was found to be highly significant (R ² = 0.848, P < 0.01). Thus, single radicle emergence counts (120 hours) could be used as an assessment of seed longevity in leek.