Effect of Seed Damage on Germination in the Common Vetch (Vicia sativa L.)

Abstract

Larvae of the tortricid moths Cydia lunulana and C. nigricana feed inside developing pods of Vicia spp. (Fabaceae: Papilionoideae) in North Yorkshire, England. In the common vetch Vicia sativa, larvae commonly consume or at least damage every single seed in the pod in which they develop. Seeds that are completely consumed cannot perpetuate the vetch species, but what about partially damaged seeds? Naturally damaged seeds were obtained from field-collected pods, and sorted into five categories: (1) no damage, (2) <10% damage (volume missing), (3) 10–25% damage, (4) 25–50% damage, and (5) 50–75% damage. Seeds were soaked and planted individually to monitor germination. While scarification of the seed coat of perfect seeds is beneficial to imbibition and germination, the percent of germination decreased with each successive damage category. That a substantial proportion of damaged seeds do germinate suggests that seed damage is not always a death sentence; but growing conditions in North Yorkshire are likely to favor the survival of seeds with seed coat intact to prevent germination in the autumn rains and plant death (before reproduction) in the winter frost.