Evolution and seed dormancy shape plant genotypic structure through a successional cycle.

Area of Science:

• Evolutionary Biology
• Ecology
• Plant Sciences

Background:

• Dormancy is a key adaptation for persistence amid environmental fluctuations.
• Previous research has not fully explored how dormancy affects evolutionary trajectories across ecological cycles.
• The predictive power of short-term fitness measures for long-term genotypic success in dormant species remains unclear.

Purpose of the Study:

• To investigate the impact of seed dormancy on evolutionary responses to natural selection over a successional cycle.
• To determine if early selection pressures are reinforced or erased by dormancy.
• To assess the long-term genotypic success and trait evolution in dormant plant populations.

Main Methods:

• Experimental field populations of *Oenothera biennis* were subjected to herbivory treatments over five generations.
• Genetic diversity and trait evolution were monitored during active growth and after prolonged seed dormancy (>5 years).
• Genotyping of over 3,000 individuals from resurrected seed banks analyzed evolutionary changes.

Main Results:

• Rapid evolution of defensive and life-history traits occurred during the active growth phase, followed by a loss of genetic diversity.
• Resurrected populations from the seed bank exhibited restored genetic diversity, diminishing prior selection responses.
• Despite resetting effects, four key traits remained differentiated between herbivory-exposed and control populations.

Conclusions:

• Seed dormancy can erase some adaptive evolutionary changes, resetting population phenotypes.
• Dormancy influences future evolutionary trajectories by altering genetic diversity and trait expression.
• This study highlights the critical role of dormancy in shaping evolutionary dynamics across ecological timescales.