Seed germination variability: why do genetically identical seeds not germinate at the same time?

This article focuses on the molecular, hormonal, and cellular mechanisms underlying variability in seed dormancy and germination, particularly the "bet-hedging" strategy observed in the model plant Arabidopsis thaliana. Bet-hedging allows genetically identical seeds to exhibit diverse germination behaviors, enhancing survival under unpredictable natural conditions but posing challenges for agricultural uniformity. Key factors influencing this variability include the antagonistic hormonal balance between abscisic acid (ABA) and gibberellic acid (GA), transcriptional noise at the single-cell level, epigenetic modifications, and the activity of specific genes such as DELAY OF GERMINATION 1 (DOG1). The review also discusses the potential impact of reintroducing wild alleles into domesticated crops, which may increase seed heterogeneity and stress tolerance but complicate seed management. Finally, it addresses seed priming as a method to improve germination vigor, noting that while it can accelerate germination, it may not fully suppress inherent variability among seeds.