Dormancy
Let’s assume you have ensured optimum substrate, temperature, gaseous environment and water for your seeds. You have established that the seeds are not immature, dead or empty. But still they have not germinated. Does that mean they are not viable? Not necessarily! The seeds may be dormant.
Dormant seeds are operating on minimum metabolism, so even when environmental conditions are adequate, something else needs to happen to break the dormancy. In the wild, plants that have evolved dormancy have done so because it is useful to their survival. Sometimes dormancy allows a plant to spread germination over time and space. Sometimes it allows the plant to synchronise its germination with optimal conditions for growth.
In genebanks, too, dormancy can be useful. It can help maintain the quality of seeds in storage. It can protect seeds from sprouting in wet and moist conditions before they enter the genebank. It can prevent seeds from germinating under unfavorable conditions, such as inside the active and base stores. It can help the seeds to remain alive for many years, ensuring a continuous source of new plants.
However, unlike in situ ecosystems, genebanks cannot rely on the rhythms of nature to break dormancy. So if you are working in an ex situ collection, a thorough understanding of the types and mechanisms of dormancy is essential, to help you work out how to coax seeds into germination.
Pause for reflection
Dormancy is less common in crops than wild relatives, because over millennia of cultivation by humans, the tendency was for dormancy to be selected against. In the past, farmers tended to select types of seeds that germinated readily when sown, even though this desirable habit may be linked to less desirable ones, such as sprouting too readily in storage, resulting in wasted seed.
Paradoxically, in the twenty-first century, re-introducing a limited amount of dormancy could be helpful to farmers who are growing crops in locations where they are prone to pre-harvest sprouting. It could eliminate this well-documented cause of waste.
Take five minutes to think about how wild relatives conserved in genebanks could be a useful source of desirable traits related to dormancy.
The cut test