Module 2: Longevity and viability
Introduction
Welcome to the second module of this online course. In module 1, you learned about the development and overall goals of seed genebanks, and considered the FAO’s Genebank Standards and Practical Guide: their uses and their limitations.
In this module, you will first consider seed longevity. It is generally recognized that the longevity of seeds increases as moisture content and temperature decline. However, scientists are still trying to figure out the optimal combination of these conditions. The CGIAR genebanks have much to contribute here, since CGIAR genebanks have built up a bank of evidence in their collections.
Longevity is closely related to the concept of viability, the second focus of this module. You will explore influences on longevity and viability, both in orthodox seeds and in species whose seeds are more challenging to store. By the end of this module, you will understand what factors can influence viability and how you can use them to improve outcomes. This will put you in a good position to apply what you have learned in your own work setting. We will give you the opportunity to read about the science of longevity and viability in more depth in our ‘Useful publications’ section.
By the end of this module, you should be able to:
- Describe how seed longevity is measured.
- Sketch graphs to show the predictable patterns in decline of seed lot viability over time.
- Define the terms p50 and p85, and how they are used.
- Give examples of the impact of changing moisture content and temperature on seed longevity.
- Explain how the daily activities of genebanks can affect viability, and how genebanks can monitor viability effectively.
- Explain how genebanks can improve their practice by learning from seeds that do not germinate.
- Evaluate the procedures in your own workflow.