Editing Seed bank (section)

==Storage conditions and regeneration==
Seeds are living plants and keeping them viable over the long term requires adjusting storage moisture and temperature appropriately. As they mature on the mother plant, many seeds attain an innate ability to survive drying. Survival of these so-called [[orthodox seed|'orthodox' seed]]s can be extended by dry, low temperature storage. The level of dryness and coldness depends mostly on the longevity that is required and the investment in infrastructure that is affordable. Practical guidelines from a US scientist in the 1950s and 1960s, James Harrington, are known as 'Thumb Rules'. The 'Hundreds Rule' guides that the sum of relative humidity and temperature (in [[Fahrenheit]]) should be less than 100 for the sample to survive five years. Another rule is that reduction of water content by 1% or temperature by {{convert|10|F-change|C-change}} will double the seed life span. Research from the 1990s showed that there is a limit to the beneficial effect of drying or cooling, so it must not be overdone.{{cn|date=December 2023}}

Understanding the effect of water content and temperature on seed longevity, the Food and Agriculture division of the United Nations and a consultancy group called Bioversity International developed a set of standards for international seed banks<ref>{{cite web|url=http://www.fao.org/docrep/019/i3704e/i3704e.pdf|title=Genebank Standards for Plant Genetic Resources for Food and Agriculture|year=2014 |location=Rome|website=FAO|access-date=7 June 2023}}</ref> to preserve seed longevity. The document advocates drying seeds to about 20% relative humidity, sealing seeds in high quality moisture-proof containers, and storing seeds at {{convert|−20|C|F}}. These conditions are frequently referred to as 'conventional' storage protocols. Seeds from species considered most important – corn, wheat, rice, soybean, pea, tomato, broccoli, melon, sunflower, etc. are stored in this way{{fact|date=October 2024}}. However, there are many species that produce seeds that do not survive the drying or low temperature of conventional storage protocols. These species must be stored [[cryogenically]]. Seeds of citrus fruits, coffee, avocado, cocoa, coconut, papaya, oak, walnut and willow are a few examples of species that should be preserved cryogenically.{{cn|date=December 2023}}

Like everything, seeds eventually degrade with time. It is hard to predict when seeds lose viability and so most reputable seed banks monitor germination potential during storage.<ref>{{Cite journal |last1=Waldhardt |first1=R. |last2=Fuhr-Bossdorf |first2=K. |last3=Otte |first3=A. |date=2001-11-29 |title=The significance of the seed bank as a potential for the reestablishment of arable-land vegetation in a marginal cultivated landscape |url=https://we.copernicus.org/articles/2/83/2001/ |journal=Web Ecology |language=English |volume=2 |issue=1 |pages=83–87 |doi=10.5194/we-2-83-2001 |doi-access=free |bibcode=2001WEco....2...83W |issn=2193-3081}}</ref> When seed germination percentage decreases below a prescribed amount, the seeds need to be replanted and fresh seeds collected for another round of long-term storage.<ref name="HoEl">Hong, T.D. and R.H. Ellis. 1996. A protocol to determine seed storage behaviour. IPGRI Technical Bulletin No. 1. (J.M.M. Engels and J. Toll, vol. eds.) International Plant Genetic Resources Institute, Rome, Italy. {{ISBN|92-9043-279-9}} [https://www.cbd.int/doc/case-studies/tttc/seedstorage.pdf]</ref>

Seeds banks may operate in much more primitive conditions if the aim is only to maintain year-by-year seed supplies and lower costs for farmers in a particular area.<ref name="FAO-Mozambique">{{cite web | title=The gatekeepers of Mozambique's community seed banks | website=UN FAO ([[Food and Agriculture Organization]] of the United Nations) | url=http://www.fao.org/fao-stories/article/en/c/1416545/ | access-date=2021-09-14}}</ref>