[UrbanCropCircle] Fwd: The Overstory #218--Seed storage

Tue May 19 02:05:36 PDT 2009

Begin forwarded message:

> From: "The Overstory E-journal" <overstory at agroforestry.net>
> Date: May 18, 2009 10:31:33 PM PDT
> To: "The Overstory E-journal Subscriber" 
> <ingela at sustainableballard.org>
> Subject: The Overstory #218--Seed storage
> Reply-To: "The Overstory E-journal" <overstory at agroforestry.net>
>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 607 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0006.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: ovlogo108x252.jpg
Type: image/jpeg
Size: 8242 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0006.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: aflogo-hosted-by.jpg
Type: image/jpeg
Size: 4642 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0007.jpg>
-------------- next part --------------
> Journal Home | Previous Editions | Submissions | Support |
> Current Projects | Publications | About Us | Links
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 616 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0007.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: _MG_7185CElevitch.jpg
Type: image/jpeg
Size: 35603 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0008.jpg>
-------------- next part --------------
>  Optimal storage conditions can ensure that seeds retain viability as  
> long as possible. (pictured: Leucaena leucocephala seeds)
>
> The Overstory #218
>
> Seed storage
>
> By Anne Mbora
>
> May 18, 2009
>
> Conference announcement
>
> Internship opportunity
>
> Article submissions
>
> Address changes
>
> The Overstory #218
>
> Seed storage
>
> By Anne Mbora
>
> Introduction
>
> Seed can maintain viability for long periods if it is properly stored.  
> When seed is stored in unfavorable conditions, it quickly dies. This  
> article describes ways of keeping seed alive through proper seed  
> storage.
>
> Why should I store seeds?
>
> Tree seed is stored for various reasons. All reasons for seed storage  
> encompass some element of future use of the seed.
>
> ? The main aim of seed storage is to keep the seed alive and in good  
> condition.
>
> ? Good seed years must be taken advantage of especially for species  
> that only flower periodically. Ocotea usambarensis and  
> Dipterocarpaceae for example, only flower once in several years.  
> Similarly, many tree species do not produce the same amount of seed  
> each year. Therefore, you may want to collect more seed in the year  
> when production is high for use in years when production is low.
>
> ? Conserving genetic information: the threat of extinction to  
> provenances and species necessitates taking measures to conserve seed  
> genetic information. Long-term seed storage, for example, conservation  
> of seed by the Millennium Seed Project of The Royal Botanic Gardens,  
> Kew, is one of the important measures of genetic conservation.
>
> ? Preparation for the planting season: if the harvesting and planting  
> seasons do not coincide, you may need to store seed to bridge the time  
> between collection and sowing.
>
> ? Future demand: the demand for a certain species may be very low when  
> you collect the seed, but may be higher than the production at a later  
> time. Under these conditions, you need to keep some seed in stock so  
> that you can buffer the differences between demand and supply.
>
> ? Avoiding deterioration: even if the time between collection and  
> planting is very short, pests such as rodents, birds or beetles or  
> fungi can attack the seed. You should store the seed in a place that  
> is free from pests and pathogens.
>
> ? Security: another reason for storing seed even if the time between  
> collection and planting is short is to keep them safe. Demand for seed  
> can be very high, such that it raises the probability of seed being  
> stolen.
>
> ? Food storage: You may wish to store seed so that you can use it at a  
> later date as food. In some countries, tree seeds and fruits are  
> eaten. Examples of such species include Tamarindus indica, Adansonia  
> digitata, Ziziphus mauritiana and Acacia spp.
>
> How should I prepare seed for storage?
>
> Carry out seed drying just before storage and as quickly as possible  
> after extraction. This helps to:
>
> ? Avoid seed deterioration in storage and thus extend viability.
>
> ? Reduce rotting of seeds in storage.
>
> ? Improve resistance of seed to pests and diseases during storage.
>
> Tree species are divided into three different classes according to the  
> maximum period that their seed can be stored, taking into  
> consideration their temperature and moisture content requirements. In  
> nature, species show a range in their maximum storage period. The  
> three classes guide you on the best storage period for each species.  
> Storage time depends on storage conditions; under bad conditions, all  
> seeds will die quickly, while under optimal conditions, lifespan is  
> extended.
>
> Recalcitrant seeds should be dried under shade to retain a high level  
> of moisture content (20-40%), in order to keep them alive. The  
> temperature at which the seed is stored should be around 12-15?C.  
> Recalcitrant seeds cannot be kept for long under conventional  
> conditions in seed storage containers. Examples of recalcitrant seed  
> are Mangifera indica, Persea americana, Syzygium cuminii, Trichilia  
> emetica and Vitellaria paradoxa.
>
> Intermediate seeds can only withstand a limited level of drying - to a  
> moisture content of 15-19%. They are sensitive to low temperature,  
> thus should be stored in high temperatures. Intermediate seeds cannot  
> be stored for a very long time before losing viability. You should use  
> shade drying or air drying methods that are suitable for seeds  
> extracted from pulpy fruits. Air dry for 1- 3 days before storing or  
> plant the seeds immediately for better germination. Examples of  
> intermediate seed are Azadirachta indica, Maesopsis eminii, Dovyalis  
> caffra and Artocarpus heterophyllus.
>
> Orthodox seed is commonly dried under direct sunlight for 2-3 days to  
> a moisture content of 5-8%. The period of drying will depend on the  
> relative humidity of the air, the species and the air temperature.  
> Orthodox seeds can also be dried above the fireplace (smoke drying),  
> or where farmers dry their firewood during the rainy season. You  
> should be careful not to overheat and kill the seed. Orthodox seed can  
> be stored for a fairly long period of time before losing viability. As  
> a rule of thumb, for orthodox seeds, the mean viability period (seed  
> life-span) doubles each time the moisture content is lowered 1% below  
> the maximum 14-15% moisture content level that is acceptable for  
> storage.
>
> Seed can be treated against pests with locally available  
> preservatives, for example, leaves of neem or the ash of any other  
> tree species, before storage. Each container should have two labels -  
> one inside and one attached outside with at least the species name,  
> date of collection, number of parent trees, seed source, weight of  
> seed and collector's name.
>
> How long can I keep tree seed?
>
> The length of time that seed remains alive varies according to the  
> species or the place where the seed was collected. The length of time  
> also varies between seeds of the same species that were collected from  
> the same place. This time also depends on morphological, physical,  
> physiological and health conditions of the seed. The length of time  
> that seed stays alive depends very much on the storage conditions -  
> when storage conditions are bad, all seed dies quickly.
>
> In general, seed loses viability as time progresses until ultimately,  
> all seeds die. The viability of seed is expressed as the percentage of  
> the number of seeds that germinate from the whole lot after a given  
> period of seed storage. The period for which seed can be stored varies  
> from species to species - some can be stored for longer than this and  
> others for much less. Seed that is stored under conditions that are  
> less favourable to its survival will lose viability more quickly. This  
> is an indication of the importance of storing seed properly.
>
> As mentioned above, the period that seed can stay alive depends a lot  
> on the species to which it belongs. Some species cannot be stored for  
> long periods whatever the storage conditions. Other species can be  
> stored for long periods so long as the storage conditions are good.
>
> How should I store orthodox seeds?
>
> Orthodox seeds should be stored in clean, dry airtight containers. The  
> containers should be properly filled with seed, and then closed off  
> after the seed is put in. Gourds can also be used as seed storage  
> containers.
>
> If properly dried, orthodox seeds can be stored at room temperature.  
> Most seeds can be stored for longer periods in refrigerated conditions  
> (O?C to 5?C or even down to -20?C). Some hard-coated species can be  
> stored at room temperature almost as long as when refrigerated.
>
> Orthodox seeds of most species will remain viable for 1-2 years when  
> stored under fair to good conditions at the farmer and NGO level.  
> Viability can be extended by reducing seed moisture contents and by  
> lowering the storage temperature.
>
> As a rule of thumb, the mean viability period doubles each time the  
> moisture content is lowered by 1% below the 14-15% moisture content  
> which is the maximum content for successful storage. In other words if  
> the viability was 2 years at 14% then if you drop the moisture content  
> to 13% it will be 4 years. Similarly, again as a rule of thumb, the  
> mean viability period doubles each time the mean storage temperature  
> is lowered by 5?C. This ranges from the highest temperatures  
> encountered during the drying of orthodox seeds (50?C) down to O?C.
>
> In general, orthodox seeds are stored at 5-8% moisture content and at  
> temperatures of 0-5?C.
>
> How should I store intermediate seeds?
>
> These seeds can withstand relatively low moisture contents <12%), but  
> they cannot withstand low temperatures <5?C). After the seeds'  
> moisture content is lowered, store them in a clean, dry, airtight  
> container for 4-6 weeks at ambient temperatures. Do not store them in  
> refrigerated surroundings.
>
> How should I store recalcitrant seeds?
>
> Recalcitrant seeds need to be stored at high moisture levels. They can  
> only be stored for 1-2 weeks before losing viability. These seeds  
> cannot withstand surroundings with low temperatures or low relative  
> humidity. For short-term storage, put recalcitrant seeds in permeable  
> containers to allow ventilation.
>
> To maintain their moisture content, recalcitrant seeds should be mixed  
> with a medium (sawdust, peat or vermiculite) that is slightly  
> moistened with distilled or de-ionized water. Seeds and the medium  
> should be mixed at a ratio of 1:2, and then stored at ambient  
> temperatures and kept moist.
>
> How do I keep relative humidity low during storage?
>
> Orthodox seeds must always be kept in a well-ventilated cool, dark and  
> dry place. The seeds' initial moisture content should be low enough to  
> avoid respiration.
>
> If small portions of seed are likely to be removed frequently from the  
> cold storeroom, seeds should be stored in small amounts. Seed can be  
> stored in small sealed plastic bags within a larger container. The  
> volume of air within the container should be low compared to the  
> volume of seeds in the container. If the amount of air is large, the  
> seeds will absorb a lot of moisture from the fresh air each time the  
> seed container is opened. Place substances that absorb moisture such  
> as roasted rice husks, newspaper, charcoal, or silica gel in the  
> container as the volume of seed decreases.
>
> Note that seeds with high oil content have a lower moisture content  
> than seeds with a low oil content and high protein or starch contents.
>
> REFERENCES
>
> Albrecht J. (ed). 1993. Tree seed handbook if Kenya. Nairobi: Kenya  
> Forestry Research Institute/Deutsche Gesellschaft fur Technische  
> Zusammenarbeit.
>
> Indonesia Forest Seed Project. 2001. Demo room poster on storage.  
> Bandung: Indonesia Forest Seed Project.
>
> Mortlock W 1998. Guideline 1: Native seed storage for revegetation.  
> Yarralumla: FloraBank.
>
> Mulawarman, Roshetko M.J., Singgih M.S. and Djoko I. 2003. Tree seed  
> management - seed sources, seed collection and seed handling: a field  
> manual for field workers and formers. Bogor: Winrock International and  
> World Agroforestry Centre. 54 pp.
>
> Robbins A.M.J. and Shrestha N.B. 1986. NR Study-note F120d. Basic  
> rules for storing tree seed. Tree seed handling: a manual for field  
> staff in Nepal. Field Document 11. Bandung: National Tree Seed  
> Project.
>
> Schmidt L. 2002. Guide to handling if tropical and subtropical forest  
> seed. Humlebaek: DANIDA Forest Seed Centre.
>
> Thomsen K. and Stubsgaard F. 1998. Easy guide to controlling seed  
> moisture during seed procurement. Humlebaek: DANIDA Forest Seed  
> Centre.
>
> ORIGINAL SOURCE
>
> This article was excerpted with the kind permission of the publisher  
> from:
>
> Mbora, A. 2006. "Seed storage." In: Kindt R., Lilles? J.P.B., Mbora  
> A., Muriuki J., Wambugu C., Frost, W., Beniest J., Aithal A., Awimbo  
> J., Rao S., Holding-Anyonge C. Tree Seeds for Farmers: a Toolkit and  
> Reference Source. Nairobi: World Agroforestry Centre. web link
>
> ABOUT THE PUBLISHER
>
> The World Agroforestry Centre is a non-profit research organisation  
> whose
>  vision is a rural transformation in the developing world resulting in  
> a massive
>  increase in the use of trees in rural landscapes by smallholder  
> households for
>  improved food security, nutrition, income, health, shelter, energy and
>  environmental sustainability. We are one of the 15 centres of the
>  Consultative Group on International Agricultural Research (CGIAR).
>  Headquartered in Nairobi, Kenya, we operate five regional offices  
> located in
>  Brazil, Cameroon, Indonesia, Kenya, and Malawi, and conduct research  
> in
>  eighteen other countries around the developing world. We receive our
>  funding from over 50 different governments, private foundations,
>  international organisations and regional development banks.
>
> The World Agroforestry Centre (ICRAF)
>  United Nations Avenue
>  PO Box 30677, GPO 00100
>  Nairobi, Kenya
>  Tel: +254 20 7224000, via USA +1 650 833 6645
>  Fax: +254 20 7224001, via USA +1 650 833 6645
>  E-mail: icraf at cgiar.org
>  Internet: www.worldagroforesty.org
>
> WEB LINKS
>
> Guide to Handling of Tropical and Subtropical Forest Seed is an  
> exceptional guide for forest tree seed handling from scientific,  
> practical and administrative perspectives. Available online
>
> A guide to forest seed handling, FAO publication.  
> http://www.fao.org/DOCREP/006/AD232E/AD232E00.htm#TOC
>
> Seed Storage Practices for Native Hawaiian Plants (generally  
> applicable to a wide range of seeds worldwide).  
> http://hawaiiconservation.org/_library/documents/ 
> seed%20storage%20manual.pdf
>
> "Seed Technology for Forestry in Hawaii--How and why to collect,  
> order, and use quality seed":  
> http://www2.ctahr.hawaii.edu/oc/freepubs/pdf/RM-4.pdf
>
> The Forest Genetic Resources site published by the Food and  
> Agriculture Organization of the United Nations has information on seed  
> collection, processing, propagation and improvement:  
> http://www.fao.org/forestry/seeds/en/
>
> RELATED EDITIONS OF THE OVERSTORY
>
> The Overstory #134--Seed Source Establishment and Management
>  The Overstory #130--Seed Sources for Collection
>  The Overstory #120--Seed Collection
> The Overstory #58--Guidelines for Seed Production of Agroforestry Trees
>  <http://www.agroforestry.net/overstory/overstory58.html>
> The Overstory #43--Essentials of Good Planting Stock
>  <http://www.agroforestry.net/overstory/overstory43.html>
> The Overstory #31--Tree Domestication
>  <http://www.agroforestry.net/overstory/overstory31.html>
>
> Conference announcement
>
> The 2nd World Congress of Agroforestry will be held in
>  Nairobi, Kenya, 20-29 August 2009. The overall Congress theme is
>  "Agroforestry - The Future of Global Land Use". For the latest  
> information,
>  visit <http://www.worldagroforestry.org/wca2009/>.
>
>
> Internship opportunity
>
> Advanced study internship in tropical agroforestry
>  with the people who bring you The Overstory E-Journal:
>  <http://www.agroforestry.net/internship>.
>
>
> Article submissions
>
> Have you written an article in the last 5 years on
>  a topic that you think would interest other Overstory subscribers?
>  Would you like it to be circulated in edited form to over 8,000
>  subscribers in 185 countries? Then submit it to the Overstory
>  for consideration--it's that easy! Please read our submission  
> criteria:
>  <http://www.agroforestry.net/overstory/ovsubm.html>.
>
>
> Address changes
>
> Please send e-mail address changes to
>  <overstory at agroforestry.net>.
>
> PUBLISHER NOTES
>
> Publisher: Permanent Agriculture Resources
>  Editor: Craig R. Elevitch
>
> Distributor:
>  The Overstory is distributed by Agroforestry Net, Inc., a nonprofit
>  501(c)(3) organization based in Hawaii.
>  Address: P.O. Box 428, Holualoa, Hawaii 96725 USA
>  Email: overstory at agroforestry.net ; Web site:
>  http://www.overstory.org
>
> Past editions of The Overstory: http://www.overstory.org
>
> This publication is Copyright 2009 Permanent Agriculture Resources.
>  All Rights Reserved Worldwide. For Conditions of Use please contact
>  overstory at agroforestry.net or write to Agroforestry Net, Inc. at the
>  address above.
>
> This journal is designed to provide agricultural information, but
>  is sent with the understanding that the editors and publishers are
>  not engaged in rendering consultation. If expert assistance is
>  required, the services of a professional should be sought.
>  Support The Overstory by donation, sponsorship, or book purchase.
>
> We invite you to submit your articles to The Overstory. Please visit  
> our submissions page.
>
> The Overstory is for private, individual use for educational,  
> non-commercial and informational purposes. Please read conditions for  
> use before subscribing.
>
> Click here to subscribe
>
> or send an email to overstory at agroforestry.net with:
>
> 1) your name
>  2) email address
>  3) organization (or brief project description, or your interest in
>  agroforestry)
>  4) your location (city, state, country)
>
> To remove your name from our list, simply send an email with your name  
> and email address to overstory at agroforestry.net
>
> CONFIDENTIALITY NOTE: We will never to reveal your subscriber  
> information to any third party without your prior consent. We hope you  
> will accept this invitation to sign up for this free journal.
>
>
>
> | Journal Home | Journal Previous Editions | Journal Submissions |  
> Support |
>
> | Current Projects | Publications | About Us | Links |
>
>
>
> Agroforestry Net, Inc.
>  PO Box 428
>  Holualoa, Hawaii 96725 USA
>  Contact us: email at agroforestry.net
>
> Site comments and suggestions
>
> Page Last Updated: May 18, 2009
>  agroforestry.net is Copyright ?1997-2009. All rights reserved.
>
> Mailing List Powered by Dada Mail
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: text/enriched
Size: 20782 bytes
Desc: not available
URL: <http://lists.sustainableballard.org/pipermail/urbancropcircle-sustainableballard.org/attachments/20090519/63b749b2/attachment-0008.bin>