Tree seeds categories
- Category: Management
- Author: Fabrice Feyton
- Published: June 5, 2020
- Views: 18
Seed storage is the preservation of viable seed until the time of sowing. This activity is important and essential to offset the uncertainty of seed production/ availability during bad seed years. Tree seed can be classified based on the length they can remain viable while in storage. The category determine storage methods to be used, some being viable while stored at room temperature like Eucalyptus spp, while others can only remain viable when stored under cool temperature like Alnus acuminata. There are three categories, Orthodox, Sub-orthodox, and Recalcitrant seeds.
Example: Ormosia obusta, Acacia spp, Albizia spp, Delonix regia, Eucalptus spp, Tectona grandis, and Pinus spp. Orthodox seeds must be dried to a low moisture content before they can be stored. the drying process causes orthodox seed to enter a state of dormancy, which allows seed to maintain viability for long periods. The orthodox seed of many species can be stored for 1 year at room temperature or several years in cold storage with little loss of viability
Some orthodox seed can be stored for as many as 100 years. Once dormant orthodox seeds will begin to germinate only when conditions are favorable. Orthodox stores best at moisture contents between 5-8%, but can only be achieved by oven drying
Examples includes seeds of Alnus spp, Cedrella sp, and Grevillia robusta lose viability within a few months in open air. These can be stored in same conditions as true orthodox, however they can retain viability only for six months to a maximum six years in some cases. they lose viability in the range of 0-34 % when stored at 5-20 degree Celsius with a moisture content between 5-10 %
Seeds which cannot tolerate drying below a relatively high moisture content ( Often in range of 20-50%) and which cannot be stored successfully for long periods. The seed is sensitive to low temperature, chilling damage and death may occur of stored in low temperature. This type of seed is the most difficult group of seed to store even for short periods, when stored under humid conditions, they may remain viable for slightly longer period.
Examples: Azadirachta indica, Theobroma sp, Cacao, Shorea spp, Hopea spp, and Palaquium.
For recalcitrant seed, the time between seed collection and sowing should be kept as minimum as possible. However many species of mist tropical forests are so thoroughly adapted for germination that their seeds are almost impossible to store or even transport.
Some species do not produce seed every year and seed needs to be stored before and while it is being shipped to field staff or consumers. General guidelines for seed storage are consistent for all Orthodox seed.