Genetic Resources, The role of the egyptian deserts gene bank to Conservation plant genetic resources lec 1
1. SEEDS CONSERVATION
IN GENE BANK
ElSayed Mohamed ElAzazi
Plants Ecology and Range Management Dept. 2015
North Sinai research Station Dec. 2014, by Dr. Elsayed Elazazi
5. Conservation: the link between genetic
resources and utilization
Plant Genetic
Resources
Diversity
Conservation
Utilization
(immediate
or potential)
Maxted et al., 1997a).
Utilisation Products
(New varieties, new crops,
pharmaceutical uses, pure and
applied research, on-farm diversity,
aesthetic pleasure, etc
8. In-situ
conservation
nature reserves
managed areas
Biosphere reserves
on-farm conservation
Home gardens
Seed Bank
Field gene bank
In vitro slow growth
Cryobank,
cryopreservation
Pollen storage
DNA storage
Botanical Gardens
Ex-situ
conservation
9. Seed Bank storage conditions
Long -
term
Base room
(–22 ºC,
≥ 100 years
Short-
term
Active
room (+4ºC,
40% RH)
≥ 25 years
Medium-
term
Freezing
room (–5
ºC, no frost
≥ 50 years
All data in Gene bank by accession number
All material exchange should by under MTA
16. Seed cleaning
Collections in cloth and
paper bags held in drying
rooms.
Collections cleaned to
remove empty or infested
seed and to reduce their bulk
- aim: 95% pure seeds
All cleaning done by hand,
carefully.
Photo by: Kew 2011
22. Why is it important to understand
seed-air moisture relations?
• Seed storage behaviour – response to water
removal
• Seed ripening – maturation drying
• Seed viability – impact of seed moisture
status on seed longevity
• Seed drying – how seeds dry, monitoring
seed moisture status
23. Water in seeds
•Determining seed
equilibrium humidity
(eRH) using a digital
humidity sensor
• Air and seed at
equilibrium inside
chamber
25. Sun/Shade drying
Sun drying in thin layers in
open crates allowing
plenty of air movement.
Protecting seeds from direct
sun to reduce risk of heat
damage
Photo by: Kew
26. Dry room
•Room Condition at 10-15% RH
and 10 - 25C (FAO / IPGRI Gene
bank Standards)
•Specifically designed for purpose,
taking into account maximum
• seed loading (cleaned & un
cleaned seed) and several other
factors.
10-15% RH and 10 - 25C (FAO / IPGRI Genebank Standards)
Photo from KIB China
28. Cooled incubators
(incubator driers)
•Cost effective way of drying small amounts
(up to 10 kg) of seed
•Usually run at 18ºC, giving an RH of ~15%.
•Dries 10kg of fresh seeds to 7% mc in ~ 3
weeks
•Incubator must run with refrigeration system
on constantly and must have auto defrost.
10-15% RH and 10 - 25C (FAO / IPGRI Genebank Standards)
Photo by: Kew
30. Drying with desiccants:
silica gel bin drier
•Use a suitable container with a
tightly fitting lid (e.g. a plastic box or
plastic / metal drum).
•Add 20% by (container) volume
dried (10 - 20% RH) silica gel.
•Place bags of seed in container
•Check the RH of the silica gel
weekly; if too high, oven dry a quarter
part at 100ºC and re-mix with the
remaining gel.
•Drying time (~one month) depends on the initial
moisture content of the seeds, the amount of seeds,
the type of seeds and the dryness of the silica gel.
Photo by: Kew
32. What is ‘viability’?
• A viable seed is a living seed that has the
capability of germinating
• Empty seeds and seeds without embryos are
non-viable but they should not be called dead
seeds because they never were viable
• Dead seeds are seeds that were viable but
have subsequently died
Rao, N.K.; Hanson, J.; Dulloo, M.E.; Ghosh, K.; Nowell, A.; larinde, M 2006a.
Manual of Seed Handling in Genebanks8.
33. Why should seed viability be
determined?
1. It is very important that seeds stored in the genebank are
capable of producing plants when sown in the field.
2. They must have high viability at the start of storage and
maintain it during storage.
3. Seeds with a high initial viability will also survive longer in
storage.
4. Seed viability declines slowly at first and then rapidly as seeds
age.
5. It is important to know when this decline occurs in order to
take action to regenerate the accession. Excessive deterioration
will lead to loss of material.