Viability loss during transportation and interim storage

Seed viability:

Seed viability refers to state of being aliveness, metabolically active and possesses enzymes capable of catalyzing metabolic reactions needed for germination and seedling growth. It is seed viability at the time of sowing, rather than at the time of dispatch from the seed store, which determines the number of healthy plants produced from a particular seed lot.

Factors affecting seed viability:

Temperature: Higher temperature destroys the storage contents in the seed and loss of viability occurs. Storage of seed in the low temperature keeps it viable for a longer time.

Moisture: Optimum moisture content (9% -12% for cereals) must be maintained so that there is no much damage by the insects.

Humidity: Higher the humidity, higher the spoilage, thus loss of viability.

Oxygen availability: If oxygen content is more respiration takes place at a faster rate and thus leading to deterioration of the seed.

Seed coat: It is the one which covers the seed and its viable parts. So, care should be taken not to damage the seed coat .

Mechanical damage to the seed: It is the important factor which affects the viability during storage .Any mechanical damage to the seed coat leads to leaching out of leachates. Thus leading to deterioration of the seed.

Pest and disease attacked seeds: Pests attack the nutritive tissue of the seed leading to deterioration of the seed.

Transportation of seed:

Movement of materials from the place of production to the place of requirement is termed as transportation.

Viability loss during transportation:

High and fluctuating temperatures and adverse humidity are the chief causes of viability losses during shipment.
Due to harsh lifting and placement of bags lead to damage of seeds.
Thus causing even mechanical damage which leads to the seed spoilage and invites pest and diseases.

Prevent viability loss during Transportation:
Appropriately dried seeds only should be packed.
Double wrapping should be done to avoid damage and also absorption of moisture from the atmosphere.
If the seed is of high value the transportation should be by the way of cold storage.
For long distances, shipment of sensitive seeds by air is desirable.
Small or moderate size containers generally withstand shipment better than large containers.
Fill containers completely to minimize air content and jostling of seeds during shipment.
Sealed containers are highly suitable for orthodox species, of which the seeds must be kept dry during transit.
The addition of a desiccant such as silica gel may be a useful for additional insurance if there is any risk that the seeds may absorb moisture while being transferred from storage container to shipment container.
Seeds of recalcitrant species, on the other hand, are best left unsealed, since the effect of some loss of moisture is less harmful than that of the overheating which can occur as a result of rapid respiration in sealed bags at ambient temperatures.

Interim storage:

It is a temporary storage before the permanent storage.
This term is not much used in recent times.
It is also called the transit storage.
It can be storage during transportation.
It can be storage at the retail shop.
It can be storage at the ware houses.

Viability loss during interim storage:


References:

1. Seed Technology by Ratan Lal Agarwal.
2. A text book of seed science and technology by G.V. Basavaraju, P. Ravishankar & Sarika Gowdiperu.
3. Seed Science and Technology by Subir Sen and Nabinananda Ghosh.

There are chances of unfavourable environmental condition and attack of pest and disease during interim storage which causes the loss of viability.


About Author / Additional Info:
I am a PhD student of Seed Science and Technology at IARI New Delhi