Seed Quality

Seed Quality

What is good seed quality and what contributes to good quality?  Factors affecting seed quality can be arranged into 3 main groups :

     Genetical Quality,

     This can be defined as inherited quality, resulting from;

a)    The genetical make up of the individuals of the seed source

b)    The composition of the seed source relating to the type of seed source;

·         Unidentified source.

·         Selected stand.

·         Seed production area.

·         Provenance seed stand.

·         Seed orchard.

     Physiological Quality,

     This can be defined as the quality due to the outcome of seed formation, the different processes involved like flowering, pollination, fertilization, seed development and maturity.

Important factors affecting thes process are;

a)    Stand age (juvenile, mature, over mature)

b)    Stand condition (size, form, density).

c)    Stand management (thinning, application of fertilizers).

d)    The climate.

e)    Edaphic (soil) conditions in the stand. Physical Quality,

Physical Quality,

Any treatment in the processes Involving collection, handling, storage as well as pre-sowing treatments may have an effect on the physical quality of the seed, expressed in decreased vigour.

Such treatments coud be;

a)    Collection method, for example from the tree crown or from the ground, the latter involving the risk of pathogen infections.

b)    After ripening temporary storage methods.

c)    Drying and processing methods.

d)    Storage methods (container type, storage temperature, length of storage periode).

e)    Treatments causing incomplete release from dormancy.

The best quality seed is obtained from;

a)    Mature, well managed (spaced, fertilized) stands.

b)    Of sufficient size to ensure broadly based pollination from dominant, healthy individuals.

c)    Collected in peak flowering years.

d)    Using methods, which ensure the collection of sufficiently ripe fruits/seeds.

e)    Giving consideration to the specific requirement with regard to after ripening and drying.

f)       Using subsequent processing and storage methods that do not harm the seed.

g)    Applying proper pre-sowing treatment that ensure complete dormancy release.