Resource Book on Horticulture Nursery Management

fleshy fruits and also the tree and shrub seeds. The seed are collected at proper stage,
Extraction and separation of seeds are done and then are processed for further storage –
open storage with temperature control, warm storage with moisture control, cold storage
with or without moisture control and cold, moist storage are some storage methods.
Seed Quality
Quality plants are produced only from quality seeds obtained from a reliable dealer.
Select varieties to provide the size, color, and growth of plant. Many new vegetable and
flower varieties are hybrids, which cost a little more than open pollinated types.
However, hybrid plants usually have more vigor, more uniformity, and better production
than non-hybrids and sometimes have specific disease resistance or other unique cultural
characteristics. Some seeds can be stored for several years if stored properly. But it is
advisable to purchase seeds required for a single planting year. The seed material which
does not contain the seeds of any other crop, weed seeds, or other debris is considered to
be good. Printing on the seed packet usually indicates essential information about the
variety, the year for which the seeds were packaged, and germination percentage you
may typically expect, and suggestions regarding any chemical seed treatment. If seeds are
obtained well in advance of the actual sowing date they must be stored in cool, dry
places. Laminated foils packets help ensure dry storage. Paper packets are best kept in
tightly closed containers and maintained around 4° Celsius temperature and low
humidity.
Seed Germination
There are four environmental factors which affect germination: water, oxygen, light,
and heat.
1. Water: The first step in the seed germination process is the absorption of water.
Even though seeds have great absorbing power due to the nature of the seed coat, the
amount of available water in the germination medium affects the uptake of water.
An adequate, continuous supply of water is important to ensure seed germination.
Once the seed germination process has begun, a dry period will cause the death of
the embryo.
2. Light: Light is known to stimulate or inhibit germination of some seed. The light
reaction involved here is a complex process. Some crops which have a requirement
for light to assist seed germination are Ageratum, Begonia, Browallia, Impatiens,
Lettuce, and Petunia. Conversely, Calendula, Centaurea, annual Phlox, Verbena, and
Vinca germinate best in the dark. Supplemental light can also be provided by
fluorescent fixtures suspended 6 to 12 inches above the seeds for 16 hours a day.
3. Oxygen: Respiration takes place in all viable seeds. The respiration in dormant seed
is low, but some oxygen is still required. The respiration rate increases during
germination, therefore, the medium in which the seeds are placed should be loose
and well-aerated. If the oxygen supply during germination is limited or reduced,
germination can be severely retarded or inhibited.
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