Transcript Unit 6 Seeds - MACCRAY Schools

Unit 6 Seeds
Horticulture/Landscape
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What is Propagation?
• There are many ways of propagating, or
reproducing, plants.
• The most common method of reproducing
flowering as well as vegetable and cereal
crops in through the use of seeds.
• Seeds are a means of rapidly increasing the
number of certain plants.
• Some plants don’t seed true to form.
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What is Propagation?
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What is Propagation?
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What is Propagation?
• Plants that are not produced directly from
seeds or don’t produce seeds that will grow,
such as some hybrids, must be propagated
by another method to obtain exact
duplicates.
• Hybrids:
– Are the offspring of two different varieties of
one plant, each of which possesses certain
characteristics that are desired in the new
plants.
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What is Propagation?
• Propagation may be accomplished by
division of roots; by cuttings of leaves,
stems, or roots, or by budding and grafting.
• Asexual reproduction is possible because
each cell of a plant contains all the
characteristics of the entire plant and can
regrow any missing part.
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What is Propagation?
• Plant propagation predates recorded history.
• Very early humans planted seeds or divided
plants to increase plant numbers.
• The quality of plants was improving by
using seed from the best plants to produce
other plants.
• Tissue culture or micropropagation is the
newest approach to plant propagation.
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What is Propagation?
• This is as asexual method in which a
growing shoot, tip, or bud of the plant is
separated and grown on an agar gel or other
nutrient medium.
• Thousands of new plants exactly like the
parent plant can be produced very quickly.
• This has been done for years using orchids.
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Propagation of Plants From
Seeds
• Many plants are started from seed because it
is quick and economical method.
• Proper environmental and cultural
conditions must be provided.
• These include:
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Temperature
Moisture
Light
Medium
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Propagation of Plants From
Seeds
• Seeds of annual plants which are not hybrids
generally come true from seed.
• Named varieties are specific strains of one type
of plant which have been named to indicate
their particular traits.
– Tomato plants have numerous named varieties such
as Better Boy, and Marglobe.
– Each is a different size, has different maturity dates
etc…
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– Seeds should not be saved from hybrids and planted.
Special Treatment of Seeds for
Germination
• Some seeds have a hard seed coat which
must be soaked or scratched before the
seeds are able to germinate.
• This is called scarification
• Other seeds require a moist, cold rest period
at temperatures below 37 F for 8 weeks or
longer.
– Examples: Apple, pear, peach, maple , yew.
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Special Treatment of Seeds for
Germination
• Other seeds must go through alternate
wetting and drying.
• Some must have light to germinate.
• Some must have darkness to germinate.
• Any special treatments will be printed on
the seed packet or enclosed with the
planting directions.
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Composition of Seeds
• The basis parts of a seed
are the seed coat, the
endosperm, and the
embryo.
• Seed Coat
– Is the outside covering of the
seed which protects the
embryonic plant.
– The seed coat makes it
possible for the seeds to be
transported and stored for
long periods of time. 13
Composition of Seeds
• Endosperm (Stored Plant Food)
– Is the food storage tissue which nourishes the
embryonic plant during germination.
• Embryo (Or Embryonic Plant)
– Is a new plant that is developed as a result of
fertilization.
– During germination it extends its roots and seed
leaves to form a new plant.
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Identification And Selection of
Seed
• There are several important steps in the
selection of seed.
– Identify which seeds are grown locally.
– Select seeds that have been tested for the years
growing season for germination ability and purity.
– Purchase the seeds from a reliable dealer to assure
that the variety is pure and that germination ability
is acceptable.
– Choose hybrid varieties for greater vigor,
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uniformity, and flowering ability.
Identification And Selection of
Seed
• Some new things have been done with seeds
to improve germination and uniformity or
growth.
– Seed quality has been improved and seeds have
been sorted by weight.
– This results in all seedlings coming up at the
same time.
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Identification And Selection of
Seed
• Seeds are primed or enhanced
– This is done by soaking the seeds in salt
solutions of KCL or ethyl alcohol.
– This treatment causes the growth hormones or
enzymes to become active and young roots start
to grow.
– By regulating the amount of moisture and
chemical, growth is stopped at a point where
the seed may still be safely stored.
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Identification And Selection of
Seed
• Small difficult to plant seeds are now coated
or pelletized to make them larger and easier
to plant.
• Some companies even glue them to a tape
with the proper spacing.
• All you do is stretch out the tape and cover
it with soil.
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Germination Medium
• The best medium for germination has a
favorable pH level and an adequate supply
of plant nutrients.
• A good germination medium contains one
or more of the following ingredients.
– Soil, Construction Grade Sand, Peat Moss,
Sphagnum Moss, Horticulture Grade Perlite,
Vermiculite, Jiffy Mix.
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Indirect Seeding
• Indirect seeding is a process in which seed
is sown in a place separate from where the
plants will eventually grow to maturity.
• The seedlings are transplanted one or more
times before reaching the permanent
growing area.
• Flats are made of plastic and come in many
shapes and sizes.
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Indirect Seeding
• Size selection should be determined by the
number of seeds to be sown.
• Medium is placed in the flat and leveled off
about ½ - ¾ inch below the top.
• It is best to sow seeds in rows because if
disease strikes one row it can be removed
without disturbing the others.
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Indirect Seeding
• When to seed.
– Seeds must be planted on certain dates so that
the seedlings are ready for transplanting at the
proper time.
• Sowing Seeds
– Follow the directions on the package to
determine the distance apart the seeds should be
sown.
– The seed package will also give the proper
depth the seeds should be planted at.
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Indirect Seeding
• Watering the Seed Flat
– Water aids in germination by making the seed
coat soft.
– If the flat is watered from the top, care must be
taken to avoid washing the seeds out of the flat.
– Very small seeds should never be watered from
the top.
– They may be washed too deeply into the soil.
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Indirect Seeding
• Transplanting Seedlings
– After seeds germinate, they develop seed leaves
or cotyledons, the first leaves to appear on the
plant.
– The plant should be allowed to grow until the
first true leaves are present before it is
transplanted.
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Direct Seeding
• Are plants planted directly in the permanent
growing area.
– Ex corn, beans, beets, etc…
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