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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:– 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…– Seeds should not be saved from hybrids and planted.

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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.

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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, uniformity, and

flowering ability.

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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…