Horticulture Principles and Practices

9
Sexual Propagation
PURPOSE AND EXPECTED OUTCOMES
This chapter discusses the principles of plant propagation and describes the various
methods of propagation, including the advantages of each and their best time of use.
After studying this chapter, the student should be able to
1. Describe how seeds are commercially produced.
2. List and discuss the factors that affect the use of seeds in plant propagation.
3. Describe how seed germination can be improved.
4. List and discuss the environmental conditions for seed germination.
[COLOR PLATES—see color plate 6 for additional chapter photos]
OVERVIEW
Plant propagation is simply the reproduction or duplication of a plant from a source
(mother plant). The ultimate objective of propagation is to produce more plants exactly
like the parent. Flowering plants produce seeds that can be used for propagation. Seeds
vary in size and other characteristics, which influence how they can be used for propagation.
Certain plants do not produce seed and hence can be propagated by using parts
of the plant other than seed. In some species, either seed or vegetative parts can be used
for propagation. There are advantages and disadvantages to either method of propagation.
This chapter explores the wide variety of methods of propagating horticultural
plants by seed.
There are three major purposes of propagation:
1. Preservation of germplasm. Scientists on a crop expedition collect samples of plant
materials intended for use in research endeavors. Such materials are often present in
only small quantities and must be increased. Sometimes scientists discover novelties
that arise spontaneously in nature or in a research project. These rare finds must be
preserved, and, to utilize them in any research, they must be increased. In developing
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