Barley for Food and Health: Science, Technology, and Products

2 Barley: Taxonomy, Morphology,
and Anatomy
INTRODUCTION
As shown in Chapter 1, barley is among the most ancient of cereal crops, evolving
over eons from wild to domesticated plants. A defining characteristic between
wild and modern domesticated (cultivated) barley is the toughness of the rachis
or main axis of the spike. The rachis connects the tiller (stem) to the spike
(ear), and the wild barley rachis is brittle, whereas that of cultivated barley
is tough. A tough rachis allows one to reap a harvest. In contrast, the brittle
rachis in wild species has been referred to as a “reseeding device” designed to
preserve the species (Reid and Wiebe 1978). A brittle rachis results in shattering
as soon as seeds are ripe, an effective means of seed dispersal under natural
conditions, but a distinct disadvantage for harvesting seed unless the plant is
harvested prior to ripeness. Morphological and anatomical characteristics such
as rachis strength are used to distinguish between the various species within the
genus Hordeum. Such anatomical characteristics are easily viewed, whereas other
characteristics are more difficult to determine without dissection or microscopic
evaluation. Although the primary objective of this book is to explain the health
benefits of the barley kernel and use of barley in foods, it is helpful to have a
basic understanding of the complete plant to fully appreciate the uniqueness, yet
similarity to other cereal grains. An understanding of the taxonomy, morphology,
and anatomy of crops such as barley is particularly essential to plant breeders.
In this chapter we introduce the science of barley taxonomy and briefly describe
the basic morphology and anatomy of the plant and kernel.
TAXONOMY
Linnaeus was the first to provide a botanical description of barley in his Species
Plantarium in 1753 (Bothmer and Jacobsen 1985), a description that has seen
Barley for Food and Health: Science, Technology, and Products,
By Rosemary K. Newman and C. Walter Newman
Copyright © 2008 John Wiley & Sons, Inc.
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