The definition of plant morphology is the physical appearance of a plant. It can be applied to any species and involves a detailed study of vegetative and reproductive characters in order to form a profile of a plant, which can be used to make general comparisons of plant species displaying a similar structure or detailed comparisons within a species to identify varieties (cultivars). Identifying varieties and species of plants or grains by morphological means is still the main method used in cereal breeding and varietal identification and provides the basis for the definitive description of a variety.
Plants within a species share a similar genetic base, and thus, it is possible to group them into a taxonomic family. ‘Cereals’ is a generic term used to encompass the major grain-producing species whose products are some of the world's most important staple foods and have been since man started growing them for food some 12 000 years ago. A cereal variety is a population of plants that can be identified as being clearly distinguishable from another population by stable inherited morphological characters. Wheat (Triticum aestivum), rice (Oryza sativa), and maize (Zea mays) account for over half of the cereals consumed worldwide. Cereals sit in the family Poaceae (synonymous with Gramineae). While cereals differ in detail in the way the characters of each species are expressed, they share a general commonality in growth habit and flowering parts. By understanding the morphology of each species, it is possible to use it to identify the varieties (cultivars) that exist in each classification. Recognition of the importance attached to identifying varieties is highlighted by the existence of UPOV (The International Union for the Protection of New Plant Varieties). The test guidelines put together by the 71 members of UPOV provide useful information of the major characters used in establishing the morphological identification of the different varieties of cereal species.
The following section begins with a description of the main morphological characters common to all the cereal species and is followed by further sections specific to each species. Illustrations and photographs are used to help in the identification of the characters described.
