Historical review and prospect of taxonomy of tribe Triticeae Dumortier (Poaceae)

The tribe Triticeae is a taxon in the Poaceae that includes several important cereal crops and forage grasses. All its species, including those that are not used for cereals or forage, are potential sources of genes for crop and forage improvement so they all have high economic value. Taxonomic treatments, including those of the Triticeae, are the basis for identification. They are often designed to reflect phylogenetic relationships and provide a guide for germplasm utilization. Traditional taxonomic treatments of the Triticeae were based on comparative morphology and geography. Morphological characters are phenotypes of an organism, resulting from interactions between or among dominant genes and environmental factors. Morphology cannot reflect recessive inheritance. Similar environmental conditions may result in morphological convergence in distantly related taxa and different environmental conditions in morphological divergence of closely related taxa. Consequently, traditional morphological taxonomy may result in misclassification. Cytogenetic and/or molecular genomic analysis may reveal such mistakes. On the basis of recent genomic investigations of the Triticeae, we have recognized 30 genera in this tribe. The taxonomic changes and genomic constitution of these genera are presented in this paper.