Classification of genus Triticum, sensu lato and sensu stricto, based on spike and grain morphology

摘要

The formulation of the present classifications of species of the genus Triticum associates mainly with several plant morphological factors such as fragility of the spikes spindle, grains threshability, grain sphericity, shape and position of glumes, lemmas and paleas and awns, compactness, etc. Special attention is paid to the factor "cultural/wild" form, the ploidy and the genomic constitution of the species, often supported by molecular data which provides considerable comfort in disclosing phylogenetic features in a particular taxonomic unit. Such taxonomic determination is associated with certain disadvantages. It is not sufficiently focused on the spike morphology related to the reproductive apparatus of the plant, and also the causes of phylogenetic differentiation of certain parameters, such as spike branching, multiple spikelets, as well as the ratios of quantitative properties. The existing classifications do not give a precise answer to the taxonomic position of amphidiploids in the genus Triticum, and also for those obtained from hybrid combinations with genera Aegilops, Secale, Haynaldia, Hordeum, Elymus, Leymus, Elytrigia, Agropyron, as transitional and similar forms. Based on studies of spike and grain morphology of a large number of representatives of the genus Triticum and other interspecific and intergeneric amphidiploid forms, a classification of the genus sensu lato and sensu stricto is composed. Sensu stricto, genus Triticum covers all existing wild and cultivated known wheat forms, together with interspecific artificial synthetic forms. Sensu lato, the genus includes intergeneric hybrids, for which a specific generic epithet was coined - ×Triticum, and also a specific epithet, consistent with the originator of the amphidiploid. Special attention was paid to species and amphidiploids with the genus Aegilops. Classification sensu strictissimo was also formulated where the genus Triticum brings together only diploid species, but natural amphidiploids are separated as genus Aegilotriticum, and artificial as genus ×Aegilotriticum, and the remote intergeneric amphidiploids are not subject to the classification. Drawn up in this way, the classifications cover morphological and ecological, evolutionary and phylogenetic features of the representatives of the genus Triticum.