One hundred and fifty Russian and foreign winter common wheat varieties were examined by the PAGE method. A total of 70 alleles were identified at six gliadin-coding loci. It was demonstrated that...

×Trititrigia cziczinii Tsvel. is a synthetic species obtained as a result of hybridization of different wheat and wheat- grass species. ×T. cziczinii has unique characteristics, as it is a perennial species, with the ability to grow after mowing, high adaptability, resistance to diseases and pests, high protein and gluten content in the grain. All this makes it a promising new crop for agriculture. The new species is a good object for fundamental research in the field of genetics, phylogeny and evolution of cereals (Poaceae). However, there were practically no genetic studies of ×T. cziczinii. The aim of this work was to study the genetic diversity of 24 representatives of two ×T. cziczinii subspecies (ssp. Submitans and ssp. Perenne). To estimate interspecific differences, 17 samples of other tribe Triticeae species (Triticum aestivum, Triticum durum, Agropyron glaucum and Agropyron elon gatum, as well as samples of Triticum-Agropyron and TriticumElymus hybrids) were included in the analysis. For the study, AFLP method (Amplified Fragment Length Polymorphism) was chosen, which allowed us to reveal a sufficiently high polymorphism level of the studied samples. The two primer/enzyme combinations (EcoRI-ACT/MseI-CCC, EcoRI-ACT/MseI-CTA) allow ed the iden tification of 227 fragments, 224 of them were polymorphic (98.68 %), and the level of intraspecific polymorphism of 24 ×T. cziczinii samples was 68.15 %. The iden tified fragments of AFLP spectra, specific for the ×T. cziczinii representatives and the studied wheatgrass species, can be the basis for creating markers that will detect introgressions of genetic material of the genus Agropyron in the T. cziczinii ge nome. Our results indicate a greater genetic relatedness of ×T. cziczinii to T. aestivum than to representatives of the genus Agropyron. According to the cluster analysis, representatives of ×T. cziczinii and varieties of bread wheat were combined into a single subcluster, within which the samples of two species form separate groups. At the same time, the evaluation of the intraspecific genetic diversity of ×T. cziczinii showed no reliable differentiation of representatives of the subspecies Submitans and Perenne, which is probably due to uncertain genetic nature of perenniality, the main feature that divides these subspecies. The study of the unique ×T. cziczinii collection allowed us to obtain the first data on the genetics of the species, while previous studies were focused mainly on phenotypic and economically valuable traits. AFLP analysis used in this study showed high efficiency when working with less studied species, and its results are promising and useful for understanding the genetic structure of the new species (×T. cziczinii Tsvel.).

Improvements in self-pollinated crops rely on crosses between different genotypes. It has been suggested that the repeated use of “the best” genotypes may lead to the restriction of the genetic diversity of the crop. In wheat, the analysis of gliadin (storage protein) polymorphism has provided evidence that genetic diversity was high and stable throughout the 20th century. Moreover, a worldwide analysis of gliadin polymorphism shows that genetic diversity is structured spatially across countries and their regions. Therefore, the analysis of gliadin genotypes in a given grain sample can provide reliable information about the origin of grains in this sample. An unexpected finding is that many registered common wheat cultivars are genetically non-uniform and composed of authentic biotypes (genotypically related lines originated from the initial cross) in spite of current crop-registration rules that include a strict demand for each new cultivar to be genetically uniform (DUS rules). In summary, the results suggest that each cultivar is the fruit of joint effects of a breeder and of a region’s environmental factors. We believe this finding will not be restricted to wheat and suggest there may be a need to re-evaluate relevant rules of cultivar registration for crop species in general.