Introgression within Triticeae As a Source and Inductor of Variability

Artificial introgression hybridization within Triticeae is used to expand gene pools of cultivated species. Significant progress has been achieved, first of all, for traits of resistance to biotic stressors and product quality. The improvement of the methodical basis of molecular genetics now allows us to operate with the sequences of genome/transcriptome sequences and to compare hybrid genomes within the limits of their expression with the components of the original crosses. This changed the approach to evaluating the result of introgression. Traditionally, introgression was considered at the phenotypic level as a manifestation of the trait of interest and at the level of the nucleotide sequence of alien DNA present in the introgression line. In modern works, there is a gradual shift of attention from ascertaining the appearance of the target trait among the offspring to the study of the participation of epigenetic mechanisms in its implementation: DNA methylation and the participation of transposons and noncoding RNAs. These processes are activated by the very fact of combining two different genomes in one hybrid and originating an additional level of variability, which is reflected in the formation of the target phenotype. Currently, it is becoming obvious that changes at the level of nucleotide sequences and the organization of their expression can relate to both alien and genes of the recipient genome itself.