The vegetation period consists of two main stages-the time from seedling to heading and the time from heading to maturity. The key factors involved in the transition of a plant from the vegetative to the generative developmental phase are identified, however many components and mechanisms of this pathway are still unknown. The genetics of the second part of the vegetation period (maturity time) is now poorly understood.

In this work, we have shown that in the long day the vegetation period is influenced by both the period from heading to maturity and heading time itself. We used two genetic models to identify novel loci and dissect candidate genes for wheat heading and maturity times. The first, a panel of 95 common wheat varieties, which was phenotyped for ten years. The second, a biparental population from a cross of varieties with contrasting maturity time. Both panels were genotyped with Illimina 25K Wheat Array (TraitGenetics). Methods of quantitative genetics (GWAS, genetic mapping accompanying with QTL analysis) were used to detect loci for duration of developmental phases. Further analysis let us suggest novel candidate genes for both, heading and maturity times.

A more detailed study of the different components and functioning of heading time involved different approaches. Using methods of classic genetics, we identified and characterized of novel alleles (Vrn-B3) and studied the interaction between main flowering genes (Vrn-B3a, Ppd-D1, and Vrn-1). Methods of genome editing with gRNA/Cas9 system are to study the regulation of expression of Ppd-D1 gene. This work is currently in progress and we guess it will result in plants with shortened heading time.

Thus, in this work we advanced our knowledge about genetic determinants of the first stage of the vegetation period (heading time) and identified new genetic factors influencing the second stage (maturity time).