Polyploidization is a major force in the evolution of both wild and cultivated plants. The remarkable superiority
of polyploids has been noticed plant breeders, who have used this trait in different approaches in order to obtain increasingly improved plant cultivars. Moreover, polyploidization is likely to be one of the most important mechanisms of sympatric speciation. All seed plants have experienced at least one round of whole genome duplication in their evolutionary history. The formation of polyploid plants within diploid populations tends to be isolated events. And even when a polyploid individual is formed, to reproduce it will cross with diploids, and this match is unsuccessful for the existence of the “triploid block”, a critical biological barrier in the production of viable seeds. Many species are sensitive to triploid seed production, but not all. Little is known about how polyploid plants were formed in nature and the way that triploid block has emerged in plants. Therefore, understanding of the genetic network controlling the triploid block will be fundamental since this is a preliminary step in the generation of polyploids. Here we propose: i) to study natural and recently synthesized polyploid series of several species that have been extensively characterized in the past few decades from the physiological, reproductive and ecological aspects; ii) to fill the gaps in the information on non-model species regarding: chromosomal changes, gene loss, gene expression, methylation and physiological changes and ecological features and iii) to understand the genetic network controlling the triploid block viability. The overall goal of the proposal is to allow for a synergy of inter-related European and international expertise to better understand the mechanisms of polyploidization and to facilitate the application of this increased knowledge in plant breeding.