Sexual reproduction is the most successful reproductive strategy that allows for generation of new genetic combinations every life cycle, and, thus, for extremely efficient adaptation to new environmental niches. Hence, sexual breeding is also the major tool to create novel varieties of crops and domestic animals. Meiosis is an essential prerequisite for sexual reproduction, and homologous chromosome recombination and assortment are the key mechanisms leading to genetic variation. Most of the research on meiosis is focused on understanding of meiotic recombination, but there is only a little information on how is meiosis regulated and which molecular networks determine meiotic mode of chromosome segregation. We pioneered work on regulation of meiosis in plants by characterizing several meiotic regulators and by proposing a conceptual model of meiotic progression in pollen mother cells (Riehs et al., 2008; Bulankova et al., 2010). One of my long term goals is to decipher mechanisms that govern plant meiosis and implement this knowledge in developing new breeding strategies. To this end, we performed a suppressor genetic screen in Arabidopsis that yielded ~70 mutants with altered meiosis. In this project I propose to characterize these mutant lines, and to identify underlying genes in the most interesting mutants by genetic mapping and the next generation sequencing. I further intend combining these genetic resources in Arabidopsis with biochemical approaches, primarily in the plant crop Brassica oleracea and the green algae Chlamydomonas reinhardtii, to dissect molecular circuitry controlling meiotic progression.