Features of microsporpogenesis in maize tetraploid line KRP-1

Tetraploid maize line KrP-1 is characterized by numerous deviations in the structure of mature pollen grains. The aim of the work was to study male meiosis in this line, the characteristics of which largely determine the quality of pollen and the success of fertilization. In the studied plants, anomalies of meiosis were found at all stages. They are represented by three main types: disorders of karyokinesis and cytokinesis and the formation of atypical microsporocytes. A complicated complex of disorders of meiotic divisions was revealed, including an abnormal chromosome discrepancy, incomplete cytokinesis or its absence, a change in the orientation of the division spindle and synchronization of divisions in meta-anaphase. Two groups of anomalies are rarely found in maize: partial cytokinesis in the form of “notches” or “tunnels” and the formation of atypical microsporocytes. The latter suggests the presence of a specific mutation that changes the shape of meiotic cells. Based on the obtained structural characteristics of meiosis, it is possible to assess the potential genotypic, morphological, and functional pollen heterogeneity. Many discovered violations of karyo-and cytokinesis in meiosis can be the cause of partial sterility of pollen or lead to the formation of unreduced and aneuploid gametes. However, a high percentage of formation of typical microspores indicates the possibility of using the KrP-1 tetraploid in breeding as diploid gamete donors.